Differential Diagnosis for Bilateral Miliary TB with Subcutaneous Emphysema

• Single most likely diagnosis:

  • Miliary tuberculosis (TB) with pneumothorax: This is the most likely diagnosis given the presentation of bilateral miliary TB, which is a known complication of TB, and subcutaneous emphysema, which can occur due to pneumothorax, a potential complication of miliary TB.

• Other Likely diagnoses:

  • Sarcoidosis with lymphangitic spread and pneumothorax: Sarcoidosis can mimic miliary TB on imaging and can also lead to pneumothorax, although it's less common.
  • Fungal infections (e.g., histoplasmosis, cryptococcosis) with pneumothorax: Certain fungal infections can present similarly to miliary TB, especially in immunocompromised patients, and may also lead to pneumothorax.
  • Metastatic disease to the lungs with pneumothorax: Although less likely, widespread metastatic disease to the lungs could potentially mimic miliary TB on imaging and lead to pneumothorax.

• Do Not Miss diagnoses:

  • Pneumocystis jirovecii pneumonia (PCP) with pneumothorax: Especially in immunocompromised patients, PCP can present with a similar radiographic pattern to miliary TB and is known to cause pneumothorax.
  • Cystic fibrosis with bronchiectasis and pneumothorax: While the primary presentation might differ, cystic fibrosis can lead to bronchiectasis and recurrent infections, potentially causing a miliary pattern on imaging and pneumothorax.

• Rare diagnoses:

  • Langerhans cell histiocytosis (LCH) with pneumothorax: LCH can cause a miliary pattern on chest imaging due to the infiltration of Langerhans cells into the lung parenchyma and can lead to pneumothorax.
  • Lymphangioleiomyomatosis (LAM) with pneumothorax: A rare lung disease that primarily affects women, leading to cystic lung lesions and potentially pneumothorax, although it doesn't typically present with a miliary pattern.