Hypotrophy: Etiology and severity grades
In modern pediatrics, hypotrophy rarely occurs in a baseline healthy child simply due to underfeeding. As a rule, it is a secondary condition developing against the background of severe somatic pathology (cystic fibrosis, celiac disease, congenital heart defects), when food absorption is impaired or energy expenditure increases dramatically.
The severity of hypotrophy is evaluated by three key blocks: weight deficit, depletion of subcutaneous adipose tissue (SAT), and systemic disorders.
- Grade I (mild): Body weight lag behind the age norm by 10–20%. SAT thins only on the abdomen (according to Krasnogorsky's law). The skin pales but retains elasticity. The general condition is minimally affected: turgor and appetite are slightly decreased, and psychomotor development is normal.
- Grade II (moderate): Weight deficit reaches 20–30%. The fat layer disappears on the abdomen and chest, and thins on the thighs. The skin becomes dry, and its elasticity decreases. Food tolerance drops, and stools are unstable. A mild lag in psychomotricity and a decrease in immunity are registered.
- Grade III (severe): Weight deficit exceeds 30%. SAT is completely absent, including on the face (Bichat's fat pads disappear). The skin is pale gray, hanging in folds due to a sharp drop in elasticity. Anorexia, hypothermia develop, and stools acquire a "starvation" character. Deep depression of immunity and sharp developmental delay are observed.
Paratrophy and hypostature
Paratrophy is a nutritional disorder with excessive (or at the upper limit of normal) body weight at normal height. It often occurs due to alimentary errors: overfeeding with simple carbohydrates and fats.
Clinically, paratrophy manifests as pastiness and hydrophilicity of soft tissues. Children are prone to muscle hypotonia, emotional lability, and delayed motor skills. When examining such a patient (e.g., a child receiving only carbohydrate complementary foods in the form of porridges without vegetables and protein), it is important to exclude endocrine disorders (hypothyroidism) and systemic edema.
Hypostature is a proportional lag in both body weight and height from age norms. Unlike hypotrophy, there is no disproportion. The pathogenesis is based on a deep lesion of the neuroendocrine system, often rooted in the prenatal period. The condition is extremely resistant to treatment. The exception is constitutional hypostature, which is an individual variant of the norm and does not require intervention.
Principles of dietotherapy
The basis of malnutrition correction is strictly individual dietotherapy based on the functional capabilities of the gastrointestinal tract.
- Calorie calculation: In mild hypotrophy (grade I), the calculation of proteins, fats, and carbohydrates is carried out based on the expected (ideal) body weight. In grade II, they start with the actual weight so as not to overload the GI tract, and smoothly transition to the expected weight as tolerance improves.
- "Rejuvenation" of the diet: Using products intended for a younger age. First, portion volumes are slowly increased, and only after adaptation is the qualitative composition changed.
- Nutrient priority: First of all, the proportion of carbohydrates and proteins is increased. Fats are introduced last due to difficulties with their digestion.
- Severe forms: Patients with grade III hypotrophy receive treatment in a hospital setting. They are prescribed specialized therapeutic formulas based on highly hydrolyzed protein without lactose. Such formulas are enriched with medium-chain triglycerides (MCTs), which can be absorbed directly into the portal system without the participation of lipase and bile acids.
Diagnosis of nutritional status disorders
Establishing a diagnosis requires a comprehensive approach:
- Anthropometry: Measurement of body weight and length, BMI calculation with mandatory assessment using centile charts. Caliperetry is used for an objective assessment of subcutaneous fat.
- Laboratory markers: Blood biochemistry reveals a decrease in the visceral protein pool — albumin and short-lived transferrin. Conversely, the level of $\alpha_1$-antitrypsin increases, reflecting active protein catabolism.
- Immune status: Secondary immunodeficiency is typical for malnourished children. It manifests as absolute lymphopenia, a decreased helper-to-cytotoxic cell ratio (CD4+/CD8+), and a drop in serum immunoglobulin levels.
To remember Krasnogorsky's law (the order in which subcutaneous fat disappears in hypotrophy), imagine a melting snowman: first the abdomen "loses weight" (grade I), then the chest and thighs (grade II), and finally the cheeks disappear (face — grade III).
Class and exam questions
How does hypotrophy differ from hypostature?
In hypotrophy, weight deficit is primary, leading to disproportion (weight is reduced more severely than height). Hypostature is a uniform, proportional lag of both height and weight from the norm.
Why are fats added to the diet last during the treatment of hypotrophy?
Fats are the most difficult to digest and absorb. The gastrointestinal tract of a malnourished child cannot cope with their digestion, which can lead to digestive failure.
How is paratrophy corrected in infants and toddlers?
The basis of treatment is diet therapy with a reduction in simple carbohydrates and fats, and enrichment of the diet with dietary fibers (vegetables, fruits). Massage and increased physical activity are also necessary.
What else to study on this topic
- Mechanism of medium-chain triglyceride (MCT) absorption into the portal system
- Calculation of expected body weight taking into account weight gains for elapsed months
- Differential diagnosis of secondary paratrophy and hypothyroidism
- Caliperetry: technique and interpretation of results
- The role of prebiotics and probiotics in microbiota restoration during dystrophies
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