Leigh syndrome - causes and signs of Leigh syndrome

Types of Leigh syndrome

The following types of disorders are distinguished in this disease:

• cytochrome C oxidase deficiency;
• necrotizing subacute encephalopathy of Leigh or infantile Leigh syndrome;
• Leigh syndrome in adults;
• NARP syndrome or mitochondrial DNA defect;
• X-linked Leigh syndrome;
• pyruvate carboxylase deficiency.

Most often, according to the nature of the course, this disease is:

• acute - this type of disease is extremely rare and proceeds as an acute encephalopathy;
• subacute;
• chronic.

The risk group for this disease includes:

• newborn children;
• infants;
• children under three years of age;
• people who have hereditary predispositions.

Causes

The main reasons leading to the development of Leigh syndrome:

• heredity;
• development of foci of necrosis in the brain stem, in the cerebellum;
• vascular proliferation;
• gliosis;
• gene mutations that affect the functioning of mitochondria (mainly associated with the functioning of the respiratory chain);
• various complications after degenerative diseases of the nervous system;
• the influence of mutagenic factors of various natures (biological, physical, chemical).

This disease develops with metabolic disorders, namely, with a defect and deficiency of enzymes that ensure energy metabolism in the body. This leads to a disruption in the metabolism of pyruvic acid, as well as a defect in the transport of electrons in the respiratory chain.

Symptoms

The following symptoms are characteristic of all types of Leigh syndrome:

• general weakness;
• nausea and vomiting;
• lack or deterioration of appetite;
• often accelerated weight loss;
• development of psychomotor retardation;
• tonic-clonic seizures;
• hypotension;
• symptoms of muscular dystonia;
• various respiratory anomalies;
• development of tremor in limbs;
• accompanied by impaired coordination;
• difficulty swallowing;
• optic nerve atrophy develops (blindness may develop);
• difficulty in tendon reflexes;
• rapid fatigue;
• impaired consciousness;
• drowsiness;
• reduced attentiveness.

In addition to the symptoms described above, each type of Leigh syndrome is characterized by certain signs.

Symptoms cytochrome C oxidase deficiency;

• mental retardation;
• metabolic compensatory acidosis;
• attacks of severe acidosis;
• a decrease in the level of bicarbonate is determined in the blood;
• an increase in the content of lactic acid in the blood and cerebrospinal fluid;
• pH remains unchanged.

Symptoms of necrotizing subacute encephalopathy of Leigh:

• more common in children under three years of age, but can also occur at 7 years of age (rarely);
• life expectancy is about a year;
• muscle weakness (hypotension, dystonia), which can develop into hypertonia;
• myoclonus attacks are possible;
• general weakness of the body;
• ataxia;
• tremor of the limbs;
• Babinsky's symptom positive;
• choreoathetosis;
• decreased tendon reflexes;
• possible eye damage (ophthalmoplegia, ptosis, pigmentary degeneration in the retina), which can lead to the development of blindness;
• hypoventilation;
• tachypnea;
• cardiomyopathy;
• lactic acidosis;
• symptoms of extrapyramidal and pyramidal insufficiency;

Necrotizing subacute encephalopathy of Leigh is characterized by a progressive nature of the disease.

Symptoms of Leigh syndrome in adults:

• ataxia;
• clonic twitching;
• spastic paresis;
• development of full-blown epileptic seizures is possible;
• progressive dementia;
• central scotoma;
• optic nerve atrophy.

Symptoms of Leigh syndrome with pyruvate carboxylase deficiency, in addition to the main ones, include lactic acidosis.

NARP syndrome (mitochondrial DNA defect) is characterized by the same symptoms as all types of this disease.

Diagnostics

When the first symptoms appear, as well as when suspecting the development of this disease in adults and, especially, in children, it is necessary immediately make an appointment with a neurologist or neuropathologist. The doctor will conduct a consultation and initial examination. To confirm the diagnosis of this disease, the following diagnostic tests are prescribed:

• general blood test;
• biochemical blood test;
• magnetic resonance imaging of the brain;
• morphological studies of the brain.

Treatment

An effective treatment for this disease is currently unknown. For Leigh syndrome, the following are prescribed:

• antibiotics (most often ampicillin);
• various dialysis methods;
• biotin;
• a drug that contains vitamin B1;
• protein diet.

Subacute and chronic course of the disease lead to death within a couple of years after the onset of the disease. In the case of a rapid course of the disease, death occurs due to paralysis of the respiratory center of the medulla oblongata.

Prevention

Prevention of Leigh syndrome includes:

• timely treatment of CNS diseases;
• proper nutrition.