When dengue stings the liver

The whole spectrum of dengue-induced liver disease may range from asymptomatic elevation of hepatic transaminases to incidence of acute liver failure, writes Dr Raj Vigna Venugopalan

Dengue has emerged as a common arboviral disease with a significant impact on the disease burden in the population residing in tropical countries. Dengue is spread by the bite of an Aedes aegypti mosquito, which is commonly found in tropical and subtropical climates. In India, about 63,280 dengue cases were recorded as of September 2022.

Patients have abdominal pain (18 to 63%), nausea/vomiting (49 to 58%), and loss of appetite. Symptoms such as abdominal pain and anorexia (an eating disorder) have been significantly more common in mild dengue than in severe dengue disease. Clinical jaundice has been detected in 1.7 to 17% in various
series and an increase in bilirubin has been found to be as high as 48%. Low protein levels or low albumin levels have been seen in 12.9%. A tendency for an increase in blood clotting was also seen. Liver damage has been found to be both in males and females in equal numbers.

Can dengue cause liver disease?

Severe cases of dengue have been found to cause life-threatening bleeding, low blood pressure, and organ failure. It has a profound effect on multiple organ systems, especially the liver which may result in fatty liver and acute liver failure. Hepatic manifestations (fatty liver) are caused by either dysregulated immunologic injury in response to the virus or direct viral toxicity. The whole spectrum of dengue-induced liver disease may range from asymptomatic elevation of hepatic transaminases to incidence of acute liver failure.

One of the clinical signs of liver involvement is an increase in liver size, which can occur in both mild and severe diseases but is more frequent in the former. Between 4 and 52% of adult dengue patients experience an increase in the size of the liver. Raised levels on liver function tests have been the most frequently found abnormality. Elevated levels are found in about 45 to 96% of all patients. In the majority of cases, it returns to normal levels within three weeks.

Patients with dengue-induced acute liver disease require hospitalisation and more intensive supportive care as well as constant monitoring for signs and symptoms of liver failure and complications. Performing regular liver function tests is essential to assess the progression of liver disease. Management of the disease is primarily supportive, and the outcome is usually positive. Antiviral medications may be prescribed to prevent the further progression of the disease and reduce
inflammation. The diagnosis and use of drugs that may worsen liver damage must be approached with caution. N-acetylcysteine has crucial importance in its treatment possibly by various mechanisms. N-acetyl cysteine improves liver disease in patients with dengue hepatitis, but this effect does not seem to affect the course of the illness. Proper nutrition is essential to support the liver and aid in its recovery. In rare cases, a blood transfusion may be necessary to replace lost blood or a liver transplant if the liver is hugely damaged.

(This author is a consultant in medical gastroenterology.)