The bacterium releases the endotoxin, hemolysin and lipase increases the toxic nature of the leptospire bacterium. The following manifestations such as vasculitis of capillaries manifested by endothelial edema, necrosis, lymphocytic infiltration. In the kidenys lepstospires migrate to the interstitium, renal tubules, amd tubular lumen causing the interstitial nephritis and tubular necrosis.
Renal failure occurs due to the renal damage and hypovolemia might occurs due to the dehydration.
Liver involvement is marked by centrilobular necrosis and Kupffer cell proliferation. Jaundice may occur as a result of hepatocellular dysfunction.
Pulmonary involvement is secondary to alveolar and interstitial vascular damage resulting in hemorrhage. This complication is considered to be the major cause of leptospirosis-associated death.
Interstitial myocarditis occurs as the cardiologic features.
Hemorrhage, focal necrosis, and inflammatory infiltration have been documented within the adrenal gland. Although these complications do not appear clinically, some researchers speculate that adrenal insufficiency may mediate, in part, the final vascular collapse associated with fatal leptospirosis. In acute infections the organisms persists in the host immune cells till the development of opsonizing immunoglobulin in the plasma followed by rapid immune clearance.
Presence of leptospirosis in the eye leads to chronic or recurrent uveitis.
The infection might progress to severe systemic inflammatory syndrome with hemorrhagic features. The disseminated intravascular coagulation may occur with the bleeding.
Alterations in the onset of the mental status leads to the involvement of the cerebral cortex with meningo encephalitis.
Severe and diffuse alveolar hemorrhage with massive hemoptysis can occur in the absence of typical weil disease.
Myocarditis can occur, elevated jugular venous pressure .
Severe and diffuse alveolar hemorrhage with massive hemoptysis can occur in the absence of typical Weil disease.
Cholecystitis and pancreatitis occurs.
Uveitis, iridocyclitis, and chorioretinitis may occur late into illness and may persist for years.