In the latest Case Record of the Massachusetts General Hospital, a 70-year-old woman was admitted because of intermittent fevers and new-onset back and leg pain. Imaging of the lumbar spine revealed abnormalities in the vertebral bodies adjacent to the L5–S1 disk space. A diagnostic result was received.
Brucellosis is widespread in the Middle East. Serologic surveys have shown that 2 to 15% of camels in this geographic area have antibodies against brucella. A recent report describes brucellosis in two persons returning home to Singapore after drinking unpasteurized camel’s milk during the Hajj pilgrimage. In animals in the Middle East, Brucella melitensis (serovar 2 or 3) predominates; in humans, serovar 3 is the cause of most cases.
• What is the typical presentation of brucellosis?
Fever is the primary symptom of brucellosis, often with chills; osteoarticular disease is the most common complication when focal infection is diagnosed. One third of patients with brucellosis have hepatic or splenic enlargement, and 10% have genitourinary involvement. Brucellosis often involves the spine; in children, the sacroiliac joint is most frequently involved; in older patients spinal infection is most frequent, and 60% of cases are lumbar, most often at the L4 or L5 level.
• How do you distinguish a spinal infection secondary to tuberculosis from one involving brucella?
According to the authors, it has been suggested that the constellation of back pain, elevations in the erythrocyte sedimentation rate and the level of serum C-reactive protein, a history of previous tuberculosis, and involvement of posterior spinal elements on imaging is pathognomonic of tuberculosis. Marked destruction of vertebral bodies, usually in the thoracic or thoracolumbar area, is more common in tuberculosis, whereas disk destruction is seen more often in brucellosis. Paravertebral abscesses are less common in brucellosis than in tuberculosis, but they can occur. On MRI, a well-defined abnormal paraspinal signal and a thin, smooth abscess wall suggest tuberculous infection.
Morning Report Questions
Q: How is brucellosis diagnosed?
A: The incubation period for brucellosis ranges from 1 to 2 weeks for acute disease to months for late disease. Diagnosis of brucellosis can prove difficult. In automated blood-culture systems, growth often can be detected after 3 to 5 days of incubation. Laboratory personnel should be alerted to the need to hold the cultures longer than the customary 5 days and also to take precautions to avoid infection themselves. If cultures are negative, a presumptive diagnosis can be made serologically, although seropositivity can derive from previous infection and not necessarily indicate active infection, especially in people who have resided in endemic regions.
Q: What is the appropriate treatment for brucella infection?
A: Initial treatment typically includes doxycycline for six weeks and IM streptomycin for the first 14 to 21 days, or six weeks of doxycycline and rifampin.