Coxiella burnetii and lobar pneumonia.
C burnetii is the causative agent of Q fever. (1,2) Although there are some reports of person-to-person spread, most Q fever infections result from inhalation of infectious aerosol particles from parturient ruminants derived from a wide variety of animals, such as cows, goats, sheep, cats and occasionally dogs, due to the fact that the organism has high concentrations in the placenta of infected animals. (3,4) However, this contact may be indirect, and other animals' products may be involved. In our case, the patient had a domestic dog, but was not around the breeding period.
It is estimated that C burnetii infection is asymptomatic in 60% of the cases and only 2% of the acute infected patients need hospitalization. (3) Hepatomegaly with abnormal liver function tests is also common. (2) Pneumonia, with (similar to our case) or without hepatitis, is usually mild, but respiratory distress needing mechanical ventilation occasionally occurs. (1) Generally, the clinical feature of Q fever pneumonia varies greatly and depends on the geographic origin of the infection and host factors. (2)
Although C burnetii is considered a causative agent of atypical pneumonia (range: 0.8%-5.8% of CAP), (5) in our case, radiological (lobar pneumonia) and laboratory (86% polymorphonuclear cells) findings at admission were compatible with typical bacterial CAP. It is estimated that 17 (6.3%) of 272 patients with Q fever pneumonia had segmental consolidation. (1) However, it has been suggested that there is a second type of acute Q fever pneumonia presenting as bacterial CAP due to a mixed infection with S pneumoniae or H influenzae. (5) However, in our case, clinical and laboratory findings as well as treatment responsiveness were not able to establish a case of mixed infection.
In conclusion, prompt diagnosis, based on epidemiologic (geographic characteristics, exposure to risk factors), clinical and serologic data, is essential, since acute Q fever pneumonia may present with atypical laboratory and radiological findings.
Evangelos Cholongitas, MD
Chrysoula Zouli, MD
Chrysoula Pipili, MD
Konstadinos Katsogridakis, MD
Konstadinos Rellos, MD
Maria Dasenaki, MD
Department of Internal Medicine
General Hospital of Sitia
1. Marrie TJ. Coxiella burnetii pneumonia. Eur Respir J 2003;21:713-719.
2. Parker NR, Barralet JH, Bell AM. Q fever. Lancet 2006;367:679-688.
3. Raoult D, Marrie T, Mege J. Natural history and pathophysiology of Q fever. Lancet Infect Dis 2005:5:219-226.
4. Marrie TJ. Q fever pneumonia. Curr Opin Infect Dis 2004;17:137-142.
5. Okimoto N, Asaoka N, Osaki K. et al. Clinical features of Q fever pneumonia. Respirology 2004;9:278-282.
|Printer friendly Cite/link Email Feedback|
|Publication:||Southern Medical Journal|
|Article Type:||Letter to the editor|
|Date:||Nov 1, 2006|
|Previous Article:||Baclofen-induced neurotoxicity in chronic renal failure patients with intractable hiccups.|
|Next Article:||Atypical presentation of Crohn disease in an Asian-Indian patient.|