Final: Endocrine and Urinary Flashcards
What is the difference between an “easy keeper” and an “overly fed” horse or pony?
“Easy keeper” - horse is not fed too much but is still fat/gaining weight, possibly poor quality hay/feed
“Overly fed” - poor horsemanship
T/F: Hepatic lipidosis is commonly a secondary condition which rarely fatal.
False, up to 80% fatal (but commonly secondary)
Match the term with the correct value:
Hyperlipidemia, Hypertriglyceridemia, Hyperlipemia
TG>500 mg/dl, plasma clear
TG<500 mg/dl, plasma clear
TG >500 mg/dl, serum cloudy
Hypertriglyceridemia: TG>500 mg/dl, plasma clear
Hyperlipidemia: TG<500 mg/dl, plasma clear
Hyperlipemia: TG >500 mg/dl, serum cloudy
What is the classical presentation of fatty liver disease?
Mid-winter
Mini pony female >15 yo
ADR
Inappetence
Not drinking water
With concurrent condition (colic, choke, anorexia, PPID, pregnancy)
What are the 2 hormones involved in fat metabolization? What activates them?
Lipoprotein lipase- activated by insulin (Favors TG accumulation)
Hormone sensitive lipase- activated by catecholamines/ACTH (inhibited by insulin) (Mobilizes stored fat)
*INSULIN role stressed in lecture*
What, in addition to supportive care and nutritonal support, is used to treat hyperlipidemia?
Heparin (to counteract hormone sensitive lipase)
Insulin (to trigger lipoprotein lipase)
What are the 3 principal components of equine metabolic syndrome (EMS)?
Increased adiposity
Hyperinsulinemia
Insulin resistance
Also LAMINITIC SIGNS (minor but radiographic evidence of recurrent episodes)
What are the 2 types of insulin resistance?
Compensatory: due to decreased tissue response (most common)
Uncompensatory: due to pancreatic (beta cell) insufficiency
Compensatory can lead to uncompensatory
What causes laminitis in horses with EMS? How is this defined clinically?
Persistant hyperinsulinemia
Hyperinsulinemia= >30 microU/mL when fasted
What metabolic issue is this preputal swelling indicative of?
EMS
Enlargment of adipose tissue in what region is used as a scoring system for EMS? What score indicates EMS?
Neck region
3
In addition to fasted insulin levels, what tests can you do to assess hyperinsulinemia?
Insulin tolerance test (IR= lvl not 50% decreased within 30min)
Oral sugar test (IR if >60 at either post reading)
Combine Glucose Insulin test (IR= BG above baseline for 45min or longer)
Why is increasing activity an important aspect of treating EMS?
Exercise improves insulin sensitivity
Aids in weight loss
What can you give if a horse with EMS has persistent obesity despite diet changes and exercise management?
Levothyroxine sodium
How could you determine whether a horse with EMS who has a low tT4 or tT3 has hypothyroidism?
Do TRH stimulation test, EMS will have normal TRH stim test results
T/F: Low T3 in conjunction with low T4 is highly indicative of hypothyroidism.
False, NOT indicative of hypothyroid
What drug decreases serum T4?
Phenylbutazone
What is primary hypothyroidism? How is it confirmed? What about secondary hypothyroidism?
Primary: deficiency or excess in iodine
Test= decreased T3 and T4 with elevated TSH
Secondary: pituitary or hypothalamic dysfunction
Test= [TSH]
Tertiary= defect of hormone use at periphery
What is the best way to diagnose hypothyroidism?
TRH or TSH stimulation test
Melanocyte stimulating hormone (MSH) is the primary product of ______ cleavage in the pars ______. It is a potent anti-inflammatory hormone as well as an anti-pyretic. In the ____ (season) the hormone level begins to increase.
POMC (proopiomelanocortin)
intermedia
Fall
What hormone does cortisol counteract? What does this contribute to?
Insulin
Hyperglycemia
PPID is a neurodegenerative disease with loss of _______ inhibitory input to the _______ of the pars intermedia.
Dopaminergic
Melanotropes
What is the most important risk factor dor PPID? What chronic condition in old horses warrents PPID as a DDx?
Age (common when 18-20yo)
Foot problems
What is the most unique and specific clinical sign associated with PPID?
Hirsutism
What plasma component causes the behavioral abnormalities seen in PPID?
High B-endorphins
Which muscles test to atrophy with PPID? Where are common areas for abnormal fat distribution seen with this disease?
Epaxial and gluteal
Fat: Along crest of neck, over tail head, and on sheath or mammary region, above the eyes (supraorbital fossa)
What are the 3 causes of PUPD/dehydration in the Cushinoid horse?
- Loss of ADH (Due to pars nervosa compression)
- Hypercortisolemia (increase thirst and GFR)
- Osmotic diuresis (due to hyperglycemia and glucosuria)
Cushinoid horses have difficulty thermoregulating, what is a commen clinical sign associated with this?
Hyperhidrosis
Infertility is a clinical sign associated with Cushing’s/PPID. What is given to treat this? When should it be discontinued and what should be given in its place?
Pergolite (dopamine agonist)
3 months before foaling (to avoid agalactia) and give Domperidone (increases prolactin)
T/F: PPID is the most common cause of laminitis.
True
What is a reason why horses who have laminitis due to PPID do not show clinical signs or signs of pain?
Increased B-endorphins can increase pain tolerance
There is no standard for how to diagnose PPID in horses. What are some tests used and what is considered ‘gold standard’?
GOLD STANDARD= Dex suppresion test (Normal= cortisol suppresion <1)
ACTH plasma concentration
TRH or ACTH stim test
Less common:
MSH plasma concentration
Domperidone stim test
When are plasma concentrations of a-MSH and ACTH the highest?
Autumn (Aug-Oct)
So don’t do MSH or ACTH stim tests then - false +
What is the treatment for PPID?
Pergolide (dopamine agonist)
Other: Trilostane (improve CS), Cyprohepatidine (old school, appetite stimulant)
When compared to plasma, how much more concentrated should urine be?
3-4 x
(900-1200 mOsm/L)
T/F: Urine scalding is a typical in an overweight horse and can be a sign of neurological dysfunction.
True
What type of urinary catheter is used in mares?
Balloon catheter (filled w/saline)
What is normal USG in adults? Foals?
Is the urine acidic, alkaline or neutral normally?
Adults: 1.020-1.050
Foals: 1.008
Alkaline urine
Which of the following is NOT a cause of hyperglycemia in horses?
Exercise
Xylazine
Liver failure
PPID
Corticosteroids
Septicemia
Liver failure
What crystals are normal and abdundant in horse urine?
Calcium carbonate
Calcium oxalate
T/F: GGT can be measured in the serum or in urine to investigate renal tubular damage.
False, only urine
How many of the nephrons must be non-functional for creatinine to exceed normal values?
2/3 of all nephrons
What lab tests can be done to evaluate the urinary system?
Fractional excretion of electrolytes (can’t do this if on fluids)
Urinary enzymes - Urine:Serum ratios
You centrifuge discolored redish urine and it stays the same after centrifugation. What caused the pigmenturia?
Myoglobin
What part of the urinary tract is blood coing from when find it in early urination? End urination? What if it is present throughout?
Early = Urethra or bladder
End = Proximal urethra
Throughout= Bladder or upper tract
What are 4 causes of intravascular hemolysis?
IV DMSO
Water intoxication
Red maple toxicity
Neonatal isoerythrolysis
What condition in quarter horses causes hematuria?
Urethral fear - fistula between urethra and corpus spongiosum (penis)
What horses most commonly get nephroliths and urethral calculi? What do these progress to?
Young adult racehorses
Progress to CRF
How do horses with nephroliths present? What can be seen on ultrasound?
With colic
Hydronephrosis
What is the most common calculus?
Calcium based cystic calculi
Which cystic calculi are large, friable and spiculated? Which are smooth but hard and difficult to break?
Calcium carbonate
Calcium phosphate
A diet high in what predisposes to bladder stones?
Alfalfa
What antimicrobials can be used for bladder infections?
Trimeth-Sulfa
Aminoglycosides
Penicillin
Ceftiofur
What does retention of the urination posture for several seconds after voiding, tail flagging, flatulence during voiding, and constant dripping indicate?
Dysurea (Dysuria)
What antibiotics can cause acute tubular necrosis?
Aminoglycosides (prolonged admin, >10d)
Oxytetracycline (used for contracted tendons in foals)
Polymixin B (used for endotoxemia)
What are the 3 phases of ARF?
Induction
Maintenance
Recovery (can take 4-6 weeks for full concentrating ability)
Which is the correct order, from most to least nephrotoxic, for these aminoglycosides?
a. Neomycin > Gentamicin > Amikacin
d. Amikacin > Gentamicin > Neomycin
c. Gentamycin > Neomycin > Amikacin
a. Neomycin > Gentamicin > Amikacin
In addition to urea and creatine what enzyme can be used to monitor nephrotoxicity?
GGT
Which is the correct order, from most to least nephrotoxic, for these NSAIDs?
a. Flunixin > Ketoprofen > Phenylbutazone
b. Phenylbutazone> Ketoprofen >Flunixin
c. Phenylbutazone > Flunixin > Ketoprofen
c. Phenylbutazone > Flunixin > Ketoprofen
What renal biopsy finding with ARF signals a good prognosis for nephron function?
Intact basement membrane
What is the IVF rate for ARF treatment? How long are fluids administered at this rate?
40-80 ml/kg/day
Until creatinine decreases/azotemia resolves dramatically
What drug is given for ARF because it may be beneficial to help the healing of renal tissue? What are side effects and counterindications?
Misoprostol (synthetic prostaglandin analog)
Can cause diarrhea and colic
C/O’d in pregnant mares (abortion)
In addition to decreased EPO production, what causes anemia in CRF?
Uremic toxins cause extravascular hemolysis (decrease RBC lifespan)
How low do you expect albumin to be with CRF?
<2.5 mg/dl
Which shows more systemic clinical signs, upper or lower urinary tract infections?
Upper
Fever, weightloss, illness
Which of these is not an organism commonly associated with UTIs?
- E.coli*
- Streptococcus*
- Proteus*
- Klebsiella*
- Pseudomonas*
Streptococcus
How do you rule out psychogenic polydipsia?
Water deprivation test
If PP then will concentrate urine
