Differential Diagnosis

The patient's presentation is complex, with multiple laboratory abnormalities and imaging findings. Here's a breakdown of the differential diagnosis:

• Single most likely diagnosis

  • Invasive pulmonary aspergillosis: The "reversed halo" sign on imaging, along with the patient's severe presentation, including acute kidney injury, thrombocytopenia, and elevated liver enzymes, suggests a severe fungal infection. The patient's low sodium and elevated total and direct bilirubin also support a diagnosis of invasive aspergillosis, which can cause disseminated disease.

• Other Likely diagnoses

  • Pneumocystis jirovecii pneumonia (PCP): Although the imaging findings are not typical for PCP, the patient's severe presentation and laboratory abnormalities could be consistent with PCP, especially if the patient is immunocompromised.
  • Cryptococcal pneumonia: The "reversed halo" sign can also be seen in cryptococcal infections, and the patient's laboratory findings, including elevated liver enzymes and low platelets, could be consistent with disseminated cryptococcosis.
  • Bacterial pneumonia with sepsis: The patient's elevated WBC, acute kidney injury, and thrombocytopenia could be consistent with severe bacterial pneumonia, although the imaging findings are not typical.

• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)

  • Mucormycosis: Although less likely than aspergillosis, mucormycosis can present with similar imaging findings and can be deadly if not treated promptly.
  • Histoplasmosis: Disseminated histoplasmosis can cause severe disease, including respiratory failure, and should be considered in the differential diagnosis, especially if the patient has been exposed to the fungus.

• Rare diagnoses

  • Pulmonary candidiasis: Although rare, pulmonary candidiasis can cause severe disease in immunocompromised patients and should be considered in the differential diagnosis.
  • Pulmonary nocardiosis: Nocardiosis can cause pulmonary infections with similar imaging findings and should be considered in the differential diagnosis, especially if the patient has a history of immunocompromise or exposure to the bacteria.