An HIV-positive 38-year-old man with a history of injection drug use presented to the emergency department with abdominal and back pain that worsened with motion. He denied fever and vomiting. During the past 2 months, the patient had been treated for a urinary tract infection (UTI) 4 times and evaluated for a renal calculus, which had been ruled out. He was currently receiving ciprofloxacin, ibuprofen, and HAART.
The patient was afebrile. Examination revealed tenderness in the left mid abdomen, left lower quadrant, and left costovertebral angle. Neurologic findings were normal. A lateral lumbar spine radiograph showed an abnormality at the L2-3 level, which suggested diskitis. A CT scan of the abdomen confirmed the diagnosis. There was no evidence of cord compression.
Glucose level was 121 mg/dL; potassium level was 3.4 mEq/L. White blood cell (WBC) count was 11.4 3 103/µL, with normal differential. Urinalysis showed 1 to 5 WBCs per high-power field.Two weeks earlier, urinalysis had shown 10 to 25 WBCs per high-power fieldand rare bacteria. A blood culture grew Pseudomonas.
Vertebral osteomyelitis/diskitis is frequently diagnosed late. Often, patients have symptoms for weeks or months before plain films show evidence of bone inflammation or loss of disk height. Fever and elevated WBC counts are variable findings.
In this patient, the abnormal urinalysis results led other physicians to suspect a UTI. However, men with recurrent or refractory pyelonephritis require further evaluation. In addition to UTIs, osteomyelitis may mimic other disease processes and conditions, such as appendicitis, which can cause reactive pyuria.
This patient initially received piperacillin/tazobactam and vancomycin because of his previous injection drug use and possible infection with methicillin-resistant Staphylococcus aureus. Based on the blood culture results, the regimen was switched to ceftazidime and tobramycin. After 5 weeks, he was discharged with oral levofloxacin, 750 mg qd for 4 weeks. Five months later, the condition recurred.
(Case and photograph courtesy of D. Brady Pregerson, MD.)