endocrine Flashcards
What is responsible for regression of female internal structures in XY males?
Presence of mullerian inhibiting factor
What is responsible for the formation of male external genitals in XY infants?
Presence of androgens
What is the age at which precocious puberty can be defined?
In boys - age 9
In girls - age 7
What is the first step in diagnosis of a child with premature adrenarche?
Bone age
What is the appropriate treatment in a child with premature adrenarche but normal bone age?
Follow clinically
What androgens are typically high in premature adrenarche?
DHEA and DHEAS
What may be a cause of premature adrenarche?
Exogenous or endogenous androgen OR late onset CAH
What should be done in a child with premature adrenarche and advance bone age?
ACTH stimulation test and
Serum testosterone
What is the cause of premature thelarche?
Exogenous or endogenous estrogen OR premature activation of the hypothalamic pituitary axis
What is the underlying cause of persistant Müllerian duct syndrome ?
Mullerian inhibiting substance not formed or there is a lack of receptors
What is the diagnosis in an XY male with formation of uterus, Fallopian tubes and upper vagina?
Persistant Müllerian duct syndrome
What is the phenotypic findings in klinefelter syndrome ?
Small testicles and penis
No internal or external female genitalia
What is the inheritance pattern of androgen insensitivity ?
X linked
What is the underlying cause of an XY male with no external male genitalia and a blind ending vagina with no uterus?
Androgen insensitivity - peripheral receptors are resistant to testosterone
Which 3 syndromes may present with panhypopituitarism?
Prader Willi
Kallmann
Septo-optic dysplasia
What condition is due to increased androgen causing ambiguous genitalia in females and excessive scrotal pigmentation in males?
Congenital adrenal hyperplasia
How is CAH inherited?
Autosomal recessive
What is the most common cause of CAH?
21 hydroxylase deficiency
What lab findings will be present in congenital adrenal hyperplasia?
Low Na
High K
High 17 hydroxyprogesterone
How is prenatal screening for CAH performed?
Molecular genetic testing of fetal cells
NOT via amniotic fluid measurement of 17 hydroxyprogesterone
What should be done if 17 hydroxyprogesterone assay is positive?
Repeat. If positive again, get serum electrolytes and urinary excretion of Na/k
How is congenital adrenal hyperplasia treated?
Hydrocortisone
What is the name of primary adrenal deficiency ?
Addison
What are the classic symptoms of Addison disease?
Hyperpigmentation due to high ACTH
Low Na and high K due to low aldosterone
How is secondary adrenal deficiency different from primary adrenal deficiency?
In secondary deficiency... The problem is the pituitary gland Normal ACTH (no hyperpigmentation) Normal aldosterone (normal K and Na)
What symptoms can present if a patient abruptly stops taking glucocorticoids?
Signs of adrenal insufficiency …muscle weakness, decreased BP, increased pulse
What 3 studies should be done if you suspect Turner syndrome ?
Karyotype
LH:FSH
TSH (Turner associated with hypothyroidism)
What diagnosis should you consider in a short female with scant Breast tissue and pedal edema?
Turner syndrome
Which disease should you consider in a patient with disproportionate short stature?
Achondroplasia
What disease shows early puberty followed by accelerated growth that ends with short adult height?
Congenital adrenal hyperplasia
What disease should you consider in an 11 year old with delayed bone age who is overweight?
Hypothyroidism
What is the most important determinant for ultimate adult height in a child who is tall for age?
Sexual maturity rating
What disease should you consider in a male with gynecomastia and learning disability?
Klinefelter
What disease should you consider in a child with tall statue who suffers from sudden death?
Marfan syndrome
What is the main fatal developmental anomaly in Marfan syndrome ?
Cardiac defect (Aortic aneurysm )
What disease presents as a tall child with large head circumference and cognitive deficits?
Soto’s syndrome
What diagnosis should you consider in a patient who is tall and overweight but has advanced bone age?
High caloric intake
What is the likely explanation of a patient on levothyroxine whose T4 and TsH levels are both elevated?
Poor compliance
What can be the long term consequences of delayed treatment of hypothyroidism?
Learning disability and diminished fine motor skills
What diagnosis should you consider in a newborn with poor feeding, hypotonia, Macroglossia and a hoarse cry?
Hypothyroidism
How long after treatment of started should T4 and TSH levels be rechecked?
1 month
In secondary hypothyroidism, are TSH levels low or high?
TSH levels may be low or normal (dz is due to poor function of hypothalamus or pituitary gland)
What is the other name for chronic lymphocytic thyroiditis?
Hashimotos
What is the most common cause of goiter in adolescence?
Hashimotos
What antibodies may be abnormal in hashimotos ?
Anti-thyroglobulin and anti-thyroid peroxidase
What are the presenting symptoms of hashimotos?
Hypothyroidism (most commonly)
Can present in thyrotoxicosis with transient high thyroid hormone
What disease is cause by thyroid stimulating immunoglobulin?
Graves’ disease
What disease may present with decreased muscle strength, hyperactivity and lid lag?
Graves’ disease
What GU symptoms may be present in Graves’ disease?
Increased urination at night
Decreased menstrual flow
Decreased frequency of menses
How can you distinguish Graves’ disease from subacute thyroiditis?
Radioactive iodine uptake will be high in graves but low in subacute thyroiditis
What would be the treatment for Subacute thyroiditis?
Supportive care / monitor
What disease may cause irritability, tremors and SVT in the immediate newborn period ?
Neonatal thyrotoxicosis
What is the treatment for neonatal thyrotoxicosis?
Methimazole or propylthiouracil
Radioactive iodine
Thyroidectomy
What do you do if you discover a solitary thyroid nodule in an adolescent?
FNA !! Watchful waiting is the WRONG answer
What type of radiation is a risk factor for thyroid cancer?
Ionizing radiation (UV radiation is not a risk factor)
How do you distinguish a hot vs cold thyroid nodule?
Fine needle aspiration biopsy ( 131 iodine scan is no longer the correct answer)
When should you suspect thyroid binding globulin (TBG) deficiency?
Abnormally low T4
Normal free T4
Euthyroid patient
Normal TSH
What is the treatment for thyroid binding globulin deficiency?
Nothing! Normal free T4 is maintained
What are the 4 ways to diagnose diabetes based on glucose levels?
2 random values >200.
Symptoms + 1 random glucose >200
Fasting glucose >126
2hr post GTT >200
When should patients with type 1 diabetes have lipid level testing?
Starting at age 12
When should type 1 diabetics have eye exams?
Starting at age 10
If a patient comes in with high Na which corrects with rehydration, what should you consider?
Siadh
When should bicarb be given to a patient in dka ?
When PH is <7.1 and only to bring it up to 7.2
Do not use if hypokalemia unless K supplements have been started !!
How can you distinguish type 1 and type 2 diabetes via labwork?
Autoantibodies against pancreatic beta cells are present in type 1
You are evaluating an obese child with acanthosis nigricans. What is the most likely lab finding?
Low HDL - trick question because acanthosis is correlated with insulin resistance not necessarily diabetes
What are the 5 components of metabolic syndrome ?
High triglycerides Low HDL HTN Fasting glucose >100 Truncal obesity
What is the definition of hypercalcemia?
Calcium >11
What are the 4 main causes of hypercalcemia ?
Williams syndrome
Ingestion (vit A and D, thiazides)
Skeletal dysplasia or immobilization
Hyperparathyroid
What is the appropriate treatment for a child who has been bedridden for a prolonged period of time who develops high calcium but is otherwise well appearing?
Fluids, LASIx and EKG monitoring
What is the definition of hypocalcemia?
Ionized Calcium <4.5 or total calcium <8.5
What diagnosis should you consider in a patient with muscle spasms, seizures, vomiting and prolonged QT?
Hypocalcemia
What is the name & cause of the finding where muscle contraction occurs when tapping anterior to the ear lobe?
Chvostek sign / hypocalcemia
What is the name and cause of the carpal muscle spasm with blood pressure cuff inflation?
Trousseau sign / hypocalcemia
What are the 5 main causes of hypocalcemia?
Pseudohypoparathyroidism Poor nutrition Digeorge syndrome Nephrotic syndrome Renal insufficiency
What is the likely diagnosis in a patient with hypocalcemia and hypophosphatemia?
Vitamin D deficiency
What is the likely diagnosis in a patient with hypocalcemia and hyperphosphatemia?
Hypoparathyroidism
What are the values of PTH and calcium in a patient with pseudohypoparathyroidism?
High PTH and low calcium
What is the underlying problem in an LGA infant who is hypoglycemic and hypocalcemic?
Diabetic mother
What is the likely diagnosis in a patient with seizures resistant to diazepam treatment?
Hypocalcemia
What are the 4 risk factors for developing rickets?
Breastfeeding without vit D supplement
Poor exposure to sunlight
Low birth weight / prematurity
Anticonvulsant medications
What are the 2 causes of rickets?
Low calcium and/or low phosphate
What diagnosis should you consider in a patient with bone pain, anorexia, poor growth, widening wrists and delayed tooth eruption?
Rickets
What is rachitic rosary?
Enlarged costochondral junctions due to rickets
What lab findings confirm vitamin D deficient rickets?
High PTH
Low calcium
Low phosphate
Low 25 hydroxy vitamin D
What is the cause of vitamin D dependent rickets type 1?
Inadequate renal production of 1,25 dihydroxy vitamin D
How would you know the difference between the autosomal recessive vs nutritional deficiency as the cause of rickets?
In vitamin D dependent rickets there will be no clinical improvement with vitamin d replacement
What are the lab findings in vitamin D dependent rickets?
Low calcium
Low phosphate
Very low 1,25 dihydroxy vitamin D
Normal 25-hydroxy vitamin D
What is the difference between vitamin D dependent rickets type 1 and 2?
Type 1 has decrease 1,25dihydroxy vitamin D due to poor production
Type 2 has high 1,25dihydroxy vitamin D due to end organ resistance
What is the cause X linked hypophospatemic rickets?
Excessive phosphate loss through the kidneys
What is the treatment for X linked hypophospatemic rickets?
Phosphate and 1,25 dihydroxy vitamin D
In which form of rickets is the PTH normal?
Vitamin d resistant (X linked familial hypophospatemia)
