Endocrine

Question 1

Normal variant short stature

Answer 1

• Familial (or genetic) short stature
• Constitutional short stature
• Normal growth velocity
• Height falls below the third percentile

Question 2

Familial (or genetic) short stature

Answer 2

• Height at least 2 SDs below the mean
• Short MPH
• Normal bone age
• Normal onset puberty
• Minimum growth of 2 inches per year

Question 3

Constitutional short stature

Answer 3

• Height at least 2 SDs below the mean
• History of delayed puberty in either or both parents
• Delayed bone age
• Late onset puberty
• Minimum growth of 2 inches per year

Question 4

Pathologic short stature

Answer 4

• Height 3 SDs below mean
• Abnormal growth velocity
• Proportionate: normal U/L ratio, can be prenatal or postnatal
• Disproportionate: increased U/L ratio (rickets, skeletal dysplasia)

Question 5

Postnatal causes of short stature

Answer 5

• Malnutrition
• Cyanotic heart disease
• Renal disease
• GI disease
• Endocrine disease
• Psychosocial dwarfism (eg neglect)

Question 6

Prenatal causes of short stature

Answer 6

• Environmental exposures (e.g. in utero exposure to alcohol or tobacco)
• Chromosomal disorders (e.g. Down syndrome, Turner syndrome)
• Genetic syndromes (e.g. Russell-Silver syndrome, Prader-Willi syndrome)
• Viral infection (eg CMV, rubella)

Question 7

Bone age less than chronologic age

Answer 7

• Constitutional short stature
• Hypothyroidism
• Hypercorisolism
• GH deficiency
• Chronic diseases

Question 8

Bone age equal to chronologic age

Answer 8

• Familial short stature
• Intrauterine growth retardation
• Turner syndrome
• Skeletal dysplasia

Question 9

Female puberty

Answer 9

• Onset between 7-13 years
• Thelarche: breast development
• Adrenarche: pubic or axillary hair
• Breast buds are usually the first sign of puberty, although in 15% of girls, pubic hair develops first
• Menarche: menstrual cycle
• Menstruation begins between 9-15 years

Question 10

Male puberty

Answer 10

• Onset between 9-14 years
• Testicular enlargement is usually the first sign of puberty
• 75% of the testicular volume is the seminiferous tubules

Question 11

Precocious puberty

Answer 11

• Girls: breast development or pubic hair before 7 years or menarche before 9 years
• Boys: testicular changes, penile enlargement, or pubic or axillary hair before 9 years

Question 12

Premature thelarche

Answer 12

• Visible or palpable breast tissue only, with no other secondary sex characteristics
• Pattern should be normal
• No pubic hair should be apparent
• Common and benign
• Caused by a transient activation of the HPGA, resulting in transient ovarian follicular stimulation and a release of low levels of estrogen

Question 13

Premature adrenarche

Answer 13

• Early onset of pubic or axillary hair occurs without the development of breast tissue or enlarged testes
• More common in girls than boys

Question 14

Isosexual precocious puberty or central precocious puberty

Answer 14

• Early onset of gonadotropin mediated puberty is a normal state, except that the hypothalamus has been activated earlier than usual
• More common in girls than boys
• Girls: idiopathic
• Boys: sexual precocity tends to be organic and all cases need evaluation with an MRI of the head
• CNS abnormalities that may cause isosexual precocious puberty include hydrocephalus, CNS infections, cerebral palsy, benign hypothalamic hamartomas, malignant tumors such as astrocytomas and gliomas, and severe head trauma
• Hypothyroidism - but in this case there is poor growth and a delayed bone age