Chronic nutritional disorders

Basic concepts and classification

For an accurate assessment of a child's nutritional status in pediatrics, the concepts of physiological norm and pathology are clearly differentiated.

Normotrophy is the reference, normal nutritional status. Under this condition, indicators of physical development (weight and height) fully comply with physiological standards. This state is inextricably linked with adequate neuropsychic development and the full functioning of all body systems.

Dystrophy is a chronic nutritional disorder. This pathology is based on an imbalance: insufficient or, conversely, excessive nutrient intake, as well as impaired assimilation. This leads to systemic failures in the morphofunctional state of internal organs.

Historically, in domestic practice, it has been customary to rely on the classification of G.N. Speransky. He identified four main forms of dystrophies:

• Hypotrophy
• Paratrophy
• Hypostature
• Polyhypovitaminosis

The modern clinical approach requires a more comprehensive assessment. Today, the diagnosis is formulated taking into account three critical criteria: the clinical form (with mandatory reference to the patient's age), the time of disease manifestation, and the leading mechanism of its development.

Hypotrophy and causes of its development

Hypotrophy is a polyetiological chronic nutritional disorder. Its main diagnostic criterion is body weight deficit relative to age and height. In severe cases, linear growth delay is added to this deficit. In pediatric practice, interchangeable synonym terms are often used to denote this condition: "nutritional deficiency" and "protein-energy malnutrition" (PEM).

The high incidence of dystrophies in young children is explained by anatomical and physiological prerequisites. The functional immaturity of the child's body is compounded by colossal demands driven by accelerated growth and extremely intense metabolism.

Factors triggering the development of hypotrophy are divided into two periods:

1. Prenatal factors. These are based on impaired uteroplacental blood flow. Key causes: burdened maternal somatic or obstetric-gynecological history, intrauterine infections, age factors, and the teratogenic effect of certain medications.
2. Postnatal factors:
3. Alimentary: gross violations of feeding technique, quality, or regimen.
4. Infectious and somatic: past or chronic diseases.
5. Genetic: hereditary metabolic defects and various congenital malformations.

Pathogenetic cascade and its consequences

Regardless of which primary etiological factor provoked the problem, a universal cascade of metabolic disorders is triggered in the body. First, a deep depletion of energy depots—fats and carbohydrates—occurs. Then, protein metabolism is inevitably disrupted: catabolic processes (breakdown) begin to prevail over protein synthesis processes. In the final stage, a pronounced deficit of essential trace elements is formed.

This pathogenetic cascade has severe clinical consequences:

• Neurological disorders. Due to the deficit of plastic substrates necessary for brain development, psychomotor development delay occurs, and the child's speech and cognitive functions are suppressed.
• Immunological disorders. A global decrease in protein synthesis and a lack of trace elements naturally lead to a drop in immunoreactivity.
• Formation of a vicious circle. The developed secondary immunodeficiency makes the child vulnerable to frequent infections. Infectious processes, in turn, further enhance catabolism, which critically worsens the initial nutritional disorder.

Overweight and general patterns

Nutritional disorders do not always proceed with weight deficit. There are serious risks associated with overfeeding. Thus, excessive protein intake in the first year of life stimulates pathologically accelerated weight gain. In modern pediatrics, this is considered a significant predictor of metabolic syndrome development at an older age.

It is important to understand that any prolonged nutritional disorders are characterized by a universal triad. Regardless of whether the pathology proceeds with excess, deficit, or even normal body weight, it is always accompanied by three mandatory components:

1. Deep metabolic disorder.
2. Development of polyhypovitaminosis.
3. Decrease in the body's general immunoreactivity.

Class and exam questions

What else to study on this topic

• Modern approach to formulating a diagnosis (clinical form, time of manifestation, mechanism)
• Anatomical and physiological prerequisites of dystrophies in young children
• Influence of intrauterine infections and teratogens on uteroplacental blood flow
• Connection between secondary immunodeficiency and catabolic processes
• Hereditary metabolic defects as a factor in the development of dystrophies

Other topics in "Chapter 3. Adaptation, Early Childhood Nutrition, Rickets"

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.