Veterinary Medicine - Endocrinology Flashcards
Hypothyroidism - What are the 2 main etiologies and what are their prevalence?
Lymphocytic Thyroiditis (50%)
Idiopathic Follicular Atrophy (50%)
Hypothyroidism - Common dermatological findings
Truncal bilateral symmetric alopecia
Myxedema (Classic “Sad Face”)
Hypothyroidism - Possible neurological findings
Cranial nerve deficits (Trigeminal Facial Vestibulocochlear )
Peripheral neuropathy (Can present up to Quadriparesis)
Seizures (Due to hyperlipidemia and hyperviscosity syndrome)
Hypothyroidism - What is the prevalence of weight gain?
Only 40% of cases
Hypothyroidism - Possible ocular findings
Lipid keratopathy
Keratoconjunctivitis Sicca (Concurrent with Lympocytic thyroiditis)
Retinal detachment (Hyperviscositiy syndrome)
Hypothyroidism - Possible cardiological findings
Bradycardia, Weak pulse, AV-Block
Hypothyroidism - Classic lab findings
Hypertriglyceridemia\ Hypercholesterolemia (75-90% of cases)
Mild non-regenerative anemia
Mild increase - ALP AST ALT CK
Hypothyroidism - What is the Prevalence of Dermatological Signs?
60-80% of cases (Most common sign!)
Hypothyroidism - What causes mild increase in liver enzymes? What enzyme increases the most
Vacuolar Hepatopathy
ALP > AST ALT
Hypothyroidism - In what percent of cases is TSH not above the threshold?
30% of cases
Hypothyroidism - What are 2 possible explanations for low T4 and normal TSH in a lethargic dog?
Hypothyroidism with normal TSH (30% of cases)
Euthyroid sick syndrome (decrease in T4 due to another illness)
Hypothyroidism - What 2 drugs can cause a decrease in T4?
Glucocorticoids
Phenobarbital
Hypothyroidism - Why do anti-thyroglobulin antibodies can interfere with thyroid panel interpretation? What is the solution?
Sometimes antibodies are formed against T4 as well - Which are then read as T4 on the thyroid panel - causing a false increase
Use Free-T4
Hypothyroidism - What are the 2 tenets of treatment monitoring? Explain
T4 levels - 4-6 hours after administration of Levothyroxine - Indication of absorption and possible overdosing
TSH levels - Checks the actual efficacy of the treatment
Hyperthyroidism - Commonly caused by…? Usually UniBilateral?
Thyroid Adenoma, Bilateral
Hyperthyroidism - Easy thing to do on physical examination when suspecting the disease?
Thyroid slip - Palpate along the trachea (90% of Cases - enlargement of thyroid gland)
Hyperthyroidism - Possible GI clinical signs
Polyphagia
Vomiting
Diarrhea
Hyperthyroidism - Possible urinary tract related clinical sign
PuPd
Hyperthyroidism - What is the most common CBC finding? In what percentage of cases?
Erythrocytosis (50%)
Hyperthyroidism - What is the most common panel finding? In what percentage of cases?
Increased liver enzymes (90%)
Hyperthyroidism - What is the drug of choice for conservative treatment? What are the indications?
Methimazole
Patient won’t undergo definitive treatment (Surgery Radioactive iodine)
Pre-op (Stabilize the patient Reduce the size of the gland)
Patient with concurrent diseases (i.e. CKD)
Hyperthyroidism - What is the definitive treatment?
Radio-Iodine (If available - Best)
Thyroidectomy
Cushing’s Disease - Most common etiology for the disease
Pituitary Dependent Hyperadrenocorticism (PDH) - Adenoma of the hypophysis (75% of Cases)
Adrenal tumor (25%)
Cushing’s Disease - Common clinical signs
Panting
Polyphagia
PuPd
Pendulus abdomen (“Pot Belly”)
Cranial organomegaly
Dermatological findings: Symmetric truncal alopecia Hypotrichosis, Hyperpigmentation, Comodons, Calcinosis Cutis, Skin infections
Urinary tract infections
CNS signs (In cases of macroadenomas in PDH)
Cushing’s Disease - Why do patients sometimes present with central neurological signs?
Macroadenomas in the hypophysis
Cushing’s Disease - Common complications
PTE
UTI
Urinary calculi
Skin infections
Gallbladder mucocele
Diabetes Mellitus
Hypertension
Central neurological signs
Metastasis (In cases of adrenal tumor)
Cushing’s Disease - Common CBC findings
Stress Leukogram
Erythrocytosis
Thrombocytosis
Cushing’s Disease - Common panel findings
Increase in ALP (C-ALP + Cholestasis due to Vacuolar Hepatopathy)
Increased liver enzymes
Hypercholesterolemia
Hypertriglyceridemia
Cushing’s Disease - Common UA findings
Decreased USG (Isosthenuria)
Proteinuria
Cushing’s Disease - Common US findings
Diffusely hyperechoic liver (Vacuolar hepatopathy)
PDH - Normal to bilaterally enlarged adrenal glands
AT - Adrenal mass \ Enlarged adrenal gland while the other adrenal gland is smaller than normal
Cushing’s Disease - Most specific diagnostic screening tool?
ACTH Stimulation test
Cushing’s Disease - LDDST - If any suppression is detected - Can the location of the pathology be determined?
Yes - PDH
Cushing’s Disease - LDDST - If no suppression is detected - Can the location of the pathology be determined?
No - Can be either AT or PDH
Cushing’s Disease - 2 Options for medical treatment for PDH
Trilostane (Inhibition of cortisol synthesis)
Lysodren (Adrenolytic)
Cushing’s disease - What is the indication for radiotherapy
PDH with Macroadenoma - to lessen CNS signs only!
Cushing’s Disease - Signalment and Prognosis
Middle age - Old dogs (>6)
MST ~2 Years
Cushing’s Disease - Common concurrent disease diagnosed along with it in cats is…?
Diabetes Mellitus
Cushing’s Disease - Most sensitive diagnostic screening tool?
Urine Creatinine Cortisol Ratio
Cushing’s Disease - ACTH Stimulation test is more sensitive for PDH AT? Why?
PDH
AT can lose their receptors for ACTH and become autonomous, therefore producing a false negative result
Cushing Vs. Addison - Age of onset
Cushing - Middle age - Old
Addison - Young - Middle age (But can be at any age)
Addison’s Disease - What Is usually affected first - Glucocorticoid or Mineralocorticoid secretion?
GC first (Atypical Addison’s disease)
2nd - Mineralocorticoid (weeks - months later)
Addison’s Disease - Clinical Signs
Atypical Addison’s:
Lethargy
Anorexia
Vomiting
Diarrhea
Hematochezia
Melena
Hematemesis
Addisonian crisis:
Hypovolemic Shock
Collapse
Seizures (Hypoglycemia)
Bradycardia (Hyperkalemia)
Regurgitation (Megaesophagus) - Rare
Addison’s Disease - CBC Findings
Eosinophila
Lymphocytosis
*Alternatively - Lack of stress leukogram in a sick animal
Hemoconcentration (Dehydration)
*Alternatively: Mild non-regenerative anemia Regenerative anemia in cases of GI ulcers
Addison’s Disease - Panel Findings
Hyperkalemia & Hyponatremia
Low Sodium Potassium ratio (<26)
Azotemia (Urea > Creatinine due to significant pre-renal element GI bleeding, AKI due to hypovolemia also possible)
Hypoglycemia (30%)
Hypocholesterolemia (GI loss and decreased absorption)
Hypoalbuminemia +- Hypoproteinemia (PLE)
Increase in liver enzymes (Hypoxia)
Addison’s Disease - DDs for low sodium : potassium ratio
Addison’s Disease
AKI
Urinary tract block
Uroabdomen
Certain GI parasites (e.g. Trichuriasis)
Effusions Repeated chylothorax drainage
Addison’s Disease - Possible findings in thoracic X-Rays
Microcardia
Megaesophagus (Rare)
Addison’s Disease - Possible abdominal US findings
Normal to decreased size of adrenal glands
Addison’s Disease - Diagnosis
ACTH Stimulation Test
Addison’s Disease - Treatment (Addisonian crisis situation)
Fluids +- Dextrose in case of hypoglycemia
Treat Hyperkalemia (Bicarbonate Dextrose +- Insulin Calcium gluconate)
Glucocorticoid & Mineralocorticoid supplementation:
Dexamethasone (Doesn’t interfere with ACTH Stimulation)
Hydrocortisone IV (GC + MC)
Prednisone PO + Fludricortisone PO (when starts to recover)
Treat GI Ulcers AKI
Addison’s Disease - What are the 2 long term treatment options
1) Fludrocortisone (Glucocorticoid + Mineralocorticoid activity)
50% of dogs will need addition of GC (Prednisone)
2) DOCP (Only Mineralocorticoid) + Prednisone
Diabetes Mellitus - Insulin dependent disease in dogs and cats?
Yes to both
Dogs start as ID because of autoimmune insulinitis (Diabetes type 1) and decrease in insulin production), Cats start as non-ID (Diabetes type 2) but due to amyloid deposition and destruction of beta-cells -> Becomes ID
Diabetes Mellitus - Etiologies
Hereditary Genetic (Dogs)
Pancreatitis (Dogs and Cats)
Obesity
Acromegaly (25% of DM cases in cats)
Pregnancy
Cushing’s Disease (Common concurrent disease in cats)
Diabetes Mellitus - What are the 3 hallmark clinical signs
Polyphagia
Weight loss
Pu\Pd
Diabetes Mellitus - Common ocular related finding in dogs
Cataract
Diabetes Mellitus - Common neurological sign in cats
Peripheral neuropathy (Plantigrade walk on hindlimbs)
Diabetes Mellitus - Diagnosis
History and classic clinical signs + Hyperglycemia & Glucosuria
*Hyperglycemia and glucosuria in cats can be not as specific as it can also happen in times of stress
Fructosamine
HbA1c
Diabetes Mellitus - Common CBC Findings (Trick question)
None
Diabetes Mellitus - Common Panel Findings
Hyperglycemia
Hypercholesterolemia
Hypertriglyceridemia
Increased liver enzymes (ALP > ALT) - due to Vacuolar Hepatopathy
Diabetes Mellitus - Why is it important to do a urinalysis in an animal suspected of DM? What are the possible findings?
UTI - Common
(Due to the urine is being more dilute and neutrophil dysfunction)
USG - can be normal or only slightly low (due to glucosuria)
Bacteria
Proteinuria
RBC
WBC
Diabetes Mellitus - What are the 3 tenets of treatment?
Insulin
Diet (Cats - High protein content, Dogs - High fiber content)
Exercise
Diabetes Mellitus - What is the main problem we want to monitor and avoid during treatment that can lead to hospitalization
Hypoglycemia
Diabetes Mellitus - Monitoring options
Monitor clinical signs! Decrease in Pu\Pd, Polyphagia, Weight gain
Freestyle libre
Glycosylated Hb
Fructosamine
Continuous Blood Glucose Curve
Diabetes Mellitus - Fructosamine measures mean glucose of the past…?
2 Weeks
Diabetes Mellitus - Glycosylated Hb measures the mean glucose of the past..?
3 Months
Diabetic Ketoacidosis - Basic pathogenesis (3 elements)
Lack of insulin secretion (DM Type 1)
Anorexia Low caloric intake
Increased secretion of diabetogenic hormones (e.g. Glucagon, Cortisol)
Diabetic Ketoacidosis - Common causes
Inflammation Infections:
Periodontitis
UTI
Pneumonia
Pancreatitis
Pyometra
Endocrinopathies:
Cushing Acromegaly
Pregnancy\Diestrus
Diabetic Ketoacidosis - Clinical signs
Lethargy
Depression
Anorexia
Vomiting
Pu\Pd
Hypovolemic shock (e.g. Tachycardia, Tachypnea, Hypothermia, Prolonged CRT etc.)
Kussmaul respirations
Diabetic Ketoacidosis - After the Patient is Fully Stabilized - What is our Next Big Goal?
Find the Predisposing Disease! (i.e. Infections)
What electrolytes are most affected in DKA? How are each affected?
Hyponatremia - Blood Glucose draws fluids from the interstitium and dilutes the sodium
Hypokalemia - Vomiting / Insulin administration / Osmotic diuresis due to glucosuria and ketonuria.
Hypophosphatemia - Osmotic diuresis / Insulin administration
Hypomagnesemia - Insulin administration
Diabetic Ketoacidosis - Treatment
Fluids
Anti-emetics
Analgesia (if indicated)
antibiotics (a lot of DKA cases are due to infectious processes, such as UTI)
Electrolyte supplementation (Potassium, Phosphate that were lost due to osmotic diuresis)
Insulin:
1) Start with Regular Insulin IMCRI. Blood Glucose levels should be decreased no more than 50 mg\dL\hour
2) When Blood Glucose levels drop below 250 mg\dL - administer fluids + Dextrose in addition to regular insulin. If BG levels drop below 150 mg\dL - Only supply animal Dextrose and cease Regular Insulin.
3) When the animal starts to recover, is well hydrated and eats on its own - Try switching to Insulin SC (e.g. NPH for dogs\Glargine for cats) after each meal)
DKA - What is a big clue that a patient is suffering from Hypomagnesemia?
Hypokalemia that doesn’t normalize despite supplementation
Diabetes Mellitus - An animal diagnosed with DM presents with unbalanced glycemic control (i.e. Hyperglycemia). What are you’re next steps?
Verify with the owners:
1) Proper Insulin administration and storage
2) Feeding according to guidelines (e.g. Proper diet suited for DM, fixed meal times and no snacks in between (Easier in dogs.
If owners are operating according to instructions - check for and treat pathologies that can lead to Insulin-resistance (e.g. Infection\Inflammation such UTI, Pancreatitis, Concurrent Endocrinopathies such as Cushing, Acromegaly, Hyperthyroidism, Neoplasia Pregnancy, Diestrus).
Acromegaly - Signalment and Etiology
middle-age to Old cats
Pituitary Neoplasia
Acromegaly - Clinical Signs
Enlarged Mandibles (Prognatism)
Enlarged paws
Organomegaly
Acromegaly - Diagnosis
1) IGF-1 levels - Increased - Can also be increased in Diabetes Mellitus
2) Brain imaging - CTMRI - Pituitary Tumor
Acromegaly - Treatment
Somatostatin analogues
Hypoparathyroidism - Treatment
Acute seizuring - Calcium Gluconate IV
Long term:
1) Vitamin D analogous - For life
2) Calcium supplements - until ionized calcium levels reach low-normal to normal levels, then slowly taper off.
Hypoparathyroidism - What is a classical clinical sign that can manifest at the time the dog is brought to the clinic? Explain
First-time seizure at the vet clinic
Stress => Panting => Blood becomes slightly more alkalemic => Ionized calcium binds to albumin => Less ionized calcium is available at the blood stream than usual => Seizure
Hypoparathyroidism - Prognosis
Excellent. Normal life expectancy.
Hyperparathyroidism - Clinical signs
Anorexia
Lethargy
Vomiting
Diarrhea
Pu\Pd
Stranguria, Pollakiuria, Hematuria (Due to Ca-Ox uroliths UTI)
Tremors
Hyperparathyroidism - Important DD for hypercalcemia with high PTH that must be ruled out
Lymphoma
Hyperparathyroidism - Prognosis
Very good. A high chance to be completely cured with definitive treatment
Hyperthyroidism - Prognosis
Generally good, MST - 3-5 Years
Hypoparathyroidism - Clinical signs
Restlessness
Muscle fasciculations
Tremors
Involuntary muscle contractions
Seizures
Behavioral changes
Coma
Cataracts
Hypoparathyroidism - Signalment
Young - middle age female dogs
Hypoparathyroidism - Diagnosis
Low total & Ionized calcium
Low PTH \ Inappropriately low (could be still in the normal range) in the face of hypocalcemia
Hypoparathyroidism - Panel findings
Low total calcium
Low ionized calcium
Hyperphosphatemia
Hyperparathyroidism - Signalment
Middle age - Old dogs
Hyperparathyroidism - Lab & Imaging findings
Panel:
High total & ionized calcium
Hypophosphatemia.
UA: Isosthenuria, Possible signs of UTI (WBC, RBC, Proteinuria), Ca-Ox crystals
Cervical US: Enlarged parathyroid glands
Hyperparathyroidism - Treatment
Treatments for hypercalcemia:
Fluids
Furosemide
Steroids
Bisphosphonates
Calcitonin.
Definitive treatments for Hyperparathyroidism:
Surgical removal of the parathyroid
Glandular ablation by radiofrequency or ethanol injection.
*Subsequent hypocalcemia Post-op is common - ongoing treatment is necessary (Vitamin D analogous, Calcium supplements)”
Primary Hyperaldosteronism - Signalment
Old cats (75% of cases above the age of 11 years)
Primary Hyperaldosteronism - Etiology
Adrenal Adenoma/ Hyperplasia / Carcinoma (Can be bilateral)
Primary Hyperaldosteronism - Clinical signs + Lab finding
Hypertension:
Ocular (Blindness / Hemorrhage / Retinal Detachment)
Epistaxis
CNS Signs
Worsening of Cardiac (Murmur / Gallop) and Kidney disease (Azotemia / PUPD).
Hypokalemia: Muscle weakness / Paresis / Neck ventroflexion / Plantigrade walk.
In addition to Hypokalemia, Metabolic Alkalosis can also be seen due yo excess H+ secretion in the kidneys.
Primary Hyperaldosteronism - Diagnosis
Hypertension
Hypokalemia.
Ultrasound - Adrenal mass (False negative is very possible if micronodular hyperplasia).
Gold standard: High Aldosterone (or even normal) in the face of high BP and hypokalemia
Primary Hyperaldosteronism - Treatment
Medical:
Spironolactone (Aldosterone antagonist)
Amlodipine
Potassium supplements
Low-sodium diet.
Surgery: Adrenalectomy (Treatment of choice)
Idiopathic Hypercalcemia - Common Signalment & How to Diagnose
Young - middle aged cats
High ionized Ca+
normal PTH
No Malignancy (Neoplasia) or other causes found
At what calcium levels can you start to see clinical signs of hypocalcemia (total and ionized calcium)
Total calcium - <6 mg\dL.
Ionized calcium - <0.6 mg\dL.
What is the main panel finding in SIADH?
Hyponatremia
Hyperthyroidism - Signalment, Common history/clinical signs
Cat - 10 y.o.and older.
Weight Loss
Polyphagia
Pu\Pd
Vomiting
Diarrhea
Tachycardia
Tachypnea
Hyperthermia
Dermal Changes
Behavioral Changes (Either More Aggressive or Calmer).
Target organ damage from hypertension (E.g. blindness from retinal detachment, CNS signs, L-CHF)
Hyperthyroidism - Common sequela(s) if left untreated
Retinal detachment -> Acute Blindness
CKD
Heart disease
CNS signs (e.g. Stroke)
Cachexia
Hyperthyroidism - After starting treatment - which organ requires monitoring?
Renal Function
Hyperthyroidism - Common lab findings / diagnostics
Erythrocytosis
lymphocytosis
Hypocholesterolemia
Electrolyte Changes (Vomiting / Diarrhea)
Slight liver enzyme elevation
Low CK (Sarcopenia).
UA: Proteinuria
Hyperthyroidism - What are the 4 Treatment Options
Radioactive Iodide (I131) - If available - treatment of choice
Surgery
Methimazole
Low iodine diet
Hyperthyroidism - Prognosis
Good to Excellent (~5 years in old Cats) - Depending on method of treatment
