Endocrinology Flashcards
Initial workup for adrenal incidentaloma?
- 1 mg overnight dexamethasone suppression test
- plasma aldosterone-plasma renin activity ratio
- urine metanephrines and catecholamines, (and serum metanephrines for high likelihood)
Features of adrenal incidentaloma that suggest malignancy?
- bilateral or large lesions >4 cm
- irregular or inhomogenous morphology
- contrast enhancement with delayed washout
- high-attenuation lesions >20 HU
When to remove adrenal incidentaloma?
- > 4 cm or if functioning
How do DPP-4 inhibitors work and what are two examples?
- inhibits the breakdown of GLP-1 and GIP, which leads to glucagon suppression, insulin release, and therefore decrease blood glucose
- ex. sitagliptin (Januvia) and linagliptin (Tradjenta)
Causes of stridor after thyroidectomy, and how to distinguish between them?
- immediately after extubation -> recurrent laryngeal nerve injury
- few hours after extubation -> wound hematoma compression
- greater than few hours after and preceded by paresthesias or muscle cramps -> likely 2/2 transient hypocalcemia (common 60-90% pts) or inadvertent parathyroidectomy
Etiologies of metabolic alkalosis with hypokalemia? How to distinguish?
- vomiting
- diuretic use
- abnormal sodium handling- Bartter or Gitelman
- urine chloride is low in vomiting because GI losses cause chloride to be reabsorbed by kidneys
- patients taking diuretics or who have abnormal sodium handling are unable to reabsorb it so they have high urine chloride
What endocrine screening do all new hypertensive patients require?
TSH
In amiodarone-induced thyrotoxicosis, radioactive iodine uptake levels are:
undetectable or low
TSH, T3 and T4 levels in euthyroid sick syndrome?
low T3 typically, normal T4 and TSH
Evaluation of thyroid nodule?
- TSH and thyroid u/s
- TSH low-> radioactive iodine scintigraphy
TSH normal or high- consider FNA based on size and u/s findings
3. radioactive iodine scintigraphy shows: hot nodule (hyperfunctioning): treat the hyperthyroidism
cold nodule (hypofunctioning or indeterminant): consider FNA based on size and u/s findings
Etiology of primary adrenal insufficiency (Addison’s Disease)?
- Autoimmune
- Infections
- Hemorrhagic infarction
- Metastatic
Clinical presentation of primary adrenal insufficiency?
- fatigue, weakness, anorexia/wt loss, salt cravings
- GI symptoms
- postural hypotension
- vitiligo or hyperpigmentation
- hyponatremia, hyperkalemia
- may lead to acute adrenal crisis: hypotension, shock ,abdo pain, AMS
Diagnosis of primary adrenal insufficiency
ACTH, serum cortisol, high dose ACTH stimulation test/cosyntropin
primary: low cortisol, high ACTH
secondary/tertiary: low cortisol, low ACTH
indications for parathyroidectomy in primary hyperparathyroidism
age >50 osteoporosis serum ca >1 mg the upper limit of normal urine ca loss >400/day renal insufficiency- CrCl <60 ml/min
In central (secondary) hypothyroidism, ex. pituitary tumor, what lab value do you use to titrate levothyroxine?
Free T4
TSH is usually low or inappropriately normal in central hypothyroidism, and does not respond to levothyroxine