To the editor: An 18-year-old woman presented to my office with severe left buttock pain radiating down her posterior thigh, and mild left lower quadrant pain. She had no nausea, vomiting, diarrhea, chills, fever, or sweats. Her medical, family, and social history and review of systems were noncontributory. She was allergic to penicillin.

On examination, she was in moderate distress. Her temperature was 37.2°C (99.0°F). No icterus was present. Her abdomen was benign, and findings on pelvic examination were normal. Her left sciatic notch was tender, with a positive left straight-leg raise. My initial impression was acute sciatica, but the abdominal pain and high normal temperature made my diagnosis uncertain. I prescribed celecoxib and rest, and arranged close follow-up.

That night, she presented to the emergency department with a fever of 39.4°C (103.0°F), nausea, headache, and dry cough. The pain had radiated into the lower and middle portions of the back. Her complete blood count and urinalysis were within normal limits, and a urine pregnancy test was negative. Blood cultures were drawn and she was sent home.

The next day, blood cultures grew gram-negative rods. She was admitted to the hospital with a provisional diagnosis of sciatica and pyelonephritis, and she was started on levofloxacin. At admission, her vitals were as follows: blood pressure, 100/60 mm Hg; pulse rate, 96 beats per minute; and temperature, 39.8°C (103.7°F). She was in moderate distress. Her abdomen was soft and nontender with no organomegaly. She had positive psoas and obturator signs. The blood cultures grew Salmonella sensitive to ciprofloxacin and gentamicin. The patient had not traveled recently and had no diarrhea. She denied eating any unusual foods, but later revealed working in a fast food restaurant where she handled raw chicken and beef with her bare hands.

Lumbar spine and magnetic resonance imaging (MRI) of the hip were read as “minimal disk herniation of L4-L5, pelvic organs normal, bladder slightly distended, and scant increase of fluid in the left hip joint.” I asked a senior radiologist to review the hip MRI. He said, “The psoas muscle is lighting up like a light bulb.” As I spoke with him, I searched PubMed for the terms “psoas” and “Salmonella.” I found seven references^1–6 to Salmonella psoas myositis and sacroiliac osteomyelitis. These diagnoses explained the patient's symptoms, signs, and MRI findings.

The patient improved. A bone scan showed osteomyelitis of the left sacroiliac joint and inflammation of multiple muscles. This was confirmed by a tagged white blood cell scan. The patient was discharged on the seventh hospital day, and ciprofloxacin was continued for six weeks, by which time she had fully recovered.

This case illustrates the continued importance of bedside diagnostic skills, the need to consider the clinical context in interpreting imaging studies, and the key roles that the family physician and the Internet can play in the care of a patient with a complex illness.