Rift valley fever natural history, complications and prognosis
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Aakash Hans, MD[2]
Overview
Rift valley fever is a self-limiting illness in majority of patients. The symptoms appear around 2-3 days after exposure. The main symptoms are fever and body aches. Fever usually subsides by 3-4 days after the beginning of symptoms. Complications can arise if the fever recurs again after remission and the patient continues to be febrile. Neurological, ophthalmological and hemorrhagic features are the commonly seen complications. Prognosis is good for most of the patients who only have the febrile illness which subsides on its own. The patients who suffer from complications usually recover at a slower pace out of which some succumb to the complications.
Natural History, Complications and Prognosis
Rift Valley fever (RVF) is caused by a virus belonging to the Bunyaviridae family and Phlebovirus genus, known as Rift Valley fever virus (RVFV). Majority of humans experience fever which subsides on its own, while a few go on to develop neurological symptoms, clot formation, hemorrhage or vision abnormalities.
- Natural History
- Febrile Illness :
- The patient does not develop symptoms until 4 to 5 days after exposure.
- Symptoms of fever develop all of a sudden and include generalized weakness, feeling cold, headaches, nausea and a feeling of heaviness in the righty upper abdomen.[1]
- Next, the patient develops high body temperatures 101.8 to 103.1 F along with body aches, sensitivity to light and low blood pressure. [2]
- Various other manifestations like vomiting accompanied with abdominal pain, loss of sense of taste, nosebleeds and loose stools may also be seen in some individuals.[3]
- After three to four days since the onset of illness, symptoms begin to subside and body temperatures drop back to normal.
- Some individuals may experience repeat episodes of fever and headache one to three days following recovery.[4]
- Once the body temperature becomes normal some patients develop clots in their coronary vessels or have severe pain in the abdomen or lower limbs.
- The virus is detected in the blood until third day of illness while antibodies begin to appear in the blood from the fourth day onward.[5]
- Febrile Illness :
- Complications
- Neurological manifestations :
- Cases of encephalitis following infection with RVFV have been described in the literature. [6] [7]
- Signs and symptoms included increased leukocytes and decreased levels of antibodies in the cerebrospinal fluid, retinal changes, confusion and gait disturbances.
- Paralysis of body like hemiparesis has also been reported in RVF cases. [8]
- Brain lesions due to RVF present with features of coma, increased salivation, irregular flailing movements of the upper limbs and hallucinations. [9]
- Hemorrhage :
- Cases with hemorrhage due to RVF can be fatal, with variable times reported till the occurrence of death.
- The patient develops febrile symptoms suddenly along with rashes and ecchymotic patches all over the body, bleeding from the gastrointestinal tract and gums, jaundice along with decreased blood pressure. [10]
- These patients have increased hepatic enzymes and raised levels of lactate dehydrogenase(LDH) along with decreased hemoglobin and platelet count.
- Postmortem examination shows focal involvement of liver cells pointing towards injury to hepatocytes during the illness.
- Individuals who show no signs of jaundice or any bleeding, often have kidney failure or develop disseminated intravascular coagulation (DIC), which can become fatal.[11]
- Clot formation:
- A case was reported which developed several clots after being infected with RVFV. [12]
- After the patient’s fever subsided, he developed patches on his lower limbs around the fifth day of illness.
- This was followed by inflammatory changes in the patient’s popliteal vein by the twelfth day followed by formation of pulmonary infarcts at various locations from twentieth day onwards.
- The patient developed a pulmonary embolus on the 45th day of illness which proved to be fatal.
- No liver involvement was observed during postmortem examination.
- Ophthalmological manifestations :
- Individuals can present with symptoms at variable intervals after the disease onset.
- Loss of peripheral vision or blurred vision is commonly reported after infection.
- Unilateral or bilateral eyes may be involved with features of edema in the macula, retinal bleeding or loss of transparency in the vitreous.[13]
- Majority of cases do not regain complete eye function, even after the viral infections subsides.[14]
- Neurological manifestations :
- Prognosis
- Majority of individuals develop a mild to moderate course of fever and body aches, from which they recover spontaneously.
- Complications are seen rarely with ocular problems occurring in about 1 to 2% cases, while encephalitis and hemorrhage developing in approximately 1% cases or less. [15]
- Hemorrhagic fever is associated with a high fatality rate of 50%, while the fatalities reported overall are only around 1% of total cases.
- Only 1 to 10% of cases with ocular manifestations continue to have lifelong, irreversible impairment of vision.
References
- ↑ Findlay GM, Daubney R. The virus of rift valley fever or enzootic hepatitis. Lancet. 1931;221:1350–1351
- ↑ Kitchen SF. Laboratory infections with the virus of rift valley fever. Am J Trop Med. 1934;14:547–564
- ↑ Mundel B, Gear J. Rift valley fever; i. The occurrence of human cases in johannesburg. S Afr Med J. 1951;25:797–800.
- ↑ Rift Valley fever; accidental infections among laboratory workers.SMITHBURN KC, MAHAFFY AF J Immunol. 1949 Jun; 62(2):213-27.
- ↑ Rift Valley fever; accidental infections among laboratory workers.SMITHBURN KC, MAHAFFY AF J Immunol. 1949 Jun; 62(2):213-27.
- ↑ Maar SA, Swanepoel R, Gelfand M. Rift valley fever encephalitis. A description of a case. Cent Afr J Med. 1979;25:8–11.
- ↑ Alrajhi AA, Al-Semari A, Al-Watban J. Rift valley fever encephalitis. Emerg Infect Dis. 2004;10:554–555
- ↑ Laughlin LW, Girgis NI, Meegan JM, Strausbaugh LJ, Yassin MW, Watten RH. Clinical studies on rift valley fever. Part 2: Ophthalmologic and central nervous system complications. J Egypt Publ Health Assoc. 1978;53:183–184
- ↑ van Velden DJ, Meyer JD, Olivier J, Gear JH, McIntosh B. Rift valley fever affecting humans in south africa: A clinicopathological study. S Afr Med J. 1977;51:867–871.
- ↑ Yassin W. Clinico-pathological picture in five human cases died with rift valley fever. J Egypt Publ Health Assoc. 1978;53:191–193.
- ↑ Al-Khuwaitir TS, Al-Moghairi AM, Sherbeeni SM, Al-Ghamdi AS. Rift valley fever hepatitis complicated by disseminated intravascular coagulation and hepatorenal syndrome. Saudi Med J. 2004;25:528–531
- ↑ Schwentker FF, Rivers TM. Report of a fatal laboratory infection complicated by thrombophlebitis. J Exp Med. 1933;59:305–313
- ↑ Siam AL, Meegan JM, Gharbawi KF. Rift valley fever ocular manifestations: Observations during the 1977 epidemic in egypt. Br J Ophthalmol. 1980;64:366–374
- ↑ Ayoub M, Barhoma G, Zaghlol I. Ocular manifestations of rift valley fever. Bull Ophthalmol Soc Egypt. 1978;71:125–133.
- ↑ https://www.nj.gov/agriculture/divisions/ah/diseases/riftvalley.html