Endocrine Flashcards

Question

What is Pituitary dwarfism?

Answer 1

* Failure of Rathkes pouch ectoderm to differentiate into the adenohypophysis * **Autosomal recessive in GS** * Also occurs in Spitz, Toy Pinschers, and Karelian bear dogs * Generally normal until 2 months of age * **Manifestations due to decreased growth hormone** * Decreased insulin-like growth factor 1 * Decreased growth (retain infantile characteristics) * Retention of puppy hair progressing to alopecia

Answer 2

* Neoplastic remnants of Rathkes pouch oropharyngeal ectoderm * Occurs in Young dogs, Rare * Hypothalamic destruction and decreased hypothalamic trophic hormones

Answer 3

* Dogs, cats, and others * These can arise from any cell, but often of chromophobe origin * Hypopituitarism with endocrine gland atrophy and hypofunction

Answer 4

* Pituitary Abscesses * Most common in Cattle * Secondary to nasal septal infections * **Acts as a space occupying lesion** * **Blindness, depression, drooling, tongue prolapse** * Can mimic rabies

Answer 5

* Pituitary Diabetes Insipidus * Destruction of the neurohypophysis or supraoptic nuclei of the hypothalamus * Decreased ADH production or release * PU/PD, Dilute urine * Decreased Oxytocin * Nephrogenic diabetes insipidus * Primary renal disease, ADH is normal

Answer 6

* **Cortex** (mesoderm origin) * Zona glomerulosa * Mineralocorticoids * Zona fasciculata * Glucocorticoids * Zona reticularis * Sex steroids * **Medulla** (Neural crest origin) * Catecholamines

Answer 7

* **Mineralocorticoids** * **Aldosterone**: * Regulates blood pressure * Promotes sodium retention and potassium excretion by renal tubules * Increases intracellular fluid volume and regulates extracellular fluid volume * **Glucocorticoids** * **Cortisol** and corticosterones * Gluconeogenesis, protein and fat catablism, suppressive for inflammation and immunity * **Sex Steroids** * Progesterone, estrogen and androgens * **Catecholamines** * Epinephrine and norepinephrine

Answer 8

* **Pituitary hormones** * ACTH * **Renin-angiotensin system** * Renin (released from juxtaglomerular cell in response to low blood pressure) cleaves angiotensinogen * Angiotensin I and II contracts vascular smooth muscle and stimulates aldosterone secretion * **Neural Controls** * Catecholamine secretion

Answer 9

* Hyperfunction (Hyperadrenocorticism) * Hypofunction (hypoadrenocorticism)

Answer 10

* Primary or secondary adrenal involvement * Polyuria, polydipsia, increased appetite, weakness, alopecia, increased infection * "Cushing's Disease"

Answer 11

* Primary or secondary adrenal involvement * Anorexia, weight loss, GI disturbances, dehydration * "Addison's Disease"

Answer 12

* **Metabolic** * Adrenal dysfunction will result in metabolic alterations * **Neoplasia** * Functional or non-functional * **Cell alteration and injury** * Secondary hyperplasia is common secondary to pituitary disease * Secondary atrophy due to hypopituitarism * **Developmental anomalies** * Aplasia, hypoplasia or cysts * **Immunopathology** * Autoimmunity

Answer 13

* Genetic predisposition * pituitary neoplasia causing adrenal hyperplasia * Chemical * Exogenous administration of glucocorticosteroids

Answer 14

* Adrenal cortical adenoma or carcinoma * Most arise from the zona fasciculata * Less commonly the zona glomerulosa in cats (hyperaldoteronism) or zona reticularis in ferrets (hyperestrogenism) * Adenomas are more common than carcinoma * old dogs mainly affected, also seen in old cattle * Can be multiple or single, unilateral or bilateral * Contralateral adrenal gland atrophy occurs with functional unilateral neoplasms

Answer 15

* Result in hyperadrenocorticism * PU/PD * Increased appetite * Muscle atrophy and weakness * Alopecia (Endocrine dermatopathy) * Increased incidence of infections

Answer 16

* Clinical syndrome characterized by increased cortisol/glucocorticosteroids * Cushings disease * Most often due to ACTH-secreting pituitary adenoma * less often due to adrenal cortical adenoma or carcinoma * Lesions associated with hyperadrenocorticism * Hepatic lipidosis and glycogenosis * Epidermal and adnexal atrophy * Systemic mineralization * Skin, lung, muscle, stomach * Lymphoid tissue depletion

Answer 17

* Gluconeogenesis * Lipogeness * Protein Catabolic * Anti-inflammatory * Immunosuppression * Inhibition of fibroplasia

Answer 18

* **Diffuse adrenal cortical hyperplasia** * Common in dogs * Occurs secondary to functional chromophobe adenoma of the pituitary gland * Excessive and unregulated secretion of ACTH * **Hyperadrenocorticism is the result** * Signs and lesions are the same as those of hyperadrenocorticism caused by primary adrenal neoplasia

Answer 19

* Common age-related change in dogs, cats and horses * Some of these are functional * Increased ACTH from pituitary hyperplasia or neoplasia * Some are non-functional and of minimal to no clinical significance

Answer 20

* Phenochromocytoma * Arise in chromaffin cells of the medulla * Most common in dogs and cattle * Ganglioneuroma and neuroblastoma * Uncommon * Neuroectoderm origin

Answer 21

* Most are non-functional * Functional neoplasia results in systemic hypertension due to norepinephrine secretion * They can be benign or malignant * Malignant neoplasms often invade the great vessels * Approximately 50% metastasize in dogs

Answer 22

* Rare condition of dogs * Total agenesis is fatal * Hypoplasia results in variable degrees of hypoadrenocorticism

Answer 23

* Most common in dogs on long-term glucocorticosteroids therapy * Exogenous glucocorticosteroids result in inhibition of adrenal cortical function and subsequent atrophy

Answer 24

* **Uncommon** conditions of dogs and cats * **Immune-mediated damage** and atrophy of the adrenal cortex * May also result from destruction (chronic inflammation) or non-functional neoplasia of the pituitary gland * **Signs usually occur only after 90% of the cortex is destroyed or atrophied** * Results in **hypoadrenocorticism** * **Anorexia and weight loss** * **Diarrhea and dehydration**

Answer 25

* A wide variety of processes periodically affect the adrenal gland * This is mainly **due to the rich vascular network a the cortico-medullary junction** * Ex: * Thrombosis due to DIC * Adrenalitis due to infectious emboli * Metastatic neoplasia * 15-30% of metastatic lesion may occur here * Melanotic neoplasia, hemangiosarcoma, Lymphosarcoma

Answer 26

* Clinical syndrome characterized by **decreased adrenocortical hormones** * Addison's Disease * Mainly affects the **zona glomerulosa** * immune-mediated most common in Portuguese water dogs, Bearded Collie, Standard poodle * **Hypoaldosteronism** * Hyponatremia and hyperkalemia * Decreased cortisol is also present

Answer 27

* Two lobes with a narrow isthmus * Thyroid Epithelial cells * Arranged in follicles * Produce thyroid hormones * Thyroid C-cells * Small aggregates of cells between follicles * Produce calcitonin

Answer 28

* **Thyroid** **hormones** (Triiodothyronine; T₃ and Tetraiodothyronine; T₄) * **increased metabolism** (protein synth, glycolysis, gluconeogenesis, lipolysis * **Stimulate heart and neural function** * **Calcitonin** * **Regulation of serum calcium concentration** * **Inhibition of osteoclasts** and bone resorption and synergistic with parathormone to decrease renal phosphorus absorption * **Regulation of adrenal function** * Hypothalamic releasing factors * Pituitary hormones * TSH

Answer 29

* Hyperfunction (hyperthyroidism) * Hypofunction (hypothyroidism)

Answer 30

* Usually primary thyroid involvement * Polyphagia, weight loss, weak, tachycardia * Most common in cats

Answer 31

* Usually primary thyroid involvement * Inactivity, alopecia, lethargy, weight gain, obesity * Most common in dogs

Answer 32

* **Metabolic** * Thyroid dysfunction will result in metabolic alterations * **Neoplasia** * Usually functional, sometimes non-functional * **Cell alteration and injury** * Hyperplasia and atrophy are common * **Immunopathology** * Autoimmune destruction of the thyroid * **Developmental** * Ectopic thyroid tissue

Answer 33

* **Genetic predisposition** * Thyroid neoplasia, hyperplasia or autoimmunity * **Nutritional** * Deficiency of iodine, tyrosine or other thyroglobulin components * **Chemical** * Goitrogenic compounds * Thiouracil, sulfonamides, cyanogenic plants

Answer 34

* Thyroid follicular adenoma and carcinoma * Most common in old cats (usually adenoma) * These are often functional resulting in hyperthyroidism * There can be nodules in one or both lobes * Distinction between hyperplasia is sometimes difficult * Less Common in dogs (usually carcinoma) * These are often large, invasive, and metastatic to regional lymph nodes

Answer 35

* Most common as an age-related change in horses, dogs, and cats * Most are non-functional and of minimal significance * In cats, some of these may progress to adenoma

Answer 36

* Functional neoplasms result in hyperthyroidism (increased basal metabolic rate) * Polyphagia with weight loss * Hyperactivity and nervousness * Weakness and heat intolerance * Tachycardia * May be due to mutation in the gene coding for the TSH receptor * This is different than Graves disease in humans since there are no auto-antibodies to the TSH receptor in cats

Answer 37

* Most common in old bulls and horses * Often malignant in bulls, but incidental in horses * Bulls * These may arise due to long-term ingestion of high calcium rations * High calcium rations also induce hyperplasia initially * Pituitary or adrenal medulla neoplasia may occur concurrently * Some can be functional * Hypercalcitoninism * Vertebral osteophytes and osteosclerosis

Answer 38

* **Inhibition of thyroid hormone formation** * Nutritional deficiency of iodine or tyrosine * Goitrogenic compound ingestion * Cruciferous plants (Brassica sp.) * Drugs (phenobarbital, rifampin, among others) * Thyroid hyperplasia is the lesion * Cause varies * **Results in hypothyroidism** in postnatal animals * Stillbirth is most common when affected in utero * Neonates can also have signs of hypothyroidism * Myxedema

Answer 39

* Diffuse: * Excessive TSH stimulus due to decreased thyroid hormones * Iodine deficiency is a common cause * Multinodular * Independent of TSH (autonomous) * Mainly in old cats * Dyshormonogenic * Defective synthesis with normal iodine levels * Due to genetic defect in thyroglobulin synthesis or thyroid peroxidase * Autosomal recessive in sheep and goats

Answer 40

* Most common in dogs * **There is primary degeneration and atrophy of the thyroid gland** * Results in **hypothyroidism** * Accounts for approximately 50% of the cases of canine hypothyroidism

Answer 41

* Type of Thyroid Gland atrophy * Most common in dogs * Autoimmune destruction of the thyroid gland * There is fibrosis, atrophy, and lymphocytic infiltration of the gland * Results in hypothyroidism * Accounts for approximately 50% of these cases in dogs * Similar to Hashimoto's thyroiditis * Auto-antibodies to thyroglobulin

Answer 42

* Clinical syndrome characterized by decreased T3/T4 * Signs include: * Weight gain and inactivity * Alopecia (Endocrine dermatopathy) * Reproductive abnormalities * Hypercholesterolemia * Systemic Lesion associated with disease - The cause of ~50% of the cases of hypothyroidism in dogs * Hyperkeratosis and adnexal atrophy of the skin * Myxedema (facial edema) * Atherosclerosis * Hepatic lipidosis

Answer 43

* Chief cells * Comprise most of the gland * Produce parathormone * Oxyphil Cells * Modified Chief cells

Answer 44

* Control nd maintenance of serum Calcium levels * **Parathyroid hormone (Parathormone)** * Released in response to low serum calcium * Stimulates GI absorption and resorption of Ca²⁺ from bone, increased renal retention of Ca²⁺ and inhibits phosphorus reabsorption * **Calcitonin** (From Thyroid C-Cells) * Released in response to high serum calcium * Decreases GI absorption and resorption from bone, decreased renal retention * **Vitamin D** (From skin or diet) * Conversion to calcitriol in the kidney * Synergistic with parathormone

Answer 45

* Primary or secondary parathyroid involvement * Usually secondary (primary renal or nutritional) * Increased lameness and fractures, facial bone enlargement and weakening (fibrous osteodystrophy)

Answer 46

* Usually primary parathyroid involvement * Variable signs, including anorexia, weakness, or tetany or convulsions

Answer 47

* Metabolic * Parathyroid dysfunction will result in abnormal calcium metabolism * Metabolic problems frequently causes parathyroid abnormalities * Cell alteration and injury * Hyperplasia is common secondary to renal or nutritional disease * Idiopathic hyperplasia * Development * Cyst formation; variable significance * Immunopathology * Autoimmunity * Neoplasia * Parathyroid involvement * Non-parathyroid neoplasm producing parathormone-like substances

Answer 48

* Nutritional * Deficiency or imbalance of calcium and phosphorus * Chemical * Plants with Vitamin-D-Like activity * Genetic Predisposition * Parathyroid neoplasia or autoimmunity

Answer 49

* A clinical syndrome characterized by excessive activity of parathormone * Features: * Hypercalcemia due to enhanced intestinal absorption and bone calcium mobilization * Fibrous osteodystrophy * Bone weakness and factures * Thickened facial bones * Gastrointestinal disturbances * Muscle weakness

Answer 50

* Diets high in phosphorus and low in calcium * Grain with low quality roughage - Bran disease * Persistent hypocalcemia results in parathyroid hyperplasia and increased PTH secretion * Clinical and pathological features are those on hyperparathyroidism

Answer 51

* Dogs with chronic renal failure * Renal retention of phosphorus and loss of calcium * Decreased renal conversion of calcifediol to calcitriol also contributes to hypocalcemia * Persistent hypocalcemia results in parathyroid hyperplasia and increased PTH secretion * In long-standing cases, hyperplasia becomes autonomous (no longer responsive to Ca2+ levels * Tertiary parathyroid hyperplasia * Clinical and pathological features are those of hyperthyroidism and renal failure * Fibrous osteodystrophy * Uremia and PU/PD

Answer 52

* Mainly dogs and sometimes cats * **Persistent hypercalcemia without increased PTH** * Hypercalcemia is due to production of parathormone hormone-related peptide (PHRP), osteolytic factors, Cytokines (TNF), among other substances by certain neoplasms * Adenocarcinoma of anal sac apocrine glands * Lymphosarcoma (canine) * Plasma cell tumors (multiple myeloma) * Unregulated hypercalcemia due to PTH-like activity * Neuromuscular and cardiovascular dysfunction * Soft tissue mineralization * Parathyroid gland atrophy

Answer 53

* Grazing animals in areas with appropriate plants * Plants with Vit D activity * Cestrum diurnum * Hypercalcemia is the result * Increased bone density * Soft tissue mineralization

Answer 54

* Relatively common in dogs * Originate from embryonic duct between thyroid and parathyroid glands or other embryonic structures * Kursteiners usts * Minimal significance unless they are large and space-occupying

Answer 55

* A type of parathyroid atrophy * Uncommon in adult dogs * increased incidence in miniature schnauzers * Most likely autoimmune origin * Lymphoid infiltrate, chief cell atrophy, fibrosis * Results in hypoparathyroidism * Increased neuromuscular excitability * Decreased bone reabsorption

Answer 56

* A clinical syndrome characterized by decreased activity or response to parathormone * Features: * Hypocalcemia * Decrease bone resorption of Ca2+ * Increased phosphorus retention by tubules * Altered neuromuscular excitability * Weakness, ataxia, tremors, tetany * Paresis

Answer 57

* Mainly in cattle and dogs * Cattle - parturient paresis “milk fever” * Dogs - puerperal tetany “eclampsia” * Profound hypocalcemia * Disease often due to acute need during parturition or lactation

Answer 58

* PTH is produced, but there are reduced osteoclasts due to high Ca2+ ration * Mechanisms: * High threshold potential at neuromuscular junctions * Concurrent hypermagnesemia * Magnesium acts as a calcium channel antagonist * increased levels of VFA * Inhibitory at neuromuscular synapses

Answer 59

* Typically occurs at the peak of lactation * 2-3 weeks after whelping * More frequent in small breed dogs * Mechanisms * _Not due to inadequate PTH_ * Low threshold potential at neuromuscular junction * Na+ channels are activated with very little increase in membrane potential * Low Ca2+ in extracellular fluid lowers the threshold potential for activation of NA channels * **Repetitive firing of motor nerve fibers occurs**

Answer 60

* **Alpha Cells** * Comprise 5-30% of the islet cell population * **Glucagon** is the major product * **Beta Cells** * 60-80% of the islet cell population * **Insulin** is the major product

Answer 61

* Control of glucose metabolism * **Glucagon**: * **Increases blood glucose** concentration * increased glycogenolysis (liver and other tissues) * Enhances hepatic gluconeogenesis and FA oxidation (lipolysis) * **Insulin**: * **Decreases blood glucose** concentration * Enhances glucose entry into cells and hepatic glycogen storage * Mainly hepatocytes, skeletal muscle, adipocytes * Increased glycogenesis and glucose oxidation, Increased lipogenesis

Answer 62

* Hyperfunction (Hyperinsulinism) * Primary islet cell neoplasia * Neurological signs and weakness * Hypofunction (Diabetes mellitus) * Beta cell destruction and deficiency * Emaciation, PU/PD, Dehydration, various organ and tissue abnormalities

Answer 63

* **Metabolic**: * Endocrine pancreas dysfunction will result in abnormal carbohydrate metabolism * Metabolic problems (Amyloidosis) may cause islet cell abnormalities * **Cell alteration and injury** * Acute pancreatic necrosis of dogs will damage islets * **Developmental**: * Rare * Hypoplasia * **Immunopathology** * Autoimmunity

Answer 64

* Nutritional * Carb and fat excess or imbalance in the ration * Genetic predisposition * Neoplasia or autoimmunity

Answer 65

* Most common in dogs, sometimes in cats * Often middle-age to older female dogs * more common in smaller breeds * The problem is **inadequate insulin activity** * **Type I** (insulin-dependent) form is due to decreased insulin secretion * **Type II** (non-insulin-dependent) form is due to inadequate insulin release or target cell response * more common in cats

Answer 66

* **Islet cell hypoplasia** * **Destruction of Pancreatic islets** * acute pancreatic necrosis in dogs (chronic relapsing pancreatitis) * less often immune-mediated destruction * Islet amyloidosis in cats * **Failure of insulin release from islet cells** * **Failure of tissues to respond to insulin** * Antagonism between insulin and other hormones * Hyperadrenocorticism promotes hyperglycemia and insulin resistance * Growth hormone stimulates increased secretion of insulin-like growth factor

Answer 67

* More often **type II** * Predisposing factors: * Hyperadrenocorticism, excess GH activity, **Obesity** * **Islet amyloidosis** * **Co-secretion of** Islet amyloid Polypeptide (IAPP; **amylin**) with insulin * **Amylin fibrils can cause B-cell death** due to misfolding protein response * Insulin resistance * Decreased **uptake of glucose by insulin-sensitive cells** * Predominately hepatocytes, skeletal muscle, adipocytes

Answer 68

* Emaciation * PU/PD * Increased infections * Hyperglycemia * Glycosuria * Ketoacidosis and ketonuria

Answer 69

* **Hepatic lipidosis/glycogenosis** * **Glomerulosclerosis and glycogen nephrosis** * **Microangiopathy** * Glomerulopathy retinopathy and gangrene * **Cataracts** (shift to sorbitol pathway) * Vascular lesions and necrosis are not as prominent as in humans * Other lesion associated with any predisposing factors * Adrenal cortical hyperplasia or pituitary adenoma

Answer 70

* Rare, mainly dogs * **Insulinoma** is the most common type * a wide variety of hormones can be associated with functional islet cell neoplasia * May also see amyloidosis due to concurrent secretion of IAPP * **Neoplastic Bet cells produce excess insulin** * Hyperinsulinemia **resulting in hypoglycemia** * Neurological disease

Endocrine Flashcards

(94 cards)