Diagnostic evaluation for infectious etiology of sickle cell pain crisis

Abstract

Occult infections during sickle cell pain crisis can be associated with significant morbidity. It has been suggested that empiric workup for pneumonia and urinary tract infection (UTI) is required. A study was undertaken to determine whether clinical criteria can be used to exclude such infections as precipitants of pain crisis in adults. This retrospective, observational clinical study was conducted in an inner-city teaching hospital emergency department (ED) with 95,000 visits/year. Patients 18 years of age or older presenting to the ED with sickle cell pain crisis who had not used antipyretics within 6 hours before presentation were eligible. Ninety-four visits were evaluated. During initial evaluation the treating physician completed a questionnaire addressing systemic, pulmonary, and urinary tract signs and symptoms, Temperature and physical examination were recorded on an ED memo. Treatment modalities were at the discretion of the treating physician. All patients had a complete blood count, reticulocyte count, urinalysis, and chest radiograph. If the urinalysis was positive (>2 white blood cells) or the patient had clinical evidence of a UTI, a urine culture was obtained. UTI was confirmed through a urine culture with >100,000 colony-forming units/mL. Chest X-rays were reviewed by a staff radiologist. Definitive diagnosis of pneumonia was made by the presence of an infiltrate and a positive clinical response to antibiotic therapy. Thirty-eight patients totalling 94 visits to the ED were studied during an 18-month period. Six diagnoses of pneumonia and 3 diagnoses of UTI were made. All six patients with pneumonia had at least 4 of the signs and symptoms including fever, chills, cough, shortness of breath, sputum production, chest pain, hemoptysis, abnormal pulmonary examination, and temperature of >37.8°C. Of the three patients with UTI, two had signs and symptoms inconsistent with UTI (asymptomatic bacteriuria). In patients with sickle cell pain crisis, medical history and physical examination can be useful to predict the absence of pneumonia, but may not be as beneficial in predicting the absence of UTI. These results suggest that empiric chest x-ray may be unnecessary to exclude pneumonia; however, routine urinalysis may be indicated. Because of the low incidence of these infections, larger studies are required to confirm these findings.