Endocrinology Flashcards
What is the function of the endocrine system?
Internal communication system utilizing chemicals called hormones
Explain how the negative feedback loop works in the endocrine system
Communication moves from endocrine organ to target tissues and back to endocrine organ
What are the endocrine organs and where are they located? (6)
- Pituitary gland - Brain
- Thyroid glands - Either side of trachea in the neck
- Parathyroid glands - “
- Adrenal glands - Next to kidneys
- Pancreas - Intersection of stomach & duodenum
- Ovary & Testes - Caudal to kidneys
Pituitary gland (or Hypophysis)
1. Function
2. Location
3. Role of anterior & posterior lobe
“Master Glands”
- Function
- Gives directions to other endocrine glands - Location
- Ventromidline of the brain - Roles:
- Anterior: Adenohypophysis
- Posterior: Neurohypophysis
Thyroid glands
1. Function
2. Hormone it produces
- Function
- Production of T3 & T4 (thyroxine)
+ Iodine containing hormones
+ Adjusts metabolic rate
- In response to TSH from P gland
- Production of calcitonin
+ Decreases blood Ca level
+ Stores Ca in the bone - Produces Thyroxine (T4) and Calcitonin
Hypothyroidism
1. Etiology
2. Clinical signs
- Function
- Thyroid atrophy or thyroiditis - Signs:
- Weight gain on stable diet
- Endocrine alopecia
- Lethargy
- Heat-seeking
T/F: Hypothyroidism is more common in cats than dogs
False! It is a common disease of dog, but uncommon in cats
Endocrine Alopecia
1. Clinical signs
2. Dx
3. Tx
- Signs
- Bilateral symmetric flank alopecia
- “Rat tail,” loss of volume in fur
- Hyperpigmentation
- Dry coat/excess shedding - Dx: Blood eval
- Tests of choice fT4 & TSH
- Mult thyroid axis may need to be eval together
- Thyroid eval tests: T4, fT4, TSH, & Thyroglobulin antibodies - Tx
- Thyroid replacement hormones for life
- Monitor closely w/blood tests
T4 & clinical signs w/o thyroid panel might lead to misdiagnose Euthyroid sick in regards to endocrine alopecia
- I’m not entirely sure what this means or what to do with it but it seems important
Euthyroid Sick is the body’s ___ response to sickness.
Lowering T4 in response to illness protects animals from ___ ___, ___ ___, & ____.
Animals sick with this should not be treated with ___ medication.
- Normal response to sickness
- Muscle wasting, weight loss, & hypertension
- Thyroid medication
T/F: If the primary problem that is causing euthyroid sickness gets resolved, the thyroid will return to normal
True!
Hyperthyroidism
1. Etiology
2. Clinical signs
- Etiology
- Functional thyroid adenoma tumor - Signs
- Weight loss with excellent appetite (polyphagia)
- Vocalizing/behavior change
- Tachycardia
- Thyroid nodule
- Vomiting/diarrhea
- Hypertension
Hyperthyroidism
1. Dx
2. Therapy
- Dx
- Elevated T4
- Thyroid nodule
- Thyroid scintigraphy - Therapy
- Sx
+ Curative, although tend to not be good Sx candidates
- Methimazole
+ Monitor liver & bone marrow
- Radioactive Iodine
+ Curative
Pancreas
Endocrine vs Exocrine
Exocrine:
- Digestive enzymes
Endocrine:
- Insulin: Lowers blood sugar by moving sugar into cells
- Glucagon: Raises blood gluc by activating liver gluconeogenesis
Diabetes Mellitus defined
Inadequate secretion or utilization of insulin resulting in a disorder of carbohydrate metabolism
Diabetes Mellitus
1. Clinical signs (9)
2. Pathology
- Signs
- Polydipsia/polyuria, polyphagia, weight loss, lethargy, weakness, unkempt, plantigrade stance, sudden cataracts, obtunded - Pathology
- Persistent hyperglycemia
- Glucosuria (increased gluc in urine)
Diabetes Mellitus in Dogs
1. Predisposing factors (4)
2. Breeds at risk (4)
3. Type I or II?
- Predisposition
- Genetics
- Pancreatitis
- Endocrine disease
- Obesity - Breeds
- Poodles
- Schnauzers
- Keeshonds
- Dachshunds - Type I
Type I diabetes vs Type II diabetes
Type I
- Absolute lack of insulin production
Type II
- Relative decrease of insulin (tissues are less sensitive)
Diabetes Mellitus in Cats
1. Predisposing factors (3)
2. Obesity relationship w/diabetes (1)
3. Type I or II?
- Predisposition
- Pancreatitis
- Certain meds
- OBESITY!!! - Obesity & diabetes
- 35% of cats are obese and 60% will become diabetic - Type II
Diabetes Mellitus
1. Tx
2. Diet Therapy
3. Insulin Therapy goals
- Tx
- Oral hypoglycemics (not an option for dogs)
+ Generally don’t work well in vet med :( - Diet Therapy
- High fiber vs high protein
- Dogs do best w/high fiber (low fat)
- Cats do best w/high protein & others on high fiber - Insulin Therapy goals
- Maintain blood gluc 100-300 mg/dL
- Maintain ideal BCS
- Resolution of neuropathies
- Gen well being of Px & O
Should glucose be kept on the higher or lower side with diabetes while the patient is being treated at home with insulin?
We air on the side fo caution and allow the glucose on the high side to prevent the patient from going into a coma at home with the O.
Doing this is okay as Px shorter lifespan & unable to communicate. Keeps O a bit happier.
Insulin Overdose
1. Causes
2. Consequences
3. Tx
- Causes
- Too much insulin administered
- Px isn’t eating or is vomiting
- Px getting increased exercise
- Px needs change - Consequences: Hypoglycemia
- Weakness
- Disorientation
- Seizures
- Coma - Tx
- Feed Px if able to swallow
- Syrup on gums (ex Karo)
- IV gluc support until normalizes
Diabetes Mellitus exercise goals (4)
- Correct obesity
- Decrease insulin requirements
- Improve muscle tone
- Should be consistent and done daily as to not create variation in insulin needs
Diabetic Ketoacidosis
1. What is it?
2. Common signs (3)
3. Additional signs (6)
- A serious complication of diabetes which is fatal is untreated.
- This occurs if Px isnt Tx w/insulin!! - Common signs
- Dehydration
- Hyperglycemia
- Electrolyte derangements - Additional
- Lethargy
- Vomiting
- Weakness
- Kussmaul breathing
- Stupor
- Hyperosmolar coma
What is insulinoma?
It is a functional tumor of pancreatic B cells leading to excess secretion of insulin & chronic, severe hypoglycemia
Insulinoma
1. Clinical signs
2. Tx
- Signs
- Weakness
- Collapse
- Disorientation
- Seizures - Tx
- Sx removal or medical support
- These are normally malignant tumors
Function of adrenal medulla (3)
- Epinephrine & norepinephrine
- Signal from sympathetic nervous system
- “Fight or flight” magnification
Function of adrenal cortex (3)
- Secretes Corticosteroids (cortisol)
- Will do this as emergency to inflamm & stress - ACTH signal from P gland
- Pro: Anti-inflamm, chronic stress
- Con: Lower immune system function - Secretes Mineralocorticoids
- Aldosterone: Conserves Na+ & water in kidney to maintain blood pressure
+ Signaled by renin release by kidney as part of a hormone cascade
Hypoadrenocorticism
1. Etiology
2. Clinical signs
- Etiology
- Insufficient production of glucocorticoids
- “ of mineralocorticoids - Signs
- Intermittent vomiting/diarrhea
- Weakness
- PD/PU
- Bradycardia
- Endocrine coat pattern
Hypoadrenocorticism
1. Possible blood changes
2. ACTH Stimulation test
- Possible blood changes
- Non regenerative anemia
- Low gluc
- Low Na+ and high K
- Low WBC count - ACTH Stimulation test
- Test of choice!
- BD, ACTH administered, repeat BD & eval for cortisol, sex hormones, & aldosterone
Hypoadrenocorticism therapy
1. If severe acute:
2. If chronic:
- Acute
- IV fluids
- Electrolyte correction
- Glucocorticoids - Chronic
- Mineralcorticoid replacement
- Glucocorticoid replacement
Hyperadrenocorticism
1. Etiology
2. Clinical signs
- Etiology
- Excess cortisol in the body!!
- Pituitary tumor
- Adrenal tumor
- Iatrogenic - Clinical signs
- PD/PU (USG <1.015)
- Panting
- Abdominal fat
- Hair coat changes
- Elevated AP
Hyperadrenocorticism
1. Secondary problems
2. Therapy
- Secondary problems
- Hypertension
- Chronic infections
- Pancreatitis
- Diabetes mellitus
- Heart failure
- Cruciate ligament rupture - Therapy
- Sx removal of adrenal tumor if present
- Medical:
+ Chemo to shrink hyperplasia of adrenals
+ Chemical interference w/excess steroid production
T/F: In regards to hyperadrenocorticism, Low dose Dexamethasone Suppression test (LDDS) is the most sensitive test for Cushing’s disease
True! Although, a false positive may occur if Px is ill with another disease
