Endocrinology Flashcards
1
Q
diabetes mellitus
A
- Fasting blood sugar over 126 mg/dL
- or
- Non-fasting blood sugar over 200 (Sporadic hyperglycemia, usually during illness or after steroids, is common in children)
- HbA1C > 6.5% is suggestive, but needs to be confirmed with hyperglycemia.
- Positive result on glucose tolerance test- Rarely done in pediatrics.
2
Q
type 1 DM
A
- Insulin deficiency
- Low C-peptide
- Autoimmune destruction of pancreatic β cells
- Most common endocrine problem in children
- 1 in 300-500 people under 18 years of age
- Postprandial hyperglycemia is first finding
- Prone to ketosis with more complete insulin deficiency
- Higher rates in Caucasian populations
- Associated with other autoimmune illness (ex. thyroid disorders, Celiac)
- Clinical presentation:
- Polyuria
- may manifest as enuresis
- Polydipsia
- Polyphagia
- often with paradoxical weight loss
- Dehydration/ketosis
- abdominal pain
- vomiting
- worsening mental status/fatigue
- breath & sweat ketosis
- Polyuria
- Diabetic Ketoacidosis (DKA) – most kids who have type 1 present in DKA
- Metabolic Acidosis: arterial pH < 7.3, bicarbonate <15 mEq/L
- Ketosis: Ketones in blood (>3mmol/L) or urine (moderate-large)
- Hyperglycemia >200 mg/dL
- Often the presenting diagnosis for T1DM.
- Leading cause of morbidity and mortality in children with T1DM
- Laboratory Findings
- Elevated glucose level
- Electrolytes:
- Anion Gap
- Hyponatremia (Can be exaggerated by high glucose)
- Potassium will be falsely normal/high (Total body low)
- Renal dysfunction if long standing
- Urinalysis – very cheap and easy test! One of the most useful tests!
- glycosuria
- ketones
- You should NEVER see ketones in urine in a normal kid
- ketones
- low pH
- Auto-antibodies and insulin-like growth factor (not needed in the initial period)
- “Honeymoon” period often follows original diagnosis where the pancreas is still able to produce a significant amount of insulin.
- First presentation of DKA is often set off by acute illness. The stress of illness causes the body to require more insulin than is needed for it’s basal function.
- Long term treatment goals:
- glucose control
- insulin regimen
- diet
- Avoid complications in chronic management
- renal failure
- visual impairment
- cardiovascular disease
- iatrogenic hypoglycemia
- ketosis during dehydrating circumstances
- glucose control
3
Q
diabetic ketoacidosis
A
- Treatment of DKA
- IV Fluid Rehydration
- Often helps reduce acidosis and glucose levels
- Must be done gently. Rapid or excessive IV fluid repletion can cause cerebral edema and be fatal.
- Careful electrolyte restoration.
- Monitor electrolytes carefully and replete.
- Restoration of anabolic state
- Insulin- restores euglycemia and halts ketone production
- You would never use hypertonic saline because the kid is actually isotonic, it just looks like they aren’t
- IV Fluid Rehydration
4
Q
type II DM
A
- Insulin Resistance
- hyperinsulinemia
- reduced sensitivity to insulin
- Gradual onset of symptoms
- DKA presentation uncommon due to presence of insulin
- Growing more common in younger ages
- correlation with worsening of American obesity epidemic
- Risk factors for type II diabetes:
- Family history
- Ethnicity (African American and Latino populations at higher risk)
- Weight
- Polycystic ovarian syndrome
- Diagnosis
- random glucose concentration > 200mg/dl
- fasting plasma glucose > 126 mg/dl
- glucose tolerance testing
- 2-hour plasma glucose > 200 mg/dl
- glycated hemoglobin (HgbA1C) is used as a screening test (and is used for diagnosis in adults)
- Co-moribidities
- dyslipidemia
- hypertension
- obesity
- Treatment: Glucose control and lifestyle modification
- lifestyle
- diet
- exercise
- metformin
- reduces hepatic glucose production
- increases sensitivity to insulin
- reduces intestinal glucose absorption
5
Q
neonatal hypoglycemia
A
- Very common in first 3 days of life, as metabolic needs outstrip energy stores
- In neonates, serum level <40 mg/dL is abnormal (we think) however some lower values in the 1st 4 hours of life may be normal.
- If symptomatic with low glucose this is ALWAYS abnormal
- Jittery, lethargic, seizures
-
Differential diagnosis
- Hyperinsulinism (infant of diabetic mother)
- Causative illness (shock, heart failure, liver dysfunction)
- Intoxication (alcohol), drug effects
- Inadequate substrate (SGA, poor feeding)
- Counter-regulatory hormone deficiency
- metabolic disorder inhibiting normal response
- gluconeogenesis
- glycogenolysis
- fatty acid oxidation
- organic acid metabolic disorder
- galactosemia
- Management
- Give glucose:
- Feed the infant for mild to moderate hypoglycemia
- Give IV glucose for severe, persistent or symptomatic illness
- Normal hypoglycemia should resolve in 24-48 hours, if it persists additional workup should be considered:
- “Critical Sample” – Send blood and urine when hypoglycemic to assess the insulin and metabolic response
- Give glucose:
6
Q
adrenal gland
A
- Endocrine organ that produces hormones important for salt homeostasis, stress response, and sexual characteristics.
7
Q
congenital adrenal hyperplasia
A
- Family of disorders that is caused by inactivity of key enzymes involved in adrenal hormone production.
- These disorders result in decreased production of cortisol. As a result there is an increased release of CRH and ACTH that leads to adrenal hyperplasia.
- The 3 most common are:
- 21-hydroxylase deficiency
- 11-beta hydroxylase deficiency
- 17-alpha hydroxylase deficiency
8
Q
21-hydroxylase deficiency
A
- By far the most common form of CAH.
- Presents with virilized genitalia in females. Males may not have a detectable phenotype.
- Internal genitalia will be normal. Which is why ultrasound is useful to demonstrate presence of uterus and ovaries in virilized females.
- Tested for on the state genetic screen.
- Babies generally present with vomiting, lethargy and in salt-wasting crisis.
- Labs will show low sodium levels from salt wasting due to lack of aldosterone.
- Treatment: glucocorticoid, mineralocorticoid replacement and possible surgical correction of external genitalia.
9
Q
Addison disease
A
- Primary adrenal insuficiency
- Autoimmune destruction of adrenal cortex
- glucocorticoid and mineralocorticoid deficiencies
- Episodes of shock during severe illness
- Treated with oral glucocorticoids and mineralocorticoids
10
Q
Adrenal crisis
A
- An emergency to be aware of in any patient who has adrenal insufficiency.
- Can present with hypotension, lethargy, and shock.
- In times of stress or illness the body has an increased cortisol need that people with AI cannot compensate for.
- People with AI need stress dose steroids during these times. Anyone with known AI should have a “sick plan”.
11
Q
panhypopituitarism
A
- The pituitary gland produces 7 hormones that are integral in the function of the body.
- Anterior: TSH, ACTH, FSH, LH, GH, Prolactin
- Posterior: ADH, Oxytocin
- Loss of the pituitary gland can occur due to trauma or shock that compromises the blood supply.
- in children, special attention paid to growth hormone replacement
- thyroxine replacement
- glucocorticoid replacement
- diabetes insipidus (free water loss, hypernatremia) is treated with desmopressin
- attention to sex hormone replacement depending on age & gender
12
Q
thyroid organogenesis
A
- thyroid develops from 3rd and 4th pharyngeal pouches starting in the 4th week of gestation
- by the 7th week the thyroid has migrated and the thyroglossal duct degenerates
13
Q
congenital hypothyroidism
A
- during first two weeks of life
- large fontanelles
- hypothermia
- poor feeding
- prolonged jaundice
- beyond 1 month of age
- darkened, mottled skin
- labored breathing
- diminished stool frequency
- lethargy
- after 3 months
- umbilical hernia
- infrequent, hard stools
- dry skin with carotenemia
- macroglossia
- generalized swelling (myxedema)
- 90% due to thyroid dysgenesis: athyreosis, ectopia, or hypoplasia
- Generally diagnosed via Newborn screening in the US and usually treated before symptomatic.
- Symptomatic infants adopted from other countries may present for care.
- False positive newborn screens are seen particularly in premature infants.
14
Q
acquired hypothyroidism
A
- 6 months to 3 years:
- deceleration of linear growth
- umbilical hernia
- dry skin with carotenemia
- macroglossia, hoarse cry
- During childhood:
- Goiter
- delayed eruption of teeth, shedding of primary teeth
- muscle weakness, pseudohypertrophy
- infrequent, hard stools
- precocious sexual development: breast development or enlarged testes without sexual hair
- generalized swelling (myxedema) – may cause weight gain
15
Q
causes of acquired hypothyroidism
A
- Hashimoto’s (autoimmune) thyroiditis
- AKA lymphocytic thyroiditis
- Most common cause
- drug-induced hypothyroidism via medications
- in breastmilk
- lithium, propylthiouracil (PTU), methimazole
- endemic goiter (iodine deficiency)
- irradiation
- excision
16
Q
hashimoto’s thyroiditis
A
- Hashimoto’s thyroiditis (chronic lymphocytic, chronic autoimmune thyroiditis)
- insidious onset
- firm, freely moveable, painless goiter
- hoarseness, dysphagia
- Growth retardation
- T4, FT4 may be normal
- may be elevated (hashitoxicosis, early) or depressed (late)
- TPOAb and TGAb usually present, though titers often low
- L-thyroxine may decrease size of goiter, but otherwise not needed in euthyroid patient.
- hypothyroidism is the end result of autoimmune thyroiditis, usually in 2nd or 3rd decade. Treat with thyroid replacement medication.
17
Q
rare thyroiditises
A
- acute suppurative thyroiditis
- infection via patent thyroglossal duct
- subacute (de Quervain’s) thyroiditis
- caused by mumps, EBV, influenza, echovirus, coxsackievirus, and adenovirus
18
Q
thyroid lab tests and imaging
A
- TSH
- Age dependent especially in neonates
- TSH surge can cause false positives in neonatal screen for hypothyroidism
- T4
- primarily bound to thyroxine-binding globulin, but also binds with lesser affinity to other proteins
- free unbound T4 is active, enters cells and converted to T3 (active)
- total T4 can be abnormal while FT4 is normal:
- if TBG levels are abnormal
- certain drugs bind TBG (anticonvulsants)
- pregnancy or estrogen can stimulate TBG
19
Q
classifying hypothyroidism
A
- primary: due to defective or absent thyroid
- secondary: due to defective TSH synthesis or action (hypothalamic or pituitary hypothyroidism)
20
Q
diagnosis of hypothyroidism
A
- low FT4 diagnoses hypothyroidism
- high TSH diagnoses 1º hypothyroidism
- low FT4, low/normal TSH suggests central pituitary hypothyroidism
- hypothalamic hypothyroidism can result in mildly high TSH but TSH is incompletely glycosylated due to lack of TRH, therefore has decreased biological activity
21
Q
treatment of hypothyroidism
A
- must be individualized due to individual differences in absorption and metabolism
- overtreatment can result in early closure of cranial sutures
- should not be given at the same time as soy or iron-enriched formulas, supplemental iron or calcium, or fiber supplements, since these impair absorption
- careful monitoring of TSH/FT4 until values normalize
- after 3 years of age, annual monitoring of TSH (1º hypothyroidism) and FT4 (2º or central hypothyroidism) is adequate
22
Q
hyperthyroidism
A
- overactive thyroid
- 95% of childhood cases are due to Graves disease
- autoimmune, antibody-mediated stimulation of thyroid
- thyroid stimulating immunoglobulins (TSI) directed against TSH receptors
- can manifest as thyrotoxicosis
23
Q
graves disease
A
- autoimmune disorder
- occurs in 1 in 5000 children
- most commonly seen in adolescents
- only 2% present before age 10
- at least 5 times more common in females than males
- family history is common
- can occur in conjunction with other endocrine disorders
- difficulty concentrating and sleeping, nervousness, fatigue
- facial flushing, sweating, heat intolerance
- tremors, palpitations
- weight loss despite increase appetite; diarrhea
- proximal muscle weakness
- palpitations, tachycardia, systolic HTN with wide pulse pressure, overactive precordium
- goiter (diffusely enlarged, soft), proptosis
- menstrual irregularities
- lab findings
- elevated T4 and FT4; TSH low
- I-123 uptake elevated, not suppressed with T3
- TGAb and TSI often found (95%)
- advanced skeletal maturation, premature closure of cranial sutures
- osteoporosis with longstanding hyperthyroidism
24
Q
treatment of hyperthyroidism
A
- Urgent management:
- β-blockers
- large doses of propranolol can decrease conversion of T4 to T3
- iodide for acute management
- blocks effect of TSH on thyroid, reduces iodine trapping, reduces vascularity, inhibits release of hormone
- Thioamides reduce hormone production, may take 2-3 weeks to see response
- propylthiouracil (PTU): blocks peripheral conversion of T4 to T3
- methimazole (MMI): longer half-life
- both cross placenta, but PTU preferred during pregnancy
- both present in breastmilk, but concentrations so low that they are not a contraindication
- radioiodine ablation: oral I-131 concentrates in thyroid
- cure rate 90%
- for those who have significant side effects from medication, or who do not achieve remission with drug therapy
- permanent hypothyroidism occurs in 40-80%
- avoided in young children since risk of thyroid cancer after radiation greatest in children < 5 years
- surgical thyroidectomy (subtotal or total)
- for those who fail medical therapy, have significant side effects, have large (>80g) goiters, or severe opthalmopathy
- cure rate 90%, but has potential for complications including hypoparathyroidism, recurrent laryngeal nerve damage, permanent hypothyroidism
25
neonatal hyperthyroidism
* newborns of affected mothers are at risk for thyrotoxicosis because TSIs cross the placenta
* duration after birth depends on half-life of maternal antibodies, ranging from weeks to months
* can present with arrhythmias, heart failure, exopthalmos
* long-term sequelae include craniosynostosis, cognitive defects, rebound hypothyroidism
* treatment includes iodide, followed by PTU or MMI
* reserpine or propranolol may be needed for arrhythmias
* transection of thyroid isthmus may be considered if there is RDS due to tracheal compression
26
calcium and phosphorus
* Parathyroid hormone is secreted in response to low calcium
* PTH raises serum calcium and lowers phosphate
* **low PTH** in the setting of **low calcium** and high phosphate confirms a problem with PTH production (hypoparathyroidism)
* hypoparathyroidism often results from DiGeorge syndrome
27
rickets
* Can be the result of inadequate calcium (calcipenic) or inadequate phosphorus (phosphipenic).
* Calcipenic rickets is the most common form of acquired rickets.
* Nutritional rickets is generally from Vitamin D deficiency.
* More skin pigment and less sun exposure both lead to higher risk.
* Vitamin D supplementation is recommended for ALL children. (400IU/day 0-1yr. 600IU/day \>1yr)
Part of the evaluation for children with suspected abuse