Male Gonadal Disorders – USMLE

by / Thursday, 22 July 2010 / Published in Pediatrics

Male Gonadal Disorders

Disease Characteristics Treatment
Klinfelter’s Syndrome
  • XXY inheritance with variable expressivity
  • Diagnosis usually at puberty when no virilization
  • Tall with small testes and gynocomastia
  • Decreased testosterone
  • Incr LH/FSH (no feedback)
  • Dx with buccal smear showing barr body


XXY syndrome
  • Mild mental retardation, acne, violent, antisocial behavior
  • Diagnose with karyotype analysis
Testicular feminization syndrome
  • Defect in DHT receptor
  • Female external genitalia with sterile, undescended testes
  • Patient appears female but is sterile with blind vagina
  • Testosterone/estrogen/LH are all elevated
No tx

Remove testes

5-a-reductase deficiency
  • Ambiguous genitalia until puberty
  • At puberty a burst of testosterone overcomes the lack of DHT (masculinizing external genitalia)
  • Testosterone and estrogen are normal
  • Diagnosis is by genetic testing
Congenital adrenal hyperplasia
  • A defect in the steroid synthesis pathway causes virilization of females or failure to virilize in males
  • 21-a-hydroxylase deficiency causes 95% of all CAH cases
  • severe disease presents in infancy with ambiguous genitalia and excess salt loss
  • less severe – minimal virilization and salt loss
Hormone replacement
Prader-Willi syndrome
  • paternal imprinting
  • short limbs, floppy baby
  • hyperphagia ( obesity – increases early death likelihood)
  • mental retardation
  • classically have almond-shaped eyes with strabismus
  • diagnosis is genetic analysis
Kallmann’s syndrome
  • AD hypogonadism with anosmia
  • Decreased production and secretion of GnRH by hypothalamus
  • Diagnosis made by finding decreased circulating LH and FSH
Pulsatile GnRH

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