Correct!
3. CT of the chest without contrast
This patient presents with cough, fatigue and an episode of blood tinged sputum in the setting of known autoimmune disease. Her initial chest x-ray shows bilateral infiltrates that can be secondary to many etiologies (e.g. ARDS or infection). Computed tomography (CT) scan of the chest is helpful in narrowing the differential diagnosis through the demonstration of ground glass opacities, consolidations or nodularity (1). Although an arterial blood gas is appropriate it will be less helpful in establishing the diagnosis and she already has had a lactic acid measured. Clinically she is not presenting with cardiac disease so a cardiac angiogram is not indicated at this time. VATS lung biopsy seems premature until other tests are performed. In our patient, CT chest findings showed presence of ground glass or airspace-filling opacities that are diffuse and bilateral with greatest involvement in the right lower lobe and right middle lobe.
Figure 2. Representative lung window from the thoracic CT scan.
The patient was admitted to ICU and required intubation and mechanical ventilation, with high oxygen supplementation. With patient’s blood pressure dropping, she was started on vasopressor support and empiric cefepime and vancomycin. However, even with aggressive resuscitation with fluids, vasopressors, broad spectrum antibiotics and mechanical ventilation, she did not improve. On serial hemoglobin measurements, it was noted that patient’s hemoglobin was dropping consistently. Her initial blood and respiratory cultures were negative and lactic acid was within normal limits.
Which of the following would be most useful in making the diagnosis? (Click on the correct answer to proceed to the third of five panels)