Endocrine IV Flashcards
What is the likely explanation for the abnormal laboratory values in a pregnant woman that experiences fatigue, anxiety, and difficulty sleeping with normal TSH and elevated total T4? Thyroid examination is benign.
Increased thyroid-binding globulin (TBG) level
estrogen increases level of TBG, resulting in elevated total T4 but normal free T4 (euthyroid state); her symptoms are unrelated
What is the likely source of an androgen-secreting tumor in a female with elevated testosterone and elevated dehydroepiandrosterone sulfate (DHEAS) levels?
Adrenal tumor
causes rapidly progressive hirsutism; androstenedione, DHEA, and testosterone are produced by both the ovaries and adrenals, while DHEAS is predominantly produced in the adrenals
What is the likely source of an androgen-secreting tumor in a female with elevated testosterone and normal dehydroepiandrosterone sulfate (DHEAS) levels?
Ovaries (more common)
causes rapidly progressive hirsutism; androstenedione, DHEA, and testosterone are produced by both the ovaries and adrenals, while DHEAS is predominantly produced in the adrenals
What is the major gluconeogenic amino acid in the liver?
Alanine
What is the most beneficial therapy for reducing the progression of diabetic nephropathy?
Strict blood pressure control
some guidelines recommend a target BP of 130/80 mmHg, others recommend 140/90 mmHg
What is the most common cause of primary adrenal insufficiency in developed countries?
Autoimmune adrenalitis
What is the most common underlying cause of neuropathic ulcers?
diabetes mellitus
typically occur on the sole of the foot at weight-bearing areas (e.g. under head of first metatarsal)
What is the most important contributing factor for diabetic foot ulcers?
Diabetic neuropathy
other important risk factors include previous foot ulceration, vascular disease, and foot deformity
What is the most important initial step in management of a patient with hyperosmolar hyperglycemic state?
Fluid replacement with normal saline
may switch to 0.45% saline after a few hours if corrected Na+ levels are high; IV insulin +/- K+ are important as well, but not as important initially
What is the most sensitive test for differentiating adrenal adenoma and bilateral adrenal hyperplasia in patients without a discrete unilateral adrenal mass on imaging?
Adrenal venous sampling
What is the most serious adverse effect associated with anti-thyroid drugs (e.g. methimazole, PTU)?
Agranulocytosis
patient’s on these drugs that develop a sore throat and fever should have their WBC count checked
What is the next step in a patient with suspected acromegaly that is found to have elevated IGF-1 levels?
Oral glucose suppression test
normally, glucose rapidly suppresses GH secretion; in acromegaly, glucose will not suppress (and may increase) GH secretion
What is the next step in diagnosis for a patient with myalgias, proximal muscle weakness, elevated creatine kinase, and delayed reflexes?
Measure TSH and T4 (to evaluate for hypothyroid myopathy)
other manifestations include fatigue and other symptoms of hypothyroidism (e.g. hair loss, cold intolerance)
What is the next step in management for a diabetic patient taking metformin and nightly insulin glargine that presents with an elevated hemoglobin A1c despite normal fasting glucose levels?
Add rapid-acting mealtime insulin
this patient likely has postprandial hyperglycemia
What is the next step in management for a patient taking PTU or methimazole that develops fever and sore throat?
Discontinuation of the drug, measure WBC count
fever and sore throat in patients on PTU/methimazole suggests agranulocytosis
What is the pathophysiology underlying hyperthyroid-induced bone loss?
Increased osteoclast activity
What is the preferred first-line treatment for central diabetes insipidus?
Desmopressin (intranasal preferred over oral)
What is the preferred imaging modality for evaluation of pituitary tumors?
MRI
recommended for patients with elevated prolactin, mass-effect symptoms, very low testosterone levels, or disruptions in other pituitary hormones
What is the preferred initial test for evaluating patients with suspected acromegaly?
IGF-1 level
IGF-1 levels in acromegaly are elevated throughout the day vs. GH levels, which fluctuate widely
What is the primary treatment for papillary thyroid carcinoma?
Surgical resection
What is the recommended blood pressure goal for patients with diabetes without proteinuria?
< 140/90 mmHg
patients with diabetic nephropathy may benefit from lower BP goals (e.g. < 130/80 mmHg) but evidence is conflicting
What is the recommended insulin regimen in patients with diabetic ketoacidosis?
IV insulin initially followed by subcutaneous insulin (see below); overlap SQ & IV insulin by 1-2 hours
insulin should be held if serum K+ < 3.3 mEq/L
What is the recommended IV fluid regimen for hydration in patients with diabetic ketoacidosis?
0.9% NS initially, add dextrose 5% when serum glucose is <200.
What is the recommended treatment for patients with primary hyperaldosteronism that are poor surgical canidates?
Aldosterone antagonists (e.g. spironolactone, eplerenone)
surgery is preferred for primary hyperaldosteronism due to unilateral adrenal adenoma
What is the treatment for a patient with symptomatic primary hyperparathyroidism?
Parathyroidectomy
other indications for parathyroidectomy include age < 50 and those at increased risk for complications (e.g. Ca2+ > 1 mg/dL above normal, evidence of osteoporosis)
What is the typical underlying etiology of acromegaly?
Pituitary somatotroph adenoma (excessive secretion of GH)
What is the underlying etiology of altered mental status in patients with hyperosmolar hyperglycemic state?
Hyperosmolality
common precipitating factors include infection, medications
What medications (4) should be administered to a patient with suspected thyroid storm?
- […]
- […]
- […]
- […]
What medications (4) should be administered to a patient with suspected thyroid storm?
- Propanolol (beta blocker)
- Propylthiouracil (PTU)
- Potassium iodide (unless pregnant)
- Prednisone (or other glucocorticoid)
“the four P’s” of thyroid storm management
What musculoskeletal pathology is associated with pseudofractures (Looser zones)?
Osteomalacia
What musculoskeletal pathology is caused by impaired osteoid matrix mineralization?
Osteomalacia
i.e. defective mineralization
What pregnancy complication is associated with Hashimoto thyroiditis?
Miscarriage
due to high titers of anti-thyroid peroxidase antibodies; increased risk in both euthyroid and hypothyroid women
What should be suspected in a patient taking PTU or methimazole that presents with fever and sore throat?
Agranulocytosis
warrants discontinuation of the drug and WBC count measurement
What test should be used to screen for diabetes mellitus in patients with polycystic ovarian syndrome?
Oral glucose tolerance test
more sensitive than fasting glucose and HbA1c in patients with PCOS
What thyroid abnormality (hyper- or hypothyroidism) is associated with hyperlipidemia (e.g. hypercholesterolemia, hypertriglyceridemia)?
Hypothyroidism
most patients have high cholesterol (due to decreased LDL receptors) with or without high trigylcerides (decreased LPL activity); patients may also develop hyponatremia and asymptomatic elevations in CK and AST/ALT
What treatment option for Graves disease may be associated with worsening of ophthalmopathy?
Radioactive iodine
contraindicated in patients with severe ophthalmopathy (due to increased thyroid-stimulating immunoglobulin titers); glucocorticoids and antithyroid drugs may be given initially to minimize side effects of RAI in patients with mild ophthalmopathy
What type of thyroid nodule, hyperfunctioning (“hot”) or hypofunctioning (“cold”), is more likely to be cancerous?
Hypofunctioning (“cold”)
thyroid function is evaluated using thyroid scintigraphy, usually with I123; cold nodules should be evaluated with FNA
What vitamin/mineral deficiency is associated with carcinoid syndrome?
Niacin (B3) deficiency
serotonin and niacin are synthesized from tryptophan; increased conversion of tryptophan to serotonin may result in niacin deficiency
Which anti-thyroid drug, methimazole or PTU, is preferred in most patients?
Methimazole (exception: women during the first trimester of pregnancy)
methimazole is a 1st-trimester teratogen; PTU has a black box warning for severe liver injury
Which subtype of thyroid cancer is associated with elevated calcitonin?
Medullary thyroid carcinoma
Which subtype of thyroid cancer is associated with psammoma bodies and “orphan annie-eye nuclei”?
Papillary thyroid carcinoma
Which subtype of thyroid cancer typically invades blood vessels and metastasizes hematogenously?
Follicular thyroid carcinoma
