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Three Part Question

In a [patient with sickle cell disease presenting with painful crisis] does [routine urinalysis and chest radiography] detect [occult infection not appreciated by history or physical examination]?

Clinical Scenario

A 35-year-old female with sickle cell disease presents with pain in her arms and legs for twenty-four hours. Her pain is consistent with her usual pain crisis symptoms. She is afebrile, has normal vital signs, and no acute findings on physical exam. You promptly treat her pain. You wonder if a chest radiograph or urinalysis will detect an occult bacterial infection that may have precipitated the crisis.

Search Strategy

A MEDLINE (1966 to present)
search was performed using the key words "sickle cell" and "emergency department."

Search Outcome

The search yielded 84 research articles. Bibliographic references found in these articles were also examined to identify pertinent literature. Only original research articles were included. We identified two articles that directly addressed our question.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Pollack CV 1991 USA	74 patients, 14 years or older, with 134 presentations. A questionnaire addressing symptoms was completed by the treating physician. All patients had a complete blood count, reticulocyte cell count, chest radiograph, and urinalysis done.	Prospective study	Pneumonia	Eight cases of pneumonia. Five of these cases had no suggestive symptoms or physical exam findings.	Small study
			Urinary tract infection	Ten cases of urinary tract infection. Six patients had disease with no suggestive symptoms or physical exam findings.
Ander DS 1997 USA	38 adult patients with 94 presentations. A questionnaire addressing symptoms was completed by the treating physician. All patients had a complete blood count, reticulocyte count, chest radiograph, and urinalysis done.	Prospective study	Pneumonia	Six cases of pneumonia. All patients with pneumonia had symptoms suggestive of disease.	Small study
			Urinary tract infection	Three cases of urinary tract infection. Two cases had no suggestive symptoms of disease.

Comment(s)

Infection is a possible precipitant of painful crisis in patients with sickle cell disease. Routine diagnostic testing, defined here as testing not specifically indicated by patient history and physical examination alone, has the potential to detect such infections. Best evidence suggests that occult urinary tract infections exist in patients presenting to the accident and emergency department for painful crisis. Routine urinalysis as a means to detect these infections may be useful. The literature is limited by small sample size and few individual studies but the disadvantages to performing this simple, noninvasive test are minimal. The use of routine chest radiography in patients presenting with sickle cell pain crisis may detect occult pneumonia. While it is suggested by Ander et al. that a clinical decision rule may be possible to rule out pneumonia in this patient population, such a rule has not been defined nor prospectively validated. The disadvantages to ordering a chest radiograph include patient exposure to radiation and financial cost. These facts must be weighed against the high morbidity and mortality associated with pulmonary complications of sickle cell disease. Given these considerations and the best evidence, it is recommended to have a low clinical threshold to order chest radiography.

Clinical Bottom Line

All patients with sickle cell disease presenting with painful crisis should have a urinalysis done regardless of clinical condition to detect occult infection. A chest radiograph may detect occult pneumonia, and a low clinical threshold to order such a test is recommended.

References

1. Pollack CV, Jorden RC, Kolb JC Usefulness of empiric chest radiography and urinalysis testing in adults with acute sickle cell pain crisis Ann Emerg Med 1991;20:1210-1214.
2. Ander DS, Vallee PA Diagnostic evaluation for infectious etiology of sickle cell pain crisis American Journal of Emergency Medicine 1997;15:290-292