Welcome to Quick Thinking. A case is presented in short sections to a faculty expert who will comment on their approach to the patient as the case unfolds. These posts will focus on determining the initial differential diagnoses and diagnostic workups of complicated patient presentations.
Part 1 can be found here. Part 2 can be found here. Part 3 can be found here.
Part 3 Case Presentation by Elizabeth Ross, PGY-3:
The patient continued to complain of headache and dizziness and given the patient’s persistent and intermittent fevers he was seen by infectious disease but it was decided not to start antibiotics as there was no clear source of infection. He subsequently had a tonic-clonic seizure and was transferred to the medical intensive care unit where he was started on prednisone 80mg daily and isoniazid/rifampin/pza/ethambutol (I/R/P/E) for the possibility of both sarcoid and tuberculosis. Lymphoma was also considered as a possible diagnosis. A tissue diagnosis was considered essential however neurosurgery felt the lesion was too small and the risk of biopsy too high. He subsequently underwent the following procedures:
Bronchoscopy with transbronchial needle aspiration of a subcarinal lymph node: benign bronchial epithelial cells and few mature lymphocytes
Liver biopsy: chronic inflammatory changes in portal tracts, portal fibrosis,
no granulomata, no lymphoma
Colonoscopy with biopsies of sigmoid: (because of abdominal catscan showing thickening of sigmoid wall) within normal limits
Mediastinoscopy with resection of right level 4 node: lymph node with focally necrotizing granulomas and multinucleated giant cells. Special stains for acid fast bacilli and fungi negative.
Repeat brain MRI after approximately 3 weeks of both prednisone and I/R/P/E showed marked improvement of infundibular and hypothalamic lesion as well as leptomeningeal abnormal enhancement. This was felt to be consistent with successfully treated tuberculosis or sarcoidosis.
Commentary: Mitchell Charap, MD Abraham Sunshine Associate Professor of Medicine
The development of seizures made broad treatment a necessity, but in covering with steroids and I/R/P/E, the specific diagnosis may be masked. The finding of necrotizing granulomas on biopsy narrows the differential to tuberculosis (or a fungal infection) and sarcoid. The improvement over two weeks does not help us narrow the differential. If all cultures are negative, then one could consider discontinuing I/R/P/E, but my hunch is that both will be continued.
He was discharged with a diagnosis of tuberculosis or sarcoidosis. He is still on both prednisone and I/R/P/E. The plan was to complete the course of anti-tuberculous medications and slowly taper the prednisone over 6 months.
Unfortunately, the decision to treat both sarcoidosis and tuberculosis simultaneously creates problems in that both treatment regimens have toxicities. As a general internist managing this case, I would confer with a specialist (probably a pulmonologist) to help me decide if I can eliminate one of the treatment arms. My clinical suspicion is that the patient has sarcoidosis, but the presence of necrotizing granulomas make tuberculosis a hard diagnosis to rule out. I would therefore ask the consultant if he/she has a a high degree of certainty that sarcoidosis is the diagnosis. I would ask if the Kweim-Siltzbach test could add to the level of certainty (of course, the prior administrration of steroids makes this test not very useful). If I do not get a clear-cut answer, I would treat with both regimens until the culture results are available and then base my decision on them.
2 comments on “Quick Thinking Part 4-The Conclusion”
Thank you for an interesting exerdise in differential diagnosis. We see patients with similar problems on and off in our practice. In developing countires we would have treated this patient as a case of tuberculosis. The diagnosis of TB is very often a presumptive entity. It is difficult to prove it conclusively in our setting. Thus we normally opt to treat the condition empirically and tend to add steroids if we are not able to exclude sarcoidosis as was illustrated by your patient.
Interesting exercise. I wonder if running a PCR for TB on the CSF would have helped in the diagnosis.
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