Endocrine Literature Flashcards
In dogs that are undergoing parathyroidectomy, what are pre-op factors that are associated with post-op hypoCa?
MULTIPLE factors! NOT PTH and iCa
□ Hypo tCa: Old age, hx weakness, lack GI signs, high PTH, low CaXPhos ® Hypo iCa: intact, low BW, high BUN, lack PU/PD ® Linear Regression w/ age, BW, Ca x Phos, PTH, BUN
What happens with calcitonin in response to induced hyperCa (CaCl infusion) in cats?
VARIABLE calcitonin increased in response to hyperCa
Significant correlation in plasma calcitonin and calcitonin+ thyroid cells (IHC)
What was noted in dogs given Leventa?
Liquid l-T4: at 20 ug/kg PO q24hrs was god maintence supplementation in 50% dogs (5), minor change in 4 dogs, 1 dog needed q12hrs
§ CS of hypoT4 improved/resolved in all dogs after 4 wks
Rapid adsorption, T1/2: 11.8hrs
What are possible considerations for adult onset hypoT4 with goiter in cat?
Dietary iodine imbalance, chronic exposure to thyrotoxic substance, congenital form with late clinical presentation (similar in humans)
What is known about Tenterfield Terriers and hypoT4?
○ Congenital HypoT4 in Tenterfield Terriers
§ Goiters
§ Dysphormonogensis, thyroid peroxidase mutation (R593W)
Homooxygous (carriers can be tested for)
What effect does hypoT4 (induced) have on breeding?
Reversible periparturient mortality and low birth weights in offspring (compared to controls and tx hypoT4 dogs)
§ No diff: Interestrus interval, gestation duration, breeding behavior, or serum progesterone
What effect does hypoT4 (induced) have on peripheral neuropathyies?
Did NOT result in clinical or electrophysiologic evidence of peripheral neuropathy ( with EMG. Nerve conduction velocity, etc)
§ Did result in subclinical myopathy (histologic evidence of hypoT4 myopathy)
Name a breed that needs breed specific RR for thyroid hormones?
Sighthounds (salukis)
What effect does HypoT4 have on glucose metabolism?
Negative effect on glucose homeostasis = Insulin resistance
§ Overall glucose tolerance maintained by increased insulin secretion in hypoT4 dogs compared to controls
Possible factors: High serum Growth hormone, high IGF-1, increased abdominal fat in hypoT4 dogs
Can thyroid scintigraphy be diagnostic for hypoT4?
Uptake is useful test for thyroid function, BUT values may be nondiagnostic for hypoT4
§ Asymmetric uptake
§ Excess steroids may variably suppress technetium thyroidal uptake +/- thyroid hormones
What can be used in cats to differentiate euthyroidism from iatrogenic hypoT4?
○ Stimulation with recombinate human TSH (healthy, non-thyroidal illness, and iatrogenic hypoT4 after I131)
§ Differentiated euthyroidism from iatrogenic hypoT4 in cats
□ Baseline and post rhTSH lower than other controls
§ Thryoid/salivary gland uptake ratio (pertechnetate) differed from controls and iatrogenic hypoT4
What neurology condition has been noted to improve with thyroid supplementation?
○ HypoT4 polyneuropathy in dog (nerve bx) - Response to leveothyroxine = SLOW (6 months)
§ Recovery can occur if started before peripheral nerve fiver loss becomes severe
What is another name for TSH?
Thyrotropin
What is true regarding difference in MST bwtn azotemia in euthyroid vs iatrogenic hypoT4 cats?
§ No difference in MST btwn euthyroid azotemic and euthyroid non-azotemic cats (HUGE!!!!)
§ Iatrogenic hypoT4 contributed to the development of azotemia after tx
□ Larger portion of azotemia in hypoT4 significantly greater than euthyroid group
□ HyopT4 azotemic animals had worse survival (MST: 456 days) compared to HypoT4 nonazotemic (MST: 905 days)!!!
□ HypoT4 cats: 68% had low TT4 and increased TSH
In cats that were followed for 14 months, what were predictors of the them developing hyperT4?
§ Incidence: 7.4% (104 cats)
§ If became hyperT4: High ALP, higher prevalence of gioter at baseline compared to controls
§ Undetectable TSH (but NOT all cats with no TSH developed hyperT4)
What was seen in hyperT4 cats after 12 wks with novel lipophilic transdermal formulation of methimazole compared to oral carbimazole?
once daily transfermal methimazole (novel lipophilic formulation) applied to pinnae was as effective and safe as carbimazole (PO q12hrs) to tx hyperT4 in cats
§ No difference in T4, BW, BP, HR, ALP/ALT, BUN, Creat, USG btwn groups
§ Serum methimazole correlated poorly with TT4 concentrations in BOTH groups
What was noted about the antioxidant status in hyperT4 cats?
What happened after I131 tx?
□ No difference in blood antioxidants (GSH, ascorbate, Vit E) comapred to controls
□ Urinary isoprostanes increased in hyperT4 compared to controls
® This may reflect reversible renal oxidative stress induced by hyperT4
Plasma free Vit A higher in hyperT4 compared to controls
§ Both urinary isoprostanes and plasma free Vit A normalized with I131 tx
Is there an association btwn antioxidant status and idiosyncratic methimazole toxicosis in hyperT4 cats?
No!
When should T4 be measures after application of transdermal methimazole?
§ Timing of blood sampling does not seem to be critical to assess tx response
□ Methimazole prior to application was not significantly difference from any other time point
○ Transdermal methimazole (pluronic lecithin ogranogel) applied 2.5 mg q12hrs or 5 mg q24hrs
§ Sustained release was noted leading to prolonged suppression of T4 over 24 hours in both groups
What is known about RAAS activation and development of hypertension in hyperT4 cats?
○ RAAS Activation occurs in hyperT4 cats, BUT is NOT associated with development of hypertension
§ Plasma renin decreased after tx
§ Plasma aldosterone decreased after tx in normotensive group but did not change significantly in the hypertension-post tx group
□ Plasma aldosterone NOT influenced by changes in plasma renin in hyperT4 cats that developed hypertension after tx
® Possible RAAS dysfunction in these cats
What is true about the plasma amino acid profiles of hyperT4 cats?
○ Plasma amino acid profiles in hyperT4 cats and controls were similar
§ HyperT4 cats have significantly lower L-glutamine than controls
□ Lower: tryptophan, d-hydroxylysine
□ Higher: Cystine, citrulline, Amino butyric acid, L-asparagine, L-Alanine
§ Tyrosine, phenylalanine, iodine, and selenium NOT significantly different among with coat color or hyperT4
□ Light and dark cats OR cat w/hyperT4 or w/o hyperT4
Can NT-proBNP and cTNI be used to distingusih hypertrophy from hyperT4 from primary HCM in cats?
NO! ○ Neither NT-proBNP or cTNI distinguished hypertrophy associated with hyperT4 from primary HCM in cats
§ Both groups had higher biomarkers than controls (but not different)
HyperT4 cats (3 months after I131 tx) = Significantly lower plasma NT-proBNP and cTNI (ventricular wall thickness too)
What was seen with NT-proBNP and cTNI in cats with hyperT4 3 months after I131 tx?
HyperT4 cats (3 months after I131 tx) = Significantly lower plasma NT-proBNP and cTNI (ventricular wall thickness too)
After restoration of euthyroidism in cats with iatrogenic hypoT4 what happened to their creatinine?
§ Significant reduction in creatinine! (but also reduced BW, which could affect creat)
Significant increase in PCV, HR, ALP
What should be a consideration in a dog showing signs of hyperT4?
○ Dietary hyperT4 in dogs eating raw diet (BARF) or fed fresh/dried gullets
§ Elevated TT4 and low TSH in 12 dogs
□ CS in 6 dogs: Wt loss, aggression, tachycardia, panting, restlessness (6 dogs had no CS)
§ After diet change (8 dogs) - T4 normalized and CS resolved
Are baseline PTH and FGF-23 predictors of development of azotemic following tx in hyperT4 cats?
NO!
○ 270 hyperT4 cats (azotemic vs non-azotemic after tx): Baseline Elevated PTH, hyperphosphatemia, decreased FGF-23 and hypoCa noted
§ All parameters returned to RR with tx w/o azotemic CKD
§ After adjusting for creatinine: baseline PTH and FGF-23 were NOT predictors of development of azotemia following tx
§ Baseline FGF-23 was associated with all-cause mortality (may have some prognostic significance in hyperT4 cats)
How do PTH and calcitriol influence iCa in hyperT4 cats?
□ Thyroid hormones might influence iCa but NOT through PTH or calcitriol
○ HypoCa (low iCa) seen in hyperT4 cats § NOT associated with concurrent/unmasked CKD (higher iCa in these animals with hyperT4 than controls) or reduced calcitriol levels (higher calcitriol in hyperT4 than controls) § Plasma T4 predictor of iCa after adjustment for PTH and calcitriol
In dogs with DM that were followed for 2 years, what vascular complications were seen?
§ 55% systolic hypertension, 64% diastolic hypertension
§ 73% Microalbuminuria, 55% Increased UPC
§ 20% Retinopathy
□ No significant different of time since dx of DM or glycemic control for abnormalities (no significant association btwn the abnormalities either)
Except for proteinuria (substantial in some cases) - Clinically deleterious diabetic vascular complications were NOT seen in dogs in the study
Based on a DIAQoL-pet, in DM dogs, how many owners reported the DM negatively impacted QOL?
84%
§ Areas negatively impacting dogs/owner QOL: □ Worry, difficulties leaving dog w.family/friends, worry vision, boarding difficulties, worry hypoglycemia, social life, future care
What is known about PZI in dogs?
○ Protamine zinc recombinant human insulin (PZI) is an alternative in DM dogs (17 dogs)
§ Nadir: About 10 hrs
§ Over 60 days: Significant decreased in 10 hr BG and fructosamine
□ Improvement in PU/PD (14), BW stable/increased (16)
§ Adverse event: Hypoglycemia
What is true regarding DM in Elkhounds?
• DM in Elkhounds develops during diestrus and pregnancy (11% at dx)
○ Higher GH and lower progesterone compared to age matched controls
○ Immediate OHE (46%) improved prognosis for remission of DM
§ Lower remission if high BG at dx and long time (wks) til sx
How does glucosamine affect fructosamine in dogs?
• No significant change in serum fructosamine in healthy dogs (21 days) of glucosamine-chondroitin sulfate compared to placebo
○ Did not affect glycemic control or result in DM
What are conditions in dogs that result in hyperfructosaminemia?
DM Obesity HypoT4 Monocolonal IgA Gammopathy Dietrus/Pregnancy
Drugs (cyclosporine, prednisolone)
What are conditions in cats that result in hypofructosaminemia?
Hyperproteinemia
HyperT4
What are conditions in dogs that result in hypofructosaminemia?
Hypoalbuminemia Insulinomas Azotemia Hyperlipidemia (high TG and cholesterol) Metabolic epidermal necrosis secondary to alpha cell pancreatic tumors
Infections (Angiostrongylus vasorum and Leishmaniasis)
What is known about glargine in dogs?
○ Glargine Use in Dogs (gave dose of 0.5U/kg SQ q12hrs)
§ All dogs (10) well regulated within 38+/- 14 days
§ Mean glargine dose: 0.5 +/- 0.15U/kg
§ When fed a high fiber (insoluble) - Glargine resulted in peakless insulin that does not induce a distinct BG nadir
□ Min BG: 163 within 2 hrs of administration
Max BG: 230 within 12 hrs of administration
What has a relevant impact on glucose readings with glucometers?
○ HCT had a relevant impact on correlation btwn whole blood (glucometeres) and plasma (analyzers) in dogs
§ Glucometers (vet) more closely correlated with glucose when HCT was within or above RR
Glucometers (human) more closely approximated glucose in anemic dogs
What should not be used to measure BG on a dog under anesthesia?
○ Continuous Glucose Monitoring System should NOT be used to monitor BG in a dog under anesthesia
§ CGMS significantly different BG from glucometer during anesthesia
□ Differed by >20% on 42.9% of the paired measurements
Hypoglycemia 19.8% on CGMS by only once was detect by glucometer
What is the Glucagon Stimulation test?
Alternative to glucose tolerance test - Assess Residual B cell function in hyperglycemic peoplas, used to identify ACTH and GH def
What could be used in an ER situation of hypoglycemia at home?
SQ Glucagon (1 mg)
Can SQ glucagon do used in dogs to dx corticotrophic insufficiecny?
□ SQ glucagon did NOT increase cortisol or ACTH concentrations during study (Little use in suspected Corticotrophic insufficiency!!)
What is an alternative to regular insulin in DKA dogs?
○ Lispro insulin as CRI (0.09U/kg/hr) vs regular insulin CRI for DKA dogs
§ Lispro was safe and just as effective (12 dogs)
□ Biochemical resolution of DKA with lispro was significantly shorter (26h) compared to 61hr in dogs with regular insulin
What is an alternative to regular insulin in DKA dogs?
○ Lispro insulin as CRI (0.09U/kg/hr) vs regular insulin CRI for DKA dogs
§ Lispro was safe and just as effective (12 dogs)
□ Biochemical resolution of DKA with lispro was significantly shorter (26h) compared to 61hr in dogs with
regular insulin
What lifestyle risk factor is associated with progesterone related DM in Elkhounds?
Increased odds if overweight (owner perceived), diet not factor once controlling for BCS
What is known about Streptozotocin in sinulinoma dogs given q14 days?
• Streptozotocin in dogs with insulinoma (19): Given q2weeks (with saline diuresis and anti-emetics)
○ No myleosuppression noted
○ Mild to moderate GI toxicity
○ DM in 8 dogs (6 of which euthanized)
○ 2 nephrotoxicity (Fanconi syndrome and nephrogenic DI)
○ Increased ALT 6
○ Median progression free survival: 196 days and MST 308 days
Can the CGMS be used in cats?
YES! ○ Guardian REAL (continuous glucose monitoring device) is clinically accurate in cats with hyperglycemia (96.1%), euglycemia (100%) but slightly less accurate at low BG (91%)
§ Paired readings had good concordance 95.7%
§ Median delay after IV glucose to interstitial glucose = 11.4 mins
How do glaragine and detemir differ in healthy cats?
Onset of Action: 1.8 hrs detemir and 1.3 hr glaragine
○ Some had relatively flat curves, others had peaked curves ○ Shorter duration of action than in humans = Useful for q24hrs in some cats
What are the predictors of clinical remission in cats with DM?
Age, BW, Cholesterol, Glucose
50% (45/90): Remission
§ Achieved remission: median 48 days
§ Remission Duration: median 114 days (died) and 151 days (alive)
§ Remission more likely: Higher Age
§ Remission less likely: Increased cholesterol
§ Longer remission with higher BW
§ Shorter remission with higher BG
What is known about the arginine stimulation test in predicting clinical remission in cats with DM?
○ Arginine Stimulation Test (IV arginine to assess residual insulin and glucagon secretion) CANNOT predict remission in DM cats
§ 41% (7/17) went into remission
§ BG significantly lower in cats with remission (389 vs 506) - Lots of overlap!!!
Higher AUC of glucagon-to-insulin ratio in cats with remission - Large overlap btwn groups
Which diet resulted in a high postprandial glycemia in healthy cats?
Diet high in carbs compared to high fat vs high protein diets (5 weeks in healthy cats)
Which polymorphism has been associated with DM and overweight DSH?
Melanocortin 4 receptor (MC4R:C.92C>T)
○ Similar to humans: MC4R associated with obesity and DM (role in energy balance and appetite regulation) ○ No difference in nondiabetic overweight and lean cats ○ Overweight diabetics: 55% homozygous for allele compared to 33% lean diabetics and 30% nondiabetics § Significant difference btwn overweight DM and non-DM cats
What is the glucose status of cats with DM in remission?
§ 21 cats in remission: 19% Impaired fasting glucose; 76% impaired glucose tolerance = Considered “Prediabetic”
What are predictors of relapse from remission in DM cats?
§ Predictors of relapse: Severe glucose intolerance (>5hrs to return to BG 135)
§ Need ongoing glucose monitoring in cats in remission
Based on Randomized, prospective study (30 newly DM cats), what results in decreased insulin requirements in the following 6 months?
IV insulin for 6 days (tight glycemic control - 90-180) compared to standard glargine dosing
In newly diagnosed cats with DM what is the prognosis and what is associated with a shorter survival?
• In 114 newly dx DM cats: Median survival 516 days (1-3,486 days) = Far to good prognosis
○ Lived longer than 3 months (70%), 6 months (64%), 24 months (46%)
○ Significantly shorter survival time in cats with higher creatinine at dx
§ Hazard of dying 5% greater for each 10ug/dl increased in creatinine
○ DKA was NOT associated with survival time (NOT considered unfavorable)
What is wrong with compounded PZI?
• Comparison of commercially manufactured PZI (112 vials) vs compounded PZI (12 pharmacies, 8 vials from each)
○ All commercial PZI met USP specifications
○ Only 1 compounded PZI met USP specifications!!!
§ Endotoxin, not enough zinc, different concentrations!!
○ DO NOT USE COMPOUNDED PZI