Repro-Endo: Endocrine Pathology Flashcards
- Benign tumor of Anterior Pituitary cells
- Most commonly Prolactinoma (Benign)
- Functional (Hormone-producing)
- Features based on Hormone produced
- Tx for Prolactinoma: Dopamine agonists (Bromocriptine or Cabergoline)
- Non-functional (Silent) and present w/ Mass Effect
- Bitemporal Hemianopsia –> Optic Nerve compression
- Hypopituitarism –> Pituitary tissue compression
- Headache
Pituitary Adenoma
- Most common type of Pituitary Adenoma
- Galactorrhea and Amenorrhea (Females)
- Decreased Libido and Headache (Males)
- Tx: Dopamine agonists (Bromocriptine, Cabergoline) to supress Prolactin production (shrinks tumor) or Surgery for Larger Lesions
Prolactinoma
- Gigantism in Children w/ increased Linear Bone Growth (epiphysies not fused)
-
Acromegaly in Adults w/ Enlarged Bones of Hands, Feet, Jaw
- Growth of Visceral Organs –> Dysfunction (Heart)
- Enlarged Tongue, Deep furrows, Deep voice, Coarce facial features
- Impaired glucose tolerance (insulin resistance)
- Secondary Diabetes Mellitus –> GH induces Liver Gluconeogenesis
- Dx: Elevated GH and Insulin Growth Factor-1 (IGF-1) lvls along w/ lack of GH suppression by Oral Glucose, Pituitary mass seen on brain MRI
- Tx: Octreotide (somatostatin analog that suppresses GH release), Pegvisomant (GH receptor agonists), or Surgery
Growth Hormone Cell Adenoma
- Secrete ACTH –> Cushing Syndrome
ACTH Cell Adenomas
Rare Pituitary Adenomas?
- TSH cell Adenoma
- LH-producing Adenoma
- FSH-producing Adenoma
- > 75% of the Pituitary Parenchyma is lost
- Insufficient production of Hormones by Anterior Pituitary gland
- Nonsecreting Pituitary adenomas (adults)
- Craniopharyngioma (children)
- A/w Pituitary Apoplexy (bleeding into the Adenoma)
Hypopituitarism
- Pregnancy-related infarction of the Pituitary gland
- Gland doubles in size but Blood supply remains same –> Blood loss during Parturition precipitates Infarction
- Poor Lactation or Failure to lactate
- Loss of Pubic Hair
- Fatigue
Sheehan Syndrome
- Primary – Congenital defect of the Sella
- Secondary - Trauma
- Herniation of the Arachnoid and CSF into the Sella –> Compresses and Destroys the Pituitary Gland
- Pituitary Gland is “absent” (empty Sella) on imaging
Empty Sella Syndrome
- ADH deficiency
- Hypothalamic or Posterior Pituitary Pathology (Tumor, Trauma, Infarction, Ischemic encephalopathy, Idiopathic, or Inflammation)
- A/w Loss of Free Water –> Intense thirst
- Polyuria and Polydipsia –> Life-threatening dehydration
- Hypernatermia
- Hyperosmotic volume contraction
- High Serum osmolality (> 290 mOsm/L)
- Low Urine osmolality and specific gravity (< 1.006)
- Hyperosmotic volume contraction
- Water Deprevation test fails to increase Urine osmolality (> 50% Increase)
- Tx: Desmopressin, Intranasal DDAVP (ADH analog), Hydration
Central Diabetes Insipidus
- Impaired Renal response to ADH
- Hereditary (ADH receptor mutation), 2’ to Hypercalcemia
- Lithium or Demeclocycline (ADH antagonist)
- A/w Inherited mutations or Drugs (e.g. Lithium and Demeclocycline)
- Similar to Central Diabetes Insipidus
- Normal ADH lvls
- High Serum osmolality (> 290 mOsm/L)
- Low Urine osmolality and specific gravity (< 1.006)
- Hyperosmotic volume contraction
- No response to Desmopressin –> Kidney cannot respond
- Tx: HCTZ, Indomethacin, Amiloride
Nephrogenic Diabetes Insipidus
- Excessive ADH secretion –> Hyponatremia w/ continued urinary Na+ excretion
- Excessive water retention
- Urine osmolarity > Serum osmolarity
- A/w Ectopic production (SCC of the Lung), CNS tumor, Head trauma, Pulmonary infarction/disease, and Drugs (Cyclophosphamide)
- Clinical features a/w Retention of Free Water –> decreased Aldosterone
- Hyponatremia –> Neuronal swelling and Cerebral edema
- Low Serum osmolality
- Mental status changes (Cerebral edema)
- Seizures
- Swelling of Nerves
- Tx: Free Water Restriction, IV Hypertonic saline, Conivaptan, Tolvaptan, or Demeclocycline (blocks effect of ADH), Correct slowly to prevent Central Pontine Myelinolysis
Syndrome of Inappropriate ADH Secretion (SIADH)
- Anterior Neck Mass
- Cystic dilation of Thyroglossal Duct Remnant
- Thyroid develops at base of Tongue –> along Thyroglossal duct –> Anterior neck
- Normally involutes
- Persistant duct –> Cystic dilation
Thyroglossal Duct Cyst
- Persistence of Thyroid tissue at Base of Tongue –> Did not decent to Anterior Neck
- Presents as a Base of Tongue Mass
Lingual Thyroid
- Increased TSH
- Decreased Free T3 and T4
- Hypercholesterolemia (due to decreased LDL receptor expression)
Hypothyroidism Lab Findings
- Decreased TSH
- Increased T3 and T4
- Hypocholesterolemia (due to increased LDL receptor expression)
Hyperthyrodisim Lab Findings
- Increased level of circulating Thyroid Hormone
- Increased Synthesis of Na+-K+-ATPase –> Increases Basal Metabolic Rate
- Increased Expression of Beta1-adrenergic receptos –> Increases Sympathetic Nervous System activity
Hyperthyroidism
- Most common cause of Hyperthyroidism
- Autoantibody (IgG) that stimulates TSH Receptor (Type II) –> Increases release of TSH –> Increased Thyroid Hormone
- Women of Childbearing age (20 – 40 y.o.)
- Diffuse goiter – Constant TSH –> Hyperplasia and Hypertrophy
-
Exophthalmos and Pretibial Myxedema (dough like appearance)
- Retro-orbital Fibroblasts behind the Orbit and Overlying the Shin (during stress and childbirth) express the TSH receptor (Exophthalmos: Proptosis, Extraocular muscle swelling)
- TSH activation –> Glycosaminoglycan (Chondroitin sulfate and Hyaluronic acid) buildup –> Inflammation, Fibrosis, and Edema
- Irregular Follicles w/ Scalloped Colloid and Chronic inflammation
- Increase T4
- Decrease TSH
- Hypocholesterolemia
- Increased Serum glucose
- Risk of Thyroid Storm
- Tx: Beta-blockers, Thioamide, and Radioiodine ablation
Graves Disease
- Potentially Fatal due to Catecholamines and Massive Hormone excess in response to Stress (Childbirth, Surgery) as a Serious complication of Graves Disease and other Hyperthyroid disorders
- Agitation, Delirium, Fever, Diarrhea, Coma, and Tachyarrhythmia (death)
- Arrhythmia, Hyperthermia, Vomiting w/ Hypovolemic shock
- Tx: Treat w/ the 3 P’s
- Beta-blockers (Propranolol), Propylthiouricil (PTU), and Steroids (Prednisolone)
- PTU inhibits Peroxidase-mediated Oxidation, Organification, and Coupling –> Thyroid Hormone production
Thyroid Storm
- Enlarged Thyroid gland w/ Multiple nodules
- Hyperfunctioning Follicular cells patches working independently of TSH due to a TSH receptor mutation (rarely malignant)
- Increased T3 and T4
- Relative Iodine deficiency
- Usually Nontoxic (Euthroid)
- Rarely, regions become TSH-independent –> T4 release and Hyperthyroidism (‘Toxic-goiter’) –> Not under the control of TSH
- Jod-Basedow phenomenon – Thyrotoxicosis if a pt. w/ Iodine def. goiter is made Iodine replete
Toxic Multinodular Goiter
- Hypothyroidism in Neonates and Infants
- Mental Retardation, Short stature w/ skeletal abnormalities, Course facial features, Enlarged tongue, and Umbilical Hernia
- 6 P’s of Symptoms
- Pot-bellied
- Pale
- Puffy-faced child
- Protruding umbilicus
- Protuberant tongue
- Poor Brain development
- Thyroid is req’d for Normal brain and Skeletal development; Thyroxine (T4)
- A/w Maternal Hypothyroidism during Pregnancy, Thyroid agenesis, Thyroid dysgenesis, Dyshormonogenetic goiter, and Iodine deficiency (low [I-])
- Dyshormonogenetic goiter is due to Congenital defect in Thyroid hormone production (a/w Thyroid Peroxidase)
Cretinism
- Hypothyroidism in Older Children or Adults
- Decreased Basal Metabolic Rate
- Decreased Sympathetic Nervous system activity
- Myxedema – accumulation of Glycosaminoglycans in the skin and soft tissue –> Deepening of Voice and Large Tongue
- Weight gain w/ normal appetitie
- Slowing of Mental activity
- Muscle weakness
- Cold intolerance /w decreased Sweating
- Bradycardia w/ decreased Cardiac output –> SOB
- Oligomenorrhea
- Hypercholesterolemia
- Constipation
- A/w Iodine deficiency, Hashimoto Thyroiditis, Drugs (Lithium), Surgical removal, Radioablation of Thyroid
Myxedema
- Autoimmune destruction of the Thyroid gland (Anti-thyroid peroxidase, Antithyroglobulin antibodies)
- Modeeratly enlarged, nontender Thyroid
- A/w HLA-DR5
- Increased Risk of non-Hodgkin Lymphoma
- Most common cause of Hypothyroidism in regions where Iodine lvls are adequate
- Presents as Hyperthyroidism (Thyrotoxicosis due to Follicle dmg)
- Progresses to Hypothyroidism; decrease T4 and increase TSH
- Antithyroglobulin and Antithyroid Peroxidase Antibodies are often present –> sign of Thyroid dmg
- Chronic inflammation w/ Germinal centers and Hurthle cells (eosinophilic metaplasia of cells that line Follicles, lymphoid aggregate w/ Germinal centers) as seen on Histology
- Increased Risk of B-cell Lymphoma (marginal zone): presents as an enlarging Thyroid gland Late in the disease course
Hashimoto Thyroiditis
- Self-limited Hypothyrodism following flu-like illness
- Increased ESR, Jaw pain, Early inflammation, Very-tender Thyroid
- Histology: Granulomatous (inflammation) Thyroiditis following Viral infection
- Tender Thyroid w/ Transient Hyperthyroidism (early)
- Rarely progresses to Hypothyroidism
Subacute Granulomatous Thyroiditis (De Quervain)
- Chronic inflammation w/ extensive Fibrosis of the Thyroid gland
- Hypothyroidism w/ ‘Hard as Wood’ non-tender Thyroid gland
- Fixed, Rock-hard, Painless goiter
- Fibrosis may extend to involve Local structures (airway)
- Considered a manifistation of IgG4-related systemic disease
- Clinically mimics Anaplastic Carcinoma, but Pts. are Younger (40s) and Malignant cells are absent
Riedel Fibrosing Thyroiditis
- “Hot Uptake” – Graves Disease and Nodular Goiter
- “Cold Uptake” – Adenoma and Carcinoma
- Biopsy is performed by Fine Needle Aspiration
131-I Radioactive Uptake studies
- Benign Proliferation of Follicles surrounded by a Fibrous Capsule
- Usually non-functional
- May secrete Thyroid Hormone (less common)
Follicular Adenoma
- Thyroidectomy is Tx: for Thyroid cancers and Hyperthyroidism
- Sx Complications include:
- Hoarseness (recurrent laryngeal nerve damage)
- Hypocalcemia (due to removal of Parathyroid glands)
- Transection of the Inferior Thyroid Artery
Thyroid Cancer
- Most common type of Thyroid Carcinoma (80%)
- Ionizing XRT in Childhood (irradiation for severe acne Tx)
- Pipillae lined by cells with clear, ‘Orphan Annie eye’ nuclei and Nuclear grooves
- Papillae are often a/w Psammoma bodies
- Increased Risk w/ RET and BRAF mutations
- Often spreads to Cervical Lymph nodes (neck)
- Excellent prognosis (10 year > 95%)
Papillary Carcinoma
- Malignant proliferation of Follicles surrounded by a Fibrous Capsule w/ Invasion through the Capsule
- Uniform follicles
- Entire capsule must be examined microscopically
- FNA only examination
- Metastasis generally occurs Hematogenously
- Good prognossis
Follicular Carcinoma
- Malignant proliferation of Parafollicular “C cells” (5%)
- C cells are neuroendocrine cells that secrete Calcitonin
- Calcitonin lowers Serum Calcium by increasing Renal Calcium excretion but is inactive at Normal physiologic levels
- High lvls of Calcitonin –> Hypocalcemia
- Calcitonin often deposits w/in Tumor as Amyloid
- Bpsy –> ‘Malignant cells in an Amyloid Stroma’
- Familial cases –> Multiple Endocrine Neoplasia (MEN 2A and 2B) a/w RET oncogene mutations
- MEN 2 results in Medullary Carcinoma, Pheochromocytoma, and Parathyroid adenomas (2A) or Ganglioneuromas of the Oral Mucosa (2B)
- RET mutations –> Prophylactic Thyroidectomy
Medullary Carcinoma
- Undifferentiated malignant tumor of the Thyroid
- A/w Elderly and Older Pts.
- Invades Local Structures –> Dysphagia or Respiratory Compromise
- Bpsy –> Highly Malignant Undifferentiated
- Very Poor Prognossis
Undifferentiated / Anaplastic Carcinoma
- Chief cells regulate Serum Free (Ionized) Calcium via Parathyroid Hormone (PTH) secretion
- Increases Bone Osteoblast –> Osteoclast activity –> Releases Calcium and Phosphate
- Increases Small bowel Absorption of Calcium and Phosphate (indirectly by activating Vit. D)
- Increases Renal Calcium reabsorption (Distal tubule)
- Decreases Phosphate reabsorption (proximal tubule)
- Increased Serum Ionized Calcium lvls provide negative feedback to decrease PTH secretion
Parathyroid Glands
- Benign neoplasm, usually involving one Gland
- Often results in Asymptomatic Hypercalcemia –> Increased PTH and Hypercalcemia
- Nephrolithiasis (Hypercalciuria - Calcium oxalate stones, large white stone, most common)
- Nephrocalcinosis – metastatic calcification of Renal Tubules –> Renal Insufficiency and Polyuria
- Hypophosphatemia, Increased PTH, ALP, cAMP in Urine
- CNS disturbances (Depression and Seizures)
- Constipation, Peptic ulcer disease, Acute Pancreatitis
- Osteitis Fibrosa Cystica – resorption of bone leading to fibrosis and cystic spaces filled w/ Brown Fibrous Tissue
- “Stones, Bones, Groans, and Psychiatric Overtones”
- Lab: Increased Serum PTH, Increased Serum Calcium, Increased Urinary cAMP, and Increased Serum Alkaline Phosphatase
- Lab: Decreased Serum Phosphate
- Tx: Surgical removal of Affected Gland
Parathyroid Adenoma (Primary)
- Excess production of PTH due to Extrinsic process
- Hypovitaminosis D –> Decreased Ca2+ gut-absorption, Increased PO42- absorption
- Hypocalcemia and Hyperphosphatemia a/w Renal Failure
- Increased ALP, Increased PTH
- Renal osteodystrophy (2nd and 3rd Hyperparathyroidism)
- Most common cause of Chronic Renal Failure
- Renal insufficiency –> Decreased Phosphate excretion
- Increased Serum Phosphate binds Free Calcium
- Decreased Free Calcium stimulates all four Parathyroid glands
- Increased PTH leads to Bone resorption (Renal Osteodystrophy)
- Lab: Increased PTH, decreased Serum Calcium, Increased Serum Phosphate, Increased Alkaline Phosphatase
Secondary Hyperparathyroidism
- Refractory (autonomous) hyperparathyroidism resulting from Chronic Renal Disease
- INCREASED PTH
- Increased Ca2+
Tertiary Hyperparathyrodism
- Low PTH
- Autoimmune DMG to the Parathyroids, Surgical excision, and DiGeorge syndrome (Failure to develop 3rd / 4th Pharyngeal Pouch)
- Symptoms a/w Low Serum Calcium (Hypocalcemia) and Tetany
- Numbness and Tingling (peri-oral)
- Muscle spasms (tetany) – w/ filling blood pressure cuff and carpal spasm –> Trousseau sign or tapping of Facial nerve – Chvostek sign
- Decreased PTH and decreased Serum Calcium
- End-organ resistance to PTH
- Labs reveal Hypocalcemia w/ Increased PTH lvls
- Autosomal dominant form a/w Short Stature and Short 4th and 5th Digits
Hypoparathyroidism
- Albright hereditary osteodystrophy – autosomal dominant unresponsiveness of Kidney to PTH
- Hypocalcemia
- Shortened 4th / 5th digits
- Short stature
Pseudohypoparathyroidism
- Insulin is secreted by Beta cells, center of the islets
- Major anabolic hormone that upregulates insulin-dependent glucose transporter protein (GLUT4) on skeltal muscle and adipose tissue (glucose uptake by GLUT4 –> decreases serum glucose)
- Increased Glucose uptake by tissues leads to increased Glycogen synthesis, Protein synthesis, and Lipogenesis
- Glucagon secreted by Alpha cells; opposes insulin in order to increase Blood Glucose lvls (fasting) via Glycogenolysis and Lipolysis
Islets of Langerhans
- Insulin def. –> metabolic Hyperglycemia due to autoimmune destruction of Beta cells by T lymphocytes (Type IV)
- Inflammation of Islets
- A/w HLA-DR3 and HLA-DR4
- Autoantibodies against insulin – seen years before clinical disease develops
- Childhood manifests w/ Insulin def.
- High serum glucose –> decreased glucose uptake by fat and skeletal muscle
- Weight loss, Low muscle mass, Polyphagia – Unopposed Glucagon leads to Gluconeogenesis, Glycogenolysis, and Lipolysis –> Hyperglycemia
- Polyuria, Polydipsia, and Glycosuria – Exceeding Renal ability to reabsorbe –> Osmotic diuresis
- Hist: Islet leukocytic infiltrate
- Tx: Lifelong insulin
Type I Diabetes Mellitus
- Excessive serum Ketones
- A/w Stress (infection); Epi stimulates Glucagon –> Lipolysis (along w/ Gluconeogenesis and Glycogenolysis)
- Increased Lipolysis –> Increased Free Fatty Acids (FFAs)
- Liver converts FFAs –> Ketone bodies (Beta-hydroxybutyric acid > Acetoacetic acid)
- Hyperglycemia (> 300 mg/dL)
- Anion gap metabolic acidosis w/ Ketoacids in blood
- Hyperkalemia
- Kussmaul respirations –> Blow off the acidosis (Rapid/Deep breathing)
- Dehydration, Nausea, Vomiting, Abdominal pain, Mental status change, Fruity breath (Acetone), Psychosis/delirium, Dehydration
- Tx: Fluids, Insulin, Replacement of electrolytes (K+, Potassium), Glucose if necessary to prevent Hypoglycemia
Diabetic Ketoacidosis
- Hyperglycemia
- Increased H+
- Decreased HCO3- (anion gap metabolic acidosis)
- Increased Blood Ketone lvls
- Leukocytosis
- Hyperkalemia
- Depleted Intracellular K+ due to Transcellular shift from decreased Insulin
Labs: Ketoacidosis
- End-organ insulin resistance –> Metabolic Hyperglycemia –> Progressive pancreatic B-cell failure
- Middle-aged, Obese adults
- NOT related to HLA-DR#s system
- Obesity –> decreased numbers of Insulin receptors on skeletal muscle and Adipose tissue
- Strong genetic predisposition
- Insulin lvls increased early in disease
- Insulin lvls decreased later in disease due to Beta cell exhaustion
- Amyloid deposition in the Islets
- Polyuria, Polydipsia, Hyperglycemia, often clinically silent
- Hist: Islet amyloid polypeptide (IAPP) deposits
- Dx:
- Random Glucose > 200 mg/dL
- Fasting Glucose > 126 mg/dL
- GTT w/ Serum Glucose > 200 mg/dL 2 hrs after glucose loading
- Tx: Weight loss (diet and exercise), Initial drug therapy (Sulfonylureas or Metformin) or exogenous Insulin after Beta cell exhaustion
Type 2 Diabetes Mellitus
- High glucose (> 500 mg/dL) leads to life-threatening diuresis w/ Hypotension and Coma
- Ketones are absent due to Small amounts of Circulating Insulin
Hyperosmolar Non-Ketotic Coma
- Atherosclerosis
- Cardiovascular disease (CAD) leading cause of Death (MI) among Diabetics
- Peripheral vascular disease in Diabetics –> Nontraumatic amputations
- Cerebrovascular disease
Nonenzymatic Glycosylation (NEG) of Vascular Basement Membranes (Large)
- Diffuse thickening of basement membrane –> Retinopathy (Hemorrhage, Exudates, Microaneurysms, Vessel proliferation), Glaucoma
- Renal arterioles involvement –> Glomerulosclerosis –> Small scarred Kidneys w/ Granular surface–> Nephropathy (nodular sclerosis, progressive proteinuria, Chronic renal failiure) –> HTN
- Efferent arterioles –> Glomerular Hyperfiltration Injury w/ Microalbuminuria –> Nephrotic syndrome (Kimmelstiel-Wilson nodules in Glomeruli)
- Hemoglobin produces Glycated Hemoglobine (HbA1C) a marker of Glycemic control
Nonenzymatic Glycosylation (NEG) of Vascular Basement Membranes (Small)
- Glucose freely enters Schwann cells (myelinate peripheral nerves), Pericytes of Retinal Blood vessels, and the Lens
- Aldose reductase converts Glucose –> Sorbitol –> Osmotic damage –> Peripheral Neuropathy, Impotence, Blindness, and Cataracts
- Diabetes is the leading cause of Blindness in the Developed world
Osmotic Damage
- Tumors of the Islet cells
- < 5% of Pancreatic neoplasms
- A/w MEN 1, Parathyroid Hyperplasia, Pituitary Adenomas
Pancreatic Endocrine Neoplasms
- Tumor of Beta cells of Pancreas –> Overprodcution of Insulin –> Hypoglycemia
- Whipple triad of Episodic CNS: Lethargy, Sycope, Diplopia
- Episodic Hypoglycemia w/ Mental status changes that are relieved by administration of Glucose
- Increased C-peptide lvls (vs. Exogenous insulin use)
- Diagnosed by decreased Serum Glucose lvls (usually < 50 mg/dL)
- Increased Insulin and Increased C-peptide
- Tx: Surgical resection
Insulinomas
- Present as Treatment-resistant peptic ulcers (Zollinger-Ellison Syndrome)
- Ulcers can be multiple and can extend into the Jejunum
Gastrinomas
- Gastrin secreting tumor of Pancreas or Duodenm
- Acid Hypersecretion causes recurrent ulcers in Distal Duodenum and Jejunum
- Abdominal pain (peptic ulcer disease, distal ulcers)
- Diarrhea (malabsorption)
- A/w MEN 1
Zollinger-Ellison Syndrome
- Parathyroid tumors
- Pituitary tumors (Prolactin or GH)
- Pancreatic endocrine tumors – Zollinger-Ellison syndrome, Insulinomas, VIPomas, Glucagonomas
- Presents w/ Kidney stones and Stomach Ulcers
- 3P’s = “Diamond”
- Pituitary
- Parathyroid - Parathyroid
- Pancreas
Wermer Syndrome (MEN 1)
- Medullary Thyroid carcinoma (secretes Calcitonin)
- Pheochromocytoma
- Parathyroid hyperplasia
- A/w RET gene
- Autosomal dominant
- 2P’s - “Square”
- Parathyroids – Parathyroids
- Pheochromocytoma (adrenals) - Pheochromocytoma (adrenals)
Sipple Syndrome (MEN 2A)
- Medullary thyroid carcinoma (secretes Calcitonin)
- Pheochromocytoma
- Oral / Intestinal ganglioneuromatosis (mucosal neuromas)
- A/w Marfanoid habitus
- A/w RET gene
- Autosomal dominant
- 1P – “Triangle”
- Oral
- Pheochromocytoma (adrenals) – Pheochromocytoma (adrenals)
MEN 2B
- Present as Achlorhydria (due to inhibition of Gastrin) and Cholelithiasis w/ Steatorrhea (due to inhibition of Cholecystokinin)
Somatostatinomas
- Secrete excessive vasoactive interstinal peptide leading to watery diarrhea, Hypokalemia, and Achlorhydria
VIPomas
- Excess Aldosterone
- HTN, Hypokalemia, and Metabolic Alkalosis
- Aldosterone increases absorption of Sodium and Secretion of Potassium and Hydrogen Ions in the Distal Tubule and Collecting duct
- Increased Sodium expands Plasma Volume leading to HTN
- Edema often absent, due to Aldosterone escape
Hyperaldosteronism
- Bilateral Adrenal Hyperplasia – or -
- Adrenal Adenoma (Conn syndrome)
- Adrenal Carcinoma (rare)
- HTN, Hypokalemia, Metabolic alkalosis, and LOW Plasma Renin
- Normal Na+ due to Aldosterone escape –> No edema due to Aldosterone escape mechanism
- May be Bilateral or Unilateral
- High Aldosterone and Low Renin –> Increased Renal Perfusion pressure, downregulation of Renin
- Tx: Mineralocorticoid receptor Antagonist (Spironolactone or Eplerenone), Adenomas are usually surgically resected
Primary Hyperaldosteronism
- Renal perception of Low Intravascular Volume
- -> Overactive Renin-Angiotensin system
- A/w Renal artery stenosis, CHF, Cirrhosis, or Nephrotic syndrome
- Seen w/ Activation of the Renin-angiotensin system (e.g. Renovascular HTN or CHF)
- High Aldosterone
- High Renin
- Tx: Spironolactone
Secondary Hyperaldosteronism
- Rarely due to Glucocorticoid-remediable aldosteronism (GRA)
- Aberrant expression (AD) of Aldosterone synthase in the Fasciculata
- Presents in children as HTN, Hypokalemia, High Aldosterone and Low Renin
- Responds to Dexamethasone, Confirmed w/ Genetic testing
Familial Hyperaldosteronism
- Mimics Hyperaldosteronism
- Decreased degradation of Sodium Channels (AD) in Collecting Tubules
- HTN, Hypokalemia, and Metabolic Alkalosis in a Young Pt.
- Low Aldosterone and Low Renin
- Tx: Potassium-sparing diuretics (e.g. Amiloride or Triamterene), blocks Tubular Sodium Channels, Spironolactone is not effective
Liddle Syndrome
- Excess Cortisol
- Muscle weakness w/ Thin Extremeties – Cortisol breaks down muscle to produce Amino acis for Gluconeogenesis
- Moon Facies, Buffalo hump, and Truncal obesity – High Insulin (due to High Glucose) Increases storage of Fat Centrally
- Abdominal Striae – due to impaired collagen synthesis resulting in thinning of skin –> Ruptured blood vessels on abdomen
- Hypertension often w/ Hypokalemia and Metabolic acidosis
- High cortisol increases sensitivity of Peripheral vessels to Catecholamines
- At very high levels, Cortisol cross-reacts w/ Mineralocorticoid receptors (aldosterone is not increased)
- Osteoporosis
- Immune Suppression
- Dx: 24-hour Urine Cortisol lvl, Late night salivary cortisol lvl, low-dose Dexamethasone suppression test
- Plasma ACTH distinguishes ACTH-dependent causes Cushing syndrome from ACTH-independent causes
Hypercortisolism (Cushing Syndrome)
- ACTH-secreting Pituitary Adenoma
- Paraneoplastic ACTH secretion (SC Lung cancer, Bronchial carcinoids)
- Increased ACTH –> Bilateral Adrenal Hyperplasia
- Responsible for the majority of Enogenous cases of Cushing syndrome
Cushing Disease
- Most common cause of Congenital Adrenal Hyperplasia (90%)
- Decreased Aldosterone
- Decreased Cortisol
- Steroidogenesis is shunted towards Androgens
- Neonates: Hyponatremia, Hyperkalemia, and Hypovolemia w/ Life-threatening HTN (Salt wasting)
- Females: Clitoral enlargement (genital ambiguity due to increased Androgens)
- Non-classic form presents later in life w/ Androgen excess –> Precocious puberty (males) or Hirsutism w/ Mentrual Irregularities (Females)
21-hydroxylase deficiency
- Similar to 21-hydroxylase def. but weak Mineralocorticoids (DOC) are Increased
- HTN (sodium retention)
- Mild Hypokalemia (no salt wasting)
- Renin and Aldosterone are low
11-hydroxylase deficiency
- Decreased Cortisol
- Decreased Androgens
- Weak Mineralocorticoids (DOC) are increased leading to HTN and mild Hypokalemia
- Renin and Aldosterone are low
- Decreased Androgens (Adrenal and Gonads) lead to Primary Amenorrhea and Lack of Pubic Hair in Females or Pseudohermaphroiditism in Males
17-hydroxylase deficiency
- Dx: Screening w/ serum 17-hydroxyprogesterone lvls
- Increased in 21- and 11-hydroxylase def.
- Decreased in 17-hydroxylase def.
Screening for CAH
- Classic cause of Acute Adrenal Insufficiency w/ the Adrenal Hemorrhage (gland converted to a sac of blood)
- A/w Hemorrhagic Necrosis of Adrenal glands
- Classically due to DIC, in young Children w/ Neisseria meningitidis infection, and Endotoxic shock
- Lack of Cortisol exacerbate HTN –> Death
Waterhouse-Friderichsen Syndrome
- Most common Adrenal Medulla in Children
- < 4 y.o.
- Originates from Neural Crest Cells
- Occurs anywhere along the Sympathetic chain
- A/w Abdominal distention and a Firm, Irregular mass that can Cross the Midline (vs. Wilms tumor: smooth and unilateral)
- Homovanillic acid (HVA) a breakdown product of Dopamine in Urine
- Bombesin +
- Low liklihood of HTN
- A/w N-myc oncogene
Neuroblastoma
- Due to Atrophy or Progressive destruction of the Adrenal glands
- Def. of Aldosterone and Cortisol
- All 3 Corticol divisions and Spares the Medulla
- (3) Main causes of Adrenal Destruction:
- Autoimmune destruction (in the West)
- TB (developing world)
- Metastatic carcinoma (lung)
- HTN
- Hyponatremia
- Hypovolemia
- Hyperkalemia
- Metabolic acidosis
- Weakness
- Hyperpigmentation (ACTH stimulates melanocytes. POMC –> MSH)
- Vomiting
- Diarrhea
- Hyperpigimentation + Hyperkalemia –> Dx Primary vs. Secondary Insuff.
Addison Disease
(Chronic Adrenal Insufficiency)
- Decreased Pituitary ACTH
- No Skin / Mucosal Hyperpigmentation and no Hyperkalemia
Secondary Adrenal Insufficiency
- Tumor of Chromaffin Cells
- Increased Serum Catecholamines: Epi, NorEpi, Dopamine
- Symptoms occur in “spells” – relapse and remit
- Episodic Hyperadrenergic Symptoms (5 P’s)
- Pressure: BP –> Episodic HTN
- Pain - Headache
- Palpitations - Tachycardia
- Perspiration – Sweating
- Pallor
- Increased Serum Metanephrines / Catecholamines and Increased 24-hour Urine Metanephrines and Vanillylmandelic acid (VMA)
- A/w MEN 2A and 2B (RET gene test), vonHippel-lindaue disease (loss of tumor supressor), Neurofibromatosis Type I
- Tx: Beta-blockers followed by Surgical Excision w/ Phenoxybenzamine (irreversible alpha-blocker, alpha-antagonist)
- Very Important: “A’s before B’s” to avoid Hypertensive Crisis!
Pheochromocytoma
Rule of 10’s of Pheochromocytoma?
- Most common tumor of the Adrenal Medulla in Adults
- Derived from Chromaffin cells (from Neural crest)
- Rule of the 5x 10’s
- 10% Malignant
- 10% Bilateral
- 10% Extra-Adrenal
- 10% Calcify
- 10% Kids
- Carcinoid tumors (rare, neuroendocrine cells)
- 1/3 Metastasize
- 1/3 present w/ 2nd malignancy
- 1/3 are multiple
- Small bowel tumors (most common)
- -> secrete High levels of Serotonin (5-HT)
- Not seen if tumor is limited to GI tract (5-HT first pass metabolism)
- Recurrent diarrhea
- Cutaneous flushing
- Asthmatic wheezing
- Right-sided valvular disease
- Increased 5-hydroxyindoleacetic acid (5-HIAA) in urine
- Niacin def. (Vit. B3) –> Pellagra
Carcinoid Syndrome