Propylthiouracil-related diffuse alveolar hemorrhage with negative serologies and without capillaritis

Area of Science:

• Pulmonology
• Rheumatology
• Endocrinology

Background:

• Propylthiouracil (PTU) is a common antithyroid medication used to treat Grave's disease.
• PTU has been associated with adverse pulmonary events, including diffuse alveolar hemorrhage (DAH), often accompanied by positive antineutrophil cytoplasmic antibody (ANCA) and capillaritis.

Observation:

• A 23-year-old pregnant female with Grave's disease presented with flu-like symptoms and worsening shortness of breath.
• Diagnostic workup revealed diffuse alveolar hemorrhage (DAH) on open lung biopsy.
• Crucially, serological markers, including ANCA, were negative, and capillaritis was absent.

Findings:

• The patient's symptoms resolved rapidly after discontinuation of PTU and initiation of intravenous steroid therapy.
• This outcome suggests a direct link between PTU and the development of DAH in this patient.
• This represents the first reported instance of PTU-induced DAH occurring without positive serological markers or capillaritis.

Implications:

• This case expands the known spectrum of PTU-induced pulmonary toxicity.
• It highlights the importance of considering PTU as a potential cause of DAH even in the absence of typical ANCA positivity and capillaritis.
• Clinicians should maintain a high index of suspicion for PTU-related DAH in patients presenting with unexplained respiratory symptoms, regardless of serological findings.