Criteria and risk factors for the development of rickets

Prognostic significance of bone tissue formation

Disorders of phosphorus-calcium metabolism occurring in early childhood inevitably lead to inadequate formation of the skeletal system. This process is of colossal prognostic significance not only for pediatrics, but also for geriatric practice.

X-ray densitometry data have proven that low bone mineral density established precisely in childhood acts as a direct risk factor for severe trauma in the elderly, in particular hip fractures. Thus, achieving the maximum possible peak bone mass during the period of active child growth is the main and most reliable protective mechanism against the development of age-related osteoporosis and subsequent irreversible bone loss.

Prematurity as the leading triggering factor

When considering classic rickets, it is necessary to highlight the main factor in its development — prematurity. If a child is born prematurely (for example, their actual age is only 3 months), the leading cause of the rachitic process becomes the very fact of premature birth.

The pathophysiological justification for this phenomenon lies in intrauterine development: the maximum accumulation of calcium and phosphorus in the fetal bone tissue occurs exclusively in the last, third trimester of pregnancy. A premature infant is physiologically deprived of this crucial stage of mineralization, which naturally and rapidly leads to the development of early osteopenia.

Criteria for the period of sequelae

The period of sequelae is usually diagnosed in children older than 2–3 years. To establish a diagnosis at this stage, it is necessary to identify a specific clinical and laboratory picture that differs radically from the active phase of the disease.

Clinical and laboratory criteria include:

• Presence of persistent, visually detectable bone deformities (most commonly varus deformity of the lower extremities).
• Persistence of mild muscular hypotonia symptoms.
• Key diagnostic criterion: absolute normalization of blood biochemical parameters. Levels of calcium, phosphorus, and the enzyme alkaline phosphatase are strictly within reference ranges. This unambiguously indicates that the active process of osteomalacia is fully completed.

Analysis of the clinical picture and "red flags"

The pediatrician must be able to identify "red flags" that indicate not a classic nutritional deficiency, but genetically determined osteomalacia (hereditary rickets-like diseases or tubulopathies, such as phosphate diabetes).

Warning signs in history and clinical presentation:

• Age of manifestation and history: Development of severe deformities (valgus deformity) and pathological fractures in a child older than 3–4 years. It is especially important if this occurs despite prior adequate specific prophylaxis with vitamin D.
• Physical development: Marked growth retardation is recorded (for example, the child's height is only 88 cm at the age of 4 years).
• Family history: Identification of short stature on the paternal line, as well as the presence of undiagnosed nephrological diseases in close relatives.

Patient management tactics

Justification of the diagnosis in the presence of "red flags" is based on the exclusion of nutritional deficiency. The late age of onset, resistance to prophylactic doses of vitamin D, and family history of renal pathology require a modification of the standard tactics.

Pediatrician's action algorithm:

1. Primary screening: Before consulting narrow specialists, it is necessary to assess phosphorus-calcium metabolism. Blood is tested for calcium, phosphorus, and alkaline phosphatase levels. Mandatory is the assessment of urinary phosphorus excretion to confirm renal phosphate wasting.
2. Instrumental diagnostics: X-ray of the lower extremities is prescribed to visualize the bone tissue structure and objectively assess the degree of bone deformities.
3. Referral pathway: Having obtained baseline results, the pediatrician is obliged to refer the child to specialized experts — a geneticist and a nephrologist — for accurate verification of hereditary tubulopathy.

It is important to remember: independently prescribing therapeutic doses of vitamin D before completing the referral stage and verifying the diagnosis is a gross clinical error.

Class and exam questions

What else to study on this topic

• Methodology and interpretation of X-ray densitometry results in pediatrics.
• Hereditary tubulopathies: pathogenesis of phosphate diabetes.
• Laboratory methods for assessing urinary phosphorus excretion.
• Differential diagnosis of varus and valgus deformities of the lower extremities.

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.