Use of polymerase chain reaction in the diagnosis of Whipple's disease

Whipple's disease, a systemic, chronic infectious disease caused by Tropheryma whipplei, is extremely rare in Asian populations. A correct diagnosis is necessary due to its high mortality rate. Unfortunately, patients are apt to be misdiagnosed with connective tissue diseases since they typically present with arthritis or arthralgia. There are three diagnostic tools for Whipple's disease using intestinal tissues: 1) periodic acid-Schiff (PAS)-positive macrophages; 2) electron microscopic observation; and 3) polymerase chain reaction (PCR). It is challenging to diagnose this disease in the absence of histological findings, especially in Japan, where the clinical protocol currently used to make the diagnosis needs improvement, although symptomology and PCR results may be sufficient. Herein, we investigated a 24-year-old Japanese woman who had suffered from intermittent fever, migratory arthralgia, and watery diarrhea for several months. Her biopsied intestinal tissue was negative for foamy macrophages and PAS-positive cells, and electron microscopy did not provide diagnostic insight. PCR amplification of the specimens, however, successfully revealed T. whipplei. Whipple's disease was diagnosed based on a positive PCR result and strong clinical suspicion. The patient was treated parenterally with ceftriaxone (2 g daily) for two weeks, followed by oral treatment with 160 mg trimethoprim and 800 mg sulfamethoxazole twice per day. After one month of treatment, her symptoms disappeared and inflammatory markers returned to normal levels. This case illustrates the practicality and effectiveness of a PCR-based diagnostic test in combination with clinical suspicion to correctly diagnose Whipple's disease, especially in cases when a histological examination does not provide insight.