Yellow Fever

#med #disease #y2023

Presentation :

Incubation lasts 3-6 days followed by sudden onset fever/chills (39-40° C) , headache, dizziness, myalgias, facial flushing, conjunctival injection, nausea/vomiting, constipation, severe prostration, restlessness, and irritability.
- The pulse is usually rapid initially but, by the 2nd day, becomes slow for the degree of fever (Faget sign).
Mild disease may resolve after 1 to 3 days.
However, in moderate or severe cases, the fever falls suddenly 2 to 5 days after onset, and a remission of several hours or days ensues. The fever recurs, but the pulse remains slow. Jaundice, extreme albuminuria, and epigastric tenderness with hematemesis often occur together after 5 days of illness. There may be oliguria, petechiae, mucosal hemorrhages, confusion, and apathy.
In the most severe form (called malignant yellow fever), delirium, intractable hiccups, seizures, coma, and multiple organ failure may occur terminally.
During recovery, bacterial superinfections, particularly pneumonia, can occur.

Caused by a flavivirus transmitted by mosquito bites
- Aedes aegypti primarily in urban yellow fever
- Haemagogus and Sabethes genus forest canopy mosquitoes that acquire the virus from wild primates in jungle (sylvatic) yellow

Supportive care
- Bleeding may be treated with vitamin K.
- An H2 blocker or PPI and sucralfate can be helpful as prophylaxis for GI bleeding and can be used in all patients ill enough to require hospitalization.
Suspected or confirmed cases must be quarantined.
Vaccination with the approved, live-attenuated yellow fever vaccine is recommended for travelers to endemic areas of Africa and South America.