Differential Diagnosis for Haemoptysis in a 67-year-old Woman

Given the clinical presentation and investigations, the differential diagnoses can be categorized as follows:

• Single most likely diagnosis
  • Idiopathic Pulmonary Hemosiderosis: This condition is characterized by recurrent episodes of haemoptysis and diffuse alveolar hemorrhage without an identifiable cause. The lack of systemic symptoms, negative vasculitic screen, and absence of a clear source of bleeding on bronchoscopy make this a plausible diagnosis.
• Other Likely diagnoses
  • Goodpasture's Syndrome: Although the vasculitic screen is negative, Goodpasture's syndrome (anti-GBM disease) can present with diffuse alveolar hemorrhage and should be considered, especially if renal involvement is suspected. Further testing for anti-GBM antibodies might be warranted.
  • ANCA-associated Vasculitis: Despite a negative initial vasculitic screen, ANCA-associated vasculitis (e.g., Wegener's granulomatosis) can sometimes present with atypical or negative serology. Clinical suspicion should remain high if other systemic symptoms develop or if there's a high index of suspicion based on other findings.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Pulmonary Embolism with Infarction: Although the CTPA did not show a PE, it's crucial to consider that small peripheral emboli might not be visible on CT. If there's a high clinical suspicion, further diagnostic workup might be necessary.
  • Malignancy: Even though the patient denies weight loss and other systemic symptoms, malignancy (either primary lung cancer or metastatic disease) can cause haemoptysis. A thorough evaluation, including possibly a repeat bronchoscopy or other imaging, might be necessary to rule out malignancy.
• Rare diagnoses
  • Mitral Stenosis: This condition can lead to pulmonary venous hypertension and subsequent haemoptysis. Although less likely, it should be considered, especially if there are signs of heart disease on examination or echocardiography.
  • Pulmonary Veno-Occlusive Disease (PVOD): A rare condition characterized by occlusion of the pulmonary venules, leading to pulmonary hypertension and potentially haemoptysis. Diagnosis can be challenging and might require a lung biopsy for confirmation.
  • Trauma or Factitious Causes: Although unlikely, factitious disorder (Munchausen syndrome) or self-induced trauma could be considered if the clinical picture does not fit with other diagnoses and there's suspicion of manipulation of samples or fabrication of symptoms.

Next Steps in Management

1. Further Diagnostic Testing: Consider repeating or expanding the vasculitic screen, including tests for anti-GBM antibodies and ANCA. Echocardiography to evaluate for mitral stenosis or pulmonary hypertension.
2. Imaging: Possibly a repeat CTPA or other imaging modalities like MRI if there's a suspicion of conditions not well visualized on CT.
3. Bronchoscopy: A repeat procedure might be necessary, especially if new symptoms develop or if there's a high suspicion of malignancy or other conditions not identified on the initial procedure.
4. Lung Biopsy: In some cases, a lung biopsy might be necessary for definitive diagnosis, especially for conditions like idiopathic pulmonary hemosiderosis, PVOD, or to rule out malignancy.
5. Multidisciplinary Team Discussion: Given the complexity and the need for a comprehensive approach, discussion with a multidisciplinary team including pulmonologists, rheumatologists, radiologists, and possibly oncologists can help guide further management.