FUO and Q fever

Today we had an interesting case presented by Jack Shuler. The case was a middle age patient w/ untreated HCV with weeks of a flu-like illness, headache, and progressive respiratory symptoms and LFT abnormalities found to have multilobar pneumonia of unknown etiology until coxiella serologies returned positive. On further exposure history the patient reported living in a rural area.

qfever

Learning points:

1) FUO is defined as recurrent episodes of fever (>38.3 degrees), lasting > 3 weeks with no clear source despite a reasonable workup (>1 week in the hospital)

2) In approaching the broad differential for FUO (including rheum/ malignancy/ infection/ other), two differentials to think about if present may narrow the diagnosis.

* Is this a doxycycline deficient state? 
    * ddx includes zoonotic diseases such as brucella, Q fever (coxiella), tularemia, leptospirosis, rickettsial (RMSF, erlichiosis, anaplasmosis)
* Are there LFT abnormalities? 
    * ddx includes viral (EBV, CMV, hepatitis, HIV), biliary disease, TB, endemic mycoses (histo, blasto, coccidio), zoonotic (leptospirosis, tularemia, Q fever(coxiella))

3) Q fever should be considered in a patient exposed (even by living downwind) to farm animals presenting with a flu-like illness with prolonged fevers, LFT abnormalities and negative serologies. It is a doxycycline deficient state. Everyone with suspected Q fever should get at TTE because it can change duration of therapy.


Q fever/ Coxiella pearls

Here are some additional Q fever pearls from Jack:

  1. Q Fever is a zoonotic infection, rare in the U.S., typically acquired from farm animals (cattle, goats, and sheep), but can also develop in individuals living downwind from contaminated material.
  2. Acute infections most commonly present as a flu like syndrome with high fevers, severe headache, often accompanied by hepatitis and/or pneumonia, usually with a normal white count.
  3. Treatment is doxycycline for 14 days, longer for people with culture negative endocarditis. Serologies should be repeated 3 and 6 months after treatment to rule out persistent localized infection (i.e. endocarditis, infected aneurysms or vascular grafts, bone and joint infections). Treatment for refractory disease can be up to 18 months of doxycycline + HCQ!

Doxycycline deficient state

A doxycycline deficient state is when a person with FUO seems to respond better to doxycycline and suggests certain zoonotic conditions as being the reason for their FUO. Here is a nice case published in J Hosp Med from 2010 and discussion about doxycycline deficient states as well as zoonotic diseases.