DISEASES OF THE ENDOCRINE SYSTEM

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DISEASES OF THE ENDOCRINE SYSTEM

• PART 2

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DISEASES OF THE PARATHYROID GLANDS

• HYPERPARATHYROIDISM
• HYPOPARATHYROIDISM

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Thyroid/Parathyroid glands
1normal thyroid gland 2 and 3parathyroid
gland 4enlarged thyroid gland
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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

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Hyperparathyroidism

• Causes
• 1º hyperparathyroidismadenoma or carcinoma
• 2º hyperparathyroidismpoor 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

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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

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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 hypocalcemia
• 2. Calcium therapy (oral tabs, liquid)
• 3. Vit D supplements (promotes Ca intestinal
  absorption)

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Hyperparathyroidism

• Client Info
• Most hyperparathyroid animals show no signs when
  first diagnosed
• Run yearly chem panels on all normal, older
  animals

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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

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Hypercalcemia

• Treatment
• Fluids 0.9 NaCl
• No Ca2 containing fluids
• Diuretics (furosemide)
• Steroids
• Complications
• Irreversible renal failure
• Soft tissue calcifications

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Hypocalcemia

• Causes
• 1. Puerperal Tetany (Eclampsia)late gestation
  thru post-partum period
• Improper prenatal nutrition
• Heavy lactation
• Inappropriate Ca supplementation
• 2. Parathyroid disease
• Inadvertent removal of parathyroid during
  thyroidectomy (most common cause
• 1º Hypoparathyroidism (uncommon in animals)
• 3. Chronic renal failure
• Vit D normally activated in kidney
• Protein-losing nephropathy results in loss of
  albumin-bound Ca

http//www.thepetcenter.com/gen/eclampsia.htmlThe
_video
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Hypocalcemia

• Clinical Signs
• Restlessness, muscle tremors, tonic-clonic
  contractions, seizures
• Tachycardia with excitement bradycardia in
  severe cases (Ca is necessary for proper muscle
  contractions)
• Hyperthermia
• Stiffness, ataxic

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Hypocalcemia

• Dx
• Total serum lt6.5 mg/dl
• Tx
• IV infusion of 10 Ca gluconate solution (monitor
  HR and rhythm during infusion)
• Diazepam (IV) to control seizures
• Oral supplements of Ca (tabs, caps, syrup)
• Improve nutrition

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Hypocalcemia

• Client info
• Well-balanced diet increase volume as pregnancy
  progresses
• Signs in pregnant animal is emergency call vet
  immediately
• May recur with subsequent pregnancies
• Early weaning is recommended

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DISEASES OF THE PANCREAS

• DIABETES MELLITUS
• INSULINOMA
• EXOCRINE PANCREATIC INSUFFICIENCY

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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 gt glucagon
• Beta cells gt insulin
• Delta cells gt somatostatin

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Pancreas
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Pancreas beta cells
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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

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Insulin/Glucagon Balance
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Endocrine Pancreas

• Hyperglycemia
• Definition Excessively high blood glucose levels
• Normal in dogs 60-120 mg/dl
• Normal in cats 70 -150 mg/dl

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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

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Diabetes mellitus
Incidence Dogs 100 Type I (Insulin
dependent) Cats 50 Type I and 50 Type
II -non-insulin dependent cats can sometimes
be managed with diet and drug therapy Causes
Chronic pancreatitis Immune-mediated disease
-beta cell destruction Predisposing/risk
factors Cushings Disease Acromegaly Obesity
Genetic predisposition Drugs (steroids)
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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

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DIABETES MELLITUS

• Pathophysiology
• Insulin deficiency gt impaired ability to use
  glucose from carbohydrates, fats and proteins
• Impaired glucose utilization gluconeogenesis gt
  hyperglycemia

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Diabetes mellitus

• PATHOPHYSIOLOGY
• Clinical signs develop when
• Exceeds capacity of renal tubular cells to
  reabsorb
• Dogs BG gt 180-220 mg/dl
• Cats - BG gt 200-280 mg/dl
• Glucosuria develops
• Osmotic diuresis
• Polyuria/polydipsia
• UTI
• Suppress immune system

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DIABETES MELLITUS

• SYSTEMS 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

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Diabetes Mellitus

• Clinical Signs
• Polyuria
• Polydipsia
• Polyphagia
• Weight loss
• Dehydration
• Cataract formation-dogs
• Plantigrade stance-cats

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Diabetes in Cats Plantigrade posture
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Diabetes Mellitus Cataracts
Increase in sugar (sorbitol) in lens causes an
influx of water, which breaks down the lens fibers
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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)
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Diabetic Ketoacidosis

• Definition True medical emergency secondary to
  absolute or relative insulin deficiency causing
  hyperglycemia, ketonemia, metabolic acidosis,
  dehydration and electrolyte depletion
• DM causes increased lipolysis gt ketone
  production and acidosis

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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

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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

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DIABETES MELLITUS

• DIAGNOSIS
• CBC normal
• Biochemistry panel
• Glucose gt 200 mg/dl (dogs), gt250 (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

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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
Intermediate acting Lente (Vetsulin by Intervet) U-40 (40 units/ml)
Long acting PZI (Idexx) U-40
Long acting Insulin Detemir U-100
Long acting Insulin Glargine U-100
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Diabetes Mellitus Insulin therapy
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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

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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

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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
• Hills R/D or W/D
• CATS high protein, low carbohydrate diets
• Cats use protein as their primary source of
  energy
• Purina DM, Hills M/D
• Often a diet change in cats can dramatically
  reduce or eliminate the need for insulin
• This is particularly true for type II

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Diabetes Mellitus

• ORAL HYPOGLYCEMICS
• Sulfonylureas Glipizide cats
• Direct stimulation of insulin secretion from the
  pancreas
• Alpha-Glucosidase Inhibitors Acarbose
• Delays digestion of complex carbohydrates and
  delays absorption of glucose from the intestinal
  tract.
• Insulin is more effective than oral hypoglycemics

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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
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Diabetes Mellitus monitoring Urine glucose
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Diabetes Mellitus monitoring Urine glucose
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Diabetes Mellitus monitoring Urine glucose
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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