Hepatitis A: A viral disease with a short incubation period (usually 15–50 days), caused by hepatitis A virus, a member of the family Picornaviridae, often transmitted by fecal-oral route; may be inapparent, mild, severe, or occasionally fatal and occurs sporadically or in epidemics, commonly in school-age children and young adults; necrosis of periportal liver cells with lymphocytic and plasma cell infiltration is characteristic, and jaundice is a common symptom.1

Hepatitis B: A viral disease with a long incubation period (usually 50–160 days), caused by a hepatitis B virus, a DNA virus and member of the family Hepadnaviridae, usually transmitted by injection of infected blood or blood derivatives or by use of contaminated needles, lancets, or other instruments or by sexual transmission; clinically and pathologically similar to viral hepatitis type A, but there is no cross-protective immunity; HBsAg is found in the serum and the hepatitis delta virus occurs in some patients. May lead to acute or chronic liver disease.1

Herpes zoster: An infection caused by a herpesvirus (varicella zoster virus), characterized by an eruption of groups of vesicles on one side of the body following the course of a nerve due to inflammation of ganglia and dorsal nerve roots resulting from activation of the virus, which in many instances has remained latent for years following a primary chickenpox infection; the condition is self-limited but may be accompanied by or followed by severe postherpetic pain. Also known as the shingles.1

Human papillomavirus (HPV): An icosahedral DNA virus, 55 nm in diameter, of the genus Papillomavirus, family Papovaviridae; certain types cause cutaneous and genital warts; other types are associated with severe cervical intraepithelial neoplasia and anogenital and laryngeal carcinomas.1

Hypercoagulable states: Characterized by abnormally increased coagulation.1

Immune thrombocytopenic purpura (ITP): A systemic illness characterized by extensive ecchymoses and hemorrhages from mucous membranes and very low platelet counts; resulting from platelet destruction by macrophages due to an antiplatelet factor; childhood cases are usually brief and rarely present with intracranial hemorrhages, but adult cases are often recurrent and have a higher incidence of grave bleeding, especially intracranial. Also known as idiopathic thrombocytopenic purpura.1

Infantile spasms: An epileptic disorder characterized by flexion spasms of the neck, trunk, and limbs and psychomotor retardation.7



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