Endocrinology Flashcards
Causes of altered HgbA1c levels
IDA Blood loss/hemolysis Kidney disease Liver diseases Pregnancy Blood transfusion
What should you do with an abnormal diabetes test in a patient who has not been previously diagnosed?
Repeat testing
Other antibody in Type I DM that you haven’t been checking
Anti-tyrosine phosphatase IA-2
Metabolic syndrome factors
>40 cm waist circumference (35 in women) Fasting TGL >150 HDL <40 (<50 in women) HTN Fasting glucose >100
Pramlinitide
Amylin analogue that delays gastric emptying decreases glucagon secretion, and increases mealtime satiety
Indicated for Type I patients who are having trouble achieving glycemic control
How does metformin work again?
Decreases hepatic glucose production and increases insulin-mediated uptake of glucose in muscles
Contraindicated w/ progressive liver, kidney, or cardiac failure
Medications you CANNOT use with sulfonylureas
DDP-4 inhibitors (sitagliptin, saxagliptin, linagliptin) as these medicines cause glucose-dependent increases in insulin secretion
-Also, increases risk of pancreatitis and may be associated w/ increased in heart failure exacerbations
Vitamin deficiency that can develop w/ metformin use
Vitamin B12 (in up to 5% of patients)
Cancer drugs that are associated w/ hyperglycemia
Calcineurin inhibitors (Sirolimus, tacrolimus/prograf, cyclosporine/gengraf)
Cardiac medications that are associated w/ hyperglycemia
BBs (decrease insulin release and increase peripheral resistance)
Thiazide (decreased insulin secretion 2/2 hyperkalemia
Psych meds associated w/ hyperglycemia
2nd generation antipsychotics
Pathophysiology of DKA/HHS
Relative insulin deficiency state w/ subsequent ketone production, lipolysis
HHS typically more lethal due to it happening in younger people with better GFR allowing for higher glucosuria
Thyroid nodule suspicious characteristics
Microcalcifications, irregular borders
If extrathyroidal extension, lymph node involvement, or symptoms present, you can biopsy w/ <1cm nodules
Recommendations for nodule w/ atypia of uncertain significance or follicular lesion of uncertain significance
Repeat FNAB in 3 months
Pemberton sign
Position patient with head down and hands up and look for:
- JVD
- Facial plethora
- Flushing
=» Thoracic outlet syndrome
Most common cause of goiter in geriatric patients in the US
Multinodular goiter
Jod-Basedow Phenomenom
Administration of iodine to multinodular goiter patient causes iodine-induce hyperthyroidism
Difference in mets in papillary thyroid carcinoma vs follicular carcinoma
Papillary-Cervical lymphadneopathy but less commonly w/ distant mets
Follicular- Mets to lung, bone but less commonly w/ follicular lymphadenopathy
High risk features for recurrence in thyroid cancer
Extrathyroidal extension
Lymphovascular invasion
Poorly differentiated on histology
Metastatic disease
-Typically administer radioactive iodine after surgery in these patients
Markers monitored after treatment for thyroid cancer
Throglobulin or thyroglobulin antibody (if antibody present, use this)
Therapy for high-risk differentiated thyroid cancer
LT4 to suppress the TSH to at least less than 2 but is individualized
Anaplastic thyroid cancer
Rare but aggressive and presents as a rapidly enlarging neck mass
Median survival is 5 months as it is usually nonresectable at diagnosis; treatment for this one is chemo
Medullary thyroid cancer
Arises from parafollicular cells due to germline RET oncogene mutation (MEN syndromes)
Tx: Total thyroidectomy w/ central neck lymph node dissection
Scenarios in which T3 measurement is recommended
- Identifying isolated T3 toxicosis
- To assess the severity of hyperthyroidism and the response to therapy
- To differentiate hyperthyroidism from destructive thyroiditis
What clinical indication is there to check rT3?
None
What meds can decrease LT4 absorption?
Calcium, PPIs, Iron, sucralfate
What meds increase LT4 metabolism?
Dilantin
Carbamazepine
Rifampin
Sertraline
What drugs cause thyroiditis
Amiodarone
Lithium
Interferon-a (can also cause antithyroid antibodies to develop)
IL-2
TKIs (sunitinib)
Immune checkpoint inhibitors (nivolumab, pembrolizumab)
What drugs inhibit TSH synthesis/release?
Steroids
Dobutamine
Octreotide
What drugs increase TBG?
OCPs
Tamoxifen
Methadone
What drugs decrease TBG?
Androgens
Steroids
Niacin
Struma ovarii
Causes thyrotoxicosis in ovarian teratoma
Wolff-Chaikoff effect
Relative hypothyroidism when ingesting increased amounts of iodine
Seen in amiodarone use in first few months but usually resolves
Goal TSH for pregnant patients
<2.5; you also start treating treatment-naive patients if found to have anti-TPO and TSH is >2.5
TSH levels not consistent w/ euthyroid sick syndrome
TSH <0.01 or TSH >20
Treatment for thyroid storm
Treat inciting cause AND IV BB PTU w/ transition to methimazole when stable IV dexamethasone KI (administer one hour after thioamide)
Plasmapheresis can be considered if no response
If patient survives, thyroidectomy or radioablative therapy indicated
Med to administer empirically prior to starting treatment for myxedema coma
Glucocorticoids; after that, administer IV bolus of LT4 at 400ug
Labs that need measured in chronic hypoparathyroidism
Ca, Mg, Cr, and URINE Ca
-Urine Ca should be <300mg/24hrs; if its higher, decrease calcium supplementation as this may cause urinary stones/fall in GFR
Empty sella work up
Typically, clinics assessment and 8AM cortisol and TSH
Hyperprolactinemia is the most common abnormality tho as pituitary is still present, it is just in a round ring around the site of the sella
Cancers that met to the pituitary
Breast Lung Lymphoma Renal cell Langerhans can involve it
-Typically causes DI, optic nerve dysfunction, sometimes HA and CN palsies
What cancer drugs cause hypophysitis?
Check point inhibitors
Work up for pituitary tumor
Prolactin
IGF-1
MRI w/out with sella turcica imaging
Also check FSH, LH, TSH to see if they are LOW
Monitoring pituitary microarenkma
Repeat imaging every 1-2 years
Lab to check in patient who you are suspicious for alderosteronoma but are on an ACEI/ARB
Renin level
If low, then an actual Angiotensin-Renin level is indicated
Gene to check for with medullary thyroid carcinoma and the associated cancers
RET
Pheochromocytoma, parathyroid hyperplasia, mucosal neuroma, gastrointestinal ganglioneuroma, and Marfanoid body habitus (if MEN2B)
(These are MEN 2A and 2B tumors so remember your chart)
Common meds that can affect biochemical testing for pheochromocytoma
Tylenol, antipsychotics, SNRIs, MOAIs, TCAs, Buspirone, caffeine, cocaine, decongestants (pseudoephedrine), ethanol
Should ideally discontinue these 2 weeks prior to testing
Steroid with highest anti-inflammatory potency
Dexamethasone
Steroid with shortest half life
Hydrocortisone; this is why it requires TID dosing yah dingus
Treatment of choice for adrenal crisis
Hydrocortisone 100mg q8hrs
When adrenal insufficient patients are ill or having surgery, what should should they do with their steroid dosing?
Increase 2-3x
Testing for adrenal incidentaloma
Must be at least 1cm
Subclinical Cushings (Overnight dexamethasone suppression test) Pheo testing Aldosterone testing if patient has HTN or hypokalemia
Indications for adrenalectomy
Suspicious imaging
Growth >1cm year
Function tumor (pheo, aldosterone, subclinical Cushings)
Lab to check in an obese man with a low 8AM testosterone level
Free testosterone
These patients have elevated SHBG leading to falsely decreased 8AM testosterone levels
Lab to check after confirming low testosterone levels
LH
Workup of painful male gynecomastia
bHCG, estradiol, LH, 8AM testosterone
What does rapid onset of hirsutism in woman >30 years old worry you for
Androgen producing tumor
Eval of female hyperandrogenism
SHBG, 12-hydroxyprogesterone (check for CAH)
hCG, prolactin, FSH, TSH, DHEA if rapid to check for tumor
