A 32-year-old man comes to the clinic due to a week of escalating low back pain. The pain is dull, achy, present at rest, and worse with activity. The patient has no significant medical history. He smokes a pack of cigarettes daily and drinks alcohol occasionally. He recently began using intravenous heroin due to significant psychosocial stress at home. There is a family history of prostate cancer in his father. Temperature is 36.7 C (98 F), blood pressure is 120/80 mm Hg, pulse is 90/min, and respirations are 16/min. Gentle percussion over the lumbar vertebrae (L3 and L4) elicits exquisite pain. A full neurologic examination, including straight leg raise, is normal. Laboratory results are as follows: Which of the following is the most likely diagnosis?

Question

A 32-year-old man comes to the clinic due to a week of escalating low back pain.  The pain is dull, achy, present at rest, and worse with activity.  The patient has no significant medical history.  He smokes a pack of cigarettes daily and drinks alcohol occasionally.  He recently began using intravenous heroin due to significant psychosocial stress at home.  There is a family history of prostate cancer in his father.  Temperature is 36.7 C (98 F), blood pressure is 120/80 mm Hg, pulse is 90/min, and respirations are 16/min.  Gentle percussion over the lumbar vertebrae (L3 and L4) elicits exquisite pain.  A full neurologic examination, including straight leg raise, is normal.  Laboratory results are as follows:  Which of the following is the most likely diagnosis?

Quizplus · Accepted Answer

This patient has vertebral osteomyelitis. Injection drug users, patients with sickle cell anemia, and immunosuppressed patients are at highest risk for osteomyelitis. The spine is a frequent site of osteomyelitic infection in injection drug users. In this group, Staphylococcus aureus is the most common pathogen, but infections with gram-negative organisms also occur. Most cases of vertebral osteomyelitis are chronic (>6 weeks) and insidious with minimal symptoms. Many patients have back pain unrelieved by rest; fever is present in <50%. Physical examination often shows few findings, but tenderness to gentle percussion over the spinous process of the involved vertebra can be an important clue. Leukocytes may be elevated or normal. Platelet count is often high as a marker of inflammation/stress. The erythrocyte sedimentation rate is often significantly elevated (>100 mm/hr). MRI is the most sensitive diagnostic study. Treatment is long-term intravenous antibiotics with or without surgery. (Choice A) Ankylosing spondylitis is characterized by pain and progressive limitation of back motion. It occurs most often in young men. Symptoms are usually most severe in the morning and improve as the day progresses. Exquisite tenderness to palpation is not a classic finding. (Choice B) Lumbar disk herniation typically presents with the acute onset of back pain with or without radiation down a leg. Patients can usually recall an inciting event. The pain is worse with activity and improves with rest. The spine is not typically tender to palpation. (Choice C) Lumbar spinal stenosis is a narrowing of the spinal canal with compression of one or more of the spinal roots. Most affected patients are >60. Patients experience back pain that radiates to the buttocks and thighs. Symptoms often worsen with walking and lumbar extension and improve with lumbar flexion. Numbness and paresthesias may occur. The diagnosis is confirmed with MRI. (Choice D) Although prostate cancer is a possibility, this patient's young age, localized pain on palpation, lack of night pain, and lack of urinary symptoms make this a less likely diagnosis. (Choice E) Vertebral compression fractures can cause local tenderness to palpation, but this usually occurs in elderly patients with a history of osteoporosis. Educational objective: Tenderness to gentle percussion over the spinous process of the involved vertebra is the most reliable sign for spinal osteomyelitis. Pain is not relieved with rest. Fever and leukocytosis are unreliable findings. The erythrocyte sedimentation rate is grossly elevated. MRI is the most sensitive diagnostic study. There should be a very high index of suspicion for vertebral osteomyelitis in patients with a history of injection drug use or recent distant site infection (eg, urinary tract infection).

A 32-Year-Old Man Comes to the Clinic Due to a Week