ZSFG Morning Report 7/17/17: Pulmonary Blastomycoses, Schamroth’s sign, and the Trachea on CXR

Thank you to Alyssa Perez our amazing pulmonary fellow, for presenting a follow up on a patient with upper lobe cavitary lesions, who was ruled out for TB, initially thought to have cocci, and ultimately found to have pulmonary blastomycosis!

Top learning pearls:

  • The differential for cavitary lung lesions can be approached as infectious vs noninfectious causes.
    • Noninfectious:
      • Malignancy: specifically squamous cell cancer, can cause cavitary lesions. Also seen with small cell cancer d/t rapid growth, but less frequently than SCC.
      • Pulmonary embolism with infarction, usually seen in peripheral lung fields
      • Vasculitis (GPA)
    • Infectious: employ the typical framework of thinking about bacterial, mycobacterial, fungal, (and viral)!
      • Bacterial, including lung abscesses with anaerobic bacteria; also consider septic emboli
      • Mycobacterial: always consider TB! Nontuberculous mycobacteria (M. Aviuml, M. kansasii)
      • Fungi: Histo, Blasto, Cocci, Cryptococcus, Asperigillius
      • Parasites: Entamoeba histolytica
    • Urine histoplasma antigen test detects components of fungal cell wall, so can have cross reactivity with other endemic mycoses including Blastomyces dermatitidis infection


Physical exam teaching on clubbing and Schamroth’s sign: Clubbing is the proliferation of connective tissue between the nail bed and distal phalanx, and can indicate underlying respiratory disease. Schamroth’s sign is the the obliteration in clubbed fingers of the diamond-shaped window that normally occurs when opposite fingers are opposed.

schamroths sign for clubbing

  • This study evaluated the test characteristics of Schamroth’s sign with measured phalangeal depth ratio (the objective measurement used to define clubbing). Overall Schamroth’s sign was quite good (sens 77-87%, spec 90%)

CXR teaching with George Su: George reminded us the importance of evaluating the airway when reading CXRs. Think about this framework when assessing the airway

  • Look at Carinal angle: normal is 60-70 degrees, if greater can suggest bulky hilar lymphadenopathy or LA enlargement
  • Look for tracheal deviation: normal to have slight rightward shift at level of aortic knob, however if further deviation think about scarring and traction from pulmonary disease, also look for any evidence of pneumothorax
  • Look for airway in usual places: presence of air bronchograms in the periphery is abnormal


Thank you for the great teaching and pearls contributed by everyone at report this morning! Keep it up!


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