Endocrinology Flashcards by Huda Abdulrhman

What is the first sign of puberty in a boy?

Testicular enlargement

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What is the first sign of puberty in a girl?

Breast budding

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The height acceleration peaks in girls is at which sexual maturation rating (SMR) stage?

Between stage 2 and 3 SMR

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The height acceleration peaks in boys is at which SMR stage?

Between stage 4 and 5 SMR

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How many years after breast development does menarche start?

2.5years (approximately)

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A 5-year-old female, pubic hair, adult odor, no breast development, bone age is equal to chronological age, slightly increased dehydroepiandrosterone (DHEA) level, normal growth pattern for age

Premature adrenarche

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A 2-year-old female with bilateral breast buds, unchanged for 1year, no growth acceleration

Benign premature thelarche

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A 4-year-old female with new-onset bilateral breast enlargement, advanced bone age, and elevated luteinizing hormone (LH) and folliclestimulating hormone (FSH)

Central precocious puberty is very likely

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A 4-year-old boy presents with an adult-size phallus, pubic and axillary hair, acne, well-defined muscle tone, prepubertal size testicles

Peripheral precocious puberty

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A 4-year-old boy presents with an adult-size phallus, pubic and axillary hair, acne, well-defined muscle tone, pubertal size testicles, advanced bone age

Central precocious puberty

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A 4-year old boy with new-onset adult body odor, recent growth acceleration, pubic and axillary hair, thinning of the scrotum, enlargement of both testicles. Elevated LH and FSH.What is the best study to establish the diagnosis?

Brain MRI

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A 5-year-old girl with pubic hair, mild hyperpigmentation of skin folds, slightly enlarged clitoris

Simple virilizing CAH-21 OH deficiency

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Second newborn screen positive for high 17-hydroxyprogesterone. What is the next best step?

Repeat 17-hydroxyprogesterone test

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Newborn with proximal hypospadias (e.g., penoscrotal) and cryptorchidism

Ultrasonography for internal genitalia, karyotype, and serum electrolytes to screen for congenital adrenal hyperplasia

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What is the best treatment of congenital adrenal hyperplasia?

Hydrocortisone and fludrocortisone

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What is the treatment for a patient with congenital adrenal hyperplasia who presents with vomiting and low blood pressure?

IV hydrocortisone and IV fluid hydration

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A 2-week-old male with failure to thrive, persistent vomiting, dehydration, acidosis

CAH 21-OH deficiency (pyloric stenosis is associated with metabolic alkalosis)

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Ambiguous genitalia, nephropathy, Wilms tumor, renal failure by 3years of age

Denys–Drash syndrome

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Female phenotype at birth with undifferentiated streak gonads, presence of vagina/fallopian tubes, at puberty no breast development/menstruation, development of gonadoblastoma is the highest risk

Swyer syndrome (XY pure gonadal dysgenesis)

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Newborn with a small penis, bifid scrotum, urogenital sinus, blind vaginal pouch, testes are in the inguinal canal, raised as a female, virilization occurs at the time of puberty, enlargement of penis and scrotum, sperm formation, and normal adult height

5-alpha reductase deficiency (autosomal recessive)

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Infant phenotypically female at birth, raised as female, vagina ends in a blind pouch, no uterus, no fallopian tubes, intra-abdominal testes, normal breast development, no menses, normal male adult height, testosterone level is normal

Androgen insensitivity syndrome; 46, XY (X-linked recessive disorder)

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XY normal male phenotype, inguinal hernia, undescended testis, Müllerian structures found incidentally (uterus and fallopian tubes)

Persistent Müllerian duct syndrome

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A 4-year-old with precocious puberty, large caféau-lait spots, skeletal fibrous dysplasia, and vaginal bleeding are associated with

McCune–Albright syndrome

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A slow growth rate in the first 2years of life (

Constitutional growth delay

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Short child, growth velocity is 5 cm/year. Bone age is consistent with chronological age, father and mother are short

Genetic/familial short stature

A 4-year-old, height

Growth hormone deficiency

Common hormone deficiency associated with single maxillary central incisors, septo-optic dysplasia, cleft lip, cleft palate, and microphallus

Growth hormone deficiency

Normal length and weight by birth initially that drops by 1-year, conjugated hyperbilirubinemia, hypoglycemia, broad facies, and microphallus

Congenital growth hormone deficiency

Decreased levels of IGF-1 and IGF-BP3 are seen in which hormone deficiency?

Growth hormone deficiency

Normal growth hormone levels, height

Idiopathic short stature

How do you calculate the mid-parental height for a male?

[Mother height + Father height +13 cm]/2

How do you calculate the mid-parental height for a female?

[Mother height + Father height—13 cm]/2

Pseudotumor cerebri, slipped capital femoral epiphysis, and gynecomastia are the possible side effects of which hormonal therapy

Growth hormone

A 7-year-old boy with a progressive headache, vomiting without nausea, bitemporal hemianopsia, short stature, weight gain, and fatigue. What is the next best step?

Brain MRI (craniopharyngioma)

A 7-year-old boy, at birth, was large for gestational age, macrocephaly, a rapid growth rate in the first 3 years of life; now presenting with cognitive deficiency, autistic behavior, attention deficit hyperactivity disorder (ADHD), large and protruded head, large hands and feet, hypotonia, clumsiness, advanced bone age

Cerebral gigantism (Soto syndrome)

Boy with hypoplasia of optic nerves, nystagmus, an absence of septum pellucidum, schizencephaly, seizures, hypopituitarism, presented with hypoglycemia, jaundice, and micropenis at birth

Septo-optic dysplasia (De Morsier syndrome)

A 17-year-old female, amenorrhea, headache, galactorrhea, visual field defect; the pregnancy test is negative, and serum prolactin is > 200 mg/ dL. MRI showed a pituitary mass of 15 mm with encroachment on the optic chiasm

Prolactinoma (macroadenoma)

A 17-year-old boy, no signs of puberty, penis, and testicles are prepubertal, and anosmia

Kallmann syndrome (hypogonadotropic hypogonadism)

A 17-year-old male presents for a well visit. He has academic difficulty, gynecomastia, small firm testicles (

Klinefelter syndrome 47, XXY karyotype

A 16-year-old female, short stature (

Turner syndrome; 45, X karyotype

The most common cardiac defect associated with Turner syndrome

Bicuspid aortic valve

Newborn girl had cystic hygroma on fetal ultrasound, lymphedema of the feet, webbed neck, heart murmur, and horseshoe kidney

Turner syndrome; 45, X karyotype

A 5-year-old male, lymphedema of the feet at birth, short stature, webbed neck, strabismus, hearing loss, joint laxity, pulmonary stenosis, intellectual disability, normal karyotype

Noonan syndrome (mutations in the RASMAPK pathway)

Newborn screen of a 6-day-old boy showed abnormal thyroid-stimulating hormone (TSH) level of 230 mIU/L (elevated TSH > 40 mIU/L). Physical examination is unremarkable. What is the next best step?

Obtain confirmatory TSH and free thyroxine now but initiate the treatment immediately, before the results of the confirmatory tests are available

What is the optimal care of neonates with congenital hypothyroidism?

Early diagnosis before age 10–13 days and normalization of thyroid hormone blood levels by age 3 weeks

The most common cause of congenital hypothyroidism

Thyroid dysgenesis

What is the treatment of congenital hypothyroidism and how should the treatment be given?

Levothyroxine tablet (initial dose is 10–15 mcg/ kg/day) should be crushed and mixed with breast milk or formula (cannot be mixed with soy formula)

Low free T4, elevated TSH

Primary hypothyroidism

Low free T4, normal or low TSH

Central hypothyroidism

High free T4 and T3, low TSH

Hyperthyroidism (most common)

Normal or low free T4, high T3, low TSH

Hyperthyroidism (less common)

Normal T4, low T3, normal/low TSH, the patient has pneumonia

Euthyroid sick syndrome

Low total T4, normal free T4, normal TSH

Thyroxine-binding globulin deficiency (TBG), hypoproteinemia, e.g., malnutrition and nephrotic syndrome

A 11-year-old female with no growth for 2 years, tired, constipated and “yellowish” skin

Hypothyroidism (likely Hashimoto)

Adolescent with thyroid enlargement, no symptoms, TSH and free T4 are within the reference range, positive antithyroid peroxidase (TPO)

Hashimoto thyroiditis

A 14-year-old girl, school troubles, getting in fights, appears to be on drugs because of red bulgy eyes and irritability

Graves disease (hyperthyroidism)

What is the best test to confirm the diagnosis of Graves disease?

Thyrotropin receptor-stimulating immunoglobulin (TSI)

A painful thyroid gland that started after viral infection associated with elevated ESR with an eventual return to normal thyroid function

De Quervain thyroiditis—initial hyperthyroid phase, then hypothyroid phase with eventual recovery

Newborn child with tachycardia, irritability, hypertension, mother with a history of Graves disease?

Neonatal thyrotoxicosis

The most common symptom of hyperthyroidism or Graves disease

Weakness/fatigue

The most common side effect of antithyroid drugs (e.g., methimazole)

Transient urticarial rash

The best diagnostic test for solitary thyroid nodule

Fine needle aspiration biopsy; US-guided

The most common thyroid cancer in pediatric patients

Well-differentiated thyroid (follicular/papillary) carcinoma

Medullary thyroid cancer, hyperparathyroidism, pheochromocytoma

Multiple endocrine neoplasia (MEN)-2A

Medullary thyroid cancer, pheochromocytoma, mucosal neuroma

MEN-2B

Low to normal serum Ca, low serum phosphate, high alkaline phosphatase, low 25-(OH) vitamin D, high parathyroid hormone (PTH)

Vitamin D deficiency (rickets)

Normal serum Ca, low serum phosphate, very high alkaline phosphatase, normal vitamin D, failure to thrive, hypotonia, delayed dentition

Hypophosphatemic rickets or X-linked hypophosphatemic rickets

What is the mode of inheritance of hypophosphatemic rickets?

X-linked dominant

High serum PTH, low serum Ca, high phosphate, short stature, stocky habitus, soft-tissue calcifications/ossifications, short fourth and fifth metacarpal bones

Albright hereditary osteodystrophy (pseudohypoparathyroidism type 1A)

Short stature with stocky body habitus, soft-tissue calcification/ossifications, short fourth and fifth metacarpals with normal PTH, normal calcium, and normal phosphate

Pseudopseudohypoparathyroidism—due to paternal mutation

Normal serum Ca, low serum phosphate, very high alkaline phosphatase, non-anion gap metabolic acidosis, developmental delay, cataracts, glaucoma

Oculocerebrorenal dystrophy (Lowe syndrome)

A 7-year-old with obesity, hyperphagia, small hands and feet, small penis, cryptorchidism, and cognitive deficiency

Prader–Willi syndrome

What is the chromosomal deletion of Prader–Willi syndrome?

Paternal chromosome 15q11-q13 deletion

Obesity, retinitis pigmentosa, hypogonadism, intellectual disability

Bardet–Biedl syndrome or Laurence–MoonBiedl syndrome

Adolescent female, obesity, acanthosis nigricans, HBA1c 6.9%, elevated testosterone and LH, hirsutism, no ovarian cysts noticed on ultrasonography

Polycystic ovary syndrome

Failure to thrive, microcephaly, intellectual disability, ptosis, strabismus, syndactyly, pyloric stenosis, and low-plasma cholesterol

Smith–Lemli–Opitz syndrome (autosomal recessive)

Polydipsia, hypernatremia, serum osmolarity > 300 mOSm/kg, urine osmolarity

Diabetes insipidus (DI)

Patient with meningitis on IV fluids, hyponatremia, hypo-osmolality, elevated blood pressure, inappropriately concentrated urine, and high urine sodium level

Syndrome of inappropriate antidiuretic hormone secretion (SIADH)

What is the best initial treatment for the patient with SIADH in the previous example?

Reduce IV fluid rate (fluid restriction)

A patient underwent neurosurgery for a brain tumor, develops dehydration, hyponatremia, high urine output, hypovolemia, low blood pressure, high urine Na

Cerebral salt wasting

Cerebral salt wasting is associated with which hormone is being elevated?

Atrial natriuretic peptide

What is the best treatment for a patient with cerebral salt wasting dehydration?

Isotonic fluid hydration

Patient with diabetes insipidus comes in for water deprivation test, after administration of DDAVP (desmopressin) the urine becomes concentrated

Central diabetes insipidus

Patient with diabetes insipidus comes in for water deprivation test, after administration of DDAVP there is no effect on urine concentration

Nephrogenic diabetes insipidus

Child with obesity, height 95th percentile for age

Cushing syndrome

A 7-year-old boy with a history of severe asthma, presents with a 3-day history of worsening nausea, abdominal pain, and vomiting, he was on a high dose of inhaled steroids for 1 year. Lately, the child is not compliant with medications. What is the most likely cause of his symptoms?

Adrenal insufficiency

Child is presents with fatigue, nausea, weight loss, hypotension, volume depletion, and diffuse hyperpigmentation

Addison disease

Child with type 1 diabetes mellitus, well controlled, suddenly develops hypotension and shock

Addison disease

Best initial treatment for a patient with diabetic ketoacidosis within the first hour who presents with volume depletion, e.g., tachycardia, prolonged capillary refill time, and elevated blood urea nitrogen and creatinine

IV hydration: 10 mL/kg of intravenous normal saline over 1 h

The most common cause of death in children who have type 1 diabetes

Diabetic ketoacidosis (DKA)

What is the most common cause of recurrent DKA?

Insulin omission

The most common cause of death related to DKA in children

Cerebral edema

Adolescent female presents with recurrent vaginal candidiasis, BMI > 97th percentile, hypertension, acanthosis nigricans. What is the next best step?

Fasting blood glucose level

Adolescent female presents with polyuria, polydipsia, BMI > 97th percentile, hypertension, acanthosis nigricans; her blood glucose level is 200 mg/dL, A1C is 7%. What is the best treatment?

Metformin

Adolescent female presents with polyuria, polydipsia, BMI > 97th percentile, hypertension, acanthosis nigricans; her blood glucose level is 350 mg/dL, A1C is 10%. What is the best initial treatment?

Insulin Blood glucose level ≥ 250 mg/dL, A1C ≥ 8.5% insulin is the best initial treatment

What is the A1C goal recommended by the American Diabetes Association for all pediatric age-groups with type 1 diabetes mellitus?

A1C target

A 3-day-old infant, 10 lbs at birth, jittery

Infant of a diabetic mother with hypocalcemia

A 9-year-old male with sweating, jitteriness, and tachycardia with sudden onset of symptoms

Hypoglycemic episode Treatment: 15 g of carbohydrate

A 9-year-old male who has altered mental status glucose is noted to be 45 mg/dl. Best treatment?

IM glucagon

An infant with a history of tetralogy of Fallot presents with jitteriness and muscle twitching that has been worsening over the past few days. Blood glucose level is 85 mg/dL, and the calcium level is 7 mg/dL. What is the most likely cause?

Hypoparathyroidism

A 5-day-old infant, small jaw, broad nose, tetralogy of Fallot, seizure

DiGeorge/velocardiofacial (VCF)

A 3-month-old male with elfin facies, supravalvular aortic stenosis, now with serum Ca of 12.2

Williams syndrome

A 4-day-old male with hypoglycemia, omphalocele, hemihypertrophy

Beckwith–Wiedemann syndrome

Which childhood tumor is associated with Beckwith–Wiedemann syndrome?

Wilms tumor

A 10 lb plethoric neonate, requiring 15 mg/kg/min dextrose infusion. The mother without gestational diabetes mellitus (DM)

Congenital hyperinsulinism

A 5-year-old male previously healthy with throat pain and loss of appetite for 2 days, suddenly starts feeling dizzy, jittery, becomes unconscious in ER; the glucose level is 37 mg/dL, high level of serum and urine ketone, undetectable serum insulin, elevated serum cortisol, and growth hormone. What is the most likely cause?

Ketotic hypoglycemia (treatment is IV dextrose)

An 18-month-old thin boy with mild fever overnight presents with loss of consciousness and hypoglycemia

Ketotic hypoglycemia (diagnosis of exclusion)

A 5-day-old male with a small phallus, jaundice, now with glucose of 45 mg/dl and ketones in urine after 4 h of fasting

Hypopituitarism (adrenocorticotropic hormone (ACTH), growth hormone (GH) deficiency)

A 6-year-old with nighttime headaches, height has fallen from 25th percentile to 5th percentile over 1 year. Enuresis

Intracranial tumor in the region of the pituitary

An 18-month-old male, length, and weight “stalled” for 9 months. Stools remarkably odorous

Celiac/malabsorption

What are the components of metabolic syndrome?

Impaired glucose Low HDL High triglycerides Elevated blood pressure Central obesity