Typhoid fever is a bacterial illness caused by Salmonella typhi, a gram-negative rod found only in humans. It is characterized by persistent fever, abdominal pain, severe anorexia, mild diarrhea, and delirium. Most cases in the US are acquired abroad and involve children, adolescents, and young adults.
Ocular manifestations are rare in typhoid fever.
Following ingestion of an infectious dose of at least 10,000 bacteria, mucosal penetration occurs in the distal ileum resulting in a transient asymptomatic bacteremia. The organisms survive and multiply within mononuclear phagocytes located in lymph nodes, spleen, liver, and bone marrow. The clinical phase of the disease begins within 1-3 weeks when persistent bacteremia results. Hematogenous spread to ileal Peyer patches and the gall bladder reintroduces bacteria to the gut lumen and stool cultures again become positive, allowing continued fecal-oral spread of the disease. Mucosal ulceration overlying hyperplastic Peyer patches in the ileocecal region may result in pain, diarrhea, bleeding, and occasional perforation.