Propylthiouracil-Induced ANCA-Associated Vasculitis Presenting with Multiple Sterile Abscesses, Mononeuritis Multiplex, and Splenic Vein Thrombosis

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Conference Proceeding

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Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV) are rare autoimmune diseases that can affect different organ systems. Drug-induced AAV can be caused by many medications, but has commonly been described with the antithyroid drug propylthiouracil (PTU). We present a case of a 72-year-old female who presented with multiple sterile pustules and abscesses, mononeuritis multiplex, and splenic vein thrombosis, who was diagnosed with PTU-induced AAV.

Case Presentation

A 72-year-old female presented with a chief complaint of worsening pain and swelling in her right hand for 10 days. She was on treatment with propylthiouracil 50 mg daily for the last six months for hyperthyroidism. Physical examination revealed abscesses on the dorsum of her right hand and dorsal surface of the fourth digit of her left hand. She was also noted to have a right foot drop and bilateral lower extremity weakness. Lab findings included WBC: 15.4 bil/L, (Neu 12.7 bil/L), Hgb: 9.3 g/dL, PLT: 454 bil/L, CRP: 207 mg/L, ESR >130 mm/hr. UA: 100 mg/dL of protein, 1+ blood. Autoimmune workup revealed negative ANA, anti-CCP, RF, positive p-ANCA (>1:640), elevated MPO and IgM. Blood and wound cultures were consistently negative. Biopsy of skin lesions were non diagnostic. EMG showed absent right peroneal motor nerve conduction. Sural nerve biopsy revealed “foci of vasculitis without significant qualitative fiber loss or demyelination”, consistent with the diagnosis of mononeuritis multiplex. MRI of her right hand showed diffuse soft tissue edema with adjacent skin ulceration. A CT angiogram of chest and abdomen showed left upper and left lower lobe segmental branch pulmonary emboli, and splenic vein thrombosis with splenic infarcts. PTU was discontinued. The patient was treated with induction with IV methylprednisolone 250 mg every six hours for three days, which was transitioned to oral prednisone 60 mg daily, and Rituximab 375 mg/m2 weekly for four weeks. She improved clinically and the steroids were tapered and stopped. She was in remission during follow-up after 3 months.


Drug-induced ANCA associated vasculitis is a rare but important side effect of many medications. This rare complication is common in young females being treated with PTU for Graves' disease. Even though the most common organ systems involved are the kidneys, lungs and skin, more rare manifestations can also occur, including VTE and neurologic involvement as in our case. Treatment depends on the severity of clinical symptoms, but in most cases includes cessation of the drug responsible, induction with high dose IV or oral steroids, and cyclophosphamide and/or rituximab. Maintenance treatment is rarely required in cases of drug induced AAV, as relapses are rare. Prognosis is usually better than primary AAV, but cases with severe multi-organ involvement and grim prognosis still exist. This case serves as a reminder that rare diseases can present atypically, and clinicians need to be aware of these presentations.


American College of Physicians Internal Medicine Meeting, April 27-29 2023, San Diego, CA