The secondary mitochondrial liver diseases are caused by a metal, drug, toxin or endogenous hepatotoxic metabolite. In the past, the most common secondary mitochondrial hepatopathy was the Reye’s syndrome, whose prevalence reached a peak in the 1970s and that had a mortality rate> 40%. Although mortality has not changed, the prevalence has decreased from> 500 cases in 1980 to 535 cases per year in the 90s.
How Long Does It Take To Get Reye’s Syndrome?
It is precipitated in a genetically individual susceptible due to the interaction of a viral infection (influenza, chicken pox) and the use of salicylate. Clinically, it is characterized by a viral disease that seems to be resolving and the acute onset of vomiting and encephalopathy. The neurological diseases symptoms can progress rapidly to seizures, coma and death. Liver dysfunction is invariably present when vomiting develops, with coagulopathy and increased SGOT, SGPT (hepatic enzymes) and ammonium. It is important to draw attention to the fact that patients remain anicteric (absence of jaundice, a yellowish pigmentation of the skin and mucous) and serum bilirubin levels are normal.
Liver biopsies show microvesicular steatosis with no evidence of inflammation or hepatic necrosis. Death is usually secondary to increased intracranial pressure and hernia. The surviving patients have a full recovery of hepatic function, but should be carefully screened for oxidation of fatty acids and defects of the transport of fatty acids.
Reye syndrome is a biphasic disease, in which there is a viral prodrome (infection of the upper respiratory tract, varicella or gastroenteritis, more frequent in younger children) followed several days or weeks -average 3 days- after a sudden encephalopathy and incoercible vomiting, (which means intractable or uncontrollable vomiting).
Different families of viruses have been implicated: Influenza B (most common), influenza A, and varicella-zoster virus are the most frequent; parainfluenza, adenovirus, coxsacky A and B, echovirus, Epstein-Barr virus, rubella, measles, cytomegalovirus, herpes simplex virus, parainfluenza and poliomyelitis virus. Reye syndrome may appear after vaccination with active virus vaccines.
Neurological symptoms usually appear 24-48 hours after the first vomiting; the lethargy is usually the first neurological symptom and progressively appears irritability, delirium, seizures or coma. The degree of neurological deterioration varies from one patient to another and is determined by the intensity of cerebral edema and the existence of intracranial hypertension associated or not with a decrease in cerebral perfusion pressure.
It is associated with hepatomegaly in 50% of cases. It does not usually have jaundice or is minimal.
It is necessary to suspect a congenital metabolic disease if there is a recurrence of symptoms or precipitating factors, including a prolonged fast, change of diet or some type of associated metabolic stress, and if another family member presents compatible symptoms.
The definition criteria for Reye syndrome are the following:
- Acute non-infectious encephalopathy, documented clinically by impaired consciousness, CSF with less than 8 leukocytes / ml or brain tissue sample demonstrating edema without perivascular involvement or meningeal inflammation.
- Hepatopathy documented by biopsy or necropsy, or up to 3 times increase in ASAT, ALAT (hepatic enzymes) or ammonium.
- No reasonable explanation for cerebral or hepatic abnormalities.
There is no effective treatment for most patients with mitochondrial liver diseases. Neurological involvement often prevents the orthotopic liver transplant. Several mixtures of drugs have been proposed, it includes antioxidants, vitamins, cofactors and acceptors of electrons, but controlled studies have not been completed randomized to evaluate these drug combinations.
Therefore, current therapeutic strategies are supportive. It is necessary to monitor the intracranial pressure, fighting cerebral edema (whose presence is practically constant), keeping breathing and controlling haemostasis disorders and other biochemical alterations; this involves obtaining venous access and artery (for electrolyte control, glycemia, coagulation tests and other parameters meters) and perform assisted intubation and ventilation.