The Diagnostic Reasoning That Helped Save a 27-Year-Old’s Life

A 27-year-old man is brought in by his wife for five days of worsening fever, coughing, and shortness of breath. He refused to go to the emergency department and was only brought in once he had became confused and, too weak to walk, was crawling on the floor.

His wife states that the patient was complaining of abdominal discomfort for two days prior to coming to emergency. Patient also experienced diarrhea for the last two days, but not black or red.

  • No nausea
  • No vomiting
  • No recent travel
  • Wife is not sick
  • Has no past medical history
  • Takes no medications
  • Is a non-smoker

Fever 102. tachy 105. BP 130⁄70 Sat 90% on Room air. Patient is A and O x 2 only to self and wife.

What do you want to test?

This case, shared by an internal medicine physician, highlights the valuable discussion that physicians have every day on Figure 1. In response to the above, a dermatologist was able to puzzle out the underlying cause of these symptoms. Here is a lightly edited exchange these two physicians had:

Dermatologist: Great case!

Internist: Thank you! Coming from a top contributor like you, it is an honor!

Dermatologist: Labs and cxr (chest x-ray) please. I’m thinking infection, infection, infection.

Internist: Answer would be yes, yes, yes, and indeed! CXR with patchy infiltrates and WBC 14. CK (creatine kinease) high at 500.

Dermatologist: This is not my specialty so forgive me, but I’m going to go back to basics. CK are from muscle. So elevated CK is due to muscle injury but this isn’t horribly high, so maybe just sign of overall illness and explains his severe weakness. Causes of infection in young patient might include bacterial meningitis, flu, pneumonia. Can we get a spinal tap or image his brain? There’s got to be a clue there.

Internist: You are on the right track with infection of course. CK in this case hinted toward a specific infection. Na is low at 129. That’s another hint. The patient has SOB (shortness of breath) and coughing so I think it is worthwhile to investigate the lungs further. Good thought about spinal tap since patient has altered level of consciousness. You are doing great! CT head (scan) is negative.

Dermatologist: Ahhh…maybe the hint is that low sodium can cause confusion. Especially in light of head CT negative. Is this low enough to cause this level of confusion?

Internist: Yes. It contributes but in this case the hypoxia can add on top of it, too. What other labs would you like?

Dermatologist: So let me back up. Diarrhea can cause low sodium through fluid loss. So his main symptoms are GI (gatrointestinal), elevated CK and lung sxs (symptoms). Does he work with air conditioners?

Internist: Very right! In this case the underlying disease is the cause for the diarrhea. You are very close! He does not work with AC but he works in a car wash. Strep Ag sent and pending.

Dermatologist: Was anyone else affected? What do you do in this case? Does it have to be reported to the dept of health?

Internist: Not reported. Usually patient is a smoker or immunocompromised but this patient is neither. He was intubated and given IV Zithromax and Ceftriaxone Legionella Ag is positive. No one else is affected. Even the wife.

Dermatologist: Wow!!! A car wash…how does one get legionella from a car wash?

Internist: It doesn’t have to be AC or shower head. The idea is misting with infected water. Legionella is an atypical pneumonia. Can present with confusion and GI symptoms such as diarrhea or pain , and sometimes low Na and slightly increased CK. LDH May increase too. Weakness is more severe than the usual pneumonia. Treatment is IV Zithromax (azithromycin) or Levaquin (levofloxacin). In the past we feel higher dose of IV Zithromax of 1000 mg is needed but my ID pal said 500 mg is good enough.

Published June 2021

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