Epidemiology
Signs and Symptoms
Investigations
100

What is the Incidence of CAH

1 in 10000 to 15000

100

Identify 2 symptoms of an adrenal crisis.

Any of the following - diarrhoea/vomiting, dehydration, confusion, seizures, coma.


100

What hormone is elevated in CAH due to a 21-hydroxylase deficiency and is a key diagnostic marker

17-hydroxyprogesterone (17-OHP)


200

What are population risk factors for Classic CAH

Native Americans and Yupik people

200

Low aldosterone levels can lead to disrupted levels of 2 main electrolytes. Identify these 2 electrolytes and explain whether CAH leads to high/low levels.

Sodium - low, Potassium - high.


200

This hormone is low in CAH, causing increased ACTH secretion due to loss of negative feedback

Cortisol

300

What are genetic risk factors for CAH

  • Autosomal recessive caused by mutations in the CYP21A2 gene - carriers are usually asymptomatic
  • Family history, and parental carrier status
  • Parental consanguinity
  • elevated 17-OHP in prenatal testing
300

Explain the typical physical growth/development patterns of a (46, XX) individual with classic CAH. Refer to both bones and genitalia in this answer.

Rapid growth/development of bones during early life, but early fusion of growth plates leads to a shorter adult height.

External male genitalia (due to androgens), but normally developed uterus/ovaries (due to no AMH and persistence 

300

This test shows hyponatremia, hyperkalemia, metabolic acidosis and sometimes hypercholeremia

Serum electrolyte test (UEC)



400

This special test involves administering synthetic ACTH and measuring the rise in 17-OHP levels

ACTH stimulation test (synacthen test)


500

This genetic test identifies mutations in the gene responsible for 21-hydroxylase enzyme production 

CYP21A2 PCR gene test


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