Q fever spondylitis: 2 cases report

Dear Editor,

Q fever is a zoonosis caused by Coxiella burnetii. This microorganism is an intracellular bacterium and causes acute and chronic infections. The most common manifestations of this entity include endocarditis, chronic vascular and osteoarticular infections.

The diagnosis is based on histological examinations, serology and/or PCR in cell cultures.^1–4

Spondylitis caused by C. burnetii (Q fever) is a rare entity, with few cases reported to date. Therefore, we believe it is of interest to describe the cases of 2 patients assisted in our center with this diagnosis.

Case 1

A 49-year-old man with no significant history, suffering from lumbosacral pain for 2 weeks, without fever or any other symptoms. Normal physical examination except for lower back pain on palpation. Blood test with normal complete blood count, liver and kidney biochemistry, ESR and PCR. Normal chest X-ray. Blood cultures, PPD and Quantiferon^® were negative. In lumbar MRI, signs of L3–L4 spondylodiscitis with peri-vertebral abscesses and abscesses in the left psoas muscle and left anterior intraspinal-epidural abscess (L3–L4 and L4–L5) (Fig. 1). Pathological anatomy with signs of chronic granulomatous inflammation and multinucleated giant cells. Kinyoun, Gram, Ziehl–Neelsen staining, Lowenstein and PCR negative for mycobacteria. Brucella, Bartonella serologies and Rose Bengal were negative. Serology for C. burnetii was positive (Coxiella IgG positive phase I 2560; phase II 1/640, IgA phase I 1/800, phase II 1/25). Normal echocardiogram and visceral arterial Doppler ultrasonography. With the diagnosis of Q fever spondylodiscitis, the therapy used was hydroxychloroquine 200 mg/12 h, doxycycline 100 mg/12 h and rifampicin 600 mg/24 h for 2 years. Subsequently, the therapy was changed to doxycycline with levofloxacin 750 mg/24 h for 3 years until negative serology.

Fig. 1.

Lumbar MRI of cases 1 and 2.

During the follow-up, the patient presented good clinical and radiological evolution. In a control MRI in 2010, improvement of peri-vertebral abscesses. In the 2012 control MRI: residual changes in the L3–L4 intervertebral disc space in relation to the old spondylodiscitis without edematous-inflammatory signs at the vertebral bodies.

Case 2

A 59-year-old woman with a history of osteoarthritis and dorsalgia for 4 years of controlled evolution with analgesia. She consulted for back pain worsening, that led to a significant functional impairment, without fever or any other accompanying symptoms. A physical examination highlighted selective pain to palpation of Th7–Th8 vertebrae, the rest being anodyne. Blood test with normal complete blood count, liver and kidney biochemistry, ESR and PCR. Normal chest X-ray. Blood cultures, PPD and Quantiferon were negative. In the bone scintigraphy, signs of spondylodiscitis in Th8–Th9; and in thoracic MRI with ankylosing spondylitis of the Th8–Th9 mid-thoracic segment and spondylodiscitis and right Th6-Th7 vertebral arthritis without involvement of the spinal canal (Fig. 1).

Biopsy with microbiological study (Gram, Ziehl–Neelsen staining, bacteria culture, Lowenstein and PCR for mycobacteria) showed a negative result. The pathological anatomy was not conclusive (insufficient specimen) and the patient refused to undergo a new puncture. Brucella and Bartonella serologies and Rose Bengal test were negative. Serology for C. burnetii was positive (Anti-Coxiella IgG phase I 1/1280, phase II 1/640, IgA phase I 1/400, phase II 1/50, IgM phase I negative, phase II 1/50). Normal echocardiogram. The patient underwent 9 months of tuberculostatic therapy and doxycycline 100 mg/12 h, subsequently maintaining doxycycline 100 mg/2 h and rifampicin 600 mg/12 h along with hydroxychloroquine 200 mg/12 h for 2 years. Subsequently, when serology improved, therapy was changed to doxycycline and levofloxacin 750 mg/24 h. After 4 years of evolution, the patient presented clinical and radiological improvement. Control MRI at year 2 shows improvement of edema from Th4 toTh10 predominant in Th5.

Although spondylitis due to Q fever is a rare entity in our setting, it should be considered in the differential diagnosis of infectious spondylitis. In the bibliography, there are only 20–30 reported cases.

And, to a greater extent, in patients with subacute forms of presentation, where the pathological anatomy shows granulomatous lesions and the diagnosis of tuberculosis has not been verified. The best methods of microbiological diagnosis are those that allow direct detection of the bacteria (cell culture and polymerase chain reaction, PCR). Indirect immunofluorescence is very sensitive and specific. These diagnostic methods should also be associated with antibody titers (IgG and/or IgM), higher than the cut-off point.

Since it requires antibiotic therapy for months, the patient should undergo clinical, radiological and serological follow-up. The decrease of over 2 antibody titers is considered a good evolution. To consider healing, we require IgG <1:400 and negative IgA, in this case the treatment could be withdrawn.⁵