Rickets (Medical Students)
A 4 year old child is being investigated for bowed legs.
1. Interprete the following investigations (normal values in brackets).
Calcium 2.15 (2.2 - 2.7)
Phospate 1.1 (1.30 - 2.00)
ALP 850 (100 - 350)
Calcidiol 22 (> 50)
Mild hypocalcaemia, significant hypophophataemia, markedly elevated alkaline phosphatase (suggesting increased osteoblastic activity, low vitamin D levels.
2. What is the clinical diagnosis?
Vitamin D deficiency rickets
3. What do you expect the parathyroid hormone level to be?
Raised (secondary hyperparathyroidism).
- Vitamin D deficiency → reduced intestinal calcium absorption
- Falling calcium stimulates PTH secretion
- PTH increases bone resorption and renal phosphate excretion
- This contributes to the low phosphate level and helps maintain serum calcium
4. Name other clinical features which may be present.
- Delayed growtth
- Bone pain
- Muscle weakness
- Widening of wrists and ankles
- Frontal bossing
- Craniotabes
- Rachitic rosary (prominent costochondral junctions)
- Harrison sulcus
- Delayed tooth eruption or enamel defects
5. What is the most likely cause of rickets?
- Limited sunlight exposure
- Darker skin pigmentation
- Restricted diet
- Malabsorption disorders
6. Outline the management.
Oral vitamin D supplimenation, monitoring, nutritional advice and prevention.