Endocrine Flashcards
Action of ACTH following binding in adrenal cortex
Adenyl cyclase
Indication to supplement iron
decreased percentage of bound transferrin
Nutritional secondary hyperparathyroidism
Decrease in Ca, increase in P
Most Se and Sp test for diagnosis of subclinical ketosis
Blood beta-hydroxibutyrate (BHB)
8 year old mare with laminitis and infertility, choose test
Resting insulin
Cushing’s can predispose to what kind of pneumonia?
Aspergillus pneumonia?
Purpose of anionic diet in dry cows.
Compensated metabolic acidosis
Best test for herd monitoring of ketosis.
Acetoacetic acid in milk.
Foal with increased levels of T3 T4 at birth 10 time more than its mare
Normal don’t do anything
Mares exposed to high or low I2 diets may result in
Hypothyroidism
What is true with respect to PPID and alpha MSH?
alpha MSH-is influenced by season, seasonal variability
Best treatment for PPID
Dopaminergic agonist D2
Ponies prone to laminitis best dx in winter
Insulin 52 uU/L
Horse with Hypercalcemia and hypophosphatemia:
Hypercalcemia of malignancy
Problems in a herd with ketosis, DAs, drop milk production what is the best to measure in the prepartum?
NEFAs
Most common cause of hypophosphatemia in beef cows
Twins at end of gestation
Best to prevent pregnancy toxemia in small ruminants
Feed with base BCS and number of lambs
Horse with big head and Xr of teeth
Secondary hyperparathyroidism and dx with FE of P in urine (high)
Beef cow treated with MgOH for long time and now recumbent. Treatment?
Calcium (metabolic alkalosis decrease iCa)
Cow treated with isoflupredone for various days
Hypokalemia
In which diet would be best to develop a DCAD ration to prevent hypocalcemia
Alfalfa hay to dry cows
Hypomagenesmia cattle with neurological sx associated with?
hypomagnesemia, hypocalcemia, normokalemia
Parenteral nutrition in horse with hyperlipemia
60% of energy of rest
Increase iCa and normal PTH
Primary hyperparathyroidism
Nutritional secondary hyperparathyroidism
Increase excretion of P
Horse with weight loss, lethargy, hypercalcemia, hypokalemia
Pseudohyperparathyroidism
Cow seizuring, most likely electrolyte abnormalities?
hypomagnesemia, hypocalcemia
Horse that is obese, effect on adiposites?
Decrease adiponectin ©
In primary ketosis in goats, what is usually increased?
Increase in NEFAs
Clinical signs of hypothyroidism
Lethargy, exercise intolerance, poor hair coat, weight gain
Why horses with PPID cannot suppress cortisol release?
ACTH secretion from pars intermedia is not subject to glucocorticoid feedback
What is the effect of pergolide mesylate?
Dopamine D2 receptor agonist. Downregulates POMC production
Gene associated with EMS
Melanocortin-4 receptor Regulates feed intake, insulin sensitivity and adiposity
Test to assess hepatic insulin clearance
C-peptide to insulin ratio
Which receptor is impaired in IR horses?
GLUT-4
Most important phenotypic marker for IR
Cresty neck Fat in that area has more IL-1b and IL-6
Postpartum cow with hemoglobinuria. On evaluation you observe a low BCS and bad quality of pastures. You suspect nutritional deficiency. Which is your main differential diagnosis?
Hypophosphatemia —> reduction of osmotic resistance of RBCs But… study showed no relationship between hypophosphatemia and intravascular hemolysis
What are the vasoregulatory effects of insulin
VD: PIK3 pathway –> NO VC: MAPK pathway –> endothelin 1
Theories that link obesity with IR
- Downregulation insulin signaling pathways by adipokines and cytokines 2. Lipotoxicity in insulin-sensitive tissues
Gold standard test for EMS
Euglycemic hyperinsulinemic clamp (quantitative and specific)
What can you assess with the CGIT?
Amount of insulin secreted by the pancreas Clearance rates for insulin
Which test is recommended for postprandial hyperinsulinemia?
Oral sugar test
What is included in the NSCs?
WSC and starch
Indications for pharmacologic intervention in cases of EMS
- 3-6 month therapy while management takes effect 2. Refractory cases
What is the best diagnostic test for diabetes insipidus?
ADH ©
Hormone that is considered the main secretagogue for ACTH in adult horses
AVP (arginine vasopressin, ADH)
Main hormones produced at the pars intermedia of the pituitary gland
a-MSH, CLIP, b-LPH –> ACTH is precursor
Minimal production of ACTH
What test will more accurately diagnose CIRCI (transient adrenal inssuficiency)
Low-dose ACTH stimulation test
(Only evaluates the adrenal component)
Which tests are used to assess the HPA axis
Insulin tolerance test –> Gold standard
CRH stimulation test. Both ACTH and cortisol are measured
Also.. Metyrapone test
Diagnosis of pheochromocytoma
urinary cathecholamine level
What is the most consistent laboratory finding in hypervitaminosis D?
Hyperphosphatemia
Most probable cause of anhidrosis
Desensitization or down-regulation of b2-adrenoreceptors
Decreased expression of water channel aquaporin-5
Laboratory findings in cases of secondary hyperparathyroidism ©
- Hyperphosphatemia
- Hypo/normocalcemia
- ↑PTH
- Hypocalciuria
- Hyperphosphaturia
- ↑ALP
Risk factors for anhidrosis ©
Hot and humid climate
Clinical signs of hypothyroidism in horses ©
- Lethargy
- Cold intolerance
- Poor hair coat
- Weight gain/obesity
- Exercise intolerance
Best treatment for EMS ©
- Reduce NSC content of feed –> ideally < 10% of dry matter
- Limit grass pasture
- Obese horses: hay 1.5% of ideal BW (Not <1%)
- Exercise
- Medical: Levothyroxine sodium
Horse presented for colic. On admission heart rate was increased and on abdominal ultrasound you suspect hemoperitoneum. The horse was diagnosed for PPID and has a thyroid adenoma. Which endocrine neoplasm could be implicated in the clinical signs observed?©
Pheochromocytoma
Which test better reflects ketone blood levels?
Milk ketones –> ~50% of blood concentration
Why hypocalcemia causes paresis in cows?
Less Ca in motor endplate –> less release Ach
Why metabolic alkalosis worsens hypocalcemia?
Calcium will bind to albumin to decrease SID
Which cows are more susceptible to milk fever?
>3rd lactation –> less PTH rcpts or vit D3
Risks factors for milk fever in prepartum
- Metabolic alkalosis
- High Ca diet
- Low Mg diet
- High P in diet
When would you start a DCAD
Last 3 weeks of gestation
Optimal urine pH to prevent milk fever
Holsteins: 6.2-6.8
Jerseys: 5.8-6.3
<5.5 metabolic acidosis
Beef cows in ryegrass are at risk of ______
Hypomagnesemia
Low in Mg and high in K and N
Risk factors for hypomagnesemia
- Low Mg diet
- Low Na diet
- High K diet
- High rumen pH (>6.5)
When is it better to assess Mg status in cows?
Within 12 hours of calving (> 2 mg/dL)
Why is hypocalcemia a risk factor for hypophosphatemia?
Hypocalcemia stimulates PTH –> increase P excretion in saliva and renal
Best diagnostic test in a down cow that appears to be alert and eating
Measure P, possible hypophosphatemia
“Alert downers”
How would you treat hypophosphatemia in a dairy cow?
Correct hypocalcemia first (reduce PTH and recover GI motility)
First calving heifer, down “S shape” neck and paradoxic aciduria.
Heifer was treated with isoflupredone (mineralocorticoid) and glucose precursors previously. What is your presumptive diagnosis?
Hypokalemia
