Case report: Propylthiouracil-induced serious side effect: Perinuclear antineutrophil cytoplasmic antibody-associated vasculitis or IgA vasculitis?

Introduction: Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a rare disease characterized by the inflammation and destruction of small blood vessels and circulating ANCAs. Drugs such as antithyroid drugs (ATDs), especially propylthiouracil (PTU), have been used for the production of ANCAs and cause the development of drug-induced AAV. The pathogenesis of this disease is unclear but could be related to the physiological processes affecting the degradation of neutrophil extracellular traps (NETs). At present, PTU is widely used in patients with Graves' disease (GD) who are preparing for pregnancy and whose condition has not been controlled. Once drug-induced AAV has occurred with important organ damage, considering NETs have a significant role in the immune system, whether the cessation of drugs could stop the progression of organ damage is unclear, and a consensus regarding standard treatment has not been established.

Patient Concerns: In this case report, a female patient who planned pregnancy was hospitalized with multiple joint pain, impaired renal function, and hematuria. Immunofluorescence of the renal biopsy demonstrated spherical and diffuse mesangial distribution of IgA (3+). Autoimmune serology demonstrated positivity for autoantibodies against p-ANCA and an anti-MPO titer 74.72 RU/mL.

Diagnosis: She was diagnosed with PTU-induced p-ANCA-associated and IgA-associated vasculitis (IgAV).

Interventions: The patient accepted low doses of glucocorticoid, immunosuppressive therapy and RAI treatment.

Outcomes: Both her kidney function and thyroid function remained were on the mend.

Conclusion: The authors believe that this type of patient needs to fully consider their pregnancy preparation needs, suspend pregnancy when a small chance of GD remission is indicated, and avoid the use of drugs with reproductive toxicity and other serious adverse events. The multidisciplinary combination therapy of low-dose glucocorticoids and immunosuppressants combined with iodine radiotherapy is one reasonable scheme. At the same time, it is necessary to eliminate the organ damage caused by other reasons. This report provides a clinical treatment basis for patients with drug-induced vasculitis manifestations who cannot receive an accurate diagnosis.