A 3-month old male child with normal genitalia presents to the emergency department with severe dehydration, hyperkalemia and hyponatremia. The measurement blood levels of which of the following will be helpful ?
Correct Answer: 17-hydroxy progesterone
Description: Ans. is 'a' i.e., 17 hydroxyprogesterone 3 month old child with normal genitalia along with salt wasting and hyponatremia suggests congenital adrenal hyperplasia due to 21 hydroxylase deficiency.Congenital adrenal hyperplasiaCongenital adrenal hyperplasia is a group of autosomal recessive disorder characterized by deficiency of an enzyme involved in the synthesis of cortisol or aldosterone or both.Clinical manifestations * The clinical manifestations are related to the degree of cortisol deficiency and / or the degree of aldosterone deficiency. In some cases these reflect the accumulation of precursor hormones.Clinical presentation in Males * 21 hydroxylase deficiency (Testosterone production increased)Generally not identified in the neonatal period because the genitalia are normal.These male neonates present at age 1-4 weeks with failure to thriveRecurrent vomitingDehydrationHypotensionHyponatremiaHyperkalemiaShock17 hydroxylase deficiency, 3 b hydroxysteroid dehydrogenase deficiencyAmbiguous genitalia (because of inadequate testosterone production in first 3 months of life).Clinical presentation in Females21 hydroxylase, 11 fiesta hydroxylase, 3 fiesta hydroxysteroidThey have ambiguous genitalia at birth due to excess androgen production in utero.17 hydroxylase deficiencyFemales appear phenotypically female at birth but later on in life do not develop breast or menstruate absence of estrogen.Diagnosis of congenital adrenal hyperplasiaThe common feature of all congenital adrenal hyperplasia is - Inadequate production of cortisol, aldosterone or both in the presence of accumulation of excess concentrations of precursor hormones.Cortisol and aldosterone deficiency is common to all congenital adrenal hyperplasia, the distinguishing feature is the accumulation of excess concentration of precursor hormones.21 hydroxylase deficiencyHigh serum concentration of 17 hydroxyprogesteroneIncreased concentration of urinary pregnanetriol (metabolite of 17 hydroxy progesterone's)11 B hydroxylaseExcess concentration of 11 deoxy cortisol and deoxycorticosteroneElevation in the ratio of 24 hour urinary tetrahydro compound S to tetrahydro compound F.Both are accompanied by elevated levels of 24 hour urinary 17 ketosteroids, the urinary metabolites of adrenal androgens 3 b hydroxysteroid dehydrogenase * Abnormal ratio of17 hydroxypregnenolone to 17 hydroxyprogesterone andDehydroepiandrostenedione to AndrostenedioneMore on congenital adrenal hyperplasia 21 a hydroxylase deficiencyTwo forms of this deficiency include -Salt wasting adrenogenital ismSimple Virilizing adrenogenital ismSalt wasting syndrome (complete lack)The salt wasting syndrome results from complete lack of 21 hydroxylase. There is no synthesis of mineralocorticoids and glucocorticoids in the adrenal cortex.Decreased mineralocorticoids causes marked sodium loss in the urine, resulting in hyponatremia, hyperkalemia, acidosis and hypotension.Because of the enzyme block, there is increased formation of 17- hydroxyprogesterone, which is then shunted into the production of testosterone.This may cause virilism (pseudo-hermaphroditism) in female infants. That is (XX) Female with 21 hydroxylase deficiency develops ovaries, female ductal structures and external male genitalia.But in the male child the effect of increased testosterone will not be manifested at the time of birth.The complete 21 hydroxylase deficiency or salt wasting syndrome usually comes to light only after the birth because in utero the electrolytes and fluids can be maintained by maternal kidneys.Males with this disorder comes to clinical attention 5 to 15 days later because of salt losing crisis while females comes to attention soon after the birth because of the virilization.Simple Virilizing adrenogenital syndrome (Partial deficiency)Occurs in individuals with partial deficiency of 21 hydroxylaseLess severe deficiency of mineralocorticoid, is sufficient for salt reabsorption, but the lowered glucocorticoid fails to cause feedback inhibition of ACTH secretion. Thus level of aldosterone is mildly reduced testosterone increased and ACTH elevated with resultant adrenal hyperplasia.116 hydroxylase deficiency -RareLeads to decreased cortisol and increased ACTH.This in turn leads to the accumulation of DOC (deoxycorticosterone) and 11 deoxy cortisol both of which are strong mineralocorticoids. This results in increased sodium retention by the kidneys and hypertension, hypokalemia.Patients also develop virilization due to androgen excess.17 a hydroxylase deficiency -Patients with deficiency of 17 hydroxylase also have impaired cortisol production, increased ACTH and secondary increased DOC.These patients, however, cannot synthesize normal amount of androgens and estrogens.This is because the gene that codes for 17 a hydroxylase is the same for the enzyme in the adrenal cortex and the gonads and the deficiency is same in both organs.Because of decreased sex hormones genotypic females develop primary amenorrhoea and fail to develop secondary sex characteristics while genotypic males will present as pseudohermaphrodite.
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Pediatrics
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