Infectious Diseases in Clinical Practice:
A 42-year-old Chinese man was found to have leptospire by urine dark-field microscopy, a cardiac aneurysm, brain abscess, and kidney and liver infarct. Immunohistochemistry staining confirmed the presence of leptospires in the various tissues. This is the first tissue-proven case of infective endocarditis caused by leptospire species.
*Buddhist Tzu Chi General Hospital, Central Offices, Taiwan, Republic of China; †Department of Medicine, Miriam Hospital, Providence, RI and ‡Buddhist Tzu Chi University, Taiwan, Republic of China.
Address correspondence and reprint requests to Chia-ching Jackie Wang, MD, Department of Medicine, Miriam Hospital, 164 Summit Ave, Providence, RI 02906. E-mail: firstname.lastname@example.org.
Patient is a 42-year-old Chinese man whose past was only significant for a fall to the ground from a ladder 4 months previously. One month later, he was first hospitalized with a 3-day history of fever, sudden-onset right-sided weakness, and altered mental status. He demonstrated no improvement for 3 weeks. After he was discharged, he again presented with progressive weakness for 1 week. His social history was notable because he worked in an open market near chickens, and he also kept a common hill myna as a pet. Upon admission, physical examination was only remarkable for right-sided weakness.
Blood cultures from the first admission grew methicillin-resistant Staphylococcus aureus. He was treated with vancomycin and ceftazidime and subsequently discharged. During the second admission, white blood cell count was 20,000/μL with a left shift. Serology for Leptospira was negative. However, dark-field examination of the urine demonstrated presence of spirochetes. A partial 16s Leptospira DNA (Fig. 1) was detected in urine by nested polymerase chain reaction (PCR), which was performed to detect 16S ribosomal DNA gene of Leptospira species. The corresponding oligonucleotide primers were based on the previous descriptions.1 To determine the specificity of the oligonucleotide primers for Leptospira species, a number of pathogenic organisms and 6 reference strains of Leptospira were tested using these primers for PCR. Each reference strains of Leptospira species produced a positive signal (a 290-base pair [bp] band in agarose gel electrophoresis). The sequence alignment of amplified fragment revealed the presence of Leptospira interrogans.
Computed tomography (CT) and magnetic resonance imaging of the brain revealed a 26 × 20-mm ring-enhanced lesion in the left parietal lobe. Chest film showed a soft lesion at the left lower medial lung field. Computed tomography of the lumbar spine showed no lesions. However, chest CT showed a large left ventricular apical aneurysm (Fig. 2). Magnetic resonance imaging of the heart also confirmed a left ventricular aneurysm. Transesophageal echocardiography did not visualize vegetations but detected severe mitral regurgitation. Lower sectional images of the abdomen CT revealed a liver infarct and a right kidney infarct.
Cardiac surgery was performed to remove the ventricular aneurysm and mitral valve. Warthin-Starry stain and immunohistochemistry stain of the aneurysm and valve confirmed the presence of Leptospira spirochetes (Figs. 3, 4). The Leptospira spirochetes were further demonstrated in needle-biopsy specimens of liver (Fig. 5), kidney and the excised brain tissue (Fig. 6). His urine was still positive for L. interrogans by nested PCR after a 90-day course of intravenous crystalline penicillin G, followed by a 9-month oral penicillin V therapy. His serological tests for Leptospira-immunoglobulin M became weakly positive. The patient was then treated with a combination therapy of oral rifampin and penicillin V for a synergistic effect for a total of 18 months. Finally, his Leptospira-immunoglobulin M was shown to be negative.
Leptospirosis is a zoonotic disease that is maintained by the persistent colonization of spirochetes in the proximal renal tubules of the carrier animal. Most epidemiological studies demonstrated evidence of leptospirosis in both wildlife and domesticated animals, including cattle, sheep, goats, rats, and dogs.2-5 A minority of articles has also found leptospirosis in chickens and birds.6,7 Historically, certain occupational exposures, such as sewer maintenance, livestock farming, butchering, rice farming, and other agricultural activities, have been shown to be particularly important.8 However, recent outbreaks in recreational-adventure events,9 seasonal floods,10 and conditions of slum living11 made leptospirosis a zoonotic disease of global importance.
The protean manifestation of leptospirosis can mimic the clinical presentation of many other diseases. In comparison with elevation of cardiac enzymes and electrocardiographic alterations regarding the cardiac involvement in Weil syndrome, there are few published cases in medical literature available to demonstrate its association with infective endocarditis.
We present a case of leptospirosis presenting as left ventricular aneurysm and valve endothelium involvement to demonstrate the clinical pleomorphism of this disease. This case is valuable for demonstration of spirochetes in surgical specimens of the excised aneurysm, mitral valve, and brain tissue and in needle-biopsied specimens of liver and kidney. It suggests direct invasion of both cardiac tissue and endothelium as a possible pathogenesis, and coinfection with S. aurues bacteremia is a possibility.
Leptospirosis could present as a chronic disease, and S. aureus bacteremia might be related to leptospirosis. We hypothesize that a recent blunt force trauma might be a triggering event for clinical leptospirosis, and we have been confirming our suspicion in other cases that we see. Literature search showed no previous reported cases of tissue-proven infective endocarditis caused by Leptospira species.12,13 We recommend considering Leptospira as a possible etiologic agent in patients with appropriate evaluation of exposure history and triggering event.
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