Year : 2009 | Volume
: 20 | Issue : 6 | Page : 1047--1052
Acute renal failure associated with the rift valley fever: A single center study
Mohamed El Imam, Mohamed El Sabiq, Mustafa Omran, Abdulla Abdalkareem, Muhamadani A El Gaili Mohamed, Ahmed Elbashir, Osman Khalafala
Faculty of Medicine, Gezira University, Medani Teaching Hospital, Gezira Hospital for Renal Diseases and Surgery, Gezira, Sudan
Mohamed El Imam
Urologist, and Transplant Surgeon, Faculty of Medicine, University of Gezira, P.O. Box 20, Gezira
Renal impairment is a frequent occurrence among patients with the rift valley fever (RVF), and is probably the result of hypovolemia and multiple organ dysfunctions in the majority of cases. This study was conducted to estimate the incidence of renal impairment in patients with RVF as well as to determine the associated mortality. Data of all patients admitted with renal impairment to the Gezira Hospital for Renal Diseases, Sudan, during the epidemic of RVF between September 2007 and January 2008 were analyzed. The total number of patients with RVF was 392 of whom, 194 were admitted to the Medani Teaching Hospital. Renal impairment was detected in 60% of the admitted patients; 90% of them needed dialysis treatment. The mortality rate was 31% in patients with acute renal failure, 25% in those with the hepatorenal syndrome and 31% in patients with primary hepatic involvement and mild renal impairment. The overall mortality was 40%. Our study suggests that RVF remains a major cause of acute renal failure with considerable mortality, although progression to chronic renal failure was not seen. Early renal substitution therapy fosters the best hope for survival
|How to cite this article:|
El Imam M, El Sabiq M, Omran M, Abdalkareem A, El Gaili Mohamed MA, Elbashir A, Khalafala O. Acute renal failure associated with the rift valley fever: A single center study.Saudi J Kidney Dis Transpl 2009;20:1047-1052
|How to cite this URL:|
El Imam M, El Sabiq M, Omran M, Abdalkareem A, El Gaili Mohamed MA, Elbashir A, Khalafala O. Acute renal failure associated with the rift valley fever: A single center study. Saudi J Kidney Dis Transpl [serial online] 2009 [cited 2020 Jul 11 ];20:1047-1052
Available from: http://www.sjkdt.org/text.asp?2009/20/6/1047/57261
Hemorrhagic fever viruses are a diverse group of viruses that cause a clinical disease associated with fever and bleeding disorders, classically referred to as viral hemorrhagic fevers. The many viruses that are associated with this illness belong to one of the four families: Filoviridae, Arenaviridae, Bunyaviridae and Flaviviridae. 
Rift Valley Fever (RVF) is an arboviral disease produced by a bunya virus belonging to the genus phlebovirus. Several species of Aedes and Culex are the vectors of this virus that affect sheep, goats, buffalos, cattle, camel and human beings. 
It may be encountered as an uncomplicated influenza-like illness, but may also present as a hemorrhagic disease with liver involvement. There may be ocular and/or neurological lesions as well. 
The high activity of the RVF virus is related to a tremendous increase in the mosquito population, which follows periods of heavy rainfall. Indeed, rainfall creates an ecologically humid environment that favors the proliferation of breeding sites and the development of RVF vectors. 
The virus is transmitted transovarially or it may remain dormant in mosquito eggs during dry inter-pizootic periods. Animal involvement is characterized by abortion in pregnant animals and high mortality in newborn lambs, kids and calves. Human beings experience the virus as influenza-like illness and/more rarely, complications such as encephalitis or retinitis may cause severe hepatitis and jaundice. 
Virus transmission to man also occurs by contamination when handling infected meat or by inhaling natural virus aerosol; wild rodents apparently do not serve as RVF reservoirs, while domestic animals act as amplifying hosts. 
Renal impairment is a frequent occurrence among patients with RVF, and it appears to be the result of hypovolemia and multiple organ dysfunctions in the majority of patients. The renal failure may be attributed to a direct virusrelated injury in a proportion of the patients as suggested by immunofluorescence studies in the glomeruli of affected patients. ,,,10] Human cases of RVF continue to occur in Sudan and till end of November 2007, 436 human RVF cases including more than 161 deaths were reported from Gezira, Sennar and the White Nile States. Of them, the largest number of human cases has been reported from the Gezira State (271 cases). 
This study was performed to estimate the incidence of renal impairment, the demographics and modes of presentation as well as to determine the mortality rate related to renal impairment in patients with RVF.
Patients and Methods
This study was conducted in the Gezira Hospital for Renal Diseases and Surgery and the Medani Teaching Hospital, Gezira, Sudan. From the beginning of September of the year 2007, the Gezira state in Sudan was greatly affected by an epidemic of RVF as declared by the WHO authorities.  All districts of the state were involved and a total of 392 patients were seen of whom, 194 patients were admitted in the Medani Hospital. The health authorities utilized all their resources in a collaborative and co-ordinated manner in order to implement preventive and supportive measures.
For purpose of treatment of suspected cases, an isolation ward was allocated within the vicinity of the general hospital with separate dedicated staff, who were appropriately trained. A special ministerial committee supervised the whole process.
Suspected cases were admitted to the hospital and diagnosis was based not only on circumstantial evidence, but also on laboratory evidence. Physicians, pathologists and a representative from the epidemic control unit were in charge and actively shouldered the responsibility in managing these patients. Nephrologists were also included in the team.
Renal failure was diagnosed on the basis of clinical and laboratory findings. Treatment of renal failure was either conservative or with peritoneal dialysis, when felt necessary. Peritoneal dialysis was performed with 60 to 200 exchanges through soft catheters with antibiotics routinely administered as prophylaxis. Serial evaluation of renal function tests was done to assess the progress of the patient. Precautions while taking blood samples, nursing and drug delivery were ensured for all the working staff. Insecticide coated nets were provided for all patient beds.
In patients with hepatic and renal insufficiency, we adopted the standard measures of strict conservative treatment for hepatic encephalopathy with cautious intensive care and monitoring of electrolyte balance.
Hematological indices were estimated at admission for all patients and repeated when necessary. The tests were performed at a reliable laboratory under the direct supervision of a consultant hematologist.
Supportive treatment in the form of transfusion of blood and/or blood products was administered when required. Competent good nursing care and protective measures were instituted efficiently. Patients with ocular or other manifestations were referred to, and managed by the relevant team.
Data, which was already saved and analyzed, was then retrieved from this working group and incorporated within the pool.
The epidemic of RVF started in September 2007 ended by January 2008. The total number of patients with RVF reported from the entire state of Gezira was 392 of whom, 194 were admitted to the Medani teaching hospital. The mean age of the study patients was 34 years; there were no patients under 15 years of age. Male to female ratio was approximately 3 : 1. All districts were involved. Renal impairment was detected in 60% of the admitted patients; 90% of them were dialyzed.
The leading symptoms in our series were fever, bleeding diathesis and jaundice [Table 1],[Figure 1]. Patients were categorized into four major groups: hemorrhagic, renal, hepatorenal or hepatic. Ocular manifestations, if present, were referred to the ophthalmology hospital for further management.
Frank isolated renal impairment was found in 85/157 patients, combined hepatic and renal impairment was seen in 27/157 patients and 45/157 patients presented with hepatic impairment and minor renal problems. Patients with renal impairment generally had bleeding diathesis, although in certain cases, the only presentation was oliguria, pedal and/or pulmonary edema.
All patients with renal failure were subjected to the standard management of acute renal failure. Therapy with peritoneal dialysis was delivered when there were biochemical or symptomatic indications using soft catheters and 60200 cycles. Strict follow-up with serial investigations and clinical evaluation was instituted in all patients. The mean blood urea levels among the study patients were as follows: In 3% it was between 20-50 mg/dL, in 22% between 51-100 mg/dL, in 20% between 100-200 mg/dL and in 9%, it was more than 200 mg/ dL. The serum creatinine levels ranged between 3 mg/dL and 21 mg/dL.
Patients with hemorrhagic manifestations received fresh frozen plasma and/or fresh blood, as and when required. No antiviral drugs were administered. Antibiotics were administered to all patients as prophylaxis against peritonitis. Progression to chronic renal failure did not occur in any patient. Out of the 112 patients who underwent dialysis, 34 died (30.3%) which included 23 males and 11 females [Table 2]. Eighteen of the 45 patients with hepatic disease died. Death in these patients occurred on the first or second day of admission.
The mortality was 31% in patients with acute renal failure, 25% in those with hepatorenal disease and 31% in patients with hepatic disease associated with minor renal impairment. The overall mortality among all patients with RVF during the epidemic was 40%.
The epidemic started to decay in the beginning of January 2008 due to the stringent measures taken by the concerned team [Figure 2].
State of the epidemic and patient criteria
In the last three months of 2007, an acute episode of an ill-defined severe febrile illness presented to the Medani Teaching Hospital with severe hemorrhagic manifestations. This initially did not attract any extra attention and early cases were thought to be from the state of White Nile, where there were similar cases. Soon, the number of patients increased dramatically and the whole case was addressed and assigned officially as an epidemic. The suspicion of RVF arose and the patients were recorded accordingly [Figure 2]. Rift Valley Fever is usually found in regions of eastern and southern Africa, but the virus also exists in most countries of sub-Saharan Africa and in Madagascar.
It is a zoonosis that mainly affects domestic animals such as cattle, buffalo, sheep, goats, camels and occasionally humans.  The bunya viruses are transmitted by mosquitoes usually of the genus Aedes. Humans also can get the disease after handling blood or body fluids of infected animals. Aerosol spread of the infection has been reported in laboratory workers when working with virus cultures or laboratory samples containing viruses. 
Usually, RVF is mild and associated with fever and abnormal liver indices, but in its severe form, hemorrhage, encephalitis and retinitis may occur. , All the hemorrhagic fever viruses induce a similar syndrome. The incubation period varies from one to 21 days. The disease can progress to respiratory problems, severe bleeding, kidney failure and shock. All hemorrhagic fevers can induce micro-vascular damage and capillary leak syndrome. 
The total number of patients reported in the Gezira state was around 392 of whom, 194 were admitted to our hospital. Of these 194 patients, 157 were referred for management of renal problems. Of them, 62 were females and 95 were males. This ratio could be explained by the male members being involved in risky jobs like herding and butchery.
The age-range in these groups was between 15 and 65 years with a mean of 34 years. This revealed that those in the active years of life were the commonest to be affected. However, no age was immune although those who were in tangible contact with animals were at higher risk.
Proposed mode of transmission
A proper history with strict attention to the activity of patients in the previous months was conducted with special consideration to their jobs. This helped in identifying the most likely mode of transmission including animal contact in 75 patients, animal product in 38, mosquito bite in 18, while the mode of transmission was uncertain in 26 patients. However, this proposal could seriously be questioned by the fact that mosquitoes are present in large numbers in all residences of the region.
It was also obvious that the majorities of patients was either from rural areas or were nomadic villagers. Larger towns were less involved in this epidemic.
It is known that the virus is transmitted to humans through mosquito bites or by exposure to blood and body fluids. Additionally, drinking raw un-pasteurized milk from infected animals can also transmit RVF. Routine vaccination of livestock in Africa is not undertaken because it is prohibitively expensive, thus leading to endemicity of the virus in most of the African countries. ,
The Ministry of Health and the WHO declared the diagnosis of RVF by the end of September 2007. It is known that hemorrhagic fevers should be suspected in any patient presenting with severe illness and evidence of hemorrhagic tendency, especially if he/she has travelled to, or resided in an area where the virus is endemic. 
When the epidemic was established, clinical awareness was optimized to the zenith. Any patient who presented with obscure febrile condition, severe prostration and flu-like symptoms was a subject for strict evaluation. Frank severe cases with bleeding and jaundice or oliguria were the leading caveat for picking patients. 
Rift Valley Fever should be considered as a cause of acute renal failure in endemic countries. However, progression to chronic renal failure has not been reported. Early renal substitution therapy fosters the best hope for survival. Hepatic impairment puts an added impact on the morbidity of patients with RVF. Collaborative medical services provide the best method for controlling the epidemic.
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