Endocrine Flashcards
Diagnostic method of choice for thyroid nodules
Fine Needle Aspiration
Clinical signs of hyperthyroidism (list 7)
Weight loss in spite of ravenous appetite, palpitations, heat intolerance, moist skin, fidgety and hyperactive behavior, tachycardia, and sometimes atrial fibrillation or flutter
Lab tests that confirm hyperthyroidism (list two)
TSH (will be low) and T4 (will be high)
“Hot adenoma” of thyroid
Thyroid nodule, almost never cancer, but can be the source of hyperfunction. Nuclear scan will show if it is the source. Pts have the option of excising the affected lobe.
Patient with “stones, bones, and abdominal groans”
Hyperparathyroidism; usually found incidentally with high calcium
Cushing disease features (7 physical and 5 medical conditions)
Round face (moon facies), ruddy face (plethora), hairy (hirsutism), buffalo hump, supraclavicular fat pads, obese trunk with abdominal stria, and thin weak extremities. Osteoporosis, diabetes, hypertension, amenorrhea, and mental instability are also present.
Lab workup for Cushing’s disease (list two)
Overnight dexamethasone suppression test, and then 24-hour urine free cortisol
Zollinger-Ellison (gastrinoma) clinical presentation
Appears as virulent peptic ulcer disease, resistant to therapy, and extensive (several ulcers rather than one, extending beyond first portion of the duodenum). Sometimes watery diarrhea.
Zollinger-Ellison workup
Measure gastrin, which can be in the thousands. If that value is on the border (in the hundreds) do secretin test. Secretin should drive gastrin down normally, fails if there’s a tumor. Locate the tumor with CT scan (with contrast) of the pancreas and nearby areas. Remove it. Omeprazole helps those with metastatic disease.
Insulinoma clinical presentation
CNS symptoms because of low blood sugar, always when the patient is fasting.
How can you tell the difference between an Insulinoma and overdose of exogenous insulin?
With exogenous insulin, insulin will be high but C-peptide will be low. Both will be high with insulinomas.
Devastating hypersecretion of insulin in the newborn, and required treatment.
Nesidioblastosis. Requires 95% pancreatectomy.
Consider this if a patient is described as having Migratory necrolytic dermatitis, resistant to all forms of therapy, with mild diabetes, a touch of anemia, glossitis, and stomatitis
Glucagonoma. resect it.
Drugs that help with metastatic, inoperable glucagonoma
Somatostatin and Streptozosin
What should you suspect in a patient with hypokalemia and hypertension? Mechanism?
Hyperaldosteronism. Aldosterone acts on the distal convoluted tubule of the kidney to increase sodium reabsorption. This causes passive reabsorption of water and increases extracellular volume and blood pressure. To balance the positively charged sodium ions, potassium is excreted in the urine.
Patient with hypokalemic, hypernatremic, metabolic alkalosis
Primary hyperaldosteronism
How to tell the difference between primary hyperaldosteronism caused by hyperplasia vs. adenoma
Hyperplasia will react appropriately to posture: more aldosterone produced upright.
No response to posture indicates adenoma.
Suspect this in thin, hyperactive women who have attacks of headache, flushing, and palpitations, with episodic or sustained extremely high blood pressure.
Pheochromocytoma
Workup for pheochromocytoma
24-hour urinary determination of vanillylmandelic acid (VMA-easy to do, but may give false positives), metanephrines (more specific), or free urinary catecholamines. Follow with CT scan of adrenal glands or radionuclide studies if looking for extraadrenal sites. Tumors are usually large.
Suspect this in patients who are typically young and have hypertension in the arms, with normal pressure (or low pressure, or no clinical pulses) in the lower extremities. Chest x-ray shows scalloping of the ribs (erosion from large collateral intercostals).
Coarctation in the aorta
Two distinct groups of patients who have renovascular hypertension
Young women with fibromuscular dysplasia or old men with arteriosclerotic occlusive disease. In both groups hypertension is resistant to the usual medications, and a telltale faint bruit over the flank or upper abdomen suggests the diagnosis.
Hypercortisolism AKA
Cushing’s syndrome
Hyperaldosteronism AKA
Conn’s syndrome
Functional adrenal tumors typically secrete which three hormones?
Cortisol (Cushing’s), Aldosterone (Conn’s), and Catecholamines (Pheochromocytoma)
Two endogenous causes of hypercortisolism
Cortisol-producing adrenal adenoma, or a tumor producing ACTH usually in pituitary (more common)
Cushing’s syndrome vs. Cushing’s disease
Syndrome = constallation of features and findings, regardless of etiology. Disease = specifically the ACTH-producing pituitary adenoma.
Great treatment for hyperaldosteronism
Spironolactone (an aldosterone antagonist)
Physical effects of hypokalemia (list 3)
Muscle cramping, muscle weakness, and rarely paralysis
Fear this cancer in a person with Cushing’s syndrome, because they’re usually found late and are very lethal
Adrenocortical Carcinoma
What is an Adrenal Incidentaloma?
An incidentally discovered mass seen on imaging performed for an unrelated reason.
Most common adrenal mass
Nonfunctional benign adrenocortical adenoma
Zones of the adrenal gland, and what hormones they produce
Outer Cortex has three zones: Glomerulosa, Fasciculata, Reticularis (Good For Rashi). They produce aldosterone, cortisol, and androgens, respectively.
Inner Medulla produces catecholamines.
Suspect this in patients with hypernatremic, hypokalemic, metabolic alkalosis.
Hyperaldosteronism
Lab tests for hyperaldosteronism (list 2)
Plasma aldosterone to renin ratio (will be super high, because renin will be low). Serum potassium.
Lab tests for hypersecretion of catecholamines (pheochromocytoma). List 2.
24-hour urine metanephrines or catecholamines. Plasma metanephrines or catecholamines.
FYI urine is more specific, plasma is more sensitive.
Pheochromocytoma pts require what pre-operatively?
Alpha-blockade (eg Phenoxybenzamine) for 10-14 days prior to surgery. Sometimes coupled with beta-blockade if necessary.
When should you biopsy adrenal masses?
You shouldn’t.
What blood vessel should you be wary of during right adrenalectomy
The short, posterior adrenal vein entering the IVC.
What to can you give a pt w/ unresectable pheochromocytoma to reduce secretion of catecholamines?
Metyrosine (aka demser)
Most common demographic that gets primary hyperparathyroidism
Postmenopausal women
MEN-1 consists of what?
hyperparathyroidism, pituitary adenomas, and pancreatic neuroendocrine tumors
MEN-2A consists of what?
hyperparathyroidism, medullary thyroid cancer, and pheochromocytoma
MEN-2B consists of what?
marfanoid habitus, oral neuromas, medullary thyroid cancer, and pheochromocytoma
How does a hypercalcemic crisis present?
Nausea, vomiting, confusion, and mental status changes. This is a medical emergency, as severe hypercalcemia can lead to cardiac arrhythmias and coma.
Chvostek’s sign
Facial twitch in response to tapping on the facial nerve, anterior to the external auditory canal. This reflects early tetany and is a sign of hypocalcemia that may arise after parathyroidectomy
Trousseau’s sign
Flexion of the wrist and metacarpophalangeal joints and extension of the digits following inflation of a blood pressure cuff around the arm to greater than systolic blood pressure. Similar to Chvostek’s sign, this marks early tetany due to hypocalcemia.
principal mediator of calcium homeostasis
parathyroid hormone
Confirmatory labs for primary hyperparathyroidism
High serum PTH, high serum calcium, and high urine calcium. The high urine calcium helps distinguish from FHH.
Equation to correct calcium based on patient albumin
0.8*(normal albumin - pt albumin)+calcium
Most common renal manifestations of hypercalcemia (5)
Nephrolithiasis (kidney stones), nephrocalcinosis, polyuria, polydipsia and renal HTN
GI manifestations of hypercalcemia
Constipation, nausea, vomiting, heartburn, and abdominal pain
Neuro manifestations of hypercalcemia
Fatigue, depressed mood, difficulty concentrating, impaired memory, anxiety, sleep disturbance, proximal muscle weakness, and psychomotor symptoms. Stupor and coma in extreme cases (>14 mg/dL) or the elderly
Pathophysiology of primary hyperparathyroidism
Enlargement and hypersecretion by a single (80 %) adenoma or multiple (20 %) parathyroid glands hyperplasia or multiple adenomas). The cell population within parathyroid adenomas is monoclonal or oligoclonal.
What Is the Pathophysiology of Secondary Hyperparathyroidism?
Response to prolonged hypocalcemia from chronic kidney disease or vitamin D deficiency which leads to parathyroid hyperplasia (polyclonal expansion) with excessive PTH secretion. Serum calcium levels can be low or normal.
What Causes Tertiary Hyperparathyroidism?
Persistent excess secretion of PTH following renal transplantation. Renal transplantation restores normal vitamin D homeostasis and reverses secondary hyperparathyroidism in >95 % of cases within 1 year.
Test to help localize the involved gland in hyperparathyroidism
99-m technetium sestamibi scanning and ultrasound are the most frequently used imaging tests to localize the involved gland(s) in primary hyperparathyroidism
Classic triad of sx in pheochromocytoma
headaches, flushing, palpitations
In a pt w/ coarctation of the aorta, what assc disorders should you consider?
In children, PDA. In everyone, Turner syndrome and bicuspid aortic valves
Why Do Patients with Pheochromocytoma Have Hyperglycemia?
Catecholamines are potent stimulators of hepatic glucose production and inhibitors of insulin secretion and action, leading to elevated serum glucose
Best imaging studies for pheochromocytoma
CT or MRI with contrast. Best is nuclear imaging with I-MIBG, a catecholamine precursor taken up by chromaffin cells
5 P’s of pheochromocytoma
Pressure (episodic HTN), pain (headaches), perspiration, palpitation, pallor
What cells comprise a pheochromocytoma
Chromaffin cells of the adrenal medulla
Cause of death in thyroid storm, and what meds to give.
High-output cardiac failure. Give Beta blockers and propylthiouracil (PTU)
Symptoms of hypothyroidism
Fatigue, weight gain, lethargy, hair changes, cold intolerance, constipation, difficulty with memory/cognition, impaired libido, and impaired fertility
What Is the Significance of a neck mass Moving Up and Down with Swallowing?
The thyroid gland moves cranially when a patient swallows, due to its attachment to the trachea via the ligament of Berry. A mass that moves with the thyroid is more likely to originate within the thyroid gland as opposed to some other part of the anatomy (lymph nodes, for instance). In rare circumstances, an aggressive thyroid cancer will become fixed due to local invasion of surrounding structures. This is a worrisome sign.
Suspect this in a patient with flushed face, warm skin, tremor, weight loss with possible muscle wasting, tachycardia, widened pulse pressure, and hyperactive reflexes.
Severe or long-standing hyper-thyroidism
Suspect this in a patient with periorbital swelling with puffy face and extremities, fine hair, loss of the outer aspects of the eyebrows, waxy or clammy skin, and weight gain
Severe or long-standing hypo-thyroidism
What Are the Actions of Thyroid Hormones?
In general, T4 and T3 regulate basal metabolic rate, growth and development, and sensitivity to catecholamines with effects on many organ systems.
Most common endocrine malignancy in US
thyroid cancer
What are psammoma bodies
Microscopic finding of round, laminar collections of calcified tissue. Seen in papillary thyroid cancer but also found in a number of malignant and benign lesions.
Lab tests to work up a thyroid nodule
TSH. If abnormal, f/u w/ T4 and T3
Imaging studies for a thyroid nodule
Bedside neck ultrasound
Which thyroid nodules should undergo FNA?
Thyroid nodules >1 cm in size, nodules w/ u/s suggestive of malignancy (e.g., internal microcalcifications), or those w/ hx of growth. Suspicious cervical lymph nodes should also undergo FNA during the same encounter.
Surgical tx of a suspected thyroid follicular neoplasm
Thyroid lobectomy. Take the whole lobe. If that confirms follicular carcinoma, return to OR to take whole thyroid.
Two elements of postoperative management for thyroid cancer
Radioactive Iodine Ablation, and Suppressive Thyroxine Therapy
Major structures that can be damaged during thyroidectomy
Recurrent laryngeal nerve, and parathyroid glands
After a thyroidectomy, the Patient Develops Stridor in the Recovery Room: The Neck Wound Appears to Be Tense. What Is the Next Step?
Probably an expanding hematoma. Decompress it by cutting the sutures and opening the wound.
