Her vital signs are as follows: temperature, 100.1°F (37.9°C); heart rate, 80 beats per minute; blood pressure, 110 mm Hg systolic, 70 mm Hg diastolic; respiratory rate, 28 breaths per minute.
The patient is alert and shows no signs of toxicity; her sclerae are anicteric. Her lungs are clear. The patient's abdomen is soft and flat but mildly tender in the middle and right lower quadrant. She has no signs of rebound pain or guarding. No mass is present, and her bowel sounds are normal.
Her pelvic examination reveals a normal cervix, no discharge via os, no cervical motion tenderness (CMT), and mild right adnexal tenderness but no mass. Her rectal tone is normal, no mass is present, and the rectum is nontender. Abdominal CT with oral and intravenous contrast enhancement was performed.
Among her laboratory findings, the white blood cell (WBC) count is 2100 per microliter; the result of a beta human chorionic gonadotropin test is negative; urinalysis findings are normal; and levels of sodium, potassium, chloride, carbon dioxide/bicarbonate, BUN, creatinine, and glucose (chem 7) are normal.
ANSWER
Pelvic retention of contrast material from recent hysterosalpingography: The benign clinical appearance of the patient and the absence of the expected peritoneal signs at abdominal examination conflicted with the abdominal CT scan that shows free contrast agent in the pelvis. Presumed perforated appendicitis was ruled out by means of careful history taking, which revealed the recent hysterosalpingographic examination. The patient was discharged home with the diagnosis of viral syndrome, and follow-up with her primary care physician was arranged. Whether the abdominal pain was due to erythromycin use or associated with the viral syndrome is unclear.