Podcast
Questions and Answers
What are common muscle symptoms associated with hypothyroidism?
What are common muscle symptoms associated with hypothyroidism?
Which test is considered the best initial assessment for thyroid function?
Which test is considered the best initial assessment for thyroid function?
In which condition would TSH levels be high while T3 and T4 levels are low?
In which condition would TSH levels be high while T3 and T4 levels are low?
What major symptoms may indicate a life-threatening hyperthyroid condition?
What major symptoms may indicate a life-threatening hyperthyroid condition?
Signup and view all the answers
What is the primary cause of Grave's disease?
What is the primary cause of Grave's disease?
Signup and view all the answers
Which of the following drugs is a synthetic form of T4?
Which of the following drugs is a synthetic form of T4?
Signup and view all the answers
What condition can result from critically ill patients that may resemble central hypothyroidism?
What condition can result from critically ill patients that may resemble central hypothyroidism?
Signup and view all the answers
What typically occurs due to T-cell lymphocyte activation in hyperthyroid conditions?
What typically occurs due to T-cell lymphocyte activation in hyperthyroid conditions?
Signup and view all the answers
What effect does levothyroxine have in terms of hormone levels?
What effect does levothyroxine have in terms of hormone levels?
Signup and view all the answers
How does SIADH impact sodium levels in relation to thyroid conditions?
How does SIADH impact sodium levels in relation to thyroid conditions?
Signup and view all the answers
What is a common clinical finding in hyperthyroidism associated with Graves' disease?
What is a common clinical finding in hyperthyroidism associated with Graves' disease?
Signup and view all the answers
What is the primary mechanism of action of Methimazole?
What is the primary mechanism of action of Methimazole?
Signup and view all the answers
Which side effect is least likely to occur with the use of thionamides like PTU and Methimazole?
Which side effect is least likely to occur with the use of thionamides like PTU and Methimazole?
Signup and view all the answers
In the context of thyroid nodules, what characterizes a 'hot' nodule?
In the context of thyroid nodules, what characterizes a 'hot' nodule?
Signup and view all the answers
What is the primary concern when using amiodarone in patients with thyroid disease?
What is the primary concern when using amiodarone in patients with thyroid disease?
Signup and view all the answers
What does the Wolff-Chaikoff effect refer to?
What does the Wolff-Chaikoff effect refer to?
Signup and view all the answers
Which of the following is a characteristic histological finding associated with papillary thyroid cancer?
Which of the following is a characteristic histological finding associated with papillary thyroid cancer?
Signup and view all the answers
What is the most common cause of congenital hypothyroidism?
What is the most common cause of congenital hypothyroidism?
Signup and view all the answers
What is the recommended initial treatment in patients experiencing severe symptoms of hyperthyroidism?
What is the recommended initial treatment in patients experiencing severe symptoms of hyperthyroidism?
Signup and view all the answers
What is a key feature of Riedel’s thyroiditis?
What is a key feature of Riedel’s thyroiditis?
Signup and view all the answers
Which of the following thyroid cancers typically arises from C cells?
Which of the following thyroid cancers typically arises from C cells?
Signup and view all the answers
What does a 'cold' nodule indicate in a thyroid scan?
What does a 'cold' nodule indicate in a thyroid scan?
Signup and view all the answers
What is the most likely consequence of chronic autoimmune thyroiditis?
What is the most likely consequence of chronic autoimmune thyroiditis?
Signup and view all the answers
What is the primary treatment for adrenal adenomas?
What is the primary treatment for adrenal adenomas?
Signup and view all the answers
Which medication is considered the drug of choice for conditions requiring potassium-sparing diuretics?
Which medication is considered the drug of choice for conditions requiring potassium-sparing diuretics?
Signup and view all the answers
What is the common clinical presentation of a catecholamine-secreting tumor?
What is the common clinical presentation of a catecholamine-secreting tumor?
Signup and view all the answers
How are metanephrines typically measured for diagnosing pheochromocytoma?
How are metanephrines typically measured for diagnosing pheochromocytoma?
Signup and view all the answers
What condition is associated with the amplification of the N-myc proto-oncogene?
What condition is associated with the amplification of the N-myc proto-oncogene?
Signup and view all the answers
What pharmacological agent is used for the preoperative management of patients with catecholamine-secreting tumors?
What pharmacological agent is used for the preoperative management of patients with catecholamine-secreting tumors?
Signup and view all the answers
Which hormone is noted to have a low plasma level in specific types of adrenal disease?
Which hormone is noted to have a low plasma level in specific types of adrenal disease?
Signup and view all the answers
What is the significance of measuring urinary HVA/VMA levels?
What is the significance of measuring urinary HVA/VMA levels?
Signup and view all the answers
Which feature is considered a rare paraneoplastic syndrome associated with neuroblastoma?
Which feature is considered a rare paraneoplastic syndrome associated with neuroblastoma?
Signup and view all the answers
What other conditions may be evaluated along with measuring serum PRA/aldosterone levels?
What other conditions may be evaluated along with measuring serum PRA/aldosterone levels?
Signup and view all the answers
What is the primary function of aldosterone in kidney function?
What is the primary function of aldosterone in kidney function?
Signup and view all the answers
What triggers the release of aldosterone in the body?
What triggers the release of aldosterone in the body?
Signup and view all the answers
Which hormone is primarily responsible for controlling cortisol secretion?
Which hormone is primarily responsible for controlling cortisol secretion?
Signup and view all the answers
Which of the following is NOT a consequence of elevated cortisol levels?
Which of the following is NOT a consequence of elevated cortisol levels?
Signup and view all the answers
What is one of the major effects of cortisol on the immune system?
What is one of the major effects of cortisol on the immune system?
Signup and view all the answers
Which enzyme deficiency can lead to congenital adrenal hyperplasia?
Which enzyme deficiency can lead to congenital adrenal hyperplasia?
Signup and view all the answers
Which factor predominantly influences the binding of cortisol in the serum?
Which factor predominantly influences the binding of cortisol in the serum?
Signup and view all the answers
Which symptom might indicate adrenal insufficiency?
Which symptom might indicate adrenal insufficiency?
Signup and view all the answers
What is the effect of long-term steroid use on glucose metabolism?
What is the effect of long-term steroid use on glucose metabolism?
Signup and view all the answers
What is a key effect of cortisol on muscle tissue?
What is a key effect of cortisol on muscle tissue?
Signup and view all the answers
Which of the following is related to the adverse effects of cortisol on skin?
Which of the following is related to the adverse effects of cortisol on skin?
Signup and view all the answers
What is a notable characteristic of dehydroepiandrosterone (DHEA)?
What is a notable characteristic of dehydroepiandrosterone (DHEA)?
Signup and view all the answers
How does aldosterone primarily affect electrolyte balance?
How does aldosterone primarily affect electrolyte balance?
Signup and view all the answers
What is the main hormone produced by the thyroid gland?
What is the main hormone produced by the thyroid gland?
Signup and view all the answers
What consequence can excessive iodide in the diet lead to?
What consequence can excessive iodide in the diet lead to?
Signup and view all the answers
What is the function of Thyroid Peroxidase (TPO) in the thyroid hormone synthesis process?
What is the function of Thyroid Peroxidase (TPO) in the thyroid hormone synthesis process?
Signup and view all the answers
What are the remnants of the thyroglossal duct that may persist in children or adults?
What are the remnants of the thyroglossal duct that may persist in children or adults?
Signup and view all the answers
How does estrogen affect thyroxine-binding globulin (TBG) levels?
How does estrogen affect thyroxine-binding globulin (TBG) levels?
Signup and view all the answers
What is the initial tissue source of the thyroid gland during embryonic development?
What is the initial tissue source of the thyroid gland during embryonic development?
Signup and view all the answers
What role does the Na-Iodine Symporter (NIS) play in thyroid hormone synthesis?
What role does the Na-Iodine Symporter (NIS) play in thyroid hormone synthesis?
Signup and view all the answers
What is a potential outcome of thyroid tissue existing outside of the gland?
What is a potential outcome of thyroid tissue existing outside of the gland?
Signup and view all the answers
Which hormone acts as a prohormone for T3 and is primarily produced by the thyroid gland?
Which hormone acts as a prohormone for T3 and is primarily produced by the thyroid gland?
Signup and view all the answers
What is the result of high levels of thyroid hormones on cholesterol levels in hyperthyroid patients?
What is the result of high levels of thyroid hormones on cholesterol levels in hyperthyroid patients?
Signup and view all the answers
What occurs to TSH levels after initiating therapy with a mimic of T4?
What occurs to TSH levels after initiating therapy with a mimic of T4?
Signup and view all the answers
What happens during the Wolff-Chaikoff Effect in the presence of excessive iodide?
What happens during the Wolff-Chaikoff Effect in the presence of excessive iodide?
Signup and view all the answers
What best describes the thyroid hormones' effect on metabolic activity?
What best describes the thyroid hormones' effect on metabolic activity?
Signup and view all the answers
What is the primary role of 5'-deiodinase in thyroid hormone metabolism?
What is the primary role of 5'-deiodinase in thyroid hormone metabolism?
Signup and view all the answers
What defines the basal metabolic rate in the context of thyroid hormone function?
What defines the basal metabolic rate in the context of thyroid hormone function?
Signup and view all the answers
What are the common effects of excess cortisol in patients?
What are the common effects of excess cortisol in patients?
Signup and view all the answers
Which of the following is NOT a cause of Cushing’s syndrome?
Which of the following is NOT a cause of Cushing’s syndrome?
Signup and view all the answers
How is skin hyperpigmentation linked to adrenal insufficiency?
How is skin hyperpigmentation linked to adrenal insufficiency?
Signup and view all the answers
Which physiological effect is associated with high levels of aldosterone?
Which physiological effect is associated with high levels of aldosterone?
Signup and view all the answers
What test is primarily used to differentiate the causes of Cushing’s syndrome?
What test is primarily used to differentiate the causes of Cushing’s syndrome?
Signup and view all the answers
What condition is characterized by an abrupt loss of cortisol and aldosterone, leading to shock?
What condition is characterized by an abrupt loss of cortisol and aldosterone, leading to shock?
Signup and view all the answers
During diagnosis of primary adrenal insufficiency, which of the following is expected?
During diagnosis of primary adrenal insufficiency, which of the following is expected?
Signup and view all the answers
Which treatment option is commonly used for Cushing’s syndrome?
Which treatment option is commonly used for Cushing’s syndrome?
Signup and view all the answers
What is a common symptom of secondary adrenal insufficiency?
What is a common symptom of secondary adrenal insufficiency?
Signup and view all the answers
What hormonal change directly contributes to the menstrual irregularities seen in women with excess cortisol?
What hormonal change directly contributes to the menstrual irregularities seen in women with excess cortisol?
Signup and view all the answers
Which type of adrenal insufficiency is primarily caused by a failure of the adrenal gland itself?
Which type of adrenal insufficiency is primarily caused by a failure of the adrenal gland itself?
Signup and view all the answers
What is the consequence of a low-dose dexamethasone suppression test in Cushing’s syndrome?
What is the consequence of a low-dose dexamethasone suppression test in Cushing’s syndrome?
Signup and view all the answers
How does ACTH-dependent Cushing’s syndrome cause skin hyperpigmentation?
How does ACTH-dependent Cushing’s syndrome cause skin hyperpigmentation?
Signup and view all the answers
Study Notes
Thyroid Gland
- The thyroid gland is located in the neck, and has two lobes connected by an isthmus.
- Sometimes a pyramidal lobe is present above the isthmus.
- The thyroid is supplied by superior and inferior thyroid arteries.
- The superior thyroid receives blood from the first branch of the external carotid artery.
- The inferior thyroid receives blood from the thyrocervical trunk, an offshoot of the subclavian artery.
- Thyroid tissue originates from the floor of the pharynx, composed of epithelial cells.
- The thyroid develops initially in a duct which connects to the tongue in a child.
- This duct disappears during development.
- Remnants of this duct exist in a child/adult in a structure called the thyroglossal duct.
- There are remnants of the duct such as foramen cecum in the tongue and pyramidal lobes of the thyroid.
- A thyroglossal duct cyst is a mass that may form in the midline of the neck because of a persistent remnant of the thyroglossal duct.
- Ectopic thyroid tissue can develop outside of the main thyroid gland, often found in the base of the tongue.
- Thyroid tissue contains follicles filled with colloid, a protein material.
- Follicular cells line these follicles.
- Thyroid hormones, T3 and T4, are synthesized from tyrosine and iodine.
- Iodized salt contains a small amount of iodine and was added to salt in the US in 1924.
- Thyroid hormones are synthesized from tyrosine and iodine forming T3 and T4.
- Thyroglobulin is a large protein containing numerous tyrosine molecules and is produced by thyroid follicular cells.
- Iodine, which is present in the diet as an iodide salt, is taken up by follicular cells to form thyroid hormones.
- Iodide is oxidized into I2 and then added to organic/carbon structures.
- Thyroid peroxidase (TPO) catalyzes the oxidation of iodine.
- TPO also couples MIT/DIT into T3/T4.
- Two hormones: T3 and T4 are synthesized from tyrosine and iodine.
- T4 is a prohormone and 5' deiodinase converts T4 to T3 in peripheral tissues.
- T4 is the primary thyroid hormone secreted by the thyroid which is converted to T3 which is more potent.
Thyroid Hormones
- Most thyroid hormone is formed as T4.
- T3 is more potent than T4 and acts as a prohormone.
- T3 and T4 affect metabolism.
Thyroid Histology
- Thyroid glands contain follicles that are filled with colloid.
- A single layer of follicular cells lines these follicles.
- Follicular cells synthesize hormones.
Thyroid Embryology
- The thyroid develops from pharyngeal epithelial cells.
- Initially, the thyroid is connected to the tongue by a duct.
- This connection dissipates later in development.
- Remnant tissue from this duct may remain.
Thyroid Disorders
- Thyroid disorders include hyperthyroidism, hypothyroidism, and thyroiditis.
Hypothyroidism
- Metabolism slows down.
- Symptoms include lethargy, fatigue, cold intolerance, weight gain, constipation, hyporeflexia, dry/cool skin, coarse/brittle hair, and bradycardia.
- A feature of hypothyroidism is elevated cholesterol.
Hyperlipidemia
- Elevated cholesterol is a feature of hypothyroidism (↑ total cholesterol and LDL).
- ↓ LDL receptor density is a mechanism.
- T3 upregulates LDL receptor gene activation.
Myxedema
- Myxedema is non-pitting edema.
- Hyaluronic acid deposits in the dermis causing swelling.
- Seen with Grave's disease (hyperthyroidism).
- Myxedema coma is from hypothyroidism.
Hypothyroid Myopathy
- Muscles symptoms (weakness, cramps, myalgias) with elevated serum creatine kinase are common in hypothyroidism..
- Symptoms are often present in patients with hypothyroidism.
Hyponatremia
- Hypothyroidism can cause hyponatremia (low sodium levels).
- This can occur due to high levels of ADH.
- This can cause confusion
Thyroid Replacement
- Levothyroxine (synthetic T4) is commonly prescribed for replacement therapy.
- Liothyronine (synthetic T3), which is absorbed rapidly from the intestines, is sometimes used.
- Levothyroxine is preferred due to its slower absorption and prolonged activity.
- Treatment can cause mild symptoms like hyperthyroidism (tachycardia, tremor), so the dosage is adjusted until TSH is normal.
Hyperthyroidism
- Metabolism speeds up.
- Symptoms include hyperactivity, heat intolerance, weight loss with increased appetite, diarrhea, hyperreflexia, warm/moist skin, fine hair, and tachycardia.
Thyroid Storm
- A life-threatening hyperthyroidism.
- Often precipitated by an acute event like infection, surgery, or trauma to a patient with existing hyperthyroidism.
- High catecholamine levels, fever, delirium, tachycardia, hyperglycemia, and hypercalcemia are potential complications.
Goiter
- An enlarged thyroid gland.
- Often accompanied by high TSH levels but inadequate T3/T4 production.
- Grave's thyroid stimulating antibodies can cause goiters.
Lab Findings
- TSH is the best initial test for evaluating thyroid function.
- In hypothyroidism, TSH is typically elevated, with low levels of T3 and T4.
- In hyperthyroidism, TSH is typically suppressed, with high levels of T3 and T4.
- Central hyper/hypo thyroid disease is often marked by low TSH and low T3/T4 or high TSH and high T3/T4 levels.
- Disorders in the pituitary and hypothalamus are often the cause.
Reverse T3
- Is an isomer of T3 that is derived from T4.
- Euthyroid sick syndrome, a condition that occurs in critically ill patients, is marked by low T3/T4 and elevated rT3.
Hyperthyroidism Causes
- Grave's disease, toxic multinodular goiter, amiodarone, iodine load, and early thyroiditis.
Grave's Disease
- Grave's is an autoimmune disease.
- Thyroid stimulating antibodies are produced.
- Symptoms of hyperthyroidism occur.
- Exophthalmos (bulging eyes) and pretibial myxedema can occur with Grave's disease.
- The inflammatory mechanism involves T-cell lymphocytes activating fibroblasts, specifically fibroblasts containing TSH receptors.
- Stimulation leads to glycosaminoglycan secretion, drawing in water, resulting in swelling.
Grave's Disease Diagnosis/Treatment
- Diagnosis often involves thyroid labs plus exophthalmos.
- TSH receptor antibodies/thyroid stimulating immunoglobulins can also be measured.
- Treatment includes beta blockers, thionamides, radioactive iodine ablation or surgery.
Thionamides
- Thionamides such as methimazole and propylthiouracil are used to treat hyperthyroidism.
- Inhibiting TPO to stop thyroxine synthesis is the mechanism of action.
- Some potential side effects include skin rash and agranulocytosis (rare dangerous drop in WBC).
Thyroid Cancer
- Common thyroid cancers include papillary, follicular, medullary, and anaplastic.
Papillary Carcinoma
- Often presents as a nodule; may be seen in prior radiation exposure.
- Psammoma bodies, nuclear grooves, and "Orphan Annie's eyes" are key pathology findings with diagnosis made by nuclear findings.
Follicular Carcinoma
- Similar to follicular adenomas.
- Breaks through the fibrous capsule; FNA cannot distinguish between it and adenoma over time.
Medullary Carcinoma
- Cancer of parafollicular cells.
- Produces calcitonin.
MEN Syndromes
- MEN syndromes are genetic syndromes causing multiple endocrine tumors.
- MEN 2A/2B are associated with medullary thyroid carcinoma.
- RET oncogene mutations cause MEN.
Anaplastic Carcinoma
- Highly malignant; often occurs in elderly patients.
- Characterized by undifferentiated cells, lack of usual thyroid features like papilla, follicles, or amyloid, and rapid invasion leading to a poor prognosis.
Adrenal Glands
- Located above the kidneys.
- They have a cortex and medulla.
Cortex
- Three groups of hormones.
- Mineralocorticoids (aldosterone),
- Glucocorticoids (cortisol),
- Androgens (testosterone).
Medulla
- Epinephrine, and norepinephrine.
Signal Transmission
- Catecholamines released from the neural crest cells.
- Neurotransmitters such as acetylcholine, and norepinephrine/epinephrine mediate parasympathetic/sympathetic responses in the body.
Mineralocorticoids
- Aldosterone is the most important mineralocorticoid.
- Aldosterone affects kidney function.
- Its release is controlled by the renin-angiotensin-aldosterone (RAA) system.
- Na+/water reabsorption and K+/H+ excretion is its function.
Collecting Duct
- Principal and intercalated cells are crucial in the collecting duct, regulating water and electrolyte balance with the help of aldosterone.
Adrenal Androgens
- Small contribution in males.
- 50% relevance in female adrenal hyperplasia.
- Over/under production causes abnormal sexual development.
- ACTH stimulates production similarly to cortisol.
Cortisol
- A major glucocorticoid.
- Synthesized by adrenal cortex.
- Binds to intracellular receptors and regulates gene transcription.
Pituitary-Adrenal Axis
- Hypothalamus releases hormones to control the release of cortisol via the pituitary gland.
- Corticotropin-releasing hormone (CRH) initiates this process to stimulate ACTH secretion in the anterior pituitary.
Circadian Rhythms
- Serum cortisol is highest early in the morning (about 6AM).
- Cortisol levels are lowest one hour after sleep onset.
Cortisol Binding Globulin
- Cortisol is poorly soluble in plasma.
- Bound to CBG, accounts for over 90%.
- Levels increase with estrogen.
Cortisol Effects
- Blood pressure maintenance.
- Effects on vascular smooth muscle.
- Increases vascular sensitivity (alpha1) to norepinephrine/epinephrine.
- NO mediated vasodilation.
- Cortisol affects blood pressure with hypertension in Cushing's disease and hypotension in adrenal insufficiency.
- Immune system suppression includes sequestering lymphocytes in the spleen, reducing T/B cell levels in blood, blocking neutrophil migration, increasing peripheral neutrophil count, and decreasing eosinophil counts.
- Cortisol inactivates NF-kB, key inflammatory transcription factor, mediating the inflammatory response, and controlling the inflammatory mediators (e.g., COX-2, PLA2, Lipoxygenase).
Corticosteroid Drugs
- Examples of synthetic glucocorticoids for use in disease.
Cortisol Effects in Metabolism
- Increased glucose production by the liver (gluconeogenesis), less glucose taken up by muscle and fat, resulting in increased serum glucose.
- Increased liver glycogen storage and glycogen synthase synthesis.
Cortisol Effects on Lipid Metabolism
- Increased lipolysis in adipocytes.
- Increased free fatty acids.
- Increased total cholesterol and triglycerides.
- Stimulates adipocyte growth (fat deposition).
Cortisol Effects
- Glucagon and epinephrine effects are enhanced.
- Long-term steroid use causes diabetes.
Cortisol Effects on Skin
- Muscle atrophy and decreased epidermal cell division, resulting in thinning of skin, easy bruising, and reduced collagen formation, creating stretch marks.
Cortisol Effects on Bones
- Inhibits osteoblast activity, which contributes to osteopenia/osteoporosis.
Zones of the Adrenal Glands
- Adrenal glands have distinct zones (glomerulosa, fasciculata, reticularis) with each producing specific hormones:
- Zona glomerulosa: Primarily mineralocorticoids (aldosterone).
- Zona fasciculata: Primarily glucocorticoids (cortisol).
- Zona reticularis: Primarily androgens.
- Medulla: Primarily catecholamines (epinephrine, norepinephrine).
Zona Glomerulosa
- Details of the synthesis of aldosterone.
- Steps from cholesterol to aldosterone synthesis.
- ACTH stimulation of aldosterone synthesis pathway.
Zona Fasciculata
- Steps in cortisol synthesis.
- Pathways from cholesterol to cortisol synthesis.
Zona Reticularis
- Steps in the synthesis of adrenal androgens and their pathways.
Ketoconazole
- Antifungal that blocks ergosterol synthesis in fungi.
- Also inhibits 1st step in cortisol synthesis.
- Inhibits enzymes (side chain cleavage) that inhibit androgen synthesis..
- Side effects include gynecomastia (breast development in males).
Congenital Adrenal Hyperplasia (CAH)
- Enzyme deficiency syndrome causing loss of an enzyme impacting cortisol synthesis.
- This causes a cascade of events with ACTH increasing.
- Various forms exist affecting mineralocorticoids and/or androgens.
CAH Diagnosis
- Screening with newborn blood testing for 17-hydroxyprogesterone.
CAH Treatment
- Treatment replenishes cortisol and stops overproduction of other hormones with glucocorticoids.
- Mineralocorticoids are sometimes used.
Adrenal Disorders
- Excess cortisol, insufficient cortisol, excess mineralocorticoids, and tumors are adrenal disorders.
Cushing's Syndrome
- Syndrome due to high cortisol.
- Most common cause is corticosteroid medication or some inflammatory condition.
- Cushing's disease stems from pituitary ACTH-secreting tumors.
Cushing's Syndrome: Excess Cortisol Effects
- Symptoms include hypertension, hyperglycemia, type 2 diabetes (insulin resistance), immune suppression, high risk for infections, menstrual abnormalities (irregular cycles, oligomenorrhea, amenorrhea), hirsutism in women and/or erectile dysfunction in men, and skin changes (striae, easy bruising.
- Fat redistribution with a "moon face," and/or a "buffalo hump" (fat deposits) can occur.
Cushing's Syndrome: Causes
- ACTH-independent (e.g., adrenal adenoma or glucocorticoid therapy) or-dependent causes (e.g., Cushing's disease from pituitary tumor, or ectopic ACTH from lung cancer).
Cushing's Syndrome: Diagnosis
- Measuring plasma cortisol is difficult due to circadian rhythm (highest in AM).
- Measurement of 24-hour urine free cortisol or salivary cortisol is used; or low-dose dexamethasone suppression tests.
- Differentiating between causes uses high-dose dexamethasone suppression tests.
Cushing's Syndrome: Treatment
- Often includes surgery (removal of adenoma or tumor), and antifungal medications like ketoconazole are sometimes used.
Adrenal Insufficiency
- Insufficient cortisol production, categorized as primary failure of adrenal gland and/or secondary failure of pituitary.
Adrenal Insufficiency: Symptoms
- Cortisol deficiency leads to symptoms like weakness, fatigue, weight loss, postural hypotension, nausea, abdominal pain, diarrhea, and hypoglycemia.
- Aldosterone deficiency leads to hyperkalemia, H+ retention causing acidosis, and sodium loss in urine.
Adrenal Insufficiency: ACTH Effects
- High ACTH levels cause skin hyperpigmentation (common in primary deficiency).
- ACTH stimulates MSH, another hormone.
Addison's Hyperpigmentation
- Generalized darkening of skin in areas exposed to sunlight, elbows, knees, knuckles, areas of pressure.
Adrenal Crisis
- Acute adrenal insufficiency from loss of cortisol and aldosterone causing shock, nausea, vomiting, fatigue, confusion.
- Can be linked to infection.
- Stress dose steroids can help prevent it.
Addison's Disease: Common Causes
- Autoimmune adrenalitis often the cause of antibody and cell-mediated atrophy of the adrenal gland.
- Infections (tuberculosis, fungal like histoplasmosis/cryptococcus, CMV).
Metastasis from Lung Cancer
- Cancer from lungs can spread to the adrenals without symptoms, presenting as a secondary finding from imaging studies..
Waterhouse-Friderichsen Syndrome
- Rare cause of acute adrenal insufficiency.
- Caused by adrenal hemorrhage frequently accompanied by meningococcemia.
- High mortality rate with onset of shock.
Secondary Adrenal Insufficiency
- Most common cause is glucocorticoid therapy causing chronic suppression of ACTH with adrenal atrophy over time.
Secondary Adrenal Insufficiency: Important Points
- Skin findings are absent.
- ACTH is not elevated.
- No hyperkalemia exists.
- Aldosterone is not affected.
Adrenal Insufficiency: Diagnostic Tests
- Measuring serum cortisol at 8 AM is the typical first test.
- A low level suggests adrenal insufficiency.
- Serum ACTH levels measured, with high ACTH suggesting primary disease and low ACTH indicating secondary disease.
- ACTH stimulation test helps further distinguish between primary and secondary.
Primary Aldosteronism
- A mineralocorticoid excess that is often observed at a young age.
- Symptoms include hypertension and hypokalemia (low potassium levels), muscle cramps, and weakness.
- Often, metabolic alkalosis is present
Primary Aldosteronism: Most Common Causes
- Bilateral or idiopathic hyperaldosteronism is most common.
- Aldosterone-producing adenomas are less common, also called Conn's syndrome.
Primary Aldosteronism: Diagnosis
- Measures plasma aldosterone concentration (PAC) and plasma renin activity (PRA).
- Low PRA levels and high PAC indicate primary aldosteronism.
- Distinguishing between bilateral / unilateral disease involves adrenal vein sampling.
Primary Aldosteronism: Treatment
- Surgical adrenalectomy is the definitive treatment for unilateral lesions (adenoma or hyperplasia).
- Spironolactone, a potassium-sparing diuretic, blocks aldosterone effects.
Licorice
- Contains glycyrrhetinic acid (a steroid).
- Weak mineralocorticoid effect, increasing risk of high blood pressure and hypokalemia.
- Lowers 11-beta-hydroxysteroid dehydrogenase activity, lowering the ability of the body to control cortisol levels.
Pheochromocytoma
- A catecholamine-secreting tumor.
- Located in the adrenal medulla.
- Frequently presents with episodic symptoms including hypertension, headaches, palpitations, and sweating. Clinical presentation is episodic in nature.
Pheochromocytoma: Diagnosis
- Serum catecholamine measures are not commonly used.
- Breakdown products are assessed, using 24-hour urine collection or plasma collection.
- Metanephrines (epinephrine/norepinephrine by-products) are measured via metabolism products that accumulate in the urine or blood.
- Vanillylmandelic acid (VMA) is an older but less commonly used method.
Pheochromocytoma: Treatment
- Surgery is the primary treatment for pheochromocytoma.
- Pre-operative management frequently includes alpha-blockers (phenoxybenzamine) to prevent extreme blood pressure fluctuations and beta-blockers (propranolol) during the procedure.
Paraganglioma
- A catecholamine-secreting tumor similar to pheochromocytoma but arises outside of the adrenal medulla.
Neuroblastoma
- Tumor from primitive sympathetic ganglion cells.
- Can arise anywhere in the sympathetic nervous system.
- Frequently adrenal but can be in the abdomen and/or the thorax.
Neuroblastoma: Symptoms
- Often present as abdominal pain.
- Tumor mass effect.
Neuroblastoma: Diagnosis
- Urine catecholamine metabolites (HVA and VMA) are measured via 24-hour urine collection for diagnosis.
- Opsoclonus-myoclonus-ataxia (OMA) can be observed (rapid rhythmic eye movements and ataxia).
Neuroblastoma: Key Risk Factor
- The patient's age at diagnosis frequently influences prognosis and outcome (younger age is better).
MIBG
- Metaiodobenzylguanidine (MIBG) is a chemical analog of norepinephrine.
- Labels sympathetic tissues including tumors for localization via radioactive iodine (I131).
Adrenal Adenomas
- Benign neoplasms that may secrete cortisol or aldosterone.
- May be found incidental on abdominal imaging.
- Non-functional adenomas are often observed over time for growth.
- Functional adenomas are potentially surgical candidates (aldosterone and/or cortisol producing).
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
This quiz assesses your knowledge of thyroid disorders, their symptoms, and the medications used for treatment. Test your understanding of conditions like hypothyroidism and hyperthyroidism, and the various assessments and mechanisms involved in managing these diseases. Perfect for students and healthcare professionals aiming to deepen their knowledge in endocrinology.
