Michael Saul Lundin

A 69-year-old woman with a remote history of Graves’ disease treated with radioactive iodine ablation, who was maintained on a stable dose of levothyroxine for 15 years, presented with abnormal and fluctuating thyroid function tests which were confusing. After extensive evaluation, no diagnosis could be made, and it became difficult to optimise the levothyroxine dose, until we became aware of the recently recognised biotin-induced lab interference. It was then noticed that her medication list included biotin 10 mg two times per day. After holding the biotin and repeating the thyroid function tests, the labs made more sense, and the patient was easily made euthyroid with appropriate dose adjustment. We also investigated our own laboratory, and identified the thyroid labs that are performed with biotin-containing assays and developed strategies to increase the awareness about this lab artefact in our clinics.

A 62-year-old man presented with classic signs and symptoms of eosinophilic granulomatosis and polyangiitis (EGPA, also known as Churg-Strauss syndrome)—mononeuritis multiplex, palpable purpura, hypereosinophilia, positive P-ANCA (perinuclear anti-neutrophil cytoplasmic antibodies) developed diffuse alveolar haemorrhage. The patient had longstanding mild hyponatraemia, but developed moderate and symptomatic hyponatraemia characteristic of the syndrome of inappropriate antidiuretic hormone. The patient’s serum sodium returned to his baseline- mildly hyponatraemic, after initiation of treatment targeted towards EGPA.

Epistaxis may be attributed to many causes during the winter including dry mucous membranes from low indoor humidity from heating. However, epistaxis may also be due to thrombocytopaenia. Immune thrombocytopaenia purpura (ITP) is an autoimmune disorder causing thrombocytopaenia. Viral infections sometimes lead to ITP. Vaccines, predominantly the measles-mumps-rubella vaccine, have been associated with the development of ITP. There are several published case reports regarding influenza vaccine induced ITP. However, an association between ITP and influenza vaccination has not been firmly proven yet. We report the case of an adult with three episodes of epistaxis, each within 1 week of receiving a yearly influenza trivalent inactivated vaccine, the last episode being more severe and also featuring gross haematuria.

A 68-year-old Hispanic male US Army veteran with a medical history of chronic obstructive lung disease, undefined lung scarring, heart failure with preserved ejection fraction, obstructive sleep apnoea, obesity hypoventilation syndrome [on oxygen by nasal cannula 2–4 L, bilevel positive airway

A 70-year-old man with a medical history of alcoholic cirrhosis was sent from the skilled nursing facility to the emergency department with an abnormal haemoglobin value of 68 g/L (reference 125–165), compared with 103 g/L three weeks prior. On physical examination, the patient’s left

A 21-year-old university student studying abroad in the USA presented to the emergency department with double vision, lower extremity weakness with difficulty ambulating and other neuropsychiatric symptoms. MRI of the brain and spinal cord were normal. Vitamin B₁₂ was 78 pg/mL (58 pmol/L, reference 211–911 pg/mL). The patient had been using nitrous oxide capsules used for whipped cream recharging, which she obtained from other students, a few times daily for a month for the purpose of anxiety relief. The patient was not a vegan or vegetarian. The patient was treated with intramuscular vitamin B₁₂ repletion with partial resolution of neurologic symptoms and discharged on vitamin B₁₂ supplementation.

An 18-year-old woman presented to clinic with acute pharyngitis with 4/4 Centor criteria. Rapid streptococcal antigen test was negative. The patient, who was allergic to penicillin, was prescribed azithromycin. Ultimately, after 5 days and without any corticosteroids, she presented to the emergency department with 10/10 chest pain and was admitted to the intensive care unit. CT showed nodular lung disease and blood cultures on admission grew Fusobacterium, likely Fusobacterium nucleatum. She sustained two cardiac arrests, three tube thoracostomies, acute kidney injury requiring dialysis and ventilatory failure requiring tracheostomy. After 16 days in hospital and 18 days in long-term acute care, the patient was discharged home. It is unclear how much of this could have been prevented by prescribing an antimicrobial that had activity against Fusobacterium. When severe pharyngitis occurs, Fusobacterium needs to be considered as an underlying cause. In vitro macrolides have marginal activity against most anaerobes, such as this pathogen, and should be avoided.