Fever and Limp in a 3-Year-Old Girl

Setshedi Makwinja, MD; Ben Numpang, MD; Benjamin R. Aubey, MD, MPH


October 28, 2015

A review of the literature published from 1881 through 1990 revealed that the incidence of psoas abscesses approximates four cases per 100,000 population per year, with a more recent Taiwanese study reporting that the rate of occurrence was 2.5 cases annually.[8] These incidences reflect adult patients. In Asia and Africa, 99.5% of all psoas abscesses are primary, compared with 61% in the United States and Canada and 18.7% in Europe. The causes of psoas abscess in the Western world have changed since the beginning of the 20th century. Primary psoas abscess caused by hematogenous spread from an occult source is common, especially in immunocompromised individuals.

In the past, psoas abscess was mainly caused by tuberculosis of the spine (Pott disease); but with the decline in the prevalence of infections caused by Mycobacterium tuberculosis, major pathogens associated with psoas abscesses are those related to diseases of the digestive tract. This is reflective of the role of contiguous sites of infection in the development of a psoas abscess.

Common secondary causes of psoas abscess include Crohn disease (60%), appendicitis (16%), ulcerative colitis, diverticulitis, colon cancer (11%), and vertebral osteomyelitis (10%). In secondary psoas abscesses, cultures are often mixed with Escherichia coli and Bacteroides species predominating. Staphylococcus aureus is the most common isolated organism in primary disease. Leukocytosis is the most common laboratory finding.[1,3,9]

Without localizing tenderness, the presentation of fever and irritable hip could be attributed to primary diseases of the hip; therefore, the clinician must know how to distinguish between psoas abscesses and primary hip diseases. In psoas abscess, the posterior part of the hip joint is not tender, and a fully flexed hip can be rotated without pain; this would be difficult in patients with hip problems. Digital rectal examinations produce tenderness in psoas muscle disease.

Percutaneous drainage and antibiotics are the first line of treatment, but recurrence is common. In the past, open drainage of the abscess through a McBurney or iliac crest incision was performed. Open surgical drainage allows simultaneous treatment of the underlying pathology in secondary abscess. The duration of antibiotic therapy must be individualized and graded by the clinical signs and any involvement of other sites.[4,5,10]


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