Pseudomonas aeruginosa osteomyelitis of the cervical spine.

N pyogenic spinal osteomyelitis compromise only 2-4% of all cases of osteomyelitis. The incidence is estimated at 1:250,000 per year in the general population. Cervical involvement is observed in less than 10% of the cases of spinal osteomyelitis. Pyogenic spinal osteomyelitis is usually caused by gram positive pyogens like Staphylococci and Streptococci species. They are usually seen in immuno-compromised patients or intravenous drug users.1 They frequently pose diagnostic and therapeutic challenges for the internists, radiologists, and surgeons. Pseudomonas aeruginosa (P. aeruginosa) are gram-negative bacilli that rarely cause osteomyelitis. It usually affects immuno-compromised or hospitalized patients on long-term antibiotic therapy for other conditions.1-3 Only a few short series and case reports in the literature described spinal osteomyelitis secondary to Pseudomonas species including aeruginosa. The vast majority of these cases were reported in immuno-compromised patients. We present in this report a rare case of vertebral osteomyelitis of the cervical spine caused by P. aeruginosa infection. A 60-year-old black male presented with a few weeks history of throat pain that progressed to involve the whole neck. Later, his symptoms became more intense and associated with severe neck stiffness and occipital headache. He is known diabetic, on oral hypoglycemic medications under good control. He is also a heavy smoker. He denied any history of swallowing or breathing difficulties, nausea, or vomiting. He also denied a history of fever or night sweating. He had mild weakness of the 4 limbs, but denied any sensory symptoms or sphincter disturbances. There was no recent history of contact with known patients suffering tuberculosis infection. The patient was still ambulating in a spastic gait with support. On physical examination, he was awake, oriented with fluent comprehensive speech. He had a stiff neck with very limited range of movements in all directions. He had a normal cranial nerves examination. Motor power grades in the 4 extremities were 4/5 with normal reflexes, down going planters, and normal exam of all sensory modalities. Plain x-ray images of the cervical spine demonstrated changes that involved C2, C3, and C4 vertebral bodies associated with para-vertebral soft tissue expansion at these levels and the retropharyngeal spaces. An MRI study of the cervical spine revealed an extensive destructive process in the upper cervical region extending from C2-C4 spinal segments. Evidence of intervertebral disc space involvement, and a partial collapse of the C4 vertebral body were observed. Prominent pre-, para-, and retrospinal soft tissue involvements are demonstrated with anterior epidural extension resulting in significant spinal cord compression and signal changes within the cord parenchyma at the level of the compression (Figure 1). The images were highly suggestive of an infectious process. Blood test results obtained more than once and revealed; white cells count (WBC) ranged from 8.6-12.3 x 109/L (normal range [NR]: 3.90 11.00 x 109/L) with differential counts of more than 90% neutrophils. Erythrocyte sedimentation rate (ESR) ranged from 80-140 mm/Hr (NR: up to 20 mm /Hr). The C-reactive protein (CRP) ranged from 4.8-5.7 mg/L (NR: ≤3 mg/L). Blood, urine, and sputum microbiological culture results were all negative. Other serological studies including HIV infection were non-reactive, and Brucella agglutination antibodies titer was less than 1:20. A rigid cervical orthosis was fitted on the patient’s neck. He was started on intravenous Vancomycin empirically covering the more common Clinical Note