Metabolic diseases is a very broad concept - some of them can be deadly, while others allow you to function completely normally (provided that you follow medical recommendations). The causes and strategies for treating metabolic diseases also vary. Find out which diseases are classified as metabolic diseases, how we divide metabolic diseases, what are the most common metabolic diseases and what is the treatment of metabolic diseases?

Metabolic diseasesare the result of errors at various stages of the metabolism.

Metabolism is the body of a variety of chemical reactions in general. Metabolic processes enable the supply of "fuel" to all cells in our body. Thanks to this, they are capable of performing vital functions.

Some groups of metabolic reactions are responsible for removing harmful or dangerous substances from our body.

Metabolism is an extremely complicated phenomenon; it is difficult to imagine the enormity of chemical reactions taking place simultaneously in our body. Controlling it may be like conducting a large orchestra in which each musician performs a vital role.

Metabolic diseases and metabolism

The metabolic pathways of the human body are divided into two main groups: catabolic and anabolic.

Catabolism is the totality of changes aimed at breaking down complex chemicals. The effect of catabolic reactions is to obtain particles of smaller size; in addition, energy is generated during their formation.

A typical example of a catabolic process in our body is digestion. The foods we eat are made up of large chemical molecules that cannot be absorbed by cells. The essence of the digestive process is to transform them into a small, easily digestible size. The digestive process also provides us with the energy necessary for our daily functioning.

Anabolic reactions work in the opposite way: their goal is to build complex chemicals. Building substances, on the other hand, are particles of smaller sizes. Anabolism enables the growth and development of our body tissues.

As it is not difficult to guess, unlikefor catabolism, anabolism is an energy-consuming process.

The metabolic reactions in our body are interrelated. Most of them are linked in sequential pathways of change. Products of one reaction are included in subsequent processes.

Metabolism affects all tissues of our body: some of them are more metabolically active (e.g. nervous tissue, muscle tissue), and others slightly less (e.g. skin). However, there is no tissue that is not involved in any metabolic processes. Even seemingly "inactive" bone tissue is constantly involved in the calcium-phosphate metabolism of our body.

To understand the essence of a metabolic disease, we need to recall the basic scheme of a chemical reaction. Its essence is to transform the starting substance (substrate) into another substance (product). Chemical reactions in our body usually take place with the participation of enzymes. These are molecules that facilitate and accelerate the course of the reaction.

Metabolic diseases are associated with disturbances in various stages of the metabolic pathways. The lack of certain chemical reactions (e.g. due to the deficiency of a specific enzyme) results in the lack of formation of the product of a given reaction. At the same time, excessive accumulation of the starting product (substrate) may occur, as its further conversion will be inhibited.

Due to the interrelationship between metabolic reactions, disruption of one transformation usually entails subsequent defects. For this reason, even seemingly insignificant metabolic errors (e.g. lack of one enzyme) can alter the functioning of many metabolic pathways.

The effects of such single defects are also visible in distant tissues.

Metabolic disease rarely has a "point" character - its consequences usually affect the functioning of the whole organism.

Metabolic diseases: types

Metabolic diseases can be classified according to many features: etiology, course or type of metabolic reactions affected by the defect.

The most common division concerns the cause of the disease. According to it, we distinguish congenital and acquired metabolic diseases.

  • Congenital metabolic diseasesare associated with genetic disorders that affect the functioning of certain metabolic pathways. These are relatively rare conditions; Examples include phenylketonuria, Gaucher disease and mucopolysaccharidosis.
  • Acquired metabolic diseasesare much more common, and their formation is influenced by many factors. Most of us have met them in our lifeeveryday - these are known entities such as diabetes, osteoporosis or gout.

The metabolism of our body is a huge amount of chemical reactions. To facilitate its analysis, there are often subgroups of metabolic pathways associated with the transformation of specific chemicals.

The most important types of macromolecular chemicals that are transformed in metabolic reactions are proteins, carbohydrates, lipids, and nucleic acids. In addition, the transformation of micronutrients, such as calcium or iron, is also important.

Knowing the above groups of metabolic reactions, we can assign to them some metabolic diseases. This is a classification based on the nature of the underlying disorders.

It's not hard to guess that the most common example of a carbohydrate metabolism disorder is diabetes.

A disorder in the metabolism of proteins (and more precisely, the amino acids that build them) underlies phenylketonuria.

Osteoporosis is a disease associated with disorders of calcium metabolism.

In turn, gout is the result of an abnormal metabolism of purines, which are part of the nucleic acids.

Metabolic diseases: symptoms

Metabolic diseases are a wide and heterogeneous group of diseases. So it's not surprising that there is a huge variety of their symptoms. Of course, every metabolic disease has its own characteristic symptoms.

However, a disturbance in the course of any chemical reaction in our body may result in two groups of symptoms: associated with an excess of unprocessed reactants and those resulting from a shortage of its products.

To make them easier to understand, let's take the example of phenylketonuria. It is a disease resulting from a defect in the conversion of the amino acid phenylalanine into another amino acid - tyrosine.

The symptoms of phenylketonuria are caused by a build-up of phenylalanine in the body which does not change further. At the same time, we are dealing with a tyrosine deficiency. The most dangerous complication of phenylketonuria is the deposition of phenylalanine in the brain tissue, which leads to progressive mental and motor impairment.

If not transformed properly, metabolic substrates can accumulate in any body tissue, causing a variety of symptoms. The accumulation of certain substances in the liver may result in its enlargement and dysfunction, leading to jaundice.

The deposition of urate crystals is a typical effect of gout, leading to joint pain. In turn, accumulation of galactose in the lens of the eye causes cataractsoccurring in the course of galactosemia.

Most metabolic diseases are multi-organ diseases. Metabolic disease affects the entire body; depending on a specific disease entity, the clinical picture may be dominated by dysfunction of selected organs.

In the course of a metabolic disease, there may also be a dysregulation of the systems controlling the metabolism, among which the endocrine system plays the most important role.

Progressive metabolic diseases can therefore lead to complications even from seemingly distant organs and tissues.

Acquired metabolic diseases: course and treatment

To learn about the broad spectrum of symptoms and treatment strategies for metabolic diseases, it is worth looking at specific examples of these disease entities. First, let's look at a group of common, acquired metabolic diseases. Most of them are multi-factorial; their formation is influenced by both genetic and environmental factors.

  • metabolic diseases: diabetes

Diabetes mellitus is a group of common disorders of carbohydrate metabolism related to insulin deficiency or impaired insulin response. Insulin is a hormone that allows the body's cells to use glucose. There are 2 most common types of diabetes: type 1 and type 2 diabetes.

Type 1 diabetes mellitus is caused by autoimmune destruction of insulin-producing cells in the pancreas. In type 2 diabetes, the amount of insulin is normal, but the body does not respond properly to it (it develops insulin resistance).

The cause of type 1 diabetes is an autoimmune response that overlaps with a genetic predisposition. In type 2 diabetes, genetic factors play an important role, but environmental factors (improper diet, obesity, insufficient physical activity) are of great importance.

There are also other, rarer types of diabetes, caused by taking medications, endocrine disorders, or specific genetic defects (so-called monogenic diabetes).

Metabolic disorders typical of diabetes include excess blood glucose (hyperglycemia) and its deficiency in cells (lack of insulin prevents glucose from entering cells).

Glucose is the basic energy fuel for most tissues. The inability to consume it causes the cells to switch to lipid-dependent metabolism - the tissues begin to burn fat to obtain energy.

These transformations result in the formation of large amounts of ketone bodies, which can cause one of thethe most serious complications of diabetes - the so-called ketoacidosis.

The organism in diabetes constantly tries to produce more and more glucose in order to compensate for its deficiency in cells (which, of course, is impossible without insulin). The processes of hepatic gluconeogenesis (glucose production from various substrates) are activated.

Excess glucose in the blood "draws" water from the cells and causes pollakiuria, which leads to dehydration and electrolyte disturbances. Chronic hyperglycaemia damages the kidneys, eyes, blood vessels and nervous tissue.

Pharmacological treatment of diabetes includes administration of insulin (diabetes mellitus t.1, advanced diabetes mellitus t.2) or drugs enhancing insulin secretion and action (diabetes mellitus t.2). In the case of diabetes 2, non-pharmacological methods (diet, physical activity) are also important.

Rapid metabolic disorders in diabetes (more often t.1) may even be life threatening (ketoacidosis, severe electrolyte disturbances, hypoglycaemia in the course of insulin therapy).

Diabetes complications lead to cardiovascular disease and damage to vital organs. For this reason, a diabetic patient requires comprehensive and systematic medical care.

  • metabolic diseases: dyslipidemias

Dyslipidemias are disorders of the lipid metabolism, resulting in abnormal levels of certain groups of lipids in the blood.

Dyslipidemias may be primary (genetic disorders of lipid metabolism), but secondary dyslipidemias are much more common in the population, resulting from poor nutrition, the use of certain medications, or complications of other diseases.

One of the most common dyslipidemias is hypercholesterolaemia, i.e. elevated levels of LDL cholesterol in the blood.

The most serious consequence of dyslipidemias is their negative effect on the cardiovascular system. The so-called Atherogenic dyslipidemia is a proven risk factor for the development of atherosclerosis. It is a group of lipid disorders including an increase in triglycerides and LDL cholesterol (the so-called "bad cholesterol") and lowering the concentration of HDL cholesterol (the so-called "good cholesterol").

Atherosclerosis increases the risk of life-threatening complications, such as heart attacks and strokes. The basic method of treating dyslipidaemia is lifestyle changes (diet, increasing physical activity). In addition, drugs that lower the level of LDL cholesterol and triglycerides in the blood are also used.

  • metabolic diseases: metabolic syndrome

Metabolic syndrome is a collective term for disorders of carbohydrate and fat metabolism, resulting in an increased risk of cardiovascular diseases (diabetes, hypertension, atherosclerosis and their complications). To diagnose Metabolic Syndrome, 3 of the 5 following criteria must be met:

  • abdominal obesity, i.e. waist circumference>94 cm in men and>80 cm in women
  • dyslipidemia, i.e.
    • blood triglyceride (TG) concentration>150 mg / dl or treatment for hypertriglyceridemia or
    • HDL cholesterol concentration<40 mg/dl u mężczyzn i <50 mg/dl u kobiet
  • elevated blood pressure, i.e. systolic blood pressure>130 mmHg and / or diastolic>85 mmHg or treatment of hypertension
  • hyperglycaemia, i.e. fasting blood glucose>100 mg / dl or diabetes treatment.

Early diagnosis and effective treatment of Metabolic Syndrome are critical to preventing its serious consequences. The basis of the therapy is a radical change in lifestyle (weight loss, adherence to a proper diet, increased physical activity).

  • metabolic diseases: gout

Gout is a disease that results from increased levels of uric acid in the blood. Uric acid is a product of the metabolism of purines, which are building blocks of nucleic acids (DNA, RNA). Excess uric acid can be caused by a diet rich in purines (red meat, seafood).

Other factors contributing to hyperuricemia (increased levels of uric acid in the blood) include obesity, alcohol consumption, genetic factors, certain medications, and chronic diseases (including metabolic syndrome).

Excess uric acid tends to crystallize in the joints and periarticular tissues. The first symptom of gout is often pain and swelling in the big toe, caused by the secretion of uric acid crystals in the metatarsophalangeal joint. Inflammation in gout can affect one or more joints.

Treatment after the first gout attack reduces the risk of subsequent gout attacks. The therapy uses non-pharmacological procedures (diet, physical activity) and medications (non-steroidal anti-inflammatory drugs, anti-inflammatory colchicine, allopurinol inhibiting uric acid formation or probenecid increasing its excretion in the urine).

  • metabolic diseases: osteoporosis

Osteoporosis is a metabolic disease associated with a reduction in the mechanical resistance of bones and an increase in their susceptibility to fractures. Though it seems as though osteoporosis is concernedonly bone tissue, other organs and systems may also be involved in the disease process.

Metabolic disorders leading to osteoporosis are sometimes the result of dysfunction:

  • endocrine system (hyperparathyroidism, estrogen deficiency in postmenopausal women, damage to the adrenal cortex)
  • of the excretory system (chronic kidney disease)
  • digestive system (vitamin D malabsorption)

Osteoporosis can also result from improper diet or taking certain medications (e.g. glucocorticosteroids).

Bone tissue metabolism is closely related to the body's calcium-phosphate metabolism and the hormones that regulate it (parathyroid hormone, calcitonin, the active form of vitamin D3).

Treatment of osteoporosis includes nutritional supplementation (calcium supplementation, vitamin D), non-pharmacological measures (e.g. prevention of falls) and pharmacological measures (e.g. bisphosphonates that inhibit bone tissue degradation).

Congenital metabolic diseases: course and treatment

Congenital metabolic diseases are diseases of a genetic origin, most often detected in the early stages of life. Many of these diseases are monogenic: a specific gene is damaged, leading to the disturbance of a specific stage of metabolic changes.

There is a newborn screening program in Poland, which detects the most common congenital metabolic diseases.

Newborns are tested for 27 diseases, including 20 rare metabolic defects. Such an early detection of a metabolic disease enables the implementation of appropriate procedures from the very first moments of a child's life. Thanks to this, it is often possible to avoid serious complications of metabolic diseases.

  • metabolic diseases: phenylketonuria

Phenylketonuria is a metabolic disease caused by a defect in the enzyme that converts the amino acid phenylalanine into another amino acid - tyrosine. Symptoms of the disease result from the accumulation of excess phenylalanine in the tissue of the central nervous system, which leads to its damage.

Treatment of phenylketonuria is purely symptomatic: so far no methods are available to "repair" an inactive enzyme. Therefore, patients must follow a diet low in phenylalanine, which prevents disease progression.

  • metabolic diseases: lysosomal storage diseases

Lysosomal storage diseases is a group of diseases related to the accumulation of chemical reactants in intracellular vesicles -lysosomes. Their accumulation is the result of the lack of activity of selected enzymes, which is caused by genetic defects.

An example of lysosomal storage diseases is mucopolysaccharidoses - severe, progressive diseases caused by the accumulation of mucopolysaccharides.

Lysosomal storage diseases also include Pompe disease, caused by a lack of alpha-glucosidase. It is an enzyme that enables the proper breakdown of glycogen; in the case of its deficiency, glycogen accumulates in various organs: heart, liver, muscles and the central nervous system.

Treatment for Pompe disease is currently available with the administration of modified alpha-glucosidase.

  • metabolic diseases: maple syrup disease

The name of the maple syrup disease comes from the characteristic smell of the urine of patients suffering from it - it resembles the smell of maple syrup.

At the root of the disease lies a defect in the enzyme responsible for the decomposition of the so-called branched chain amino acids: leucine, isoleucine and valine. Increased concentrations of these amino acids have a damaging effect on the central nervous system.

Maple syrup disease in Poland is detected at the earliest stages of a child's life thanks to newborn screening tests. Its chronic treatment is based on a diet with limited amount of branched chain amino acids.

  • metabolic diseases: alkaptonuria

Alkaptonuria is another metabolic disease associated with the disturbance of amino acid metabolism. The defect of phenylalanine and tyrosine transformations leads to the accumulation of an intermediate product of their transformations - homogentyisic acid.

Its excess is excreted with the urine, causing the characteristic symptom of the disease - urine darkening. Other typical features of alkaptonuria include degeneration of the joints and protection, which is the accumulation of dark blue-black pigment in the cartilage and on the skin.

Treatment of alkaptonuria consists in limiting the consumption of amino acids whose transformations are disturbed (phenylalanine and tyrosine).

  • metabolic diseases: Wilson's disease

Wilson's disease is the result of an inborn error in copper metabolism. Symptoms of Wilson's disease rarely appear shortly after birth - they usually appear after the age of 5-10.

Disrupted metabolism of copper causes its deposition in various organs - the liver, eyes and brain.

A characteristic symptom of Wilson's disease is a decrease in the concentration of ceruloplasmin in the blood. It is a protein responsible for binding and transporting copper in the body.

TreatmentWilson's disease consists of restricting the consumption of copper in the diet and administering agents that bind copper (penicillamine) or increase its excretion from the body.

Learn more about other metabolic disorders:

  • Wolf-Hirschhorn syndrome: causes and symptoms. Treatment of this rare genetic disease
  • Zellweger syndrome: causes and symptoms
  • Krabbe's disease - genetic metabolic disease
  • Abetalipoproteinemia (Bassen-Kornzweig syndrome)
  • Hemochromatosis - symptoms, types, DNA tests, treatment
  • Chondrocalcinosis (pseudogout): causes, symptoms, treatment
  • Cystinosis - causes, symptoms and treatment
  • Sitosterolemia: causes, symptoms, treatment
  • Methylmalonic acidosis - causes, symptoms and treatment
  • Alleged hypoparathyroidism or Albright's syndrome
  • Hunter's syndrome - symptoms and treatment of mucopolysaccharidosis type II
  • Lesch-Nyhan syndrome - male infertility disease
  • Smith-Lemli-Opitz syndrome is a rare metabolic disease. Is SLOS treatment possible?
About the authorKrzysztof BialaziteA medical student at Collegium Medicum in Krakow, slowly entering the world of constant challenges of the doctor's work. She is particularly interested in gynecology and obstetrics, paediatrics and lifestyle medicine. A lover of foreign languages, travel and mountain hiking.

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Gastrology