Approach
The mainstay of treatment is early recognition of infection coupled with effective isolation, early initiation of the antiviral drug ribavirin, and best available supportive care in a hospital setting.[Figure caption and citation for the preceding image starts]: Managing suspected Lassa feverAdapted from Houlihan C, Behrens R. Lassa fever. BMJ. 2017;358:j2986 [Citation ends].
Isolation and infection control
Symptomatic patients or those with suspected infection should be isolated in a hospital setting, and all healthcare workers in contact with the patient should wear personal protective equipment (PPE).
The World Health Organization (WHO), Centers for Disease Control and Prevention (CDC), and UK Department of Health (DoH) have produced detailed guidance on PPE for viral haemorrhagic fevers, including Ebola, and this should be followed for Lassa fever:
WHO: steps to put on personal protective equipment Opens in new window
WHO: steps to remove personal protective equipment Opens in new window
Blood sample collection, packaging, and transport should be carried out according to national protocols, whilst the patient remains isolated and PPE is used. Specimens should be sent to a laboratory that is suitably equipped to handle biosafety level 4 pathogens. Before samples are sent, careful communication with laboratories is paramount to prevent transmission to laboratory staff.
Contact tracing and preventing transmission
Contact tracing should be done to identify those who have travelled with, lived with, or cared for an individual with Lassa fever within the last 21 days and who are asymptomatic. These individuals should be assessed and provided with post-exposure prophylaxis with oral ribavirin if they meet criteria (e.g., penetration of skin by a contaminated instrument, mucous membrane or broken skin exposure, participation in emergency procedures without use of appropriate PPE, or prolonged/continuous exposure in an enclosed space without use of appropriate PPE).[38] They should also be monitored for the duration of the incubation period in order to ensure rapid recognition of symptoms followed by immediate isolation. Antiviral drugs (including ribavirin) are not recommended for non-exposed close contacts due to the absence of evidence of proven effectiveness as prophylaxis. UK Department of Health: management of Hazard Group 4 viral haemorrhagic fevers and similar human infectious diseases of high consequence Opens in new window
The WHO has produced guidance on contact tracing for Ebola, and this can be followed for Lassa fever:
WHO: implementation and management of contact tracing for Ebola virus disease Opens in new window
The WHO has also published guidance for front-line healthcare workers on managing suspected and confirmed viral haemorrhagic fevers (including Lassa fever).[39]
If exposure to body fluids from a patient with suspected infection has occurred, the person should immediately wash affected skin surfaces with soap and water, and irrigate mucous membranes with copious amounts of water. The patient’s home and any personal belongings that could have been contaminated (e.g., clothes, linens, eating utensils, medical material) should be appropriately disinfected (e.g., sprayed with 0.5% chlorine solution in epidemic areas) or disposed of (usually by incineration). Safe burial practices are essential but are not always culturally accepted, and this continues to be a challenge.
Antiviral treatment
The antiviral drug ribavirin is a guanosine analogue that inhibits RNA-dependent RNA polymerase, although the exact mechanism of action in Lassa fever infection has not been agreed.[38] In the treatment of Lassa fever, intravenous ribavirin has been shown to reduce mortality from 55% to 5% if administered within the first 6 days of illness. However, there has been only one published trial of ribavirin in treating Lassa fever in humans, which had limited testing of dose.[34]
Side effects include haemolytic anaemia and infusion-related reactions, such as rigors. Side effects, particularly at the dose required to achieve theoretical efficacy, may be severe and often leads to poor adherence with treatment.[38]
Symptom management
Approximately 80% of those who become infected with Lassa virus are asymptomatic or have mild febrile symptoms. Severe disease occurs in around 20% of infected people.[2] Severe symptoms include haemorrhaging (e.g., gums, eyes, nose, rectum, and vagina [in women, particularly pregnant women]); respiratory distress; repeated vomiting; facial swelling; pain in the chest, back, and abdomen; and shock. Organs such as the liver, spleen, and kidneys can also be affected in severe disease.
Pain and fever should be managed with a simple analgesic/antipyretic (e.g., paracetamol). An opioid analgesic can be used if pain is severe. Non-steroidal anti-inflammatory drugs, including aspirin, should be avoided due to their associated increased risk of bleeding.
Bleeding is seen in around 17% of hospitalised patients with Lassa fever, although in one large study Lassa fever was identified in 74% of patients who were admitted to a hospital in Sierra Leone with bleeding.[4] Thrombocytopenia should be corrected with platelet transfusion if there is bleeding. Coagulation deficits are uncommon but should be corrected with blood products (e.g., fresh frozen plasma, cryoprecipitate) as necessary. Blood transfusion is reserved for patients who are anaemic and who have ongoing bleeding.
Intravenous fluid and electrolyte management
Diarrhoea is experienced during the course of the illness in approximately 50% of cases.[4] Patients with significant diarrhoea should have regular assessment of their electrolytes, with replacement provided as necessary. Intravenous fluids should be initiated and titrated to maintain adequate volume status.
Lassa fever encephalopathy
Encephalopathy with Lassa virus RNA detected in cerebrospinal fluid (CSF) has been reported, but only very rarely.[7][30] In symptomatic patients, encephalopathy is quite common among those who present after more than 6 days of symptoms. However, detection of Lassa virus RNA in CSF is rarely reported as lumbar puncture is rarely performed in these patients. There is no specific treatment for encephalopathy associated with Lassa fever. Patients with proven encephalopathy may benefit from ribavirin treatment. Specific encephalopathy symptoms, such as seizures, should be managed with standard care (e.g., anticonvulsants) in accordance with local protocols and availability.
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