Endocrinology Flashcards
Addison Disease signs and symptoms
- Primary adrenal insufficiency
- Fatigue, nausea, weight loss, hypotension, volume depletion, and diffuse hyperpigmentation (due to elevated ACTH)
- Hyponatremia, hyperkalemia, hypoglycemia, metabolic acidosis, low serum cortisol, high adrenocorticotropic hormone level, and eosinophilia.
Treatment of Addison Disease (acute and long term)
- Acute: fluid resuscitation, IV hydrocortisone (100 mg/m2 then 100 mg/m2/d)
- Chronic: hydrocortisone and fludrocortisone
Hyperthyroidism signs/symptoms
Fatigue, hair loss, tachycardia, hypertension, sweating
Grave’s disease labs and treatment
- Low TSH and high thyroid-stimulating immunoglobulin
- Tx: methimazole is first line, radioactive iodine and surgery are used if meds aren’t effective, also often need a b-blocker initially d/t tachycardia
Type 2 diabetes screening labs
- Fasting glucose > 125
- 2 hr glucose level during OGTT > 200
- Hgb A1c > 6.5%
Indications for growth hormone
- Born SGA and didn’t catch up to a height of at least 2 SDs below the mean by 2 years of age
- Idiopathic short stature with height less than 2.25 SD below the mean
Sex differentiation
- Presence of androgens is responsible for formation of male external genitals
- Presence of mullerian inhibiting factors results in regression of female internal duct structures
Causes of male gynecomastia
- Ketoconazole, Klinefelter syndrome
- Galactorrhea can be due to marijuana use
Order of male pubertal development
Testicular growth –> Pubarche –> Penile growth –> Peak height velocity
First sign of pubertal development in males
Testicular enlargement (usually between ages 10-11)
Cause of pubic hair development and penis enlargement in the absence of testicular enlargement
Androgen stimulation from outside gonadal area
Order of female pubertal development
Breast budding –> pubarche –> peak height velocity –> menarche
- Can begin as young as age 8
Definition of delayed puberty
- No pubertal signs by 14 in boys or 13 in girls
Most common cause of delayed puberty in boys
Constitutional delay - benign, will have bone age 2 or more years delayed
Tx: IM testosterone
Causes of delayed puberty in girls
Can have constitutional delay but also commonly have functional gonadotropin deficiency (anorexia) and primary ovarian failure (Turner)
Tx: oral estrogen
Definition and causes of premature adrenarche
Presence of androgenic sexual characteristics (hair, acne, odor) without estrogenic sexual characteristics (breast development, menarche) and without growth spurt
- Elevated DHEA and DHEA-S, low testosterone
- Can also be caused by exogenous androgen, endogenous androgen secreting tumor, late onset congenital adrenal hyperplasia, or PCOS
Causes of premature thelarche
- Breast development in girl younger than 8 with no other sex symptoms
- Usually benign and due to premature activation of hypothalamic pituitary axis
- Can be due to exogenous sex steroids or estrogen producing tumors
Benign premature thelarche age and future risks
- Can happen in infants/toddlers and again in childhood but resolves by age 4
- 10% go on to develop central precocious puberty
- Also increased risk for PCOS
Early development of puberty in addition to acceleration in linear growth or advanced bone age
Central precocious puberty
- Before age 9 in boys or 8 in girls
- Leads to short adult height
Mccune Albright syndrome
- Peripheral precocious pubery
- Cafe au lait spots
- Polyostotic fibrous dysplasia
Workup for central precocious puberty
- Imaging (depending on symptoms may need brain MRI, ovarian/adrenal ultrasound)
- Bone age xrays
- Labs: LH, FSH, adrenal steroids
Treatment for precocious puberty
GnRH agonist leuprolide to stop the progression
- Often used in males, age < 6, those with rapidly advancing symptoms, or those with psychosocial disturbances
Genetic males (XY) with external female genitalia but no uterus
Androgen insensitivity syndrome
- Prenatal amnio shown XY but is born a girl
- Teenage girl with primary amenorrhea –> workup shows no uterus or ovaries
Micropenis with hypogylcemia
Panhypopituitarism
- Need to check all pituitary hormones
- Can be part of: Prader Willi, Kallmann, or septo-optic dysplasia
Newborn presenting with septic picture and male with excessive scrotal pigmentation or female with ambiguous genitalia (posterior labial adhesions and clitoral hypertrophy)
Congenital adrenal hyperplasia
Presentation of CAH in an older kid
- No medical care
- Growth delay
- Hirsuitism
- Amenorrhea
- -> autosomal recessive
Biologic cause of CAH
- Deficiency of 21-hydroxylase
- Leads to lack of aldosterone and cortisol which leads to increased testosterone and virilization
Labs in CAH
- Hyponatremia, hyperkalemia
- 21-hydroxylase deficiency
- 17-OH levels are high, high testosterone
- Low cortisol
Screening protocol for CAH
- Newborn screen tests for levels of 17-OH, if high then need to repeat the test
- If repeat test is high then need to measure serum electrolytes and urinary sodium/potassium excretion
Electrolyte abnormalities associated with adrenal crisis
Hypoglycemia, hyponatremia, hyperkalemia
- Treat initially with glucose containing fluids, then IV hydrocortisone, then glucocorticoid replacement
Primary adrenal deficiency symptoms
- Increased ACTH levels but no production of aldosterone
- Hyperpigmentation, salt wasting, hyperkalemia, hyponatremia, fatigue, weight loss
Tx with fludrocortisone and hydrocortisone
Addison disease is the autoimmune form
Muscle weakness and decreased cardiac function following stopping adrenocorticoid or glucocorticoid medication
Secondary adrenal insufficiency - would not commonly see electrolyte imbalances
Secondary adrenal deficiency has what abnormal levels
- LOW ACTH (pituitary isn’t making it) but CRH is normal (made in the hypothalamus)
- Normal electrolytes because aldosterone is normal and no hyperpigmentation because no excess ACTH
How does ACTH stimulation test work
- Give ACTH to test the adrenals
- If no cortisol rise happens, it’s primary adrenal deficiency
- If cortisol rise happens, then it’s secondary adrenal insufficiency
Acne, purple striae, hirsutism, virilization, buffalo hump, increased BMP with growth arrest
Cushing syndrome (excess glucocorticoid)
- Will also have delayed bone age
- MCC is chronic use of topical, inhaled, or oral corticosteroids
- Cushing in infants = MCCUNE ALBRIGHT
Lab tests to diagnose Cushing syndrome
- 24 hr urinary free cortisol excretion is gold standard
- Midnight sleeping plasma cortisol level
- If midnight levels are undetectable –> CT/MRI to look for adrenal tumor
- If midnight levels are elevated –> MRI to look at pituitary
Diabetes insipidus, exophthalmos, lytic bone lesions
Langerhans cell histiocytosis (posterior pituitary disease)
- Posterior part only makes ADH and oxytocin
Growth rate before puberty
5-6 cm/year
Peak growth age and SMR during puberty
- SMR 3 in both boys and girls
- Boys peak growth is about 2 years after girls
- Peak growth for girls is about 1.5 years before menarche at SMR3
Cranial irridation side effects with growth
- Growth hormone deficiency due to damaging pituitary so can lead to short stature
Micropenis, severe postnatal growth failure, hypoglycemia, short stature
Congenital growth hormone deficiency
- Can be associated with septo-optic dysplasia, breech presentation, prolonged jaundice
- Bone age will be delayed
Normal bone age with low weight and low height
Chronic malnutrition
Decrease in growth rate in early teen years, delayed onset of puberty, bone age below chronological age
Constitutional delay - more common in males
Growth velocity decelerates around 6-18 months of age but then follow the curve, bone age is equal to chronological age
Familial short stature
Delayed bone age, cold intolerance, constipation, dry skin
Hypothyroidism
Tall kid and want to know the most important determinant for ultimate adult height
SMR (to know how much growing they have left to do)
- Next would be bone age
Tall stature, learning disabilities, small testicles, gynecomastia, delayed puberty
Klinefelter syndrome (47 XXY)
Tall stature, macrocephaly, cognitive deficits
Soto’s syndrome
Tall, overweight, normal to advanced bone age
High caloric intake (exogenous obesity)
MCC preventable intellectual disability worldwide
Congenital hypothyroidism
Poor feeding, jaundice, constipation, hypotonia, hoarse cry, large tongue, umbilical hernia, large anterior fontanelle
Congenital hypothyroidism - although 95% are asymptomatic at birth
Newborn screening for congenital hypothyroidism
- Initial total TSH followed by T4 if needed
- If failed need test of free T4 and TSH
- 85% of cases are sporadic and due to thyroid dysgenesis
Boys with low total T4 but normal free T4 and TSH
Thyroxine binding globulin deficiency (X linked)
- T3/T4 are bound to TBG but it’s the free hormone that is metabolically active
- Dx confirmed by measuring aTBG level
Low TSH, low free T4
Secondary hypothyroidism due to pituitary or hypothalamic disease
Hypothyroidism symptoms or asymptomatic with presence of a goiter
Hashimoto thyroiditis
- Autoimmune (chronic lymphocytic thyroiditis)
- MC in females
Labs in hashimoto
- T4 can be normal if compensated but they have a high TSH
- Also have anti-thyroglobulin and anti-thyroid peroxidase antibodies
- Can be transiently hyperthyroid (hashitoxicosis)
Difference with radioactive iodine uptake in Graves vs Hashimotos
- High in Graves, normal/low in Hashimotos
Bulging eyes, emotional lability, weight loss, sleep disturbance, lid lag
- Graves
- Can also have itching, tremors, sweating, increased urination at night, decreased menstrual flow
Antibody involved in Graves disease
- IgG antibody (thyroid stimulating immunoglobulin)
- Tx with methimazole (blocks organification of iodide and decreases thyroid synthesis)
- PTU not preferred d/t risk of hepatitis and neutropenia
Newborn with irritability, tremors, tachycardia in immediate newborn period
Neonatal thyrotoxicosis (have low TSH and high free T4)
- Due to maternal antibodies crossing placenta (can happen even if mom had thyroid ablation in the past)
- Tx methimazole
Management of a thyroid nodule
- FNA
- Most are benign but higher risk of malignancy in teenager than adult
- Can have normal or abnormal TFTs
Four diagnostic criteria for diabetes
- Hgb A1c > 6.5%
- Random glucose > 200
- Fasting glucose > 126
- 2hr glucose > 200
- Need 1/4 criteria with symptoms or 1/4 criteria on 2 separate occasions
Physiology of type 1 DM
- Destruction of ilet cells so can’t make insulin
- Symptoms and diagnosis happen when islet function is down to about 20%
Acute DKA management and rationale why
- Fluid replacement (10-20 cc/kg normal saline over 1-2 hours) –> assume 5-10% dehydration
- Hyponatremia is dilutional (hyperglycemia pulls water into the cell) and should rise as glucose comes down, if it doesn’t be worried about cerebral edema
- Total body potassium is low
- Add insulin after initial fluid bolus
- Start adding dextrose when glucose is < 300
- Give insulin until acidosis has resolved and patient can tolerate oral intake
Type 2 DM with elevated serum osmolality and serum glucose
Hyperosmolar non-ketotic coma
- Manage like hypernatremic dehydration
Definition of metabolic syndrome
Hyperinsulinemia
Dyslipidemia
Hypertension
Obesity
Causes of hypercalcemia
Williams syndrome, vitamin D intoxication, vitamin A intoxication, thiazide diuretics, skeletal dysplasias, immobility, hyperparathyroidism
Treatment for hypercalcemia
- Calcium > 11
- Fluid, lasix, EKG monitoring
Function of parathyroid hormone
- Acts on the kidney, skin, and bone to increase calcium and decrease phosphate
- Primary hyperPTH causes hypercalcemia
- Secondary hyperPTH is reactive and due to low calcium
Symptoms of hypocalcemia
- Painful muscle spasms
- Generalized seizures
- Vomiting
- Prolonged QT interval
Chvostek sign
Tapping just anterior to the ear lobe below the cheek bone, contraction of the distal muscles is a positive finding
Trousseau sign
Inflate the blood pressure cuff above systolic pressure and leave it there for 2 minutes –> positive is carpal muscle spasm
Causes of hypocalcemia
- Pseudohypoparathyroidism
- Nutritional deficiency
- DiGeorge syndrome
- Nephrotic syndrome
- Renal insufficiency
Relationship of magnesium and calcium
Elevated magnesium decreases PTH secretion so hypomagnesemia can result in intractable hypocalcemia that won’t respond to calcium until you correct the magnesium
Labs in pseudohypoparathyroidism
- High PTH
- Hypocalcemia
- End organ kidney resistance to the hormone
Bone pain, anorexia, decreased growth rate, widening of the wrist and knees, delayed tooth eruption, bowed legs
Symptoms of rickets
- Look for enlarged costochondral junctions (rachitic rosary) and softening of skull bones (craniotabes)
- Serum alkaline phosphatase levels will be elevated in all forms
Calcipenic rickets
- Parathyroid hormone is always elevated
- Three types: vitamin D deficienct, vitamin D dependent, hereditary vitamin D resistants
Risk factors for vitamin d deficient rickets
- Breast feeding without vitamin D supplementation
- Poor exposure to natural sunlight
- Low birth weight
- Infants on strict vegan diets
- Lactose intolerant/avoiding dairy
Difference in vitamin D levels (types)
- 25 hydroxy is the storage form (25 added by the liver)
- 1,25 hydroxy is the active form (1 added by the kidney)
- 25 will be low in vitamin D deficient rickets but normal in the others
Labs and treatment of vitamin D deficient rickets
- Low 25-hydroxy and 1,25-hydroxy vitamin D
- Low/normal calcium and phosphorus
- Elevated serum alkaline phosphatase
Tx with vitamin D and calcium
Why dose liver disease cause rickets
Reduced availability of bile salts in the gut and decreased absorption of vitamin D
Vitamin D dependent rickets cause and labs
- Autosomal recessive
- Inadequate renal production of 1,25 vitamin D
- Low calcium
- Tx with vitamin D and 1,25 vitamin D
Cause of phosphopenic rickets
- Renal wasting, can be X-linked if congenital
- Tx with phosphate supplementation and 1,25 vitamin D
Type 1 diabetes health maintenance
- Dilated eye exam if > 10
- Lipid panels
- Celiac screening
- TSH screening
Causes of ketotic hypoglycemia
- Benign ketotic hypoglycemia
- Hormonal deficiencies
- Glycogen storage diseases
- Abnormalities of gluconeogenesis
Causes of non-ketotic hypoglycemia
- Hyperinsulinism (can be commonly transient in neonates)
- Fatty acid oxidation disorders
First sign of puberty in girls and age
Breast development age 10.5-11
- Then 2 years before menarche
First sign of puberty in boys and age
Testicular growth age 11.5
Labs for central precocious puberty
- High LH, FSH
- High estradiol/testosterone
- Advanced bone age
- MRI brain to look at hypothalamus/pituitary
Labs for peripheral precocious puberty
- Low LH, FSH
- High estradiol/testosterone
Ages for delayed puberty
No signs by age 13 for girls or 14 for boys
