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Articles

Read the latest articles relevant to your clinical practice, including exclusive insights from Healthed surveys and polls.

By reading selected clinical articles, you earn CPD in the Educational Activities (EA) category whenever you click the “Claim CPD” button and follow the prompts. 

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Myriam Gharbi, Joseph H Drysdale, Hannah Lishman, Rosalind Goudie, Mariam Molokhia, Alan P Johnson, Alison H Holmes, Paul Aylin & Alastair D Hay
  • Clinical Articles

Don’t Delay Antibiotics for UTI

So here’s the exception that proves the rule. Urinary tract infections need immediate treatment with antibiotics to avoid an increased risk of sepsis and death. That’s the quite definitive conclusion from a large retrospective study involving GP data from the UK recently published in the BMJ. After analysing the records of over 150,000 patients, aged 65 and over presenting to their GP with a suspected or confirmed UTI, the researchers found those whose antibiotic treatment was delayed or deferred were up to eight times more likely to develop sepsis in the following 60 days compared to the group who were given antibiotics from the beginning. And those patients who were not given antibiotics at all, they were twice as likely to die as their medicated counterparts. Most of the infections were caused by Escherichia Coli, and trimethoprim or nitrofurantoin were the most common antibiotics prescribed. As the study showed, sepsis is not a common sequela of UTI, occurring in just .5% of cases. But the fact remains if antibiotics were delayed or withheld altogether the incidence jumped to 2.2% and 2.9% respectively which is significant and totally unnecessary. Understandably outcomes were worse the older the patient, and men had more adverse outcomes than women, but even accounting for multiple variable factors the basic conclusion remained the same. “Our study suggests the early initiation of antibiotics for UTI in older high-risk adult populations (especially men aged >85 years) should be recommended to prevent serious complications”, the study authors said. Of concern to the researchers was the relatively large number of older patients (about 7%) who were diagnosed with a UTI but not treated. They suggest antimicrobial stewardship programmes encouraging more judicious use of antibiotics may be at least, in part, to blame. That, and the risk of elderly patients developing Clostridium difficile infection following antibiotic use. But while ‘delayed or deferred’ antibiotic treatment was not generally associated with serious adverse outcomes for some self-limiting illnesses such as upper respiratory tract infections, this study suggests it is not a good idea for UTIs. “In our study, deferred antibiotics were associated with less severe adverse outcomes than no antibiotics for older adults but still showed a significantly higher risk of mortality compared with immediate antibiotics,” the researchers said. An accompanying editorial by a UK GP academic says the study highlights one of the many dilemmas that occur in general practice. “[GPs face] the daily challenge of ensuring that patients who are unlikely to benefit are not treated, whereas those who require antibiotics receive the right class, at the right time, at the right dose, and for the right duration,” he wrote. And while agreeing with the study authors concluding advice, that all older patients with suspected UTI should be treated from day one he does suggest further research is needed. Research could help determine the most appropriate antibiotic in this situation, and if there are any particular groups in this 65 and over cohort who it would be safe to leave off antibiotic treatment until the result of the culture and sensitivities are known. - Myriam Gharbi, NIHR Health Protection Research Unit, Imperial College London; Joseph H Drysdale, Department of Primary Care and Public Health, Imperial College London; Hannah Lishman, Medical School, St George's University of London UK; Rosalind Goudie, Nuffield Department of Population Health, University of Oxford, UK; Mariam Molokhia, Department of Primary Care and Public Health Sciences, King's College, London, UK; Alan P Johnson, Healthcare-Associated Infections and Antimicrobial Resistance Division, London, UK; Alison H Holmes, NIHR Health Protection Research Unit, Imperial College London; Paul Aylin, NIHR Health Protection Research Unit, Imperial College London This article is referenced from THEBMJ. Read the original article. - Alastair D Hay, Centre for Academic Primary Care, Bristol Medical School: Population Health Sciences, University of Bristol, Canynge Hall, Bristol, UK This article is referenced from THEBMJ. Read the original article.

By Myriam Gharbi, Joseph H Drysdale, Hannah Lishman, Rosalind Goudie, Mariam Molokhia, Alan P Johnson, Alison H Holmes, Paul Aylin & Alastair D Hay
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Dr Cameron Webb
  • Clinical Articles

Explainer: What is Murray Valley Encephalitis Virus?

Western Australian health authorities recently issued warnings about Murray Valley encephalitis, a serious disease that can spread by the bite of an infected mosquito and cause inflammation of the brain. Thankfully, no human cases have been reported this wet season. The virus that causes the disease was detected in chickens in the Kimberley region. These “sentinel chickens” act as an early warning system for potential disease outbreaks.

What is Murray Valley encephalitis virus?

Murray Valley encephalitis virus is named after the Murray Valley in southeastern Australia. The virus was first isolated from patients who died from encephalitis during an outbreak there in 1951. The virus is a member of the Flavivirus family and is closely related to Japanese encephalitis virus, a major cause of encephalitis in Asia. Murray Valley encephalitis virus is found in northern Australia circulating between mosquitoes, especially Culex annulirostris, and water birds. Occasionally the virus spreads to southern regions, as mosquitoes come into contact with infected birds that have migrated from northern regions.

How serious is the illness?

After being transmitted by an infected mosquito, the virus incubates for around two weeks. Most people infected don’t develop symptoms. But, if you’re unlucky, you could develop symptoms ranging from fever and headache to paralysis, encephalitis and coma. Around 40% of people who develop symptoms won’t fully recover and about 25% die. Generally, one or two human cases are reported in Australia per year. Since the 1950s, there have been sporadic outbreaks of Murray Valley encephalitis, most notably in 1974 and 2011. The 1974 outbreak was Australia-wide, resulting in 58 cases and 12 deaths. It’s likely the virus has been causing disease since at least the early 1900s when epidemics of encephalitis were attributed to a mysterious illness called Australian X disease.

Early warning system

Given the severity of Murray Valley encephalitis, health authorities rely on early warning systems to guide their responses. One of the most valuable surveillance tools to date have been chooks because the virus circulates between birds and mosquitoes. Flocks of chickens are placed in areas with past evidence of virus circulation and where mosquitoes are buzzing about. Chickens are highly susceptible to infection so blood samples are routinely taken and analysed to determine evidence of virus infection. If a chicken tests positive, the virus has been active in an area. The good news is that even if the chickens have been bitten, they don’t get sick. Mosquitoes can also be collected in the field using a variety of traps. Captured mosquitoes are counted, grouped by species and tested to see if they’re carrying the virus. This method is very sensitive: it can identify as little as one infected mosquito in a group of 1,000. But processing is labour-intensive.

How can technology help track the virus?

Novel approaches are allowing scientists to more effectively detect viruses in mosquito populations. Mosquitoes feed on more than just blood. They also need a sugar fix from time to time, usually plant nectar. When they feed on sugary substances, they eject small amounts of virus in their saliva. This led researchers to develop traps that contain special cards coated in honey. When the mosquitoes feed on the cards, they spit out virus, which specific tests can then detect. We are also investigating whether mosquito poo could be used to enhance the sugar-based surveillance system. Mosquitoes spit only tiny amounts of virus, whereas they poo a lot (300 times more than they spit). This mosquito poo can contain a treasure trove of genetic material, including viruses. But we’re still working out the best way to collect the poo.

Staying safe from Murray Valley encephalitis

There is no vaccine or specific treatment for the virus. Avoiding mosquito bites is the only way to protect yourself from the virus. You can do this by:
  • wearing protective clothing when outdoors
  • avoiding being outdoors when the mosquitoes that transmit the virus are most active (dawn and dusk)
  • using repellents, mosquito coils, insect screens and mosquito nets
  • following public health advisories for your area.
The virus is very rare and your chances of contracting the disease are extremely low, but not being bitten is the best defence.The Conversation

- Ana Ramírez, PhD candidate, James Cook University; Andrew Francis van den Hurk, Medical Entomologist, The University of Queensland; Cameron Webb, Clinical Lecturer and Principal Hospital Scientist, University of Sydney, and Scott Ritchie, Professorial Research Fellow, James Cook University

This article is republished from The Conversation under a Creative Commons license. Read the original article.
By Dr Cameron Webb, Ana Ramírez, Andrew Francis van den Hurk, Scott Ritchie, Dr Nicholas J Clark
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Dr Linda Calabresi
  • Clinical Articles

Enuresis Management in General Practice

Australian GPs are confident and competent at managing kids with bedwetting issues, new research confirms. But they are less sure what to do with children with daytime wetting or when childhood enuresis persists into adulthood, according to the study findings recently published in the Australian Journal of General Practice. As you may remember, back in late 2016, health professionals on the Healthed database were invited to participate in a survey designed by leading paediatric urologist, Dr Patrina Caldwell to investigate their knowledge and experience with managing urinary incontinence in childhood. Almost 1500 Australian health professionals responded, mostly GPs. Researchers found that 88% of survey participants reported being slightly or very knowledgeable about managing childhood urinary incontinence. Their confidence seems well-founded at least for nocturnal enuresis. Having been given multiple answer options about first-line management, 93% of participants correctly selected urotherapy and enuresis alarm training as the ideal first-line management for childhood enuresis. This is despite less than half (48%) being able to correctly identify the commonest cause of the condition as being abnormal physiology of sleep and bladder function. Over a third of people incorrectly thought childhood enuresis was simply a delay in developing toileting skills. However, it is a different kettle of fish when it comes to managing daytime urinary incontinence which only 81% of participants felt at least somewhat confident managing. Of concern was the finding that 18% of health professionals would treat this condition with inappropriate and potentially harmful treatments. More specifically, a small percentage of participants chose tricyclic antidepressants which used to be a popular treatment option but is now no longer recommended as first-line therapy for daytime urinary incontinence due to its potential side-effects. The situation was even worse for adult patients who had problems with enuresis that had persisted since childhood. Only 61% of participants felt they were even slightly knowledgeable managing these patients, although most chose the most appropriate first-line therapy of urotherapy and desmopressin. According to the study authors, the knowledge of the health professionals with regard to the various categories of urinary incontinence was largely reflective of the prevalence of each of the different conditions in their clinical experience. Most GPs were currently managing at least a few cases of nocturnal enuresis but the other two conditions were much rarer.

Reference

Caldwell PHY. Manocha R, Hamilton S, Scott KM, Barnes EH. Australian community health practitioners’ knowledge and experience with managing urinary incontinence that begins in childhood. Aust J Gen Pract. 2019 Jan; 48(1-2); 60-5. Available from: https://www1.racgp.org.au/ajgp/2019/january–february/managing-urinary-incontinence-that-begins-in-child
By Dr Linda Calabresi
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A/Prof Sanjaya Senanayake
  • Clinical Articles

Here’s what You Need to Know About Melioidosis, the Deadly Infection that Can Spread After Floods

The devastating Townsville floods have receded but the clean up is being complicated by the appearance of a serious bacterial infection known as melioidosis. One person has died from melioidosis and nine others have been diagnosed with the disease over the past week. The bacteria that causes the disease, Burkholderia pseudomallei, is a hardy bug that lives around 30cm deep in clay soil. Events that disturb the soil, such as heavy rains and floods, bring B. pseudomallei to the surface, where it can enter the body through through a small break in the skin (that a person may not even be aware of), or by other means. Melioidosis may cause an ulcer at that site, and from there, spread to multiple sites in the body via the bloodstream. Alternatively, the bacterium can be inhaled, after which it travels to the lungs, and again may spread via the bloodstream. Less commonly, it’s ingested. Melioidosis was first identified in the early 20th century among drug users in Myanmar. These days, cases tend to concentrate in Southeast Asia and the top end of northern Australia.

What are the symptoms?

Melioidosis can cause a variety of symptoms, but often presents as a non-specific flu-like illness with fever, headache, cough, shortness of breath, disorientation, and pain in the stomach, muscles or joints. People with underlying conditions that impair their immune system – such as diabetes, chronic kidney or lung disease, and alcohol use disorder – are more likely to become sick from the infection. The majority of healthy people infected by melioidosis won’t have any symptoms, but just because you’re healthy, doesn’t mean you’re immune: around 20% of people who become acutely ill with melioidosis have no identifiable risk factors. People typically become sick between one and 21 days after being infected. But in a minority of cases, this incubation period can be much longer, with one case occurring after 62 years.

How does it make you sick?

While most people who are sick with melioidosis will have an acute illness, lasting a short time, a small number can have a grumbling infection persisting for months. One of the most common manifestations of melioidosis is infection of the lungs (pneumonia), which can occur either via infection through the skin, or inhalation of B. pseudomallei. The challenges in treating this organism, though, arise from its ability to form large pockets of pus (abscesses) in virtually any part of the body. Abscesses can be harder to treat with antibiotics alone and may also require drainage by a surgeon or radiologist.

How is it treated?

Thankfully, a number of antibiotics can kill B. pseudomallei. Those recovering from the infection will need to take antibiotics for at least three months to cure it completely. If you think you might have melioidosis, seek medical attention immediately. A prompt clinical assessment will determine the level of care you need, and allow antibiotic therapy to be started in a timely manner. Your blood and any obviously infected body fluids (sputum, pus, and so on) will also be tested for B. pseudomallei or other pathogens that may be causing the illness. While cleaning up after these floods, make sure you wear gloves and boots to minimise the risk of infection through breaks in the skin. This especially applies to people at highest risk of developing melioidosis, namely those with diabetes, alcohol use disorder, chronic kidney disease, and lung disease.

Sanjaya Senanayake, Associate Professor of Medicine, Infectious Diseases Physician, Australian National University

This article is republished from The Conversation under a Creative Commons license. Read the original article.
By A/Prof Sanjaya Senanayake
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Dr Linda Calabresi
  • Clinical Articles

Improving the Outlook for Cerebral Palsy Children

Despite the incidence of cerebral palsy decreasing, it is still Australia’s most common cause of physical disability in childhood, experts say. And with the condition affecting over two in every 1000 live births, it is more than likely a GP will be caring for these patients in their clinical practice. The authors of a review in the latest Medical Journal of Australia highlight areas where the treating health professional, including the GP can play a role in improving these children’s health outcomes as well as their quality of life. “While there is currently a limited range of evidence-based treatments that change the underlying pathology of cerebral palsy, there are many areas in which health care professionals can change the natural history of cerebral palsy and improve participation and quality of life for children with this condition,” they said. They refer to a framework for management of patients with cerebral palsy, known as the six Fs. These Fs help both clinicians and families of the affected child set realistic goals and develop appropriate pathways to meet them. The six Fs are: Function – encourage the child to try activities and celebrate not only what they can achieve but the attempt. Family –  the family environment is vitally important to the child’s health outcomes both physically and psychologically. Significant attention, support and resources need to be directed to this. Fitness – Overall physical fitness is at least as important as exercises directed at helping overcome the particular physical disability of a child with cerebral palsy. Fun – Caregivers need to ensure the child with cerebral palsy does not miss out on this key component of childhood. Friends – Social interaction and the development of quality relationships need to be incorporated as a management goal. Future – This is all about setting realistic goals and expectations and the mapping out plans of how to achieve them, keeping in mind the other five Fs. In addition to this very grounding framework of management, the review authors went on to describe the current state of play of treatment for the various physical manifestations of cerebral palsy. Spasticity and dystonia are the most common signs of the disease and along with physical therapies such as physiotherapy, occupational therapy, splints and orthotics there are a number of medications and even some surgical options for treatment. Baclofen, diazepam and Botulinum toxin A are well-known options to treat the spasticity and dystonia. But apparently there is emerging evidence for the use of other medications such as gabapentin and clonidine. There are also some highly specialised surgeries being performed for subsets of cerebral palsy children such as deep brain stimulation for children with dystonic and dyskinetic movement, selective dorsal rhizotomy for severe spasticity in the lower limbs and even intrathecal baclofen to avoid the side effects of oral baclofen. The review also highlights three potential problem areas for children with cerebral palsy that are of particular relevance for GPs caring for children with this condition. Hip displacement is more of a risk in children with cerebral palsy, and if it is missed it can result in hip dislocation. Regular clinical and radiographic assessment is recommended. “The pelvic x-ray is taken in a standardised supine position and is usually repeated between six and 12 months, depending on the severity of cerebral palsy and the rate of progression of migration of the femoral head out of the acetabulum,” they said. Referral is recommended once migration approaches 30% Another major issue to check for in children with cerebral palsy is pain, with evidence suggesting up to 75% of young patients are regularly experiencing this. The review authors recommend carers ask about this directly, as children may not volunteer this information despite chronic pain’s well-known effect on quality of life. Pain treatment is generally fairly standard, however specific treatments are available for pain arising from unique symptoms such as dystonia or spasticity. Finally, the review authors advise treating clinicians to watch out for feeding and swallowing problems, and as a consequence of these, deficiencies in nutrition. There is a wide range of potential issues concerning eating and drinking that can affect children with cerebral palsy, including swallowing difficulty, managing utensils, posture, risk of aspiration, sensory difficulties and even excessive drooling. All of these can be managed, but the key first step is identifying there is an issue before nutritional deficiencies manifest in comorbidities such as osteoporosis. Unfortunately, as yet, we still cannot cure cerebral palsy. However, with early interventions, close monitoring and targeted therapies the natural history of cerebral palsy is being altered for the better.

Reference

Graham D, Paget SP, Wimalasundera N. Current thinking in the health care management of children with cerebral palsy. Med J Aust. 2019 Feb; 210(3): 129-35. DOI: 10.5694/mja2.12106
By Dr Linda Calabresi
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Jayne Lucke
  • Clinical Articles

One in Six Australian Women in Their 30s Have Had an Abortion – and We’re Starting to Understand Why

Abortion is a common experience for Australian women. Around one in six have had an abortion by their mid-30s, according our new research published today in the Australia New Zealand Journal of Public Health. Narratives about abortion often stigmatise women who have had one or seek access to one. But our research shows women from all walks of life may have an abortion: married, single, child-free, and mothers. In fact, women who have already had children are more likely to have a termination than those who haven’t. Women make decisions about whether or not to have an abortion in the context of their complex lives. And it’s by no means an easy decision. Our research investigated the factors associated with abortion as women move from their late teens into their mid-30s. We found women with lower levels of control over their reproductive health, whether through family violence, drug use or ineffective contraception, are more likely than their peers to terminate a pregnancy. If we want to reduce the rate of unintended pregnancies and abortion in Australia, we need to empower women to have control over their fertility and support them with appropriate health services.

Women’s experiences

We used data from five surveys of the Australian Longitudinal Study on Women’s Health to examine factors associated with “induced” abortions which were not undertaken because of a foetal abnormality. We looked at a cohort of more than 9,000 women born between 1973-78 who were first surveyed at ages 18-23 years. At the fifth survey they were aged 31-36 years. Overall, by their mid-30s, 16% of the women in this study had reported at least one abortion. We also looked at the proportion of women who reported a new abortion at each survey. At the first survey, when women were aged 18-23, 7% reported having had an abortion. In subsequent surveys, 2-3% of women reported having an abortion since the last survey. While most women reported only one new abortion, around one in ten reported two abortions, and around 2% reported three abortions. Abortion is understandably more common for women when they are in their 20s than it is when women reach their 30s. This may be because many women in their 30s are actively trying to be pregnant, or may be using contraception more effectively if they’re trying to avoid becoming pregnant. Compared with married women, those who were in a de facto relationship, were single, or divorced were more likely to have had an abortion. Women with children were more likely to have an abortion than women who did not have children. In the fourth survey, the majority of women (72%) said they hoped to have one or two children, 20% wanted three or more, while 8% didn’t want to have children. Perhaps unsurprisingly, women who had an abortion in the later surveys were more likely to have previously reported using ineffective contraception, or to have had a past abortion, than women who didn’t terminate a pregnancy in their 30s. Women whose alcohol use had recently become riskier and women who reported using any illicit drugs in the past 12 months were also more likely to have an abortion. Violence was also a big factor. Women who recently experienced partner violence were more likely to terminate a pregnancy than women who reported no violence. Even women who reported childhood sexual abuse had a significantly increased likelihood of abortion in their twenties (but not in their 30s). In fact, women reporting violence of any kind, and at any time, had a significantly increased likelihood of having an abortion.

What can we do about it?

Australia is going through a much-needed process of law reform to ensure women across the country have access to abortions as part their women’s health service. Queensland is the most recent state to remove abortion from the criminal code. Alongside this, we need to improve training and resources to for health providers to identify and help women who may be at risk of unintended pregnancy, particularly those who are using illicit drugs or are experiencing partner violence. We need better ways of reaching all vulnerable women, but especially young women experiencing reproductive coercion. We also need to ensure that all women are provided with good access to information about effective contraceptive choices. While the oral contraceptive pill and condoms are the most common methods Australian women use, long-acting reversible methods (such as intra-uterine devices and implants) can be good options for many women wanting effective contraception.The Conversation

- Jayne Lucke, Chair, Australian Research Centre in Sex, Health & Society, La Trobe University and Angela Taft, Professor and Director, La Trobe University

This article is republished from The Conversation under a Creative Commons license. Read the original article.
By Jayne Lucke, Prof Angela Taft
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Dr Linda Calabresi
  • Clinical Articles

Bad News for Sinus Sufferers

Chronic rhinosinusitis is a misery-generating condition – literally. According to a large study just published in The Journal of the American Medical Association, having chronic rhinosinusitis significantly increases your risk of depression and anxiety. And if you also have nasal polyps the risk is higher still. The Korean study was admittedly observational but it did include almost 50,000 individuals from the general population and followed them up for 11 years. Researchers found, over the duration of the study, those people with chronic rhinosinusitis were 54% more likely to develop depression and 57% more likely to develop anxiety than those people who did not suffer this condition. And if nasal polyps accompanied the rhinosinusitis the increase in likelihood for both mental illnesses jumped to the early 60s (61% and 63% respectively). So what are the implications of this study? Well – they are fairly straightforward really. “Physicians should be aware of the potential comorbidities observed in patients with [chronic rhinosinusitis] and provide therapy to reduce the risk of depression and anxiety in these patients,” the study authors helpfully concluded. What we don’t know of course, being simply an observational study without any intervention to test, is whether effectively treating the rhinosinusitis helps the depression or anxiety, and importantly, whether surgically removing the polyps can make a difference to this psychological side-effect. The researchers actually even distance themselves from the conclusion that chronic rhinosinusitis causes depression and anxiety, citing the chicken and egg phenomena. “Whether depression and anxiety amplify the symptoms of [chronic rhinosinusitis] or whether these conditions are the consequence of [chronic rhinosinusitis]is unknown,” they said. But they do say their findings support previous research that has suggested an association between the conditions. They also say their study allowed analysis of the specific phenotype responsible for the chronic rhinosinusitis – whether it be predominantly T1 or T2 response derived. What they found was the association held true regardless of the phenotype – suggesting this was more to do with personality and symptoms than physiology. All in all, what the study authors suggest is that given how common chronic rhinosinusitis is in the population, it is worthwhile keeping a high indexation of suspicion for the development of depression and anxiety not only for the patients’ current quality of life but also because these conditions can affect health outcomes down the line. “[T]hese psychiatric comorbidities may influence not only the diagnosis of [chronic rhinosinusitis] but also its therapeutic and surgical outcomes,” the study authors said.  

Reference:

Kim JY, Ko I, Kim MS, Yu MS, Cho BJ, Kim DK. Association of Chronic Rhinosinusitis With Depression and Anxiety in a Nationwide Insurance Population. JAMA Otolaryngol Head Neck Surg. 2019 Feb 7.  DOI: 10.1001/jamaoto.2018.4103 [Epub ahead of print].
By Dr Linda Calabresi
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Sullivan Nicolaides Pathology
  • Clinical Articles

Guide to Allergy Testing

Allergic disorders result from an inappropriate, usually IgE-mediated, immune response upon exposure to either environmental or food allergens. Common manifestations of allergy include rhinoconjunctivitis, asthma, eczema, acute urticaria and anaphylaxis. Disorders, such as chronic urticaria, hereditary angioedema and T-cell contact dermatitis (metal allergy), while clinically similar in some ways, are not IgE-mediated. Allergic disease manifests in different ways through life and the likely causative agents can also change with age (see Table 1).

Tests used in the diagnosis of IgE-mediated allergy

Total IgE Higher levels of total IgE are often found in patients with allergic conditions. However, normal total IgE does not exclude allergy. Total IgE is also elevated in other conditions including parasitic infections and allergic bronchopulmonary aspergillosis. It is used increasingly in determining anti-IgE therapy in moderate to severe asthmatics. Allergen-specific IgE Allergen-specific IgE can be detected for a large variety of allergens. The presence of a specific IgE to allergen can suggest allergic disease and is detected via a blood test (RAST or radioallergosorbent test) or skin prick test. RAST tests detect many of the different proteins within an individual allergen. Recombinant allergen testing Of the many proteins within a substance, only a few may cause allergic symptoms. Recombinant allergen testing looks for specific characterised protein within an allergen. Interpretation of RAST tests The presence of detectable specific IgE to an allergen does not confirm the patient is allergic to that substance. All results must be interpreted in conjunction with the clinical history of the patient. Low levels of detectable specific IgE can confirm the presence of allergy in the right clinical context. RAST testing aids in the assessment of, and identification of allergic sensitisation, but is not to be used alone as the deciding factor for inclusion or exclusion of allergy. As the level of specific IgE increases, the likelihood of clinical relevance also increases. As shown in Table 2, different allergens have different specific IgE level cutoffs at which serious allergy is >95% likely (positive predictive value or PPV). The range of values is vastly different between allergens and is affected by age and also by geographic region. Table 2 defines levels at which exposure, or a challenge, would be highly hazardous for a patient. Importantly, many patients could have serious reactions at much lower levels.   [table id=1 /]   [table id=2 /]

RAST tests

RAST tests are available for a range of allergens, however Medicare criteria limits rebates based on the number, type and frequency of tests. Medicare Australia limits rebates for RAST tests to a maximum of four specific allergens and/or mixes per pathology request and a maximum of four RAST test episodes per year. When ordering RAST tests, it is advisable to include allergens the patient feels are relevant and those likely for the clinical scenario. For common clinical scenarios we recommend the following: Childhood eczema Age <2 years: Milk, Egg, Wheat, Peanut Age >2 years: Milk, Egg, Peanut, Dust mite Additional allergens or an extended RAST combined allergy panel may be ordered. Asthma and allergic rhinoconjunctivitis Dust mite, Grass mix, Animal dander Additional allergens may be ordered or substituted if relevant (e.g. cat dander instead of animal dander). An extended RAST inhalant panel is also available. Default panel if no allergens are specified and no clinical notes are provided Age <5 years: Dust mite, Grass mix, Food Mix Age >5 years: Dust mite, Grass mix, Animal Mix Anaphylaxis Anaphylaxis is a severe life-threatening allergic reaction. It is recommended these patients require specialist assessment by a clinical immunologist or allergist. Initial testing should look for the causative allergen if possible. It is important to note that a negative RAST test does not exclude the allergen tested. RAST testing recommendations ­
  • Test individual likely causative allergen i.e. food, stinging insect. ­
  • Tryptase, if done within 2-6 hours of reaction, can support the occurrence of an allergic reaction. ­
  • Useful as an assessment of mastocytosis (condition with increased numbers of mast cells)

Extended RAST panels

Extended RAST panels have been developed to represent the common allergens encountered clinically in practice. They are particularly relevant in our geographic region and replace the skin prick test panel which is no longer available. Additional allergens may also be requested. All results must be interpreted in conjunction with the patient’s clinical history. Extended RAST Food Panel ­
  • Covers common food-related allergens
  • Almond; Hazelnut; Sesame seed; Banana; Mango; Shrimp (prawn); Cashew; Milk (cow); Soybean; Codfish; Peanut; Walnut; Egg white; Rice; Wheat
Extended RAST Nut Allergy Panel ­
  • Broad collection of commonly consumed nuts, including peanuts ­
  • Individual nut testing with appropriate clinical history is preferred ­
  • Recommend to discuss results with a clinical immunologist or allergist
  • Almond; Macadamia; Pine nut; Brazil; Peanut; Sesame seed; Cashew; Peanut (Ara-h2); Walnut; Hazelnut; Pecan
Extended RAST Combined Allergy Panel ­
  • Combination of common food and environmental allergens ­
  • Replaces the skin prick test panel (no longer available)
  • Almond; Dust mite; Mould mix; Cashew nut; Egg white; Peanut; Cat dander; Grass mix; Shrimp (prawn); Codfish; Hazelnut; Soy; Dog dander; Milk (cow); Wheat
  • * Preferable for children (<12 years) due to low serum volume
Extended RAST Inhalant Panel ­
  • Covers common environmental allergens ­
  • Useful for asthma and allergic rhinitis
  • Acacia (wattle); Blomia tropicalis; Dust mite; Alternaria alternate; Cat dander; Eucalyptus; Aspergillus fumigatus; Cladosporium; Horse dander; Bahia grass; Common ragweed; Johnson grass; Bermuda grass; Dog dander; Perennial rye grass

Recombinant allergens

Omega-5 gliadin ­
  • A component of wheat ­
  • Associated with anaphylaxis ­
  • Often in the context of eating wheat and physical activity within 1-2 hours
Alpha-gal (mammalian meat allergy) ­
  • Associated with anaphylaxis; often delayed following consumption of meat (beef, lamb, pork) ­
  • Related to tick bites
Peanut Allergy Risk Assessment ­
  • Peanuts like all food is made up of many different proteins ­
  • Ara-h2 is associated with anaphylaxis to peanut ­
  • Can assist with risk assessment and should be done in conjunction with a clinical immunologist or allergist ­
  • A negative Ara-h2 in peanut positive patient does not imply there is no risk to anaphylaxis
  • Results of RAST tests can also be of use in monitoring ongoing allergy in patients in conjunction with their treating clinician

How to order allergy tests

RAST tests - standard panels Medicare Australia limits rebates for RAST tests to a maximum of four specific allergens and/or mixes per pathology request and a maximum of four RAST test episodes per year. Extended RAST tests (Medicare rebate + $120* per panel)
  • Extended RAST Food
  • Extended RAST Nut
  • Extended RAST Combined
  • Extended RAST Inhalant
Please note, extended RAST panels are not bulk billed. Recombinant allergen tests (Medicare rebate + $60* each)
  • Alpha-gal
  • Omega-5 gliadin
  • Peanut (Ara-h2)
  • Peanut Allergy Risk Assessment
  General Practice Pathology is a regular column each authored by an Australian expert pathologist on a topic of particular relevance and interest to practising GPs. The authors provide this editorial free of charge as part of an educational initiative developed and coordinated by Sonic Pathology.
By Sullivan Nicolaides Pathology
shutterstock_557796589
Dr Linda Calabresi
  • Clinical Articles

E-cigs Work Better than Nicotine Replacement Therapy

It’s a controversial topic here in Australia. But a new UK study, just published in the New England Journal of Medicine, gives strong support the role of e-cigarettes as a smoking cessation therapy. The randomised controlled trial of almost 900 adult smokers wanting to quit found the one-year abstinence rate was 18% among the e-cigarette users compared to 9.9% among those who were randomised to receive nicotine replacement therapy. Much of the difference could be attributed to adherence to the assigned product. After 12 months, 80% of the e-cigarette group were still using the device whereas only 9% of the alternative group were still taking their nicotine replacement therapy despite being able to choose between the patch, gum, lozenge, nasal spray, inhalator, mouth spray, mouth strip, and microtabs (or any combination of these). Participants in both groups underwent the same multi-session behavioural support as per best practice guidelines. This study provides some of the strongest evidence to date that e-cigarettes are significantly better than nicotine replacement therapy in helping people quit smoking, the study authors suggest. “This is particularly noteworthy given that nicotine replacement was used under expert guidance, with access to the full range of nicotine-replacement products and with 88.1% of participants using combination treatments,” they said. The researchers suggested e-cigarettes had better adherence rate because they were more effective at reducing the symptoms of withdrawal when quitting smoking, because the refillable devices are better at delivering nicotine compared with options such as gum or patches. They also suggest the nicotine dose provided by e-cigarettes was easier to tailor to individual needs than other replacement options. And even though people using the e-cigarettes were more likely to get mouth or throat irritation, this side effect was generally mild and tolerable especially compared to withdrawal symptoms such as constipation, mouth ulcers and weight gain. In general, the researchers claim replacing cigarettes with e-cigarettes is a definite positive in terms of health outcomes and much better than other nicotine replacement options, but they suggest the high rate of adherence in the e-cigarette group may have some negative connotations. “This can be seen as problematic if e-cigarette use for a year signals ongoing long-term use, which may pose as-yet-unknown health risks,” they said. As an accompanying editorial points out, fundamentally nicotine is highly addictive. While electronic cigarettes have been proven to be a great tool in helping people get off normal cigarettes, there may be an issue if non-smokers, especially teenagers take up vaping, making them vulnerable to becoming smokers further down the track. “The cigarette company may well see e-cigarettes as addictive bait that will lead young people toward smoking,” the US editorial authors suggest. They suggest this potential problem could be relatively easily averted by ensuring e-cigarettes aren’t manipulated to enhance their appeal, specifically the authorities should not allow the manufacture of flavoured nicotine products. However, they too acknowledge e-cigarettes have a significant role to play in solving this public health problem – ‘by helping people who are users of combustible tobacco products stop smoking by switching to vaping.’

References:

Hajek P, Phillips-Waller A, Przulj D, Pesola F, Smith KM, Bisal N, et al. A Randomized Trial of E-Cigarettes versus Nicotine-Replacement Therapy.  N Engl J Med. 2019 Jan 30;  DOI: 10.1056/NEJMoa1808779 [Epub ahead of print] Drazen JM, Morrissey S, Campion EW. The Dangerous Flavors of E-Cigarettes. N Engl J Med. 2019 Jan 30. DOI: 10.1056/NEJMe1900484 [Epub ahead of print]
By Dr Linda Calabresi
measles
Prof Kristine Macartney
  • Clinical Articles

Why People Born Between 1966 and 1994 Are at Greater Risk of Measles – and what to Do About It

Australia was declared free of measles in 2014. Yet this summer we’ve seen nine cases of measles in New South Wales, and others in Victoria, Western Australia, South Australia and Queensland. High vaccination rates in Australia means the measles virus doesn’t continuously spread, but we still have “wildfire” outbreaks when travellers bring measles into the country, often unknowingly. If you haven’t received two doses of measles vaccine, you are at risk of contracting measles.

How can you catch it?

Measles is a highly contagious virus that spreads by touching or breathing in the same air as an infected person. The virus stays alive in the air or on infected surfaces for up to two hours. An infected person is contagious from the first day of symptoms (fever, cough and runny nose). These general symptoms start about four days before the rash develops, meaning contagious people can spread the virus even before they realise they have measles. If you’re not immune to the virus, through vaccination or past infection, the chance of becoming ill after being near someone with measles is 90%. Being in the same café, waiting in line at the checkout or flying on the same aeroplane as an infected person could be enough to pick up the disease.

Why is it so dangerous?

Measles causes a fever, cough, and a rash that starts around the hairline and then spreads to the whole body. It can also cause middle ear infections (otitis media), chest infections (pneumonia), and diarrhoea. Swelling and inflammation to the brain (encephalitis) occurs in 1 in every 1,000 cases and can lead to permanent brain damage or death. In 2017, 110,000 people died from measles worldwide. Even after surviving the initial illness, measles can cause a devastating and fatal complication known as subacute sclerosing panencephalitis (inflammation of the brain) many years later.

Why are people in their 20s to 50s more at risk?

To protect yourself against measles, you need two doses of measles-mumps-rubella (MMR) vaccine. Children in Australia routinely get this vaccine at 12 and 18 months of age. The second dose is given in combination with the chickenpox vaccine. It’s important to have two doses of MMR vaccine, especially if you haven’t reached your mid-50s. Most people older than this would have been infected with measles before vaccination was routine. People aged in their 20s to early 50s (those born from 1966 and 1994) are most likely to have only had one dose of MMR vaccine. While we’ve had the measles vaccine in Australia since 1968, a two-dose program was only introduced in 1992. A brief school-based catch-up program from 1993 to 1994 offered school children a second dose. Another school-based program provided children with catch-up vaccinations in 1998*. For those who missed out on the school program, catch-up vaccinations were given on an ad-hoc basis via GP clinics. So not everyone in this age group would have received two doses of the measles vaccine. If you are this age, you may not be not fully protected against measles. Checking with a GP or immunisation nurse is the best way to be sure. They will check your records, and may do a blood test if you have no proof of immunisation. Even if you can’t be sure of past vaccinations, it’s still safe to have an extra vaccine. And it’s free for those who need a catch-up dose. If you have a child under 12 months of age and you’re heading to a country with measles, an early additional vaccine dose can be given to protect your baby from measles. This ideally should be done at least a month before you travel, to ensure an immune response has time to develop. The routine scheduled doses at 12 months and 18 months will still need to be given later.

What if you’re not protected?

Unfortunately, there is no treatment for measles. Getting adequately vaccinated is the best form of defence against this serious disease. If you think you’ve been exposed or may be ill from measles, see your GP or call Health Direct or your public health department as soon as possible. If exposed, but not yet ill, it may not be too late to get a protective vaccine and ensure you don’t spread the disease to others. If you are unwell, and suspect measles, call ahead to let the clinic know so they can make provisions to keep you away from other patients in the waiting room. Other, more common, diseases can look like measles, so an urgent specific test (throat swab) must be done to confirm the infection. If measles is proven, public health workers will trace your contacts and your treating doctor will monitor you for complications.

Are we at risk of measles returning in Australia?

Australia currently has all-time high vaccine coverage, with 94.5% of five-year-old children fully immunised at the end of 2017. By keeping vaccine coverage near or above 95%, herd immunity where there are enough people vaccinated helps prevent measles from spreading to others, including those who cannot be vaccinated. But in our interconnected world, we must work together to reduce the threat of measles worldwide by boosting immunisation programs in regions with low coverage, including in the Asia Pacific. Measles have resurfaced in some countries due to falls in vaccine coverage from unfounded safety concerns as well as weak health systems. In the first six months of last year, for instance, Europe had 41,000 cases of measles, nearly double the total number of the previous year. This, among other factors, has prompted the World Health Organisation to list vaccine hesitancy as a top ten threat to global health in 2019. A continued global coordinated effort will be required to maintain elimination and prevent resurgence of this deadly disease in Australia. * Correction: this article has been updated to note a school-based catch-up program also operated in 1998.The Conversation

- Kristine Macartney, Professor, Discipline of Paediatrics and Child Health, University of Sydney and Lucy Deng, Staff Specialist Paediatrician, National Centre for Immunisation Research and Surveillance; Clinical Associate Lecturer, Children's Hospital Westmead Clinical School, University of Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.
By Prof Kristine Macartney
shutterstock_345680990
Dr Linda Calabresi
  • Clinical Articles

Preventing Alzheimer Disease

At first read, the study results seemed disappointing. Yet another promising premise fails to deliver when it comes to actual proof. But the researchers aren’t ready to give up on this hypothesis just yet. In fact, commentators on the study say the results offer ‘great hope’ and represent ‘a major leap forward.’ The SPRINT MIND study, recently published in JAMA was investigating whether intensive blood pressure control (to a systolic less than 120mmHg) worked better than standard blood pressure control (SBP<140mmHg) at reducing the risk of mild cognitive impairment and dementia. This randomised controlled trial was a component of the well-publicised Systolic Blood Pressure Intervention Trial (SPRINT) which looked at the effect of more intensive blood pressure control on cardiovascular and renal outcomes in addition to cognitive function in over 9000 people without a history of diabetes or stroke. Basically, what this study showed was that intensive blood pressure control to a target of less than 120mmHg did not reduce the incidence of probable dementia compared to lowering BP to a target of less than 140mmHg. Depressing, yes? No, say the study authors. Firstly, they say the study demonstrated no ill-effects of intensive BP lowering – which has been an issue of concern for some who have been worried that lowering the BP could decrease cerebral perfusion thereby harming cognitive function. In fact, the study authors showed quite the opposite was true. The intervention actually helped protect cognitive ability. “This is the first trial, to our knowledge, to demonstrate an intervention that significantly reduces the occurrence of [mild cognitive impairment], a well-established risk factor for dementia, as well as the combined occurrence of [mild cognitive impairment] or dementia,” they said. The study authors suggest the lack of benefit in dementia may be due to the fact the SPRINT study was terminated early following the demonstration of benefit of intensive BP control on cardiovascular outcomes and all-cause mortality. Because of this shortened time frame and the fact that there were fewer than expected cases of dementia, they suggest the study may have been ‘underpowered’ to show a result for lowering the risk of dementia. They also say there were fewer cases of dementia among the intensive treatment group compared with the standard treatment group (7.2 vs 8.6 cases per 1000 patient years) even though this wasn’t statistically significant. We cannot know whether this trend would have reached statistical significance had the intervention continued. An accompanying editorial views the study and the results with a good deal of positivity. “For older adults, almost all of who have concern about being diagnosed with Alzheimer Disease and related dementia, [this study] offers great hope,” the US epidemiologist, Dr Kristine Yaffe, said. She points out that this a readily modifiable risk factor, and we should be accelerating our efforts into investigating whether this, along with other vascular health interventions such as physical activity, can indeed prevent dementia, building on the positive results of this study. “The SPRINT MIND study may not be the final approach for prevention of Alzheimer disease or other cognitive impairment but it represents a major leap forward in what has emerged as a marathon journey.”

Reference

Yaffe, K. Prevention of Cognitive Impairment With Intensive Systolic Blood Pressure Control. JAMA [Internet]. 2019 Jan 28. DOI: 10.1001/jama.2019.0008 [Epub ahead of print]
By Dr Linda Calabresi
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Suzanne Mahady
  • Clinical Articles

What’s Behind the Increase in Bowel Cancer Among Younger Australians?

Bowel cancer mostly affects people over the age of 50, but recent evidence suggests it’s on the rise among younger Australians. Our study, published recently in Cancer Epidemiology, Biomarkers and Prevention, found the incidence of bowel cancer, which includes colon and rectal cancer, has increased by up to 9% in people under 50 from the 1990s until now. Our research examined all recorded cases of bowel cancer from the past 40 years in Australians aged 20 and over. Previous studies assessing bowel cancer incidence in young Australians have also documented an increase in the younger age group. This trend is also being seen internationally. A study from the United States suggests an increase in bowel cancer incidence in people aged 54 and younger. The research shows rectal cancer incidence increased by 3.2% annually from 1974 to 2013 among those aged age 20-29. Bowel cancers are predicted to be the third most commonly diagnosed cancer in Australia this year. In 2018, Australians have a one in 13 chance of being diagnosed with bowel cancer by their 85th birthday. Our study also found bowel cancer incidence is falling in older Australians. This is likely, in part, to reflect the efficacy of the National Bowel Cancer Screening Program, targeted at those aged 50-74. Bowel cancer screening acts to reduce cancer incidence, by detecting and removing precancerous lesions, as well as reducing mortality by detecting existing cancers early. This is important, as bowel cancer has a good cure rate if discovered early. In 2010 to 2014, a person diagnosed with bowel cancer had a nearly 70% chance of surviving the next five years. Survival is more than 90% for people who have bowel cancer detected at an early stage. That is why screening is so effective – and we have previously predicted that if coverage rates in the National Bowel Screening Program can be increased to 60%, around 84,000 lives could be saved by 2040. This would represent an extraordinary success. In fact, bowel screening has potential to be one of the greatest public health successes ever achieved in Australia.

Why the increase in young people?

Our study wasn’t designed to identify why bowel cancer is increasing among young people. However, there are some factors that could underpin our findings. The increase in obesity parallels that of bowel cancer, and large population based studies have linked obesity to increased cancer risk. Unhealthy lifestyle behaviours, such as increased intake of highly processed foods (including meats), have also been associated with increased bowel cancer risk. High quality studies are needed to explore this role further. Alcohol is also thought to be a contributor to increasing the risk of bowel cancer. So, should we be lowering the screening age in Australia to people under the age of 50? Evaluating a cancer screening program for the general population requires a careful analysis of the potential benefits, harms, and costs. A recent Australian study modelled the trade-offs of lowering the screening age to 45. It showed more cancers would potentially be detected. But there would also be more colonoscopy-related harms such as perforation (tearing) in an extremely small proportion of people who require further evaluation after screening. A lower screening age would also increase the number of colonoscopies to be performed in the overstretched public health system and therefore could have the unintended consequence of lengthening colonoscopy waiting times for people at high risk.

How to reduce bowel cancer risk

One of the most common symptoms of bowel cancer is rectal bleeding. So if you notice blood when you go to the toilet, see your doctor to have it checked out. A healthy lifestyle including adequate exercise, avoiding smoking, limiting alcohol intake and eating well, remains most important to reducing cancer risk. Aspirin may also lower risk of cancer, but should be discussed with your doctor because of the potential for side effects including major bleeding. Most importantly, we need to ensure eligible Australians participate in the current evidence-based screening program. Only 41% of the population in the target 50-74 age range completed their poo tests in 2015-2016. The test is free, delivered by post and able to be self-administered.The Conversation   This article is republished from The Conversation under a Creative Commons license. Read the original article.
By Suzanne Mahady, Eleonora Feletto, Karen Canfell

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