PART 2 DISEASES OF THE ENDOCRINE SYSTEM. HYPERPARATHYROIDISM HYPOPARATHYROIDISM DISEASES OF THE...
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Transcript of PART 2 DISEASES OF THE ENDOCRINE SYSTEM. HYPERPARATHYROIDISM HYPOPARATHYROIDISM DISEASES OF THE...
PART 2
DISEASES OF THE ENDOCRINE SYSTEM
HYPERPARATHYROIDISMHYPOPARATHYROIDISM
DISEASES OF THE PARATHYROID GLANDS
Thyroid/Parathyroid glands
1=normal thyroid gland2 and 3=parathyroid gland4=enlarged thyroid gland
Parathyroid gland
Secretion: Parathyroid hormone (PTH, Parathormone)
Function: ↑ plasma Ca2+ concentration 1. ↑ osteoclast activity 2. ↑ Ca++ absorption from GI tract 3. ↑ Ca++ reabsorption from kidney tubules
Hyperparathyroidism →hypercalcemia
Hypoparathyroidism →hypocalcemia
Hyperparathyroidism
Causes: 1º hyperparathyroidism—adenoma or carcinoma 2º hyperparathyroidism—poor diet; low Ca intake;
renal disease
Clinical signs: Many animals show no clinical signs signs occur as organ dysfunction occurs
urinary/renal calculi (high plasma Ca++) cardiac arrhythmias, tremors (Ca++
necessary for normal muscle contraction) Anorexia, vomiting, constipation weakness
Hyperparathyroidism
Dx:Routine chemistry panel
↑ blood Calcium (normal: ~8-10 mg/dl)) +/- ↓ blood Phosphorus
PTH assay normal PTH: dogs ~20 pg/ml, cats ~17 pg/ml In a normal animal: if blood Ca++ is high, PTH is low (neg feedback) 1º Hyperparathyroidism: Ca++ high, PTH elevated
Ultrasound of neck – enlarged glands, abdomen - uroliths
Hyperparathyroidism
Tx:1. Surgical removal of diseased parathyroid
Other options:2. Ultrasound-guided chemical (ethanol) ablation
3. Ultrasound-guided heat (laser) ablation
Post-Op Care:1. Hospitalize for 1 wk; ↓PTH may predispose animal to hypocalcemia2. Calcium therapy (oral tabs, liquid)3. Vit D supplements (promotes Ca intestinal absorption)
Hyperparathyroidism
Client Info1. Most hyperparathyroid animals show
no signs when first diagnosed2. Run yearly chem panels on all
normal, older animals
Hypercalcemia: Other causes
Causes Neoplasia (lymphoma, perianal
gland tumors) Renal failure Hypoadenocorticism Vitamin D rodenticide Drugs or artifacts
Clinical signs vary with cause PU/PD, anorexia, lethargy, vomiting,
weakness, stupor/coma (severe), uroliths
Hypercalcemia
Treatment Fluids: 0.9% NaCl
No Ca2+ containing fluids Diuretics (furosemide) Steroids
Complications Irreversible renal failure Soft tissue calcifications
Hypocalcemia
Causes:1. Puerperal Tetany (Eclampsia)—late gestation thru
post-partum perioda. Improper prenatal nutritionb. Heavy lactationc. Inappropriate Ca++ supplementation
2. Parathyroid diseasea. Inadvertent removal of parathyroid during
thyroidectomy (most common causeb. 1º Hypoparathyroidism (uncommon in animals)
3. Chronic renal failure—a. Vit D normally activated in kidneyb. Protein-losing nephropathy results in loss of albumin-bound
Ca
http://www.thepetcenter.com/gen/eclampsia.html#The_video
Hypocalcemia
Clinical Signs:1. Restlessness, muscle tremors,
tonic-clonic contractions, seizures 2. Tachycardia with excitement;
bradycardia in severe cases (Ca++ is necessary for proper muscle contractions)
3. Hyperthermia4. Stiffness, ataxic
Hypocalcemia
Dx:Total serum <6.5 mg/dl
Tx:1. IV infusion of 10% Ca gluconate
solution (monitor HR and rhythm during infusion)
2. Diazepam (IV) to control seizures3. Oral supplements of Ca (tabs, caps,
syrup)4. Improve nutrition
Hypocalcemia
Client info:1. Well-balanced diet; increase
volume as pregnancy progresses2. Signs in pregnant animal is
emergency; call vet immediately3. May recur with subsequent
pregnancies4. Early weaning is recommended
DIABETES MELLITUSINSULINOMA
EXOCRINE PANCREATIC INSUFFICIENCY
DISEASES OF THE PANCREAS
Review of pancreas functions
Long flat organ near duodenum and stomach
Exocrine function (the majority of the pancreas): Digestive enzymes
Endocrine function – islets of Langerhans Alpha cells => glucagon Beta cells => insulin Delta cells => somatostatin
Pancreas
Pancreas: beta cells
Review
Insulin Moves glucose into cells to be used for
energy Decreases blood glucose
Glucagon Raises blood glucose
Stimulates liver to release glucose Stimulates gluconeogenesis
Other hormones from other glands perform similar functions (hyperglycemic effect) Growth hormone Glucocorticoids
Insulin/Glucagon Balance
Endocrine Pancreas
Hyperglycemia Definition: Excessively high blood
glucose levels Normal in dogs: 60-120 mg/dl Normal in cats: 70 -150 mg/dl
Diabetes Mellitus
Definition: Disorder of carbohydrate, fat and protein metabolism caused by an absolute or relative insulin deficiency
Type I – Insulin Dependent DM – very low or absent insulin secretory ability
Type II – Non insulin dependent DM (insulin insensitivity) – inadequate or delayed insulin secretion relative to the needs of the patient
Diabetes mellitusIncidence:
Dogs: ~100% Type I (Insulin dependent)Cats: ~ 50% Type I and 50% Type II
-non-insulin dependent catscan sometimes be managed withdiet and drug therapy
Causes: Chronic pancreatitisImmune-mediated disease -beta cell destruction
Predisposing/risk factors:Cushing’s DiseaseAcromegalyObesityGenetic predispositionDrugs (steroids)
Diabetes mellitus
Age/sex: Dogs: 4-14 yrs, females 2x more likely
to be affected Cats: all ages, but 75% are 8-13yrs,
neutered males most affected
Breeds: Poodles, Schnauzers, Keeshonds, Cairn Terriers, Dachshunds, Cockers, Beagles
DIABETES MELLITUS
PathophysiologyInsulin deficiency => impaired
ability to use glucose from carbohydrates, fats and proteins
Impaired glucose utilization + gluconeogenesis => hyperglycemia
Diabetes mellitus
PATHOPHYSIOLOGY: Clinical signs develop when:
Exceeds capacity of renal tubular cells to reabsorb
Dogs – BG > 180-220 mg/dl Cats - BG > 200-280 mg/dl
Glucosuria develops Osmotic diuresis Polyuria/polydipsia UTI Suppress immune system
DIABETES MELLITUSSYSTEMS AFFECTED:
Endocrine/metabolic: electrolyte depletion and metabolic acidosis
Hepatic: liver failure 2° to hepatic lipidosis (mobilization of free fatty acids to liver leads to hepatic lipidosis and ketogenesis)
Ophthalmic: cataracts (dogs) from glaucoma
Renal/urologic: UTI, osmotic diuresis
Nervous: peripheral neuropathy in cats
Musculoskeletal: Compensatory weight loss
Diabetes Mellitus
Clinical Signs:PolyuriaPolydipsiaPolyphagiaWeight loss Dehydration Cataract formation-dogs Plantigrade stance-cats
Diabetes in Cats: Plantigrade posture
Diabetes Mellitus: Cataracts
Increase in sugar (sorbitol) in lens causes an influxof water, which breaks down the lens fibers
Diabetic Ketoacidosis
2 metabolic crises: ↑ lipolysis in adipose tissue → fatty acids →ketone bodies →ketoacidosis →coma (insulin normally inhibits lipolysis)↑ hepatic gluconeogenesis (in spite of high plasma glucose levels)
(insulin normally inhibits gluconeogenesis)
Diabetic Ketoacidosis
Definition: True medical emergency secondary to absolute or relative insulin deficiency causing hyperglycemia, ketonemia, metabolic acidosis, dehydration and electrolyte depletionDM causes increased lipolysis => ketone
production and acidosis
Diabetic Ketoacidosis
Diagnosed with ketones in urine or ketones in blood Can use urine dip stick with serum.
Clinical Signs All of the DM signs Depression Weakness Tachypnea Vomiting Odor of acetone on breath
Diabetic Ketoacidosis
IV fluids to rehydrate 0.9% NaCl Regular insulin to decrease
blood glucose Monitor BG q 2-3 hrs When BG close to normal and
patient stable switch to longer acting insulin
DIABETES MELLITUS
DIAGNOSIS: CBC: normal
Biochemistry panel: Glucose > 200 mg/dl (dogs), >250 (cats)
UA Glucosuria!!!! (causes UTI) Ketonuria USG – low
Electrolytes may be low due to osmotic diuresis
Fructosamine levels – mean glucose level for last 2-3 weeks (dogs) Ideal to test for regulation checks
Treatment: INSULIN AND DIET
Table 1. Traditional insulin outline.
Duration/onset category
Insulin types Concentration
Rapid acting Regular (Humulin R) U-100 (100 units/ml)
Intermediate acting NPH (Humulin N) U-100
Lente (Vetsulin® by Intervet)
U-40 (40 units/ml)
Long acting PZI (Idexx) U-40
Insulin Detemir U-100
Insulin Glargine U-100
Diabetes Mellitus: Insulin therapy
Diabetes Mellitus: Insulin therapy
Beef-origin insulin is biologically similar to cat insulin:
Porcine-origin insulin (porcine lente) is biologically similar to dog insulin
Dogs and cats have responded well to human insulin products protamine zinc insulin (human recombinant PZI)
Insulin Glargine: not approved for use in cats and PZI have same duration of action
DM: Insulin therapy
INSULIN ADMINISTRATION:ALWAYS USE THE
APPROPRIATE INSULIN SYRINGE! (U-40 vs. U-100) Insulin is given in units (insulin
syringes are labeled in units, not mL)
30 units, 50 units, 100 units
DM: dietary management
DIET DOGS: high fiber, complex carbohydrate diets
Slows digestion, reduces the post-prandial glucose spike, promotes weight loss, reduces risk of pancreatitis
Hill’s R/D or W/D
CATS: high protein, low carbohydrate diets Cats use protein as their primary source of
energyPurina DM, Hill’s M/D
Often a diet change in cats can dramatically reduce or eliminate the need for insulin This is particularly true for type II
Diabetes Mellitus
ORAL HYPOGLYCEMICS:o Sulfonylureas – Glipizide: cats
o Direct stimulation of insulin secretion from the pancreas
o Alpha-Glucosidase Inhibitors – Acarboseo Delays digestion of complex carbohydrates and
delays absorption of glucose from the intestinal tract.
Insulin is more effective than oral hypoglycemics
Diabetes Mellitus: Monitoring
Find an ear vein Prick the ear to get Place drop of blood blood sample on green tip; readout in
a few seconds
Diabetes Mellitus monitoring: Urine glucose
Diabetes Mellitus monitoring: Urine glucose
Diabetes Mellitus monitoring: Urine glucose
DIABETES MELLITUS
Client Education Lifelong insulin replacement therapy Insulin administered by injection Refrigerate insulin, mix gently (no
bubbles), single use syringes Vetsulin may require vigorous shaking
Consistent diet and exercise Recheck BG or curve regularly or
fructosamine levels if animal does not eat- NO INSULIN