ATTITUDE

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ATTITUDE

• The people who get on in this world are the
  people who get up and look for the circumstances
  they want, and if they cant find them, make
  them.
• -George Bernard Shaw

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ENDOCRINE SYSTEM DISEASES

• CRINE to secrete

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Endocrine System Diseases
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Main trigger Hypothalamus
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Review of the basics

• Endocrine ____________- basic units of the
  endocrine system.
• Secrete hormones ___________ into the
  bloodstream.
• Circulate throughout body and produce effects
  when attach to receptors in or outside of cells.
• __________ glands.
• Exocrine glands- units that secrete their
  products onto epithelial surfaces through tiny
  tubes called _____________.

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Hormones

• ___________ messengers produced by endocrine
  glands and secreted directly into blood vessels.
• Produce effects when find their receptors in or
  on cells.
• Each body cell has specific receptors to certain
  hormones (___________).
• If body does not have receptor, hormone will pass
  by.
• Only certain hormones can _______ to receptors
  and when it occurs, then it changes the activity
  of the cell.

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Hormones
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Control of Hormone Secretion

• Negative Feedback System
• Endocrine glands will be stimulated to produce
  more hormone when it drops below a certain amount
  in the body.
• If hormone is of adequate levels, gland will
  either slow or stop production of the hormone
  which is called negative feedback.
• Direct Stimulation of Nervous System
• Secretion of some hormones is stimulated by
  sympathetic nerve impulses when an animal feels
  threatened.
• Fight or flight response from sympathetic nervous
  system

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DISEASES OF THE THYROID GLAND

• HYPERTHYROIDISM
• HYPOTHYROIDISM

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Hypothyroidism
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Thyroid Gland

• Gland not usually palpable
• Located at ventral cervical region along lateral
  margins of trachea
• Hormones produced
• T3 (___________________) and T4
  (_____________________), iodine containing
  hormones.
• Produced by follicular cells
• ______________ Causes Calcium deposition in
  bone which decreases blood Calcium concentrations
• Produced by parafollicular cells

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Hypothyroidism

• Definition clinical state associated with
  ____________________ which causes low cell
  metabolism in most tissues of the body
• Primary acquired 90 of dogs
• Caused by ________________or _____________________
  ____
• Also by iodine deficiency, neoplasia, infection
• Secondary acquired- RARE
• Anterior Pituitary dysfunction or destruction
  from neoplasia leads to ?TSH
• Congenital Hypothyroidism-RARE
• Cretinism (newborns)

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Hypothyroidism

• MOST COMMON ENDOCRINE DISEASE IN____________
  rare in cats
• Breeds Golden Retriever, Doberman, Irish Setter,
  Schnauzer, Cocker Spaniel, Dachshund, others
• 4-10 yrs of age
• Females
• Greyhounds and Scottish deerhounds
  physiologically have lower T4 (thyroxine)

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Hypothyroidism

• Clinical Signs - COMMON
• __________________________________
• Skin changes
• Bilaterally symmetric truncal alopecia (which
  other disease has this clinical sign? )
• ______________________ neck, axillae, and other
  areas of friction
• Seborrhea
• Superficial pyoderma
• Dry, lusterless haircoat
• Hyperpigmentation
• Cold intolerance (why?)
• Lethargy/sleeping
• Exercise intolerance

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Hypothyroidism
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Hypothyroidism
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Hypothyroidism
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Hypothyroidism
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Hypothyroidism

• Clinical signs/Bloodwork Less common
• ___________________ generalized weakness,
  ataxia, facial paralysis/paresis, seizures
  (secondary to cerebral atherosclerosis)
• _______________ Constipation, Regurgitation
  caused by megaesophagus
• Bloodwork abnormalities _____________lipidemia
  is most common, gross lipemia ( milky appearance
  to the serum), ____________________cholesterolemia
  (80), anemia (mild non-regenrative)
• Eye hyperlipidemia gt corneal lipidosis and
  anterior uveitis

Virtually all body systems are affected,
clinical signs are generally non-specific
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Hypothyroidism DIAGNOSIS

• Blood Tests
• Hypothyroid dogs have lowered level of T4
• Test total T4(TT4), /- T3 levels
• Free T4 Free T4 is thyroxine that is not protein
  bound (ED is most accurate test for fT4
  measurement)
• Basal TSH concentration
• Measures TSH in blood, should be used in
  conjunction with other tests and clinical signs

ED equilibrium dialysis
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Hypothyroidism Considerations

• Remember sick animals and animals on certain
  medications (anti-epileptics, glucocorticoids)
  may have depressed T4 levels. (_________________)
  
• Wait and re-test after treatment of underlying
  cause if clinical signs persist.
• Greyhounds have low T4 levels naturally diagnose
  based on clinical signs as well as test results
  treat if clinically evident.

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Hypothyroidism

• Treatment
• Thyroid supplement _________________
• Oral, synthetic levothyroxine (0.02 mg/kg BID)
• Daily administration (after cs resolves consider
  SID)
• Steady state levels 4/8 wks (1st 6-8 months)
• Test levels and adjust dose until T4 normal
• Want to test 4-6 hours after dose is given (when
  serum levels are highest)

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Thyroid replacement hormone (levothyroxine sodium)
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Hypothyroidism

• Client Education
• Supplement for ________________
• Daily dosing required
• Overdose gt hyperthyroidism
• Regular rechecks are recommended including
  bloodwork.
• PU/PD nervousness, weight loss, panting,
  weakness, inc. appetite
• Vet may recommend a reduced fat diet until body
  weight is satisfactory and T4 levels are normal.

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Hyperthyroidism

• Definition Pathologic, sustained, high overall
  metabolism caused by high circulating
  concentrations of thyroid hormones
• Most common Endocrine disease in ____________
  (one of the big 3 diseases of older cats)
• Very rare in dogs
• Pathophysiology
• Autonomously ___________________________, no
  physiologic controls (functional thyroid adenoma)
• Secrete _______ and ____________

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Hyperthyroidism in cats
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Hyperthyroidism

• Clinical Signs
• Multi-systemic reflects increase in metabolism
• _________________
• __________________
• Vomiting/diarrhea
• _____________________
• Tachypnea/dyspnea
• Hyperactivity
• Aggression

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Hyperthyroidism

• Clinical signs contd
• ____________________(thickening of LV and heart
  muscle)
• Hypertension
• Poor body condition
• Thickened nails
• Unkempt appearance
• ______________________ gland 70 - bilateral

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Hyperthyroid cat
Middle age to older cats Blindness with retinal
detachment Wt loss Palpable enlarged Thyroid
gland Polyphagia Aggressive Tachycardia
unkempt haircoat
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Hyperthyroid cat Goiter
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Hyperthyroidism

• Diagnosis
• Palpate enlarged thyroid gland
• Elevated T4, FT4
• X-rays for associated heart disease

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Hyperthyroidism Scintigraphy
Normal cat Normal uptake in salivary glands and
thyroid glands
Hyperthyroid cat Unilateral thyroid adenoma
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Hyperthyroidism Scintigraphy
Hyperthyroid cat Bilateral thyroid adenoma
Hyperthyroid cat Ectopic (intrathoracic) thyroid
adenoma
Hyperthyroid cat Functional thyroid
carcinoma (represents regional metastasis)
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Hyperthyroidism

• Treatment
• ______________________ (Tapazole) anti-thyroid
  drug block incorporation of iodine into
  thyroglobulin.
• Monitor q 2-3 weeks
• COMMON AND PRACTICAL FOR CLIENTS
• Radioiodine treatment I131
• Effective
• Emitted radiation destroys functioning follicular
  cells
• ______________________________________________
• Surgical removal of gland
• May cause hypothyroidism
• May result in hypocalcemia due to
  hypoparathyroidism

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Hyperthyroidism Medical Rx
METHIMAZOLE
ORAL DRUG, BUT CAN BE FORMULATED INTO A
TRANSDERMAL OINTMENT
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Hyperthyroidism

• Complications
• Renal disease/failure unveiled when thyroid
  levels controlled
• 2-3 months after medication started
• Occasionally tapazole will no longer be effective
  usually after 2-3 years of treatment
• Prognosis
• Excellent if uncomplicated
• If labs show ___________________ prior to
  treatment, prognosis more guarded

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Hyperthyroidism Client Info

• Cause of disease is unknown
• Surgery or Radiation are only cures
• Cat may become hypothyroid following Rx usually
  not clinically significant and supplementation
  can be initiated if necessary
• Following Tapazole, Blood pressure and kidney
  values should be checked routinely