Endocrine Abstracts

A 37 year old lady with relapsing Graves’ thyrotoxicosis initially managed on a ‘block and replace regime’ with propylthiouracil and levothyroxine for 7 years had her medication changed to carbimazole after a relapse from non-compliance but developed agranulocytosis. She was then restarted on an increased dose of propylthiouracil alone. Two weeks later, she developed tender purpuric lesions and was admitted after developing painful bullous lesions to her lower limbs. She had previously noted haemorrhagic lesions on her limbs but these would resolve within a week. Investigations revealed positive MPOANCA antibodies, skin biopsy confirmation of necrotising leukocytoclastic vasculitis and no evidence of systemic involvement on imaging. She had rheumatology and dermatology input regarding the vasculitic rash. Initial treatment involved stopping propylthiouracil, starting beta blockers, short course of pulsed high dose methylprednisolone and wound care. Within a few weeks, her skin lesions were improving, but she was becoming progressively more thyrotoxic. She was commenced on potassium iodide therapy in preparation for a total thyroidectomy. Unfortunately, her temperature increased and she rapidly went into septic shock due to pneumonia requiring inotropic and respiratory support on the intensive care unit before dying a few days later.

Discussion: Necrotising vasculitis remains a rare complication of propylthiouracil therapy. It is classically, as in our patient, strongly associated with positive MPO-ANCA antibodies. Clinical presentation is variable. Treatment includes discontinuation of the drug, immunosuppression and good wound care. The prognosis in the absence of major organ vasculitis as in our patient is usually good, and our patient seemed to be making good progress whilst being worked up for thyroidectomy. However, her low grade tachycardia and raised inflammatory markers masked the early onset of sepsis. Our case highlights the importance of clinical vigilance for sepsis in patients with the rare complication of propylthiouracil induced necrotising leukocytoclastic vasculitis.