Differential Diagnosis

The patient's symptoms and lab results suggest a severe pulmonary infection. Given the patient's history of acute myeloid leukemia, allergenic stem cell transplantation, and complications of acute graft-versus-host disease and prolonged neutropenia, the differential diagnosis can be organized into the following categories:

• Single Most Likely Diagnosis
  • Aspergillosis: The patient's symptoms, such as coughing up bright red blood, fever, pleuritic chest pain, and cough productive of thick brown sputum, are consistent with invasive aspergillosis. The CT scan showing nodular lesions with surrounding ground glass opacities in the right upper lobe is also characteristic of aspergillosis. The patient's immunocompromised state due to prolonged neutropenia and graft-versus-host disease increases the risk of developing invasive aspergillosis.
• Other Likely Diagnoses
  • Cytomegalovirus infection: The patient's history of stem cell transplantation and immunocompromised state make cytomegalovirus infection a possible diagnosis. However, the presence of nodular lesions and ground glass opacities on the CT scan is more suggestive of aspergillosis.
  • Candidiasis: Although candidiasis is a possible diagnosis in an immunocompromised patient, it is less likely to cause the pulmonary symptoms and radiographic findings seen in this patient.
• Do Not Miss Diagnoses
  • Pulmonary tuberculosis: Although less likely, pulmonary tuberculosis can present with similar symptoms and radiographic findings. It is essential to consider this diagnosis, especially in an immunocompromised patient, as it requires specific treatment.
• Rare Diagnoses
  • Other fungal infections: Such as mucormycosis or fusariosis, can present with similar symptoms and radiographic findings. However, these infections are less common than aspergillosis in this patient population.
  • Bacterial infections: Such as Pseudomonas or Staphylococcus aureus, can cause similar symptoms and radiographic findings. However, the patient's lack of response to oral antibiotics and the presence of nodular lesions and ground glass opacities on the CT scan make these diagnoses less likely.