What Are the Different Types of Metabolic Disease?

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Metabolic disease

According to general experience, metabolic diseases are diseases caused by metabolic problems, including metabolic disorders and strong metabolism. They mainly include the following diseases: 1. Diabetes 2. Diabetic ketoacidosis 3. Hyperglycemia and hypertonic syndrome 4 Hypoglycemia 5. gout 6. protein-energy malnutrition 7. vitamin A deficiency 8. scurvy 9. vitamin D deficiency 10. osteoporosis

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Metabolic encephalopathy

This disease is a manifestation of systemic diseases in the brain. Due to the blood-brain barrier disorder, the brain tissue is affected by the biochemical internal environment, and metabolic changes occur, leading to brain dysfunction. Common causes are: diabetes, uremia, hypercalcemia, and liver failure. Often brain dysfunction is significant, but pathological changes are not obvious. It is suggested that the nature of this type of encephalopathy is mainly a biochemical disorder. E.g:

Hepatic encephalopathy is a syndrome of the central nervous system caused by severe liver disease. Clinically, the main manifestations are thrash-like tremor, mental and behavioral changes, and unconsciousness to coma. Because of the late stage of the disease, coma often occurs, also known as hepatic coma.

The pathogenesis of this disease is very complicated, manifested in the following aspects of metabolic disorders: ammonia poisoning and energy failure. In the case of cirrhosis, due to the collateral shunt of the portal vein, ammonia (amine) substances in the intestine enter the central nervous system without liver detoxification. In astrocytes and neurons, ammonia and -ketoglutarate produce glutamic acid, which in turn produces ammonia and glutamine. During this process, a large amount of ATP and -ketoglutarate are consumed, making the cells unable to maintain the normal aerobic metabolism and energy supply of sugar. In addition to the formation of glutamine, glutamate in nerve cells can also form the inhibitory transmitter -aminobutyric acid (GABA) under the action of glutamate decarboxylase. In addition, too much ammonia can also inhibit the activity of pyruvate dehydrogenase, inhibit the activity of Na-K-ATPase, change the normal distribution of Na + and K + on nerve cell membranes, and thereby interfere with nerve conduction activities. Transmitter disorder. Including the imbalance of the original transmitter and the generation of pseudotransmitters. Aromatic amino acids in food are decarboxylated by intestinal bacteria to form tyramine and phenethylamine. After they enter the nervous system, they undergo the action of -hydroxylase in the brain to form octopamine and phenethanolamine, respectively. The structure of the two is similar to that of norepinephrine and dopamine, but the function of transmitting nerve impulses is only one tenth of that of the original transmitter. Norepinephrine and dopamine are excitatory transmitters. If excitatory impulses are not transmitted, unconsciousness and coma may occur. In addition, after dopamine was replaced, the extrapyramidal acetylcholine transmitter predominated, and flutter-like tremor appeared. As mentioned above, the increase of the inhibitory transmitter GABA due to the effect of ammonia detoxification is also related to the liver coma. Other factors such as increased short-chain fatty acids, insulin-plasma amino acid imbalance, and hypoglycemia also play a role in the occurrence of liver coma.

About half of the patients with hepatic encephalopathy may have different degrees of cerebral edema. The main lesions in patients with chronic hepatic encephalopathy are found in the gray matter, basal nucleus, thalamus, red nucleus, and substantia nigra of the brain and cerebellum. Astrocytes were proliferated in these areas, and nerve cells had no obvious morphological changes. The cytoplasm of proliferating astrocytes is not obvious, the nucleus is large, the nucleus is thickened, the cytoplasm contains glycogen (positive reaction of PAS staining), the HE stain appears pale, and there are 1 or 2 obvious nuclei Ren, this type of cell is called Alzheimer type II cell, and its GFAP staining changed from positive to negative, reflecting the disorder of its own metabolism during the process of ammonia detoxification. This kind of cell proliferation that occurs on the basis of autonomic disorders is called dystrophic astrogliosis. Long-term severe hepatic encephalopathy can also lead to loss of neurons and nerve fibers, thinning of the cerebral cortex, deep layered necrosis of the cortex, which can involve the brain, cerebellum and basal nucleus.

Congenital metabolic disorder

Congenital metabolic disorders often cause multiple system involvement. Clinically, some are mainly manifested by the nervous system, while others are prominent by the manifestations outside the nervous system: for example, in patients with hepatolenticular degeneration (Wilson's disease), some are mainly manifested as liver dysfunction with mild neurological symptoms; Some patients have prominent neurological symptoms, such as dancing signs, slow movements of hands and feet, or dementia. Another example is phenylketonuria. Metabolic disorders occur in all tissues of the body, but the clinical symptoms of the nervous system are particularly significant. It is worth noting that the same metabolic disorder can produce different clinical manifestations, and different metabolic disorders can also produce the same clinical phenomenon, so there is no clear classification of this group of diseases. People with congenital metabolic disorders still have systemic storage diseases (such as sphingosine lipid deposition, Gaucher disease), neuronal storage diseases (such as Tay-sack disease, Niemann-Pick disease), white matter malnutrition, etc. . Others involving the nervous system also have mucopolysaccharidosis, glycogen deposition, and so on. Taking white matter malnutrition as an example, it is briefly described as follows:

Leukodystrophy is a hereditary disorder of sphingomyelin metabolism that affects myelin formation. Including heterochromic white matter dystrophy, globular cell white matter dystrophy, adrenal white matter dystrophy, Alexander disease, spongy white matter dystrophy, and Pelizaeus-Merzbacher disease. This group of diseases is more common in infants and children, with poor prognosis. Among them, heterochromatic white matter dystrophy and globular cell white matter dystrophy are more common.

Metabolic diseases (a) metachromatic white matter malnutrition

Metachromatic leukodystrophy is an autosomal recessive disease. Cerebroside sulfate is deposited in the white matter and peripheral nerves of the central nervous system due to the lack of sulfatase. It is dyed with toluidine blue or crystal violet. It is not purple but yellow-brown. The shape and weight of the brain were roughly normal, and the white matter was gray-white and hard on the cut surface, and the arcuate fibers under the cortex were not involved. Microscopically, the myelin sheath was extensively formed in the white matter, axonal mutation, astrocyte proliferation, oligodendrocyte reduction, and metachromatic lipids were deposited in the cytoplasm of neurons and macrophages. The retina, optic nerve, and surrounding gods are often severely affected, and Schwann cells, hepatocytes, and renal tubular epithelial cells may also have metachromatic lipid droplets.

Metabolic diseases (b) globular cell white matter malnutrition

Globular leukodystrophy, also known as Krabbe disease, is an autosomal recessive disease. -galactosylcerosine deposits are caused by -galactocerebrosidase deficiency. The lesions were manifested by extensive myelin formation in the white matter of the brain and spinal cord, but subcortical arch fibers were not involved. Characteristic epithelioid and globular cells appeared in white matter. The diameter of the latter was 20-40 m. Galactocerebroside in the cytoplasm was positive for PAS staining and weakly positive for Sudan black staining. Electron microscopy showed that the cells contained empty tubular inclusions with irregular crystals. In addition, focal neuron loss, axonal disappearance, and reactive astrocyte proliferation can be seen. Peripheral nerves have mild focal myelin formation, Schwann cells and macrophages contain PAS-positive substances, but rarely form typical globular cells. ^[2]