# Nutritional Rickets

> Nutritional rickets for NEET-PG Paediatrics: vitamin D and calcium deficiency types, clinical signs, lab patterns and treatment notes.

- Canonical URL: https://prepelephant.com/topics/neet-pg/paediatrics/nutritional-rickets
- Exam / course: NEET-PG · Subject: Paediatrics
- Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team
- First published: 2026-10-02
- Last updated: 2026-10-02
- How to cite: "Nutritional Rickets", PrepElephant, https://prepelephant.com/topics/neet-pg/paediatrics/nutritional-rickets

## Direct answer

Nutritional rickets is defective mineralisation of growing bone from vitamin D deficiency, with or without dietary calcium deficiency, peaking in late infancy and the toddler years and again in adolescence. Vitamin D deficiency lowers calcium absorption and triggers secondary hyperparathyroidism — the biochemical signature of calcium low or normal, phosphorus low, alkaline phosphatase high and parathyroid hormone high, with low 25-hydroxyvitamin D confirming the cause. Treatment is vitamin D (daily replacement or supervised high-dose weekly regimens) with adequate calcium; prevention is 400 IU of vitamin D daily from infancy.

## What you must remember

- **Risk factors:** exclusive breastfeeding without supplementation, dark or covered skin, indoor living, prematurity, malabsorption, and the cereal-heavy, calcium-poor weaning diets of India.
- **Bony signs:** craniotabes, frontal bossing with delayed fontanelle closure, rachitic rosary (beaded anterior rib ends), widening of wrists and ankles, Harrison's sulcus, bow legs or knock knees and delayed dentition.
- **Non-osseous signs:** hypocalcaemic seizures, tetany and carpopedal spasm, laryngospasm with stridor, Chvostek and Trousseau signs, and hypotonia with a protuberant abdomen.
- **Biochemistry:** low or normal calcium, low phosphorus, high alkaline phosphatase, high PTH and low 25-hydroxyvitamin D (below about 20 ng/mL defines deficiency).
- **Radiology:** cupping, fraying, splaying and widening of the metaphyses — best seen at the wrist (distal ulna and radius) and knee — with delayed bone age; healing appears within weeks.
- **Treatment:** daily vitamin D replacement for about three months (roughly 1,000-2,000 IU in infants, 3,000-4,000 IU in older children per international consensus) or supervised weekly high-dose courses favoured in Indian practice, always with dietary calcium ensured.
- **Prevention:** 400 IU vitamin D daily from the first weeks of life, maternal supplementation, sunlight and dietary diversification.

## Common confusion

Nutritional rickets must be separated from causes that do not respond to vitamin D: X-linked hypophosphataemic rickets (very low phosphorus with normal calcium and PTH — vitamin D resistant), vitamin D-dependent rickets types 1 and 2 (the latter with alopecia), distal renal tubular acidosis and Fanconi syndromes, and chronic kidney disease (high phosphorus with low calcium — the reverse pattern). The second is calcium-deficiency rickets in Indian children on adequate vitamin D but cereal-bound, low-calcium diets — they need calcium as much as vitamin D.

## Exam-focused takeaway

NEET-PG tests rickets in three registers: signs (rachitic rosary, craniotabes, wrist widening, Harrison's sulcus), biochemistry (the low-phosphorus, high-ALP, high-PTH pattern with 25-OH-D as the confirmatory test) and the differential against hereditary and renal rickets using calcium, phosphorus, PTH and acid-base. Treatment stems ask for vitamin D with calcium and the 400 IU daily prophylaxis; radiology stems name the wrist metaphysis with cupping and fraying. The Indian angle of calcium-poor diets feeds programme questions on supplementation and fortification.

## Frequently asked questions

### What are the classic bony signs?

Craniotabes, frontal bossing, rachitic rosary, widening of wrists and ankles, Harrison's sulcus, bow legs or knock knees, and delayed fontanelle closure with delayed dentition.

### What is the typical biochemistry?

Low or normal calcium, low phosphorus, high alkaline phosphatase and high parathyroid hormone, with low 25-hydroxyvitamin D confirming vitamin D deficiency.

### Which radiograph shows changes earliest?

The wrist — cupping, fraying and widening of the distal ulnar and radial metaphyses; the knee is the other classic site.

### How does X-linked hypophosphataemic rickets differ?

Very low phosphorus with normal calcium and normal PTH, a family history and no response to usual vitamin D doses — hence vitamin D resistant — needing phosphate with active vitamin D analogues.

### How is nutritional rickets treated?

Vitamin D daily for about three months (or supervised high-dose weekly regimens per local practice) with adequate dietary calcium, healing tracked by falling alkaline phosphatase and radiograph.