PathWays Case Study: March 15

A 69-year-old man from Minnesota was admitted to the hospital due to mental status changes and intermittent fevers. The patient immigrated to the United States from Southeast Asia approximately 30 years ago. About one month prior to admission, the patient experienced a short period of fevers and shortness of breath. This was managed by his local physician as a possible case of influenza.

Two weeks later, he developed sudden-onset, left-sided weakness and drooping of his face. He was diagnosed with an ischemic stroke and was treated accordingly in a local hospital.

During the hospitalization, he developed worsening somnolence and intermittent fevers (maximum temperature 38.9°C). Hospital-acquired pneumonia was suspected and he was treated with a course of antibacterial agents with no improvement. Physical examination revealed that the patient was somnolent, but arousable, with a left-sided hemiparesis, no nuchal rigidity, and both Kernig's and Brudzinski's signs were negative. Since the presumed diagnosis of stroke was not enough to explain his somnolence and fevers, an infectious etiology was pursued.

Blood cultures were collected and demonstrated no growth after 5 days. Serologic testing was negative for HIV and  hepatitis A/B/C.  A lumbar puncture was performed and the CSF was negative for microorganisms on a Gram stain, a fungal smear, and an acid-fast smear. Chemical and microscopic studies of the CSF showed 49 total nucleated cells with 64% of neutrophils, 28% monocytes, and glucose less than 20% with a protein level of 219 mg/dL (reference range, 0-35 mg/dL).

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Fang Zhao, M.D.

Fang Zhao, M.D., Ph.D.
Resident, Clinical Pathology
Mayo Clinic




Nancy Wengenack, M.D.

Nancy Wengenack, Ph.D.
Consultant, Division of Clinical Microbiology
Mayo Clinic
Professor of Laboratory Medicine and Pathology,
Mayo Clinic College of Medicine


April Josselyn

April Josselyn is a Marketing Associate at Mayo Medical Laboratories. She is the editor of Mayo Clinic PathWays and supports corporate communications strategies and internal communications. She has worked at Mayo Clinic since 2012. Outside of work, April enjoys the outdoors and being "hockey mom" for her two sports-crazed boys.


What is a good reference for cafe studies and for more infectious disease case studies? I don’t frequently see typical cafe cases and I an frequently stumped. I am a neurologist.
In this case study: had the man returned to Asia recently? How long can m. Tuberculosis complex incubate?

“Cafe” should read CSF studies in my statement above. Sorry.

Thank you for your comment. After speaking with Nancy Wengenack, Ph.D., a clinical microbiologist at Mayo Clinic, she provided the following response:

A good textbook reference for M. tuberculosis and other infectious diseases is, “Principles and Practice of Infectious Diseases, 7th edition” by Mandell GL, Bennett JE, and Dolin R, published by Elsevier, Philadelphia, PA, 2010, chapter 250, pg. 3129-3163. A good online (and free) reference centered on tuberculosis is “Drug-Resistant Tuberculosis: A Survival Guide for Clinicians, 3rd edition,” which was just released by the Curry Center for Tuberculosis in San Francisco. The link for that reference is

In this PathWays case study, the patient had not returned to Asia recently, but M. tuberculosis can remain latent for years to decades before reactivating, and that is what we believe occurred in this case.

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