Diseases of the Endocrine System DeeDee Schumacher CVT, VTS (ECC) Jeannie Stall , R.V.T. Credits: ClipArt/ Google Images Alleice Summers
Diabetes • Diabetes Mellitus: Beta cells in pancreas quit adequate production of the hormone “insulin” or when tissues in the body become resistant to insulin Insufficient insulin to switch off glucose prod. by the liver or efficiently store excess glucose from energy foods. Blood concentration of glucose rises & exceeds level @ which the kidneys let glucose leak into the urine.
Type I vs Type II • Type I = Insulin-dependent diabetes 100 % of K9’s & 50% of cats Tx.: High fiber diet/daily insulin replacement • Type II = Non-insulin-dependent diabetes 50 % of cats Tx.: Drug therapy/ diet restriction
Diabetes cont’d …. Symptoms: • Non-ketotic diabetes Polyuria / polydipsia / wt. loss / muscle loss / sudden cataracts / polyphagia / recurrent infections/ dehydration/ plantigrade posture in cats (“hock walking”) • Ketotic diabetes All of the above + : Depression/ weakness/ tachypnea/ vomiting & “acetone” breath odor
Most likely victims….. • 4 – 14 yrs old dogs / Female dogs higher % • All ages of cats/ NM’s higher % • Poodles/schnauzers/keeshonds/beagles/ Cairn terriers/ dachshunds & cockers
Diabetes • Dx: Clin. signs / glycosuria / Fasted, bl. glucose test >200 mg/dl • Tx: High fiber-complex carb. diet ie: Hill’s R/D or W/D Regularly scheduled meals & exercise Insulin: Cats-Prozinc K9’s-Human insulin Types of insulin ie: Ultralente (long-acting) NPH (intermediate-acting)
Insulin • Care & Handling: Can be damaged by heat, rough handling or chemicals DON’T SHAKE VIAL! Gently roll/invert Refrigerate insulin Use syringes free of chemicals/soaps
Blood Glucose levels… • Blood glucose curve: Series of glucose tests to evaluate insulin dose/glucose levels NOTE: Stress can elevate glucose levels W/ fractious cat, possibly place IV cath. for multiple blood draw ease during day. High levels not good but LOW glucose can be FATAL !
Insulin Shock Dangerously low glucose levels d/t: • Inconsistent feeding schedule (type & amt.) -anorexia, vomited meal but rec’d insulin… • Unregulated exercise ( excessive activity ) • Failure to monitor bl. glu. levels • Inconsistent insulin doses / insulin care Emergency-Seizure/coma RxKaro syrup/treats
Insulinoma Insulin-secreting tumor (Beta cells in pancreas) • Symptoms d/t hypoglycemia (15-78 mg/dl): Seizures / weakness/ collapse / ataxia / brain damage / lethargy Victims: St. poodle / Irish setter / boxer / fox terrier/ Germ. Shep./ Cats: Rarely (1 Siamese) Ferrets!! • Dx: Ultrasound, bl. glu. level • Tx- Surgically remove tumor Medical mgmt. via Rx Pred /Diazoxide
Hypocalcemia • Causes: Parathyroidism Chronic/acute renal failure Acute pancreatitis Ecalmpsia (puerperal tetany) Tx: Correct underlying cause Supplement Vit. D & calcium
Normal function….. • Hypothalamus directs Pituitary gland Pituitary gland produces ACTH (adrenocorticotrophic hormone) This hormone is released into the bloodstream & stimulates the body's two adrenal glands, located near the kidneys, to secrete glucocorticoid (cortisone-like or cortisol) hormones into the bloodstream. (Cortisol helps the body respond to stress) When bl. cortisol levels are high enough--- pituitary stops secreting ACTH When bl. cortisol levels dip low , the pituitary secretes more ACTH. Adrenals respond by secreting glucocorticoid hormones in response to the pituitary, just as the pituitary responds by secreting ACTH in response to the adrenals. Net effect : A mildly fluctuating balance is achieved
Cushing’s disease • This balanced process has gone away d/t hypersecretion of cortisol • Pituitary tumor = excess ACTH • Adrenal tumor = excess cortisol • Veterinary interference= Rx Corticosteroids Result : Chronic excess of blood cortisol levels in the body AKA: Hyperadrenocorticism
Cushing’s • Symptoms : Polyuria / polydipsia / polyphagia/ sagging, pot-bellied appearance/ excessive panting / obesity muscle weakness/ lethargy/ lameness/ pruritis/ pyoderma/ bilateral, symmetrical alopecia/ abnormal gonad function / slow hair regrowth/ dark skin
Cushing’s • Hyperadrenocorticism
Cushing’s • Dx: Increased Alk. Phos/ALT/cholesterol/ bl. glu Decreased BUN / lipemia present Urine protein/creatinine ratio : Rule out only Higher ratio indicates more cortisol in urine = more in blood ACTH stimulation test: • Fasted , baseline blood sample taken • ACTH injection (Cortrosyn @ 0.25 mg/IM -K9 / 0.15 mg/IM cats) • Bl. samples @ 0 & 60 min K-9/ 0,30 & 60 min. cats • Cortisol levels measured
Cushing’s • Dx: • Low dose dexsupression test • Fasted , baseline blood sample • Dex injection (synthetic glucocorticoid) • Blood samples 4 & 8 hours later • Can’t definitively differentiate between adrenal & pituitary dogs (suggestive)
Cushing’s • Dx: • High dose dexsupression test • After dxcushings • Differentiates between adrenal & pituitary • Similar to low dose but high dose given • A dog w/ adrenal tumor won’t suppress at all. Adrenal tumor simply doesn't "care" about the level of blood cortisol so it keeps pumping out cortisol. • A dog w/ a pituitary tumor still has some limited ability to respond to feedback & should respond to a high dose of dexamethasone by showing a suppressed cortisol level.
Cushing’s • Tx • Depends on type of cushings & health of animal • Concurrent problems-complicated tx • Comfort of patient goal not to increase life span • Surgery may be indicated for adrenal tumors. • Chemotherapy : Lysodren or Ketaconazole Anipryl w/ pituitary-dependent Cushing's. NOTE: Life-long treatment ~ 20-30 month life expectancy
Equine Cushing’s Very common / Late teens to early twenties • Symptoms: Weight loss / long, poorly-shed hair/ Muscle wasting/ Lethargy/ Sweating PU / PD / Recurrent laminitis Dx: dexsuppresion test
Equine Cushing’s Tx: Good mgmt via : • Food • Hoof care • Body clipping • Dopamine receptor agonists ie: Pergolide or Bromocriptine Cyproheptadine: < $ but < effective
Addison’s Hypoadrenocorticism : Uncommon Insufficient production of mineralocorticoids (primarily aldosterone) by adrenal cortex Idiopathic / Immune mediated? / trauma/ fungal infection/ neoplasia / hereditary/ excessive Lysodren therapy
Addison’s • Symptoms : Middle-aged (< 7 yrs old), female dogs Intermittent , subtle signs / lethargy / weakness / anorexia / vomiting / diarrhea / wt. loss / P/U / P/D / bradycardia / dehydration NOTE: Consider Addison’s w/ vomiting K-9 having a > elevated BUN but not a renal case
Addison’s • Dx Hyperkalemia (elev. K ) Hyponatremia (low Na) Na:K ratio < 27:1 ( normal range b/t 27:2 & 40:1 ) > BUN , Creatinine & Calcium / < bl. glu & albumin ECG - Associated with hyperkalemia • ACTH stimulation test: • ACTH inj. incites subnormal or negative response in dogs w/ hypoadrenocorticism. Baseline & post-ACTH samples w/ cortisol level of < 2 micrograms per dl are diagnostic for hypoadrenocorticism
Addison’s • Tx: Acute Addisonian crisis • Collect samples & initiate treatment immediately • Restore blood volume-IV 0.9% saline @ 44-88 ml/kg • IV glucocorticoidsie: Solu-Delta-Cortef or IM or SQ- Percorten-V or PO- Florinef • Primary Addison’s requires lifetime corticosteriod therapy/monitoring / Flare-ups d/t stress, trauma ,sx • Prognosis: Excellent when dz. Dx’d early & appropriate therapy is begun
Hyperthyroidism Most common endocrine issue in cats -- Rarely seen in dogs unless neoplasia • Excessive prod. & secretion of triiodothyronine (T3) & thyroxine (T4) by the thyroid gland Increased metabolic rate / middle-aged to older cats Risk factors: Canned food / Cat litter / Genetics?
Hyperthyroidism Symptoms: Wt. loss / polyphagia / vomiting/ polyphagia/ tachycardia (+/- murmurs) / aggressive behavior/ enlarged thyroid gland / > systolic bl. pressure/ retinal detachment blindness Dx: Enlarged thyroid gland / > T4 / > AlkPhos, > ALT , BUN & Creatinine
Hyperthyroidism • Tx: • Surgical removal of thyroid- NOT parathyroids • Medications- Methimizole ( Tapezole ) • Radioactive iodine
Hypothyroidism Seen in dogs : Goldens/Cockers/Dobes/Schnauzers Irish setters/ Dachshunds are predisposed Decreased metabolic rate • Thyroid gland atrophy Symptoms: Lethargy / wt. gain/ “rat tail”/ hyperpigmentation/ dry coat/ alopecia/ hypercholesterolemia/ cold intolerance/ > shedding/ anemia
Hypothyroidism • Dx: Total thyroxine (TT4) test / Total T 3 (TT3) / Free T4 (FT4) • Tx: Life-long trt……. • Synthetic Levothyroxine sodium (Soloxine) Rx : 0.1 / .0.2 / 0.3 / 0.4 / 0.5 / 0.6 / 0.7 & 0.8 mg. tablets • Results in normalization of both T4 and T3 concentrations
Parathyroid Dz. • Hypercalcemia from excessive PT hormone • Older dogs (7-11 yrs), Primarily Keeshonds, also Germ. Shep., poodles, retrievers, dobes • Clin. signs: Anorexia/ V / constipation/ P/U P/D / listless /weakness/ incontinence/ exercise intolerance Tx:Sx. removal of parathyroid glands/ Heat or chemical ablation of glands