Tropheryma Whipplei Endocarditis: Case Report and Literature Review.

We describe a young man who initially presented with stroke and febrile illness. He was eventually diagnosed with Tropheryma whipplei endocarditis. This is a very rare condition and to the best of our knowledge, this is the first documented case of T. whipplei endocarditis in Australia and New Zealand regions. This report aims to increase awareness of clinicians of this very rare but potentially treatable condition. It is reasonable to exclude T. whipplei endocarditis when dealing with high-risk patients who are suspected for "culture-negative" endocarditis.

INTRODUCTION

Whipple's disease (WD) is a rare chronic multisystemic infectious disease that very rarely causes infective endocarditis (IE).[12] The presenting symptoms are usually nonspecific, and therefore, the accurate diagnosis is often delayed.

CASE PRESENTATION

A 35-year-old roof plumber presented with 1-day history of malaise, vomiting, confusion, and dysphasia with mild right-sided weakness and numbness. One-week prior, he had an infected tooth. Four months earlier, he experienced transient right-sided sensorimotor deficits. He had intermittent bilateral wrist arthralgia for 2 years. He denied intravenous illicit drug use.

On admission, he was febrile (38.2°C), in sinus rhythm, and had a diastolic murmur on auscultation. There were no stigmata of IE. Blood tests showed raised white cell count 12.9 × 109/L (4.0–11.0 × 109/L) and C-reactive protein 56 mg/L (<5 mg/L). Magnetic resonance imaging brain confirmed left parietal ischemic stroke.

A large lesion on the right coronary cusp (RCC) of the aortic valve associated with severe aortic regurgitation was documented on transthoracic and subsequent transoesophageal echocardiography. The working diagnosis was ischemic stroke due to IE, and he was treated with intravenous ceftriaxone and vancomycin. Two weeks later, he underwent bioprosthetic aortic valve replacement and mitral valve debridement. Large vegetation on the RCC of the aortic valve (30 mm × 20 mm × 2 mm) and two small vegetations on the anterior leaflet of the mitral valve were found intraoperatively.

Blood cultures, serology for hepatitis B and C and HIV, and screening for blood culture-negative endocarditis (BCNE) and vasculitis were negative. Five weeks postadmission, the result of his 16S rRNA polymerase chain reaction (PCR) from explanted valves confirmed Whipple's endocarditis. Valve histopathology showed macrophages with periodic acid-Schiff-positive organisms [Figure 1]. Electron microscopy findings also confirmed the diagnosis. Vancomycin was ceased as soon as Whipple's endocarditis was confirmed by 16S rRNA polymerase chain reaction (PCR). However, the patient continued with intravenous ceftriaxone therapy for another 2 weeks to complete a total of 7-week course before it was ceased and replaced by Bactrim DS one tablet twice daily, which was continued for 12 months. He remains well with excellent speech recovery and no residual weakness.

Figure 1

Foamy macrophages containing characteristic inclusion Tropheryma whipplei particle (periodic acid–Schiff stain)

DISCUSSION

This is the first documented case of IE due to WD in Australia. WD is a rare chronic multisystemic infectious disease with a prevalence of less than 1:1,000,000 that preferentially affects middle-aged men.[1] The classic manifestations of WD are weight loss, abdominal discomfort, diarrhea, malabsorption, and arthralgia.[1] WD is caused by T. whipplei which is found in the general environment and sewage water as well as healthy individuals’ stool.[13] The mode of transmission has been postulated to be fecal-oral route.[1] Our patient possibly had occupational exposure to the organism while working for years as a plumber.

T. whipplei endocarditis is a very rare condition with unknown incidence.[2] The aortic valve is most commonly involved.[4] Approximately 26% of patients are complicated by ischemic stroke and up to 75% report arthralgia.[4] The diagnosis is made based on tissue 16S rRNA PCR, histopathology, immunohistochemistry, and electron microscopy. The recommended antibiotic regimen includes 2–4 weeks of intravenous ceftriaxone, penicillin, or meropenem followed by 1 year of oral trimethoprim-sulfamethoxazole or doxycycline.[5] It has been proposed that patients be monitored for early relapse or reinfection with PCR on saliva and stool 3 and 6 months after commencement of treatment and annually thereafter.[6]

CONCLUSION

T. whipplei endocarditis is a rare but potentially treatable condition. Given the specific diagnostic and therapeutic approach, clinicians should have a low threshold to investigate for T. whipplei in high-risk patients with BCNE.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.