A 78 year old man presented with neck pain, fever, and malaise for 3 days. He noted progressively worsening pain and stiffness of the anterior neck bilaterally. He reported right- sided headache and subjective fevers but denied any photo or phonophobia. He had no sick contacts or recent travel. Past medical history included squamous cell carcinoma of the larynx T3N0M0 that required chemotherapy, radiation, and laryngectomy. Social history was significant for 180 pack years of tobacco smoking. Vital signs revealed a temperature of 102.5F, heart rate of 121 BPM, and blood pressure 198/76 mmHg. Neck was supple, but tender with tracheostomy stoma present and decreased ROM in all directions. The remainder of the physical exam was unremarkable. His WBC count was 13.7 with 87% neutrophils. Basic chemistry was within normal limits. Lumbar puncture was unsuccessful but blood cultures grew methicillin-sensitive Staphylococcal aureus on 4 consecutive days. Trans- esophageal echocardiogram showed normal systolic function and no valvular vegetations. MRI of the cervical spine revealed abnormal enhancement within C6 and C7 vertebral bodies consistent with osteomyelitis.
Thorough evaluation of patients with bacteremia is a critically important skill for the hospitalist. Initial workup always includes a detailed history and physical. Attention should be paid to any potential portals of entry including recent skin or soft tissue infection and presence of indwelling prosthetic devices. Bacteremia is most commonly caused by Staph aureus infection and should prompt evaluation for possible endocarditis, osteomyelitis, or other metastatic deep infections which occur in up to 30% of cases. The frequency of infective endocarditis among patients with Staph aureus bacteremia is 25-32%. Therefore, all patients with Staph aureus bacteremia should undergo echocardiography. If a transthoracic echocardiogram is normal, then trans-esophageal echocardiogram should be performed for those with pretest probability of endocarditis greater than 5%. Focused imaging should also be performed to rule out osteomyelitis.
Vertebral osteomyelitis occurs in 1 per 250,000 persons. Pathogens can reach the bones of the spine either via hematogenous spread, direct inoculation from trauma or surgery, or contiguous spread from adjacent soft tissue infection. The patient described above had undergone recent radiation to his neck putting him at risk for cervical spine osteonecrosis, which has been reported to lead to osteomyelitis. This phenomenon is rare, and in one study, 18 out of 84 patients developed osteomyelitis after radiation for head and neck carcinoma with only 1 case in the cervical spine. The mechanism is thought to be a result of necrosis of the bone caused by irradiation, which leads to reduced healing and poor resistance to infection. The patient in this case received 8 weeks of intravenous Nafcillin with improvement of his symptoms. However, 10-15% of patients with vertebral osteomyelitis develop neurologic findings or frank spinal-cord compression. Therefore, prompt evaluation and treatment by the hospitalist is imperative.
When encountering persistent bacteremia in the hospital, physicians should consider metastatic deep infections including endocarditis and osteomyelitis. Sources of osteomyelitis may include hematogenous spread, contiguous spread or due to underlying trauma, surgery or radiation.