Endo Flashcards
Electrolyte abnormalities in addisonian crisis
HypoNa, Hyper K
Late feature: hypoglycaemia
What are the typical LDL, HLD and TG findings in patients with diabetes?
TG elevated
HDL and LDL are low or normal
Aromatase converts testosterone to estradial T/F
T
In a pt with T1DM doing sick day dosing should the lantus be increased or decreased?
Increased - will have increased insulin requirements in the setting of an acute illness
During puberty breast enlargement occurs in about 10% of males T/F
F - occurs in 40-60% of males, it is due to metabolism of testosterone, usually resolves in 2-3 years and does not need treatment
Dawn phenomenon is due to noctural hypoglycaemia and subsequent rebound hyperglycaemia in the early morning T/F
F - this is the description of smogyi effect, features of noctural hypoglycaemia (nightmares, tremors and rarely sz, early am headaches)
Dawn phen - early am hyperglycaemia from growth hormone secretion, peaks around 0400 - 0500. Can tx with increased insulin dosing
In pts with DM growth spurt leads to hypo or hyperglycaemia?
Hyperglycaemia and increased insulin requirements
Precocious puberty in males often has a pathological cause T/F
T - 80%
What is the most common enzyme deficiency causing congenital adrenal hyperplasia?
Deficiency in 21-hydroxylase
Enzyme 21 hydroxylase converts what to what?
17OH progesterone to 11 deoxycortisol
Hence in deficiency will get a build up of 17OHP and a low 11 deoxycortisol. However levels of 17OHP are elevated in normal infants in the first 1-2 days of life, especially so if they are premature or ill.
Most reliable way to diagnosis 21 hydroxylase def?
Measure 17OHP at baseline and then 30, 60 min after admin of ACTH
What is the second most common enzyme def leading to congenital adrenal hyperplasia?
Clinical features?
11 beta hydroxylase def (converts 11deoxycortisol to cortisol)
Features:
Signs of androgen excess (2ndary sex characteristics w/o testicular enlargement)
HTN
Do not have adrenal crisis
First sign of puberty in girls?
Breast development
First sign of puberty in boys?
Increase in testicular volume
Time from onset of puberty to menarche is usually? What SMR does menarche usually occur?
4 yrs or less
SMR 4
In treatment of DM how often is insulatard dosed?
Twice daily
Patient on TID steroids is prescribed carbamazepine what adjustment needs to be made to the steroids?
Increase each dose of steroids
When is the peak incidence of type 1 DM?
When children start school 5-7 yrs and at puberty 10 -14 yrs
Note: there is an increased incidence after Coxsackie virus, mumps and rubella epidemics suggesting that initial viral infection triggers an autoimmune response against the islet cells. There is a seasonal variation with peaks in the autumn and winter months
T1DM is associated with an increased risk in siblings T/F
T - 1-7% risk
How often should HbA1c be checked in pts with T2DM?
every 3 months (remember life cycle of RBC is 3 months)
What are the two most common causes of acquired hypothyroidism?
Hashimotos thyroiditis
Post total body irradiation (part of the prep for bone marrow transplant)
Causes of elevated creatinine in DKA?
Dehydration
Falsely elevated Cr as the ketones interact with the Jaffe method
What physical exam finding in a male helps to differentiate central from peripheral causes of precocious puberty?
Peripheral: secondary sexual characteristics in a boy with pre-pubertal testes
Central: secondary sexual characteristics + bilaterally enlarging testes
Growth hormone deficiency has what effect on bone age?
Causes a delay in bone age
Hypothyroidism also causes a delay
What lab abnormality can been seen on sulphonylurea overdose?
Increased C peptide – stimulation of beta cells to produce both c peptide and insulin
Note in exogenous insulin OD there will be decreased C peptide
What is the risk of T1 DM in a patient who’s identical twin has type 1 DM?
30-50%
Note: glutamic acid decarboxylase, islet cell or islet tyrosine phosphatase 2 (IA-2) antibodies will increase the risk
What % of patients with T1 DM also have celiac disease?
Around 10%
Compared to untreated children by how much does growth hormone increase final height?
3-4 cm
Parathyroid hormone is secreted in response to what?
Low levels of iCal in the blood
What is the role of parathyroid hormone?
To increase renal Ca absorption and mobilise Ca and phosphate from the bone
MEN1 is associated with mucosal neuromas T/F
F MEN 2b is associated with mucosal neuromas
MEN 1 is associated with pit adenoma, parathyroid tumors and pancreatic tumors
Somatostatin has what effect on growth hormone?
Inhibits release of growth hormone
Factors that increase secretion of growth hormone?
Hypoglycaemia
Mod to high intensity exercise
Stress due to emotional disturbances, illness or fever
Dopamine agonists such as bromocriptine
Cortisol is a counter regulatory hormone of?
Insulin –> it has the opposite effects of insulin.
Hence cortisol increases gluconeogenesis, hepatic glycogenolysis and ketongensis
One of the main mechanisms of action of insulin is to induce translocation of the preformed GLUT 4 transporter to the cell surface. T/F
T - then insulin binds to the transporter which generates a signal within the cell to stimulate glucose conversion to glucose-6-phosphate and terminates metabolism or storage of the glucose molecule
How do sulphonylureas increase insulin release?
Stimulation of cell surface ATP-sensitive K+ channels
This then causes hyper polarisation and Ca influx that leads to insulin release
Is the urinary concentration of Na in a pt with SIADH low or high?
It is high, they will pass a small volume of concentrated urine.
Insulin is the mainstay of treatment of neonatal diabetes T/F
F - about 50% of pts can be managed with glibenclamide and do not need insulin
Note: neonatal DM is likely due to a monogentic mutation and genetic investigations are needed
What is Laron syndrome?
Autosomal recessive disorder caused by insensitivity to growth hormone
What is the most appropriate long term treatment for a patient with GLUT 1 deficiency?
Ketogenic diet
Note: thioctic acid can be used as an adjunct but it is not the primary treatment
How often should a patient with type 1 diabetes be seen in endocrine clinic?
Every 3 months
What is the goal of calcitonin in the body?
To decrease Ca (eg opposite effect of PTH)
A child presents with diabetes, what age should you consider other types of diabetes besides type 1 or 2?
If they are less than 1 yr old at presentation
Note: should also consider in those who rarely/never develop ketones with hyperglycaemia
A patient with new onset T1 DM is likely to have what antibodies at presentation?
Islet cells
Note: would be rare to have insulin antibodies at presentation, can have them later once they have started on exogenous insulin
What are the three layers of the adrenal cortex and what do they produce?
3 zona -
glomerulosa –> mineralocorticoids
fasciculata –> glucocorticoids
reticularis –> androgens
What is the K value in SIADH?
K is normal
Also normal acid base balance
Patient with serum hypoNa and hypo osm and concentrated urine. What pathology should be suspected?
SIADH -> retaining water, if patient’s water intake is higher than their urine output they will become hypoNa -> initial management is restriction of fluids to 2/3 maintenance
How often should an insulin pump site be changed?
Every 2-3 days
When/how is prolactin secreted?
Sleep related secretion
Note: growth hormone is also sleep related
C peptide levels can help to differentiate type 1 DM from other types T/F
T - they are more useful the longer time between the initial presentation and the test
How often is Insulatard dosed?
This form of insulin is dosed BID, useful in school aged children as they do not have to have insulin admin during school day. Usually given in am and afternoon
From what age should those with T1 diabetes be monitored for thyroid disease?
At diagnosis and then annually
In terms of an isolated findings which is more concerning premature pubarche or thelarche?
Premature pubarche (development of pubic or axillary hair without other features of precocious puberty) - likely due to androgen excess
Note: premature thelarche is usually benign and self limiting
In the thyroid what do the parafollicular cell secrete?
Calcitonin - they are also known as C cells
Thyroid hormone is synthesised at the cellular level and stored as thyroglobulin T/F
T
Testosterone, FSH and LH levels on Klinefelter syndrome
Reduced testosterone leading to increased FSH and LH due to negative feed back
Infants with 21 hydroxylase deficiency present with a salt losing crisis and ambiguous genitalia T/F
F - females will present this way; males will have normal genitalia
Below what length is a term male penis considered abnormal?
< 2cm
Note: requires endocrine evaluation
When does the American Diabetic Association recommend screening for microalbuminuria?
T1 DM - 5 years after initial diagnosis
T2 DM - at initial diagnosis
Then yearly
In a patient with nephrogenic diabetes insipidus what lab values would be expected?
Unable to concentrate urine –>
spec grav < 1.005 and urine osm < 300 mOsm/kg
HyperNa and serum osm > 300 mOsm/kg
NB: in primary polydipsia they are hypoNa and have a low serum osm
DI is defined as passage of ___ volumes of ___ urine
Large volumes of dilute urine
Pathophys of central DI?
Decreased secretion of ADH
Note: compare to nephrogenic DI in which kidney is resistant to ADH
Features of Kallmann syndrome
Red green color blindness Cleft lip/palate or other midline defect SN hearing loss GU abnormalities Mirror movements (involuntary movements mirroring contralateral voluntary hand movements) Anosmia
Growth hormone deficiency usually presents within the first 6-9 months of life T/F
F - during the first 1-2 years of life thread hormone and nutrition are more important for growth , this is why GH def does not typically present in the newborn period. It typically presents around 18-24 months old
Endocrine abnormalities associated with SUFE?
Hypothyroid
Hypopituitary
Decreased GH
Idiopathic central precocious puberty is due to early pulsatile or constant secretion of GnRH?
Early pulsatile
Growth hormone is licensed for what disorders?
Turner syndrome
Chronic kidney disease before transplantation
SGA with lack of catch up growth by 2 yrs
SHOX halopinsufficiency
Noonan syndrome
Severe idiopathic short stature
Prader willi syndome
Cause of late onset hypoCa seizure in neonate?
Hypoparathyroidism
Note: late onset if > 72 hours; causes of early onset include infant of diabetic mother; IUGR; birth asphyxia or sepsis
Features of Swyer Syndrome
AKA XY pure gonadal dysgenesis
Complete female phenotype at birth
Presence of vagina and fallopian tubes
Streak gonads –> do not produce testosterone or DHT (contrast to androgen insensitivity where testosterone is high or normal)
No breast development or menstruation at puberty
Features of 5 alpha reductase deficiency?
Elevated testosterone/DHT ratio (usually > 30)
(unable to converts testosterone to DHT)
Ambiguous genitalia
Viralisation at puberty
Management of Swyer syndrome?
Removal of the gonads as soon as diagnosis is made due to high risk of malignancy
Lab findings in androgen insensitivity syndrome?
Normal or elevated testosterone
Preserved testosterone: DHT
Criteria for diagnosis of Diabetes according to American Diabetes Association?
One of the below 4
- Fasting plasma glucose > 126mg/dl
- Symptoms and a random glucose > 200mg/dl
- Plasma glucose > 200 2 hours after OGTT
- HbA1c > 6.5%
Which has hypertension, 11 beta hydroxylase def or 21 hydroxylase def?
11 beta
Would FSH and LH be high or low in Turners syndrome?
Both would be high, as it is a primary hypogonadism
Note: low FSH and LH are found pre puberty and also in gonadotropin deficiency
Which lab tests should be ordered to evaluate premature thelarche? What results would be expected ?
Bone age (within 2 SDs of chronological age)
Estradiol (normal, < 10)
LH/FSH
Note: no other signs of puberty; typically presents around 6-12 months old and progresses over 6-18 months with a gradual reduction in size over the same time period. Can also reassure that findings is normal and re examine in 3-6 weeks without lab work
In the mgmt of DKA when should dextrose be added to the IVF?
When the glucose drops to 250 - 300
Note: if patient is making urine and K < 5, K should also be added to the fluids
What is the best initial screening test for Cushing syndrome?
24 hr urinary free cortisol level
Note: low dose dex suppression test or midnight/overnight serum or salivary cortisol level can be useful too.
Pathology of Cushing disease vs Cushing syndrome?
Cushing syndrome - due to prolonged exposure of endogenous or exogenous glucocorticoids
Cushing disease (type of syndrome) - caused by ACTH secreting pit adenoma
What is the most common endogenous cause of Cushing syndrome?
ACTH secreting pituitary adenoma (Cushing disease)
Note: overal exogenous steroid use is most common cause of Cushing syndrome
When starting someone with PCOS on an OCP which is the best progestin?
Drospirenone
Note: this is because it has low androgen effects. It is in yas and Yasmin
Graves disease is associated with elevated levels of____
Thyroid stimulating immunoglobulin
Note: it is due to thyroid receptor stimulating antibodies
Mgmt of T2 DM?
If not metabolically decompensated at presentation, guided by HbA1c
- < 8.5 : metformin and lifestyle modification
- > 8.5: consider adding basal insulin to metformin
Child with cleft lip, delayed eruption of teeth and a single central maxillary incisor, what pathology
GH def
Note: children with midline defects (eg cleft lip/palate and septooptic dysplasia) have increased risk of hypopit associated with GH def
Maternal age < 25 and pre E are both RF for T1 DM in infant T/F
F - preE and mat age > 25 are both RFs
Other RF: HLA DR3, DR4, B8, BW15; neonatal response disease and ABO incompatibility
Growth hormone supplementation is associated with sudden death in what pathology?
Prader Willi syndrome
Note: thought to actually be due to OSA and apnea –> recommended sleep study and discussion of risks/benefits prior to GH in this population
TSH and T4 in Hashimoto thyroiditis?
TSH: elevated
T4: low
TSH and T4 in primary vs central hypothyroidism?
Both have low T4
Central: inappropriately normal TSH
Primary: elevated TSH
