Lassa fever natural history, complications and prognosis: Difference between revisions
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==Prognosis== | ==Prognosis== | ||
* Prognosis of | * Approximately 15%-20% of patients hospitalized for Lassa fever die from the [[illness]]. However, only 1% of all Lassa virus infections result in death. Prognosis of Lassa fever is poor if its associated with following features<ref name=CDC>{{cite web | title = The Centers for Disease Control and Prevention | url =http://www.cdc.gov/NCIDOD/dvrd/spb/mnpages/lassaslides.htm }}</ref>. | ||
:* Increased [[viremia]]. | :* Increased [[viremia]]. | ||
:* Serum [[AST]] level > 150 IU/L | :* Serum [[AST]] level > 150 IU/L | ||
Revision as of 11:30, 9 June 2015
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [2]; Associate Editor(s)-in-Chief: Ammu Susheela, M.D. [3]
Synonyms and keywords: Lassa hemorrhagic fever; LHF
Overview
Signs and symptoms of Lassa fever typically occur 1-3 weeks after the patient comes into contact with the virus. The most common complication of Lassa fever is deafness. Various degrees of deafness occur in approximately one-third of cases, and in many cases hearing loss is permanent. Spontaneous abortion is another serious complication. Approximately 15%-20% of patients hospitalized for Lassa fever die from the illness. However, overall only about 1% of infections with Lassa virus result in death. The death rates are particularly high for women (greater than 80%) in the third trimester of pregnancy, and for fetuses, about 95% of which die in the uterus of infected pregnant mothers.
Natural History
- Signs and symptoms of Lassa fever typically occur 1-3 weeks after the patient comes into contact with the virus. For the majority of Lassa fever virus infections (approximately 80%), symptoms are mild and are undiagnosed[1].
- Mild symptoms include slight fever, general malaise and weakness, and headache. In 20% of infected individuals, however, disease may progress to more serious symptoms including hemorrhaging (in gums, eyes, or nose, as examples), respiratory distress, repeated vomiting, facial swelling, pain in the chest, back, and abdomen, and shock.
- Neurological problems have also been described, including hearing loss, tremors, and encephalitis. Death may occur within two weeks after symptom onset due to multi-organ failure.
- Clinical stages of Lassa fever (adapted from McCarthy)[2]
| Stage | Symptoms | Days |
| Stage 1 | High fever of 39°C with peaks of 40°C-41°C, malaise, weakness | Day1 -day 3 |
| Stage 2 | Headache, backache, chest pain, exudative sore throat with white patches, abdominal pain, diarrhea, nausea, vomiting, low blood pressure, anemia, proteinuria, conjunctivitis | Day4 -day 7 |
| Stage 3 | Mucosal bleeding, internal bleeding, facial edema, confusion, disorientation and convulsion | >7 days |
| Stage 4 | Coma, death | >14 days |
Complications
- Complications of Lassa fever include the following.
Sensorineural Deafness
- The most common complication of Lassa fever is deafness.
- Occurs in 1/3rd of the cases.
- Various degrees of deafness occur in approximately one-third of infections, and in many cases hearing loss is permanent.
- As far as is known, severity of the disease does not affect this complication: deafness may develop in mild as well as in severe cases.
- It could be unilateral or bilateral.
Lassa Fever in Pregnancy
- Increased mortality in 3rd trimester of more than 30% to the mother.
- Increased viremia in pregnant woman.
- Evacuation of the uterus improves mother's chance of survival.
- Placental infection of the fetus.
- Spontaneous abortion is a serious complication of infection with an estimated 95% mortality in fetuses of infected pregnant mothers.
- Increased fetal and neonatal mortality of more than 85%.
Lassa Fever in Children
Swollen Baby Syndrome
- Edema.
- Abdominal distention.
- Bleeding.
- Poor prognosis.
Prognosis
- Approximately 15%-20% of patients hospitalized for Lassa fever die from the illness. However, only 1% of all Lassa virus infections result in death. Prognosis of Lassa fever is poor if its associated with following features[1].
- Increased viremia.
- Serum AST level > 150 IU/L
- Bleeding.
- Encephalitis.
- Edema
- Third trimester of pregnancy.
References
- ↑ 1.0 1.1 "The Centers for Disease Control and Prevention".
- ↑ McCarthy M (2002). "USA moves quickly to push biodefence research". Lancet. 360 (9335): 732. doi:10.1016/S0140-6736(02)09938-5. PMID 12296302.