Reye's syndrome (Encephalopathy and fatty degeneration of the viscera)
Incidence
Between 1974 and 1980 more than 2000 cases were reported. Described in 1963. It is not an hereditary condition. More than 90% of cases reported in patients younger than 15 years.
Clinical Characteristics
It is an acute illness following a viral infection, characterized by progressive encephalopathy, hypoglycemia and disordered hepatic function. It is a generalized impairment of mitochondrial function. It may follow many viral illnesses, notably varicella, influenza and parainfluenza. Also has been associated with administration of salicilates. The incidence has decreased markedly with the decrease use of salicilates in childhood. The patient with Reye's syndrome demonstrates marked increased in both medium and long chain dicarboxilic acid. Prodromal symptoms are non-specific. Then the child deteriorates rapidly in one to three days with vomiting and onset of stupor or coma as well as seizures. Seizures occur in 85 % of patients. When patient is comatose there are changes in muscle tone with decerebrate or decorticate posture. Central neurogenic hyperventilation or shallow breathing may occur. Liver is frequently enlarged. There are abnormal liver function tests especially elevated transaminases, prolonged prothrombin time and high arterial blood ammonia with or without hypoglycemia. Bilirubin is usually normal or very mildly elevated, less than 3 mg. %. Occasionally, blood lactate and ketones may be mildly elevated. 60% of deaths occur 24 hours from the onset of CNS manifestations. Death is usually produced by severe brain edema and encephalopathy with increased intracranial pressure and brain stem compression. Complete recovery may occur in the first ten days. Triggering factors seems to be mainly respiratory infection in 70 % of cases, varicela in 30 % of cases and gastrointestinal illness with diarrhea in 5 to 15 % of cases. EEG changes correlate with the stages and prognosis of the condition. Diagnosis is suspected with recurrent vomiting followed by sudden onset of profound disturbance of consciousness associated with hepatic dysfunction and hypoglycemia, as well as abnormal liver function tests, high ammonia, hypoglycemia and normal spinal fluid. Treatment is symptomatic aim to decrease increased intracranial pressure and treat seizures. In 30 % of patients who have decerebrate posturing or seizures are left with some sequelae. Evidence of increased intracranial pressure and blood ammonia higher than 300 mmol/L was associated with higher incidence of sequelae.
Precipitants
Triggering factors seems to be mainly respiratory infection in 70 % of cases, varicela in 30 % of cases and gastrointestinal illness with diarrhea in 5 to 15 % of cases. It has been associated with administration of salicilates.
Provocation Tests
no
Diagnostic Procedures
Diagnosis is suspected with recurrent vomiting followed by sudden onset of profound disturbance of consciousness associated with hepatic dysfunction and hypoglycemia, as well as abnormal liver function tests, high ammonia, hypoglycemia and normal spinal fluid.