Critical Care, Exam 2- kat review

What does calcitonin do?

Lowers serum calcium by moving calcium into bones for storage

What are the lab findings in hypothyroidism?

High TSH and low T3 and T4

What are the signs and symptoms of hypothyroidism?

Weight gain, lethargy, bradycardia, bradypnea, cold intolerance, constipation, goiter, and low blood pressure

What is a painless diffuse goiter associated with?

Hypothyroidism

What medication precautions are important in hypothyroidism?

Use caution with blood pressure medications and opioids because they can lower BP further and cause extreme sedation

What is Hashimoto's thyroiditis?

An autoimmune disease associated with hypothyroidism

How is Hashimoto's thyroiditis diagnosed?

Anti-thyroid peroxidase antibodies

What medication treats hypothyroidism?

Levothyroxine (Synthroid)

How does levothyroxine work?

Increases thyroid hormone levels (T3 and T4)

How long must a patient with hypothyroidism take levothyroxine?

Usually for life

What is myxedema coma?

A life-threatening, extreme form of hypothyroidism

What are the signs of myxedema coma?

Decreased LOC, muscle weakness, low HR, low BP, and respiratory depression

What can trigger myxedema coma?

Untreated hypothyroidism or stopping thyroid medication

How is myxedema coma treated?

IV thyroid hormone, supportive care, and corticosteroids when indicated

Why are corticosteroids given in myxedema coma?

They treat possible adrenal insufficiency and support blood pressure and organ perfusion

What are the lab findings in hyperthyroidism?

Low TSH and high T3 and T4

What are the signs and symptoms of hyperthyroidism?

Weight loss, increased appetite, tachycardia, tachypnea, hypertension, diarrhea, and goiter

What is Graves' disease?

An autoimmune disease that causes hyperthyroidism

How is Graves' disease diagnosed?

Thyroid-stimulating immunoglobulins (TSI)

What is exophthalmos?

Bulging eyes commonly associated with Graves' disease

What is thyroid storm?

A life-threatening, extreme form of hyperthyroidism

What medications treat hyperthyroidism?

PTU (propylthiouracil) and methimazole

What is radioactive iodine used for?

Treating hyperthyroidism by destroying thyroid tissue

What precautions are needed after radioactive iodine treatment?

Follow radiation safety instructions, including limiting close contact and using separate utensils as directed

What should patients with hyperthyroidism avoid?

Caffeine and other stimulants

What diet and activity approach helps with hyperthyroidism?

Small, frequent, calorie- and nutrient-rich meals with rest periods

What is a diffuse goiter?

A uniformly enlarged thyroid gland

What is a nodular goiter?

An enlarged thyroid containing one or more nodules

What is a nontoxic goiter?

An enlarged thyroid without excess thyroid hormone production

What is a toxic goiter?

An enlarged thyroid that produces excess thyroid hormone

What is a cold thyroid nodule?

A nodule that does not take up radioactive tracer and may require evaluation for cancer

What is primary endocrine disease?

A problem originating in the endocrine gland itself

What is secondary endocrine disease?

A problem caused by dysfunction of another gland or regulatory organ

What is the most common type of thyroid cancer?

Papillary thyroid cancer

Which thyroid cancers are especially aggressive?

Anaplastic and medullary thyroid cancers are important high-risk types; anaplastic is especially aggressive

What are major complications after thyroidectomy?

Hemorrhage and hypocalcemia

Why must calcium gluconate be available after thyroidectomy?

It treats severe hypocalcemia from possible parathyroid injury

How does PTH affect calcium and phosphorus?

Raises blood calcium and generally lowers blood phosphorus

How are calcium and phosphorus related?

They generally have an inverse relationship

What are the signs and symptoms of hyperparathyroidism?

Hypercalcemia, osteoporosis, kidney stones, abdominal pain, fatigue, muscle weakness, and decreased deep tendon reflexes

What are the typical labs in primary hyperparathyroidism?

High calcium, low phosphorus, and high PTH

What causes secondary hyperparathyroidism?

Conditions such as chronic kidney disease or vitamin D deficiency

What are the typical labs in secondary hyperparathyroidism?

High PTH, with low or normal calcium and often high phosphorus in CKD

What causes tertiary hyperparathyroidism?

Long-standing secondary hyperparathyroidism causing autonomous PTH secretion

What are the typical labs in tertiary hyperparathyroidism?

High PTH, high calcium, and often high phosphorus in CKD

How is hyperparathyroidism diagnosed?

PTH, calcium, and phosphorus blood levels

How is secondary hyperparathyroidism treated?

Treat the underlying cause and manage phosphorus and vitamin D levels

What are phosphorus binders used for?

They bind dietary phosphorus in the gut to reduce phosphorus absorption

How may tertiary hyperparathyroidism be treated?

Cinacalcet and sometimes parathyroid surgery

What causes hypoparathyroidism?

Low PTH, often following thyroid or parathyroid surgery

What are the typical labs in hypoparathyroidism?

Low calcium, high phosphorus, and low PTH

What are the signs and symptoms of hypocalcemia?

Muscle spasms, tingling, twitching, and increased neuromuscular excitability

What is Chvostek's sign?

Facial muscle twitching when the facial nerve is tapped

What is Trousseau's sign?

Carpal spasm caused by inflating a blood pressure cuff

What ECG change can occur with hypocalcemia?

Prolonged QT interval

Why is hypocalcemia dangerous to the airway?

It can cause laryngospasm and bronchospasm

What is renal osteodystrophy?

Bone disease caused by chronic kidney disease and mineral imbalance

Why does renal osteodystrophy occur?

Phosphorus retention and decreased activation of vitamin D disrupt calcium and bone metabolism

What medication may treat vitamin D deficiency in CKD-related bone disease?

Calcitriol, an active form of vitamin D

What hormones are produced by the adrenal cortex?

Glucocorticoids, mineralocorticoids, and sex hormones

What are the main functions of adrenal cortex hormones?

Regulate blood sugar, blood pressure, fluid and electrolyte balance, and sexual development

What hormones are released by the adrenal medulla?

Epinephrine and norepinephrine

What are catecholamines?

Epinephrine and norepinephrine, hormones involved in the fight-or-flight response

What is the hypothalamic-pituitary-adrenal axis?

A hormone pathway that regulates cortisol production

What does CRH do in the HPA axis?

Stimulates the pituitary gland to release ACTH

What does ACTH do?

Stimulates the adrenal cortex to produce cortisol

How does negative feedback regulate cortisol?

High cortisol suppresses CRH and ACTH release

What is pheochromocytoma?

A tumor that releases excess catecholamines, usually from the adrenal medulla

What are the classic symptoms of pheochromocytoma?

Headache, hypertension, palpitations, diaphoresis, and hyperglycemia

What is the classic pheochromocytoma triad?

Headache, palpitations, and excessive sweating

How is pheochromocytoma diagnosed?

Plasma free metanephrines or 24-hour urine fractionated metanephrines

What should patients avoid before catecholamine testing?

Caffeine and other substances specified by the testing provider

What is the clonidine suppression test used for?

A second-line test to help evaluate suspected pheochromocytoma in selected cases

What happens to norepinephrine in a positive clonidine suppression test?

It fails to suppress appropriately

How is pheochromocytoma managed before surgery?

Alpha blockade first, followed by beta blockade if needed

Why must alpha blockers be given before beta blockers in pheochromocytoma?

Beta blockade first can cause severe unopposed alpha-mediated vasoconstriction and hypertension

What is Addison's disease?

Primary adrenal insufficiency causing inadequate cortisol and often aldosterone

What are the signs and symptoms of Addison's disease?

Fatigue, weight loss, hyperpigmentation, low BP, low blood sugar, low sodium, and high potassium

Why does Addison's disease cause hypovolemia?

Low aldosterone causes sodium and water loss

How is primary adrenal insufficiency diagnosed?

Low cortisol with high ACTH; ACTH stimulation testing helps confirm

What are the typical labs in primary adrenal insufficiency?

Low cortisol and high ACTH

What are the typical labs in secondary adrenal insufficiency?

Low cortisol and low or inappropriately normal ACTH

What happens during an ACTH stimulation test in primary adrenal insufficiency?

Cortisol remains low or rises inadequately

What happens during an ACTH stimulation test in secondary adrenal insufficiency?

Cortisol response may be reduced, especially with prolonged ACTH deficiency

What medications treat Addison's disease?

Hydrocortisone and, when aldosterone replacement is needed, fludrocortisone

What is an Addisonian crisis?

A life-threatening acute adrenal insufficiency causing severe hypotension and shock

What are the signs of an Addisonian crisis?

Severe low BP, confusion, weakness, abdominal pain, nausea, vomiting, and dehydration

How is an Addisonian crisis treated?

Immediate IV hydrocortisone, isotonic IV fluids, correction of glucose and electrolytes, and treatment of the trigger

When may vasopressors be needed in an Addisonian crisis?

If severe hypotension persists despite appropriate fluids and steroid treatment

What is Cushing's syndrome?

Excess cortisol exposure from any cause

What are the classic signs of Cushing's syndrome?

Moon face, buffalo hump, central weight gain, bruising, acne, striae, and muscle weakness

What electrolyte and glucose changes can occur in Cushing's syndrome?

High blood sugar, sodium retention, and low potassium, especially in severe cases

How is Cushing's syndrome initially screened?

24-hour urinary free cortisol, late-night salivary cortisol, or dexamethasone suppression testing

What is the dexamethasone suppression test used for?

Evaluating whether cortisol production appropriately decreases after dexamethasone

How does ACTH help determine the cause of Cushing's syndrome?

Low ACTH suggests an adrenal source or exogenous steroids; high or inappropriately normal ACTH suggests an ACTH-dependent cause

What causes Cushing's disease?

A pituitary tumor that produces excess ACTH, stimulating excess cortisol release

What is the difference between Cushing's syndrome and Cushing's disease?

Cushing's syndrome is excess cortisol from any cause; Cushing's disease is caused by a pituitary ACTH-producing tumor

How may Cushing's syndrome caused by an adrenal tumor be treated?

Adrenalectomy may be needed, followed by cortisol replacement if adrenal function is insufficient

Why may lifelong cortisol replacement be needed after bilateral adrenalectomy?

Both adrenal glands are removed, so the body cannot produce adequate cortisol