Liver dysfunction increases cholesterol content of the red blood cell membranes, resulting in red blood cell fragility. This leads to hemolysis, anemia, and hemoglobinuria and bilirubinemia. Death can occur within 24-48 hours. Occasionally, adult worms may go to sites other than the large veins and heart, and cause ectopic infection. If they go to the eye an individual may show conjunctival discharge, photophobia, or keratitis.
Treatment is by surgical removal of the worm.
If the worms migrate to the central nervous system, they are usually found in the arteries in the brain or the lateral ventricles. Signs vary, but may include convulsions, blindness, ataxia, excess salivation, prostration, and coma. Treatment is by surgical removal. Systemic arteries may also be involved in heartworm infection. The rear legs are most commonly affected.