Leptospirosis Clinical Manifestations, Diagnosis, Treatment and Prevention
Leptospirosis is a globally important zoonotic disease caused by spirochetes of the genus Leptospira Weils disease: a severe leptospirosis characterized by: fever, jaundice, acute renal injury, refractory shock, and hemorrhage (especially pulmonary hemorrhage). The global burden of leptospirosis is hard to quantify because of the difficulties encountered in its clinical diagnosis and the lack of efficient confirmatory laboratory testing, which limits public health reporting.
leptospirosis a zoonotic disease Human-to-human transmission does not occur sources of transmission to humans: rats, dogs, cattle, and pigs. Transmission:1. indirect contact with contaminated animal urine through surface waters, moist soil, or other wet environments2. direct contact with urine and other excreta (e.g., products of parturition, placenta) of infected animals
Pathogenesis • infects the mucosa (conjunctival, oral or tonsillar) or through macerated, punctured, or abraded skin • resist innate immune defenses • Proliferate to bloodstream or extracellularly within organs
Etiologic Agent Leptospires are difficult to culture from blood, urine, and (CSF), although certain species and serovars (e.g., L. interrogans serovar Copenhageni) are grown more easily than others. Rat-associated L. interrogans serovars Icterohaemorrhagiae and Copenhageni are mostly commonly associated with Weils disease Incubation period: average: 5–14 days range: 2–30 days
Physical examination conjunctival suffusion (dilated conjunctival blood vessels in the absence of discharge) pharyngeal erythema without exudate muscle tenderness rales on lung auscultation or dullness on chest percussion over areas of pleural hemorrhage rash (macular, maculopapular, erythematous, petechial, or ecchymotic) Jaundice Meningismus hypo- or areflexia, particularly in the legs.
Phases of LeptospirosisA. Mild uncomplicated leptospirosis usually ends in spontaneous resolution within 7–10 days without sequelaeB. Immune phase:1. return of fever, headache, other systemic symptoms after 3–10 days associated with clearance of leptospires from the blood and the appearance of antibodies2. this phase does not respond to antibiotic therapy
C. Weils disease:1. characterized by variable combinations of jaundice, acute kidney injury, hypotension, and hemorrhage—most commonly the lungs2. also affects the git, retroperitoneum, pericardium, and brain
Diagnosis has been immersed in or has had mucosal or percutaneous exposure to contaminated animal urine Hematologic abnormalities are variable but common: leukocytosis (typical in severe disease), leukopenia, hemolytic anemia, mild to moderate anemia, and thrombocytopenia. Classic Weils disease: suggested by elevated BUN and serum creatinine with mixed conjugated and unconjugated hyperbilirubinemia with SGPT elevation to less than five times the upper limit of normal
Definitive DX: presence of the organism by culture isolation, detection of nucleic acids or antigen in body fluids, or immunohistochemical visualization in tissue Leptospiral cultures do not become positive for weeks and therefore cannot guide clinical care. PCR–based assays have been used in research laboratories to detect leptospiral DNA
Gold standard: microscopic agglutination test (MAT)—performed only at the CDC Leptospires can be cultured from blood and CSF during the first 7–10 days of illness and urine beginning in the 2nd week Urine cultures can remain positive for months or years despite antibiotic therapy
Prognosis Severity of illness: pulmonary and renal dysfunction is the most important determinant of prognosis Advanced age, pulmonary involvement, elevated serum creatinine, oliguria, and thrombocytopenia are associated with a poor prognosis
Prevention No vaccine is available for human leptospirosis Prophylaxis: Doxycycline - variably effective in different settings Anticipated short-term, well-defined exposures (military training or specific adventure travel)-can be considered Long-term antibiotic prophylaxis has not been shown to be effective in preventing infection in high-transmission endemic settings
General sanitation approaches and avoidance of swimming in potentially contaminated places are recommended…. Salamat…..