Clinical Zoom meeting snippets - January 2024

The December edition of Prescriber Update includes an article on symmetrical drug-related intertriginous and flexural exanthema (SDRIFE).   This is a type 4 delayed hypersensitivity reaction presenting as a well-defined symmetrical V-shaped erythematous rash of the gluteal region or groin, hence its original name of ‘baboon syndrome’. There is often involvement of at least one other skin fold or flexural area, such as the armpit and behind the knees. 

The lack of systemic symptoms is a key characteristic of SDRIFE. Aside from the rash, the person is generally well with no other symptoms. The most common medicines associated with SDRIFE are beta-lactam antibiotics (eg, penicillins, cephalosporins), which are implicated in about 50 percent of SDRIFE cases. SDRIFE is self-limiting and should resolve when the suspect medicine is withdrawn. Re-exposure to the suspect medicine usually causes SDRIFE to recur. Topical steroids may help to resolve the rash more quickly.

More details can be found on Dermnet (including images and a list of known culprit drugs).

Medsafe has updated its alert information on use of sodium valproate in people who can father children following re-analysis of data from retrospective observational study. Recommendations for health professionals include the following.

• Use of sodium valproate within the 3 months prior to conception by people who are able to father children has been linked to a potential increased risk of neurodevelopmental disorders in children compared to those who took lamotrigine/levetiracetam.
• The potential risks to children fathered more than 3 months (the time taken for new sperm to be formed) after stopping sodium valproate are unknown.
• Inform patients of this potential risk and consider alternative treatment options for those wishing to father a child.
• Discuss the need for effective contraception when starting sodium valproate and periodically throughout treatment. If discontinuing treatment, continue effective contraception for 3 months.
• Inform patients to avoid donating sperm while taking sodium valproate and for 3 months after stopping treatment. The company has produced a guide which should be provided to all male patients of reproductive potential using sodium valproate.

In November, Bunnings and IKEA announced they would discontinue selling engineered stone because of the adverse effects on tradespeople working with the product. I have previously talked about the Accelerated Silicosis Assessment Pathway and BPAC has recently published a comprehensive article on accelerated silicosis (AS) including details of the assessment pathway. Health Pathways also gives a helpful succinct guide to the assessment pathway and would be my go-to resource if you are dealing with an AS assessment request for the first time. The BPAC article is an excellent resource for the background, management and prognosis of AS

All tradespeople who have worked with engineered stone for more than six months in the past 10 years are being encouraged to see their GP.  As at September 2023, 190 claims have been lodged with the Accelerated Silicosis (AS) Assessment Pathway.

Very briefly, the pathway involves an initial GP assessment (which may be undertaken via telehealth) to establish exposure history, risk factors and presence of symptoms. This includes past and current silica exposure, safety and hygiene measures used to reduce exposure, symptom history (respiratory, dermatological and rheumatological), smoking history, workplace monitoring (spirometry), respiratory examination if practical and consent for information to be provided to ACC. If the patient is at possible risk of AS (if they have worked with engineered stone for more than 6 months in the last 10 years) an ACC claim is completed.

ACC assess the claim and direct further investigation if required. This includes a funded 30-minute more comprehensive GP assessment including completion of the Adapted Crystalline Silica Health Form – Medical Section, spirometry and arranging of further investigations and/or specialist referral as requested by ACC. Psychosocial support may also be required for patients with confirmed AS.  

The December Waikato Public Health Bulletin notes that during the warmer summer months Waikato’s lakes are often affected by blooms of cyanobacteria which can release a toxin harmful to animals and humans. 

Detail on identification and management of cyanotoxin poisoning can be found in a helpful 2020 BPAC article. Points include the following.

• There is no test available to confirm cyanotoxin poisoning; diagnosis is based on clinical symptoms and signs in association with a history of exposure (e.g. swimming or boating on a river or lake with a current toxic cyanobacterial bloom) and exclusion of other causes. Non-specific laboratory tests or investigations that may be indicated based on the patient’s symptoms and signs.
• Symptoms are related to type of exposure eg Urticaria, dermatitis, perioral and perinasal blisters, other types of rashes with skin contact. Bronchospasm, rhinitis, sore throat, pneumonia and occasionally severe allergic reactions with inhalation.  Gastroenteritis, malaise, elevated liver enzymes and neurological symptoms (dizziness, vertigo, hearing loss, visual disturbance, seizures) with ingestion (contaminated water, shellfish, algae-based supplements).
• The time to onset and duration of symptoms is highly variable; typically, symptom onset will be within 24 hours of exposure and can last several days.
• There are no antidotes to cyanotoxins; treatment is symptomatic/supportive and based on the type and severity of symptoms. Boiling contaminated water or cooking contaminated fish or shellfish will not inactivate cyanotoxins; in some instances, heating can result in higher concentrations of cyanotoxins as the cyanobacteria break down. Cyanotoxins are also not removed by normal water filtration systems.
• A reminder that any case of suspected cyanotoxin poisoning should be notified to the Medical Officer of Health. This can be done using the Hazardous Substances Disease and Injury Reporting Tool (HSDIRT) [incorporated into some PMS or via e-referral] or by contacting the Public Health Service directly.  

The Asthma and Respiratory Foundation NZ launched a new COPD handbook to help those living with a severe respiratory condition. This handbook provides information about COPD, from the various symptoms patients may experience, to the different types of treatment and medication. It includes tips and advice about self-management and general lifestyle management.  

The foundation has also released a reference guide to support rangitahi to quit vaping. This guide aims to help health professionals who work with adolescents and young adults (AYA) to tackle vaping and e-cigarette addiction through five important steps: screening, assessment, behavioural support, pharmacotherapy, and follow-up.

The RNZCGP E-pulse December edition includes a note from College Medical Director Dr Luke Bradford referring to a recent coroner’s finding into the use of sodium nitrite being used in six suicides in Aotearoa New Zealand.

• The use of sodium nitrite has been promoted on several suicide and euthanasia websites, with people being advised to see their GP first to get a prescription for metoclopramide to take alongside it to prevent nausea and vomiting. Four of the six cases did just this. A Canadian man has recently been charged with 14 counts of second-degree murder in relation to deaths in Ontario province associated with sodium nitrite suicide kits he was selling on-line, and 90 similar deaths in the UK are being investigated.  He had apparently distributed over 1,200 kits to people in 40 countries including Aotearoa. 
• For GPs, these findings come as a timely reminder to have awareness around patients who specifically request a prescription for metoclopramide, especially patients with a history of mental health disorders, or patients who are known to be going through trauma or having suicidal ideation. These requests should trigger further exploration by the GP.
• The chemical causes methaemoglobinemia and is actually available in injectable form to treat cyanide poisoning. It is also used orally in powder form in food preservation and animal control, and in car care products (rust inhibitor) and is available commercially in Aotearoa.

In a recent Court of Appeal ruling, ACC has failed in an attempt to reject an earlier High Court ruling that a 20-year-old patient (known as AZ) with spina bifida should be eligible for ACC cover as the congenital defect was not detected at the mother’s 20-week scan and, had it been detected, the mother states she would have terminated the pregnancy.

The misdiagnosis and failure to terminate was a treatment injury that caused AZ’s personal injury, spina bifida, the court determined. “The only option to prevent the birth of a child with spina bifida was termination of the pregnancy,” the decision said. “Therefore, termination of the pregnancy would have been treatment of AZ which operated to prevent the continuation of spina bifida even though the outcome of the termination would have been to prevent AZ’s birth”.

The lawyer for ACC had argued that said the High Court was incorrect in applying the Accident Compensation Act because the treatment — the 20-week scan — did not cause the injury and that the proposed treatment, a termination of AZ in utero, was not a medical treatment of the condition, “it just ends the life”.

A single injection of the investigational antihypertensive agent zilebesiran effectively lowered blood pressure in adults with mild to moderate hypertension for up to 6 months, with what appeared to be an encouraging side-effect profile, in the phase 2 dose-ranging KARDIA-1 study. Ambulatory systolic blood pressure measured over 24 hours was significantly decreased with all zilebesiran regimens being studied, with a mean reduction in systolic BP from baseline to month 6 of around 10 mm Hg

Zilebesiran is a subcutaneous injectable that targets hepatic angiotensinogen (AGT) synthesis by RNA interference. There were four nonserious adverse reactions leading to discontinuation in the zilebesiran groups: two instances of orthostatic hypotension, one of blood pressure elevation, and one of injection site reaction.