Ortho - Rickets

Question 1

What is rickets?

Answer 1

Defective bone mineralisation causing soft and deformed bones

In adults this leads to osteomalacia

Question 2

What causes rickets?

Answer 2

Vitamin D deficiency or calcium

Rare form can also be caused by low phosphate in the blood - hereditary hyophosphataemic rickets, x-linked dominant

Question 3

What is the pathophysiology of rickets?

Answer 3

Vitamin D created from cholesterol by skin in response to UV radiation

Patients with malabsorption issues e.g. IBD, more likely to have vitamin D deficiency, standard diet cannot make up for lack of sun exposure

Vitamin D essential for calcium and phosphate absorption from intestines and kidneys, bone turnover and reabsorption

Low vitamin D leads to low calcium and phosphate, low calcium leads to secondary hyperparathyroidism, this increased resorption of calcium from bones and break down leading to soft bones

Question 4

What are some potential symptoms in rickets?

Answer 4

• Lethargy
• Bone pain
• Swollen wrists
• Bone deformity
• Poor growth
• Dental problems
• Muscle weakness
• Pathological fractures

Question 5

What bone deformities can occur in rickets?

Answer 5

• Bowing of the legs
• Knock knees - legs curve inwards
• Rachitic roasry - ends of ribs expand at costochondral junction causing lumps along the chest
• Craniotabes - soft skull with delayed closure of suture and frontal bossing
• Delayed teeth - under-developed enamel

Question 6

What are some risk factors for developing rickets?

Answer 6

Vitamin D deficiency causes e.g.
- Darker skin
- Low exposure to sunlight
- Colder climates
- Majority of time indoors

Question 7

What investigations are used for rickets?

Answer 7

Serum 25-hydroxyvitamin D

X-ray is required to diagnose rickets, may also show osteopneia

Serum calcium - can be low
Serum phosphate - can be low
Serum ALP - can be high
PTH - can be high

Question 8

What additional investigations can be used to look for other pathology when investigating rickets?

Answer 8

FBC and ferritin - iron deficiency anaemia

ESR and CRP

Kidney fucntion tests - kidney disease

LFTs

TFTs

Malabsoprtion screen e.g anti-TTG and anti EMA

Autoimmune and rheumatoid tests

Question 9

How is rickets managed?

Answer 9

Prevention
Breastfed babies are at higher risk of vitamin D deficiency compared with formula fed babies as formula is fortified with vitamin D

Breastfeeding women and children should take vitamin D supplements

Children with vitamin D deficiency
- Vitamin D treatment
- 6 months - 12 years is 6,000 units per day

Children with rickets
- Referral to paediatrics
- Vitamin D and calcium supplementation