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Pathology: Endocrine
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Pathology: Endocrine

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Questions and Answers

Which of the following glands are considered endocrine glands?

  • Liver
  • Pancreas (correct)
  • Hypothalamus (correct)
  • Kidneys

    • Hormones can only affect their corresponding target organs through direct interaction with the bloodstream.

    False

    What is the main function of trophic hormones?

    To regulate the secretion of other hormones.

    In type II diabetes, the down regulation of _____ receptors leads to insulin resistance.

    <p>insulin</p> Signup and view all the answers

    Match the following conditions with their associated gland:

    <p>Hypoadrenocorticism = Adrenal gland Diabetes Mellitus = Pancreas Thyroid hormone deficiency = Thyroid gland Acromegaly = Pituitary gland</p> Signup and view all the answers

    What is the effect of reduced secretion of a trophic hormone?

    <p>Decreased hormone production by target gland</p> Signup and view all the answers

    Endocrine diseases often result from the balanced secretion of hormones.

    <p>False</p> Signup and view all the answers

    What is the consequence of receptor failure on a target organ's response to its hormone?

    <p>Reduced end response.</p> Signup and view all the answers

    What is the primary effect of hyperplasia or neoplasia of an endocrine gland?

    <p>Increased production of hormone</p> Signup and view all the answers

    The posterior pituitary is primarily responsible for hormone production.

    <p>False</p> Signup and view all the answers

    What hormone is primarily inhibited by dopamine secretion from the hypothalamus?

    <p>ACTH (adrenocorticotropic hormone)</p> Signup and view all the answers

    Increased secretion of parathyroid hormone-related protein (PTHrp) can result in higher levels of serum ______.

    <p>calcium</p> Signup and view all the answers

    Match the following hormones with their corresponding functions:

    <p>ACTH = Stimulates adrenal hormone production TSH = Stimulates thyroid hormone production GH = Promotes growth ADH = Regulates water balance</p> Signup and view all the answers

    Which of the following conditions is a common cause of hyperparathyroidism due to renal dysfunction?

    <p>Hypocalcemia</p> Signup and view all the answers

    Negative feedback mechanisms help maintain hormone concentrations within a wide physiological range.

    <p>False</p> Signup and view all the answers

    What is the condition called when prolonged use of prednisone leads to signs of hyperadrenocorticism?

    <p>Iatrogenic hyperadrenocorticism</p> Signup and view all the answers

    The anterior pituitary is derived from tissue related to the fetal ______.

    <p>hard palate</p> Signup and view all the answers

    Match the type of tumor with the hormone-like substance it may produce:

    <p>Lymphoma = PTHrp Anal sac adenocarcinoma = PTHrp Pituitary adenoma = ACTH Adrenal tumor = Cortisol</p> Signup and view all the answers

    What is a common clinical sign of PPID in horses?

    <p>Long, thick hair coats</p> Signup and view all the answers

    Horses with PPID frequently show increased responsiveness to pain stimuli.

    <p>False</p> Signup and view all the answers

    What is the main role of cortisol in the body?

    <p>Controlling metabolism and immune response</p> Signup and view all the answers

    In the case of adrenal tumors, cortisol production remains uninhibited despite high levels of ACTH.

    <p>True</p> Signup and view all the answers

    What is the preferred testing method for diagnosing PPID in horses during autumn?

    <p>Measurement of ACTH</p> Signup and view all the answers

    Which horses are typically predisposed to Pituitary pars intermedia dysfunction (PPID)?

    <p>Older horses and ponies, particularly Morgan horses</p> Signup and view all the answers

    Horses with PPID may develop ________, resulting from the expansion of adenomas into the hypothalamus.

    <p>excessive sweating</p> Signup and view all the answers

    The ______ is responsible for synthesizing oxytocin and ADH.

    <p>hypothalamus</p> Signup and view all the answers

    Match the following clinical signs with their descriptions:

    <p>Hirsutism = Long, thick hair coats Polyuria = Increased urine production Polydipsia = Increased thirst Hyperthermia = Elevated body temperature</p> Signup and view all the answers

    What factor is NOT associated with the development of neurodegeneration in aging horses?

    <p>Excess exercise</p> Signup and view all the answers

    PPID in horses is referred to as equine Cushing’s disease.

    <p>False</p> Signup and view all the answers

    What may lead to a presumptive diagnosis of PPID in older horses?

    <p>Hypertrichosis</p> Signup and view all the answers

    The _______ test was previously considered the gold standard for diagnosing PPID but is no longer recommended with the availability of ACTH testing.

    <p>overnight dexamethasone suppression</p> Signup and view all the answers

    What is a consequence of chronic elevation of ACTH in horses?

    <p>Bilateral adrenal gland hyperplasia</p> Signup and view all the answers

    Mild to moderate hyperglycaemia may be present in horses with PPID.

    <p>True</p> Signup and view all the answers

    What clinical sign involves abnormal fat distribution around the eyes in horses with PPID?

    <p>Abnormal fat distribution</p> Signup and view all the answers

    An _______ leukogram may be observed in horses with PPID.

    <p>stress</p> Signup and view all the answers

    Which of the following is NOT a common clinical sign of PPID?

    <p>Enhanced coat shedding</p> Signup and view all the answers

    What condition is commonly associated with poorly controlled diabetes mellitus in cats?

    <p>Acromegaly</p> Signup and view all the answers

    Affected cats with acromegaly usually lose weight.

    <p>False</p> Signup and view all the answers

    Name one common clinical sign of acromegaly in cats.

    <p>Enlargement of face or paws</p> Signup and view all the answers

    Acromegaly is caused by an overproduction of __________ hormone.

    <p>growth</p> Signup and view all the answers

    Match the following components of the adrenal gland with their functions:

    <p>Adrenal Medulla = Produces catecholamines Zona Glomerulosa = Produces aldosterone Zona Fasciculata = Produces cortisol Zona Reticularis = Produces sex steroids</p> Signup and view all the answers

    What is the suggested IGF-1 level indicative of acromegaly?

    <p>1000 ng/mL</p> Signup and view all the answers

    Intracranial imaging is commonly used for diagnosing acromegaly.

    <p>True</p> Signup and view all the answers

    What is the major regulator of cortisol production in the adrenal cortex?

    <p>Adrenocorticotrophic hormone (ACTH)</p> Signup and view all the answers

    The normal cortex:medulla ratio in the adrenal gland is approximately __________.

    <p>1:1 to 2:1</p> Signup and view all the answers

    Which of the following describes the most common cause of secondary hyperadrenocorticism in dogs?

    <p>Excess ACTH from a pituitary adenoma</p> Signup and view all the answers

    Hyperadrenocorticism in dogs can occur due to iatrogenic causes.

    <p>True</p> Signup and view all the answers

    What type of adrenal tumor is typically well-demarcated and surrounded by a fibrous capsule?

    <p>Adrenocortical adenoma</p> Signup and view all the answers

    The adrenal cortex is divided into three zones: zona glomerulosa, zona fasciculata, and zona __________.

    <p>reticularis</p> Signup and view all the answers

    Match the following types of Cushing's syndrome with their definitions:

    <p>Primary hyperadrenocorticism = Excess cortisol from a neoplastic adrenal gland Secondary hyperadrenocorticism = Excess ACTH from the pituitary gland Iatrogenic hyperadrenocorticism = Resulting from corticosteroid administration</p> Signup and view all the answers

    Which clinical sign is NOT associated with Cushing’s syndrome in dogs?

    <p>Excessive shedding</p> Signup and view all the answers

    Leukocytosis with lymphopenia is not a typical finding in Cushing's syndrome.

    <p>False</p> Signup and view all the answers

    What is the main biochemical marker that can indicate hyperadrenocorticism in dogs?

    <p>Increased ALP</p> Signup and view all the answers

    The urinary cortisol:creatinine ratio is useful for ruling out a diagnosis of _____________ disease.

    <p>Cushing's</p> Signup and view all the answers

    What effect do glucocorticoids have on glucose levels?

    <p>Increase gluconeogenesis</p> Signup and view all the answers

    A small dose of dexamethasone suppresses ACTH release in normal dogs.

    <p>True</p> Signup and view all the answers

    What is the preferred method to collect urine for the urinary cortisol:creatinine ratio test?

    <p>Collect urine at home at least 2 days post vet visit</p> Signup and view all the answers

    Neutrophilia and monocytosis in dogs with Cushing's are due to reduced _____________ and emigration of cells.

    <p>margination</p> Signup and view all the answers

    Match the following tests with their descriptions:

    <p>Urinary cortisol:creatinine ratio = Cheap screening test to rule out Cushing’s Low dose dexamethasone suppression test = Measures cortisol levels after dexamethasone administration ACTH stimulation test = Evaluates adrenal gland response to ACTH stimulation Complete Blood Count = Evaluates overall blood health</p> Signup and view all the answers

    Which of the following is a common clinical sign in dogs with Cushing's syndrome?

    <p>Pot-bellied appearance</p> Signup and view all the answers

    An increased serum basal cortisol concentration is definitive evidence of hyperadrenocorticism.

    <p>False</p> Signup and view all the answers

    What concurrent disease condition may suggest a diagnosis of Cushing’s in diabetic dogs?

    <p>Persistently poor response to high doses of insulin</p> Signup and view all the answers

    Calcinosis cutis commonly occurs in about _____________ percent of dogs with Cushing's syndrome.

    <p>40</p> Signup and view all the answers

    Which of the following is a frequent complication of Cushing’s syndrome in dogs?

    <p>Bacterial infections</p> Signup and view all the answers

    What is the primary substance administered during the ACTH stimulation test?

    <p>Synthetic ACTH</p> Signup and view all the answers

    Hyperplastic adrenal glands will under-respond to the administration of ACTH.

    <p>False</p> Signup and view all the answers

    What is the expected response of a normal dog to a high dose dexamethasone suppression test?

    <p>Suppression of cortisol release</p> Signup and view all the answers

    Dogs with __________ have low plasma ACTH concentrations due to negative feedback from excessive cortisol.

    <p>adrenal tumors</p> Signup and view all the answers

    When using the ACTH stimulation test, which animal condition has the lowest sensitivity for diagnosis?

    <p>Adrenal tumors</p> Signup and view all the answers

    What percentage of cats show suppression at 4 hours in the LDDST?

    <p>Approximately 50%</p> Signup and view all the answers

    Match the following adrenal conditions to their corresponding test outcome:

    <p>Pituitary-dependent hyperadrenocorticism = Cortisol suppression after dexamethasone Adrenal tumors = No suppression after dexamethasone Iatrogenic hyperadrenocorticism = Variable ACTH response Normal dogs = Cortisol suppression after dexamethasone</p> Signup and view all the answers

    Feline hyperadrenocorticism primarily results from adrenal tumors.

    <p>False</p> Signup and view all the answers

    What must be known before measuring ACTH to confirm hyperadrenocorticism?

    <p>The diagnosis of hyperadrenocorticism must be confirmed.</p> Signup and view all the answers

    Urine cortisol to creatinine ratio is a useful screening test due to its __________ sensitivity but low specificity.

    <p>high</p> Signup and view all the answers

    Which clinical sign is reported in 81% of cats with hyperadrenocorticism?

    <p>Excessive urination and thirst (PU/PD)</p> Signup and view all the answers

    In dogs with PDH, adrenal glands are typically __________.

    <p>symmetrical and normal-sized or bilaterally enlarged</p> Signup and view all the answers

    What laboratory abnormality is most commonly found in cats with hyperadrenocorticism?

    <p>Hyperglycemia</p> Signup and view all the answers

    ACTH measurement is currently available in New Zealand.

    <p>False</p> Signup and view all the answers

    What is hyperlipidaemia defined as?

    <p>Increase in circulating lipids</p> Signup and view all the answers

    Lipoproteins are named for their size rather than their density.

    <p>False</p> Signup and view all the answers

    What is the primary organ responsible for cholesterol synthesis?

    <p>liver</p> Signup and view all the answers

    Endothelial cells in tissues such as adipose and muscle have an enzyme called __________ that breaks down lipid/lipoprotein complexes.

    <p>lipoprotein lipase</p> Signup and view all the answers

    Match the following conditions with their associated causes:

    <p>Postprandial = Transient increase in triglycerides after eating Hypothyroidism = Decreased synthesis of LDL receptors Pancreatitis = Increased hepatic synthesis of cholesterol Nephrotic syndrome = Proteinuria and hypoalbuminaemia</p> Signup and view all the answers

    What is the primary cause of clinical signs of functional phaeochromocytoma in affected animals?

    <p>Overproduction of adrenaline or noradrenaline</p> Signup and view all the answers

    What can cause the plasma to appear lipaemic?

    <p>Increase in triglycerides in VLDL or chylomicrons</p> Signup and view all the answers

    Benign neoplasms such as phaeochromocytomas have a recurrence rate of up to 15% after surgical excision.

    <p>True</p> Signup and view all the answers

    Anorexia can lead to hyperlipidaemia in horses.

    <p>True</p> Signup and view all the answers

    What clinical condition results from aldosterone deficiency due to hypoadrenocorticism?

    <p>Addison’s disease</p> Signup and view all the answers

    What is the primary production difference between T3 and T4?

    <p>T4 is produced in greater amounts than T3.</p> Signup and view all the answers

    In hypoadrenocorticism, a Na:K ratio of less than _____ is highly suggestive of the condition.

    <p>25:1</p> Signup and view all the answers

    A lipoprotein that is primarily involved in transporting cholesterol is __________.

    <p>LDL</p> Signup and view all the answers

    Which of the following conditions is linked to decreased biliary excretion of cholesterol?

    <p>Hypothyroidism</p> Signup and view all the answers

    Match the clinical signs with the condition they are associated with:

    <p>Weakness, collapse = Hypoadrenocorticism Tachycardia, hypertension = Functional phaeochromocytoma Lethargy, weight loss = Atypical Addison’s disease Thinned adrenal cortex = Idiopathic adrenal atrophy</p> Signup and view all the answers

    What electrolyte abnormality is commonly observed in hypoadrenocorticism?

    <p>Hyperkalaemia</p> Signup and view all the answers

    Cholesterol is only acquired through dietary sources in omnivores.

    <p>False</p> Signup and view all the answers

    What role does thyroglobulin play in thyroid hormone synthesis?

    <p>It brings together iodine and tyrosine to form MIT and DIT.</p> Signup and view all the answers

    Malignant phaeochromocytomas never result in metastasis.

    <p>False</p> Signup and view all the answers

    High-density lipoproteins (HDL) are often referred to as __________ lipoproteins.

    <p>good</p> Signup and view all the answers

    What diagnostic test is definitive for confirming hypoadrenocorticism?

    <p>ACTH stimulation test</p> Signup and view all the answers

    Adrenocortical atrophy can lead to deficiency in _____, glucocorticoids, and adrenal sex steroids.

    <p>mineralocorticoids</p> Signup and view all the answers

    Match the following lipoproteins with their characteristic:

    <p>HDL = Promotes cholesterol excretion LDL = Delivers cholesterol to cells VLDL = Carries triglycerides to tissues Chylomicrons = Transports dietary fat from intestines</p> Signup and view all the answers

    What is the most likely cause of idiopathic adrenal atrophy in dogs?

    <p>Immune-mediated inflammation</p> Signup and view all the answers

    Most phaeochromocytomas in animals are functional and secreting adrenaline.

    <p>False</p> Signup and view all the answers

    What are common clinical signs of atypical Addison’s disease?

    <p>Lethargy, weight loss, inappetence, vomiting, diarrhoea</p> Signup and view all the answers

    Nodular cortical hyperplasia is a common incidental finding in adrenal glands of _____ dogs.

    <p>old</p> Signup and view all the answers

    What is the significance of a 'non-stress' leukogram in the haematology of hypoadrenocorticism?

    <p>Suggests severe illness</p> Signup and view all the answers

    What is the most common cause of goitre in livestock?

    <p>Nutritional deficiencies</p> Signup and view all the answers

    Hyperthyroidism is primarily associated with an increase in T4 and T3 levels.

    <p>True</p> Signup and view all the answers

    What substance is primarily affected by T3 administration in healthy cats during the T3 suppression test?

    <p>T4</p> Signup and view all the answers

    What are two useful timepoints for monitoring treatment responses in dogs with hypothyroidism?

    <p>6-8 weeks after starting therapy and 2-4 weeks after changing dose</p> Signup and view all the answers

    Elevated free T4 levels are definitive evidence of hyperthyroidism in cats.

    <p>False</p> Signup and view all the answers

    What is the primary function of T3 in the body?

    <p>Biologically active form of thyroid hormone that increases metabolism</p> Signup and view all the answers

    Iodine deficiency may cause a non-neoplastic enlargement of the thyroid known as __________.

    <p>goitre</p> Signup and view all the answers

    Name a common illness that can suppress T4 levels in cats.

    <p>Diabetes mellitus</p> Signup and view all the answers

    Hypothyroidism is predominantly caused by secondary factors in dogs.

    <p>False</p> Signup and view all the answers

    Match the following clinical signs of hyperthyroidism in cats with their descriptions:

    <p>Polyphagia = Increased appetite Tachycardia = Increased heart rate PUPD = Increased urination and thirst Weight loss = Unintended weight reduction</p> Signup and view all the answers

    What hormone is produced by parafollicular cells in the thyroid gland?

    <p>Calcitonin</p> Signup and view all the answers

    In dogs, 90% of thyroid tumors are _____ in nature.

    <p>malignant</p> Signup and view all the answers

    Match the following diseases with their effects on insulin:

    <p>Diabetes mellitus = Insulin deficiency Insulinoma = Insulin overproduction Hypoglycemia = Excess insulin Glucagonoma = Increased blood glucose</p> Signup and view all the answers

    The major storage form of thyroid hormone is _____, while the main biologically active form is _____.

    <p>T4, T3</p> Signup and view all the answers

    Which hormone is generally increased in hyperthyroid cats?

    <p>Total T4 (TT4)</p> Signup and view all the answers

    In newborn lambs, goitre can be a consequence of iodine excess in the diet.

    <p>False</p> Signup and view all the answers

    Match the following thyroid-related terms with their definitions:

    <p>Thyrotropin-releasing hormone (TRH) = Stimulates the pituitary to produce TSH Thyroid stimulating hormone (TSH) = Stimulates thyroid follicular cells Calcitonin = Reduces serum calcium concentration Lymphocytic thyroiditis = Progressive destruction of thyroid gland</p> Signup and view all the answers

    What is the most common cause of diabetes mellitus in dogs?

    <p>β cell degeneration</p> Signup and view all the answers

    Free T4 is always low in cats with hyperthyroidism.

    <p>False</p> Signup and view all the answers

    What is a significant risk of goitre in neonatal lambs?

    <p>Dystocia due to massive swelling of the neck</p> Signup and view all the answers

    Which breed of dog is NOT commonly associated with hypothyroidism?

    <p>German Shepherd</p> Signup and view all the answers

    The increase in TSH in goitre is stimulated by a fall in __________ levels.

    <p>T4 and T3</p> Signup and view all the answers

    Calcitonin increases ionised serum calcium concentration in the blood.

    <p>False</p> Signup and view all the answers

    What type of animal is primarily affected by thyroid adenocarcinomas?

    <p>Dogs</p> Signup and view all the answers

    What is the average age at which clinical signs of hypothyroidism commonly develop in dogs?

    <p>7 years</p> Signup and view all the answers

    The endocrine pancreas is comprised of _______ cells that secrete insulin.

    <p>β</p> Signup and view all the answers

    Match the following terms to their correct description concerning thyroid gland conditions:

    <p>Goitre = Non-neoplastic enlargement of the thyroid gland Thyroid adenoma = A mildly enlarged thyroid gland with capsulated mass Hyperthyroidism = Increased metabolic state often seen in cats Euthyroid = Normal thyroid hormone levels despite clinical signs</p> Signup and view all the answers

    Match the following pancreatic cell types with their secretions:

    <p>α cells = Glucagon β cells = Insulin δ cells = Somatostatin</p> Signup and view all the answers

    What is a common clinical sign of hyperthyroidism in cats?

    <p>Increased irritability</p> Signup and view all the answers

    The rise in _____ levels due to low thyroid hormones stimulates the release of THR from the hypothalamus.

    <p>TSH</p> Signup and view all the answers

    What hormonal imbalance is often associated with obesity in cats?

    <p>Insulin resistance</p> Signup and view all the answers

    Human recombinant TSH is a cost-effective alternative for veterinary use.

    <p>False</p> Signup and view all the answers

    What is a common clinical sign of hypothyroidism in dogs?

    <p>Weight gain</p> Signup and view all the answers

    What laboratory test is typically used to assess thyroid function in cats?

    <p>Total T4 (TT4)</p> Signup and view all the answers

    Insulinoma is a benign tumor that does not require urgent treatment.

    <p>False</p> Signup and view all the answers

    High levels of TRH provide positive feedback to the thyroid gland.

    <p>False</p> Signup and view all the answers

    What condition occurs due to the inadequate production of insulin to meet metabolic demands?

    <p>Diabetes mellitus</p> Signup and view all the answers

    In the absence of kidney disease, ________ levels are typically low due to reduced muscle mass.

    <p>creatinine</p> Signup and view all the answers

    What occurs in lymphocytic thyroiditis?

    <p>Infiltration of the thyroid gland by lymphocytes and inflammatory cells</p> Signup and view all the answers

    Secondary hypothyroidism in dogs is primarily caused by a _____ that destroys TSH-producing cells in the pituitary.

    <p>tumor</p> Signup and view all the answers

    Somatostatin inhibits the release of _____ and _____ as well as digestive enzymes.

    <p>insulin</p> Signup and view all the answers

    Which of the following is NOT a function of thyroid hormones?

    <p>Reducing glucose absorption</p> Signup and view all the answers

    What is the most common type of anemia observed in endocrine disease?

    <p>Normocytic normochromic anaemia</p> Signup and view all the answers

    Hypercholesterolaemia is typically seen in about 50% of hypothyroid cases.

    <p>False</p> Signup and view all the answers

    What would you expect Total T4 (TT4) levels to do in dogs with hypothyroidism?

    <p>Decrease</p> Signup and view all the answers

    The presence of _______ indicates thyroid pathology but does not provide information about thyroid function.

    <p>thyroglobulin autoantibody (TgAA)</p> Signup and view all the answers

    Match the thyroid test with its significance:

    <p>TT4 = Traditionally measured to assess thyroid function TSH = Assesses negative feedback from T4 FT4 = Metabolically active, unbound fraction of T4 TgAA = Indicates thyroid pathology in lymphocytic thyroiditis</p> Signup and view all the answers

    Which of the following conditions can lead to suppressed Total T4 (TT4) levels?

    <p>All of the above</p> Signup and view all the answers

    The presence of an elevated TSH level is a confirmatory indicator of hypothyroidism.

    <p>True</p> Signup and view all the answers

    What is euthyroid sick syndrome?

    <p>A condition where non-thyroidal illness suppresses T4 levels.</p> Signup and view all the answers

    Mild _____ enzyme elevations may be seen in about 30% of dogs with hypothyroidism.

    <p>liver</p> Signup and view all the answers

    Match the serum concentration levels with their typical association in hypothyroid dogs:

    <p>Increased TSH = Commonly seen in hypothyroid dogs Decreased TT4 = Indicates hypothyroidism Normal TSH = Less than 20% in hypothyroid dogs Increased TgAA = Suggests thyroid pathology</p> Signup and view all the answers

    Which medication is known to potentially suppress T4 levels?

    <p>All of the above</p> Signup and view all the answers

    Free T4 levels are significantly affected by various external factors.

    <p>False</p> Signup and view all the answers

    What is the primary purpose of the oral glucose test in horses?

    <p>To assess insulin dysregulation after a carbohydrate meal</p> Signup and view all the answers

    What is the role of Reverse T3 in thyroid hormone metabolism?

    <p>To dampen the metabolic effects of thyroid hormones.</p> Signup and view all the answers

    Excessive fasting prior to measuring basal insulin is recommended.

    <p>False</p> Signup and view all the answers

    What clinical sign is most commonly associated with insulinoma due to severe hypoglycemia?

    <p>Seizures</p> Signup and view all the answers

    Low Total T4 may be due to hypothyroidism, another disease, or ______.

    <p>medication</p> Signup and view all the answers

    The insulin response remains _____ in horses with EMS compared to normal horses after the Insulin Response Test.

    <p>higher</p> Signup and view all the answers

    Match the following tests with their primary focus in assessing insulin dysregulation:

    <p>Oral glucose test = Insulin response to dietary carbohydrates Insulinoma testing = Measurement during hypoglycemia Combined glucose insulin test = Biphasic blood glucose response Insulin response test = Serum glucose measurement pre- and post-insulin</p> Signup and view all the answers

    What is a key characteristic of insulin concentrations in horses with EMS during the oral sugar test?

    <p>High insulin concentrations</p> Signup and view all the answers

    Insulinomas are exclusively found in dogs.

    <p>False</p> Signup and view all the answers

    What management practice should be avoided before insulin and glucose testing?

    <p>Transportation stress</p> Signup and view all the answers

    The combined glucose insulin test is useful to indicate _____ dysregulation in horses.

    <p>insulin</p> Signup and view all the answers

    Which hormone is primarily secreted in excess by insulinomas?

    <p>Insulin</p> Signup and view all the answers

    What is produced when two acetyl-CoA molecules combine?

    <p>Acetoacetic acid</p> Signup and view all the answers

    Acetoacetic acid is the only ketone body produced during ketosis.

    <p>False</p> Signup and view all the answers

    What condition is characterized by an accumulation of ketones and metabolic acidosis?

    <p>Diabetic Ketoacidosis (DKA)</p> Signup and view all the answers

    Increased levels of _____ hormones contribute to ketone formation.

    <p>diabetogenic</p> Signup and view all the answers

    Match the following clinical signs with their descriptions:

    <p>Polyuria = Increased urine production Polydipsia = Increased thirst CNS depression = Reduced central nervous system activity Dehydration = Deficiency of water in the body</p> Signup and view all the answers

    What does hyperglycaemia indicate in relation to Diabetic Ketoacidosis?

    <p>Increased glucose level in the blood</p> Signup and view all the answers

    Urinary dipsticks can detect acetoacetic acid and acetone.

    <p>True</p> Signup and view all the answers

    What is the primary feature of Equine Metabolic Syndrome (EMS)?

    <p>Insulin dysregulation</p> Signup and view all the answers

    Adipose tissue acts as an _____ organ, releasing hormones that affect various bodily functions.

    <p>endocrine</p> Signup and view all the answers

    Which of the following best indicates the presence of insulin resistance in horses?

    <p>High basal insulin</p> Signup and view all the answers

    All obese horses will develop Equine Metabolic Syndrome.

    <p>False</p> Signup and view all the answers

    What may characterize the fat deposition in a horse with EMS?

    <p>Cresty neck and regional adiposity</p> Signup and view all the answers

    What is the main consequence of amylin accumulation in the islets?

    <p>Hyperglycaemia development</p> Signup and view all the answers

    Chronic hyperglycaemia can lead to 'glucose toxicity' in β cells.

    <p>True</p> Signup and view all the answers

    Acute stress and pain generally result in _____ insulin concentration.

    <p>decreased</p> Signup and view all the answers

    Match the following conditions with their clinical signs:

    <p>Diabetic Ketoacidosis = Metabolic acidosis Equine Metabolic Syndrome = Insulin resistance Cushing's Disease = Long coat and laminitis Hypoadrenocorticism = Low cortisol levels</p> Signup and view all the answers

    What is a common clinical sign of diabetes mellitus in dogs?

    <p>Polyuria and polydipsia</p> Signup and view all the answers

    In diabetic cats, damage to nerve myelin sheaths can cause _________ hindlimb stance.

    <p>plantigrade</p> Signup and view all the answers

    Match the following clinical signs with their causes:

    <p>Polyuria = Osmotic diuresis due to glucosuria Weight loss = Caloric loss from glucosuria Cataracts = Osmotic effect of glucose metabolites Muscle wasting = Fat and muscle catabolism for energy</p> Signup and view all the answers

    Which component is used to reflect average glucose concentration over three to four weeks in diabetic patients?

    <p>Fructosamine</p> Signup and view all the answers

    Diabetic ketoacidosis can only be mild and is rarely life-threatening.

    <p>False</p> Signup and view all the answers

    What is a possible cause of urinary tract infections in diabetic patients?

    <p>Dilute, glucose-laden urine</p> Signup and view all the answers

    Elevated liver enzymes in diabetic patients are often due to ________ infiltration.

    <p>lipid</p> Signup and view all the answers

    What age group of dogs is most commonly affected by diabetes mellitus?

    <p>Middle-aged and older dogs</p> Signup and view all the answers

    Fructosamine concentrations should ideally be higher in females than in males.

    <p>False</p> Signup and view all the answers

    How does insulin affect the hypothalamic satiety center?

    <p>Insulin is needed for proper function.</p> Signup and view all the answers

    In diabetes mellitus, the presence of glucosuria leads to ________ diuresis.

    <p>osmotic</p> Signup and view all the answers

    Match the following breeds or conditions with their affected populations:

    <p>Diabetic dogs = Middle-aged to older dogs Diabetic cats = Elderly, often male and overweight Diabetic ketoacidosis = Canines and felines Polyuria and polydipsia = Common in both dogs and cats</p> Signup and view all the answers

    What is the common method to differentiate between transient hyperglycaemia and true hyperglycaemia?

    <p>Serum fructosamine concentration</p> Signup and view all the answers

    Study Notes

    Endocrine System Overview

    • Endocrine glands consist of specialized cells creating and releasing hormones into the bloodstream.
    • Hormones act on distal target organs through specific receptor binding, regulating body processes.
    • Hormone production adjusts in response to changes in extracellular fluid to maintain homeostasis.
    • Key endocrine glands: hypothalamus, pituitary, thyroid, parathyroid, adrenal glands, pancreas, pineal gland, ovaries, and testes.
    • Additional endocrine functions found in the liver, adipose tissue, gastrointestinal tract, and heart.
    • Endocrine diseases often arise from hormonal deficiencies or excesses.

    Hormone Secretion Variability

    • Reduced Hormone Secretion:

      • Destruction of glandular tissue or secretory cells leads to decreased hormone production.
      • In hypoadrenocorticism, adrenal destruction results in insufficient cortisone and aldosterone.
      • Trophic hormone reduction, such as TSH and ACTH due to pituitary tumors, affects target gland functions.

    • Increased Hormone Secretion:

      • Hyperplasia or tumors increase hormone production; e.g., hyperthyroidism in elderly cats.
      • Excess trophic hormone leads to hyperplasia in target glands; e.g., pituitary-dependent hyperadrenocorticism.

    • Iatrogenic Effects:

      • Prolonged external hormone therapy (e.g., prednisone) can mimic disease states.

    Pituitary Gland Structure and Functions

    • The pea-sized pituitary gland consists of anterior (adenohypophysis) and posterior (neurohypophysis) parts.
    • Anterior pituitary hormones include ACTH, TSH, growth hormone, and reproductive hormones.
    • The posterior pituitary releases oxytocin and ADH synthesized in the hypothalamus.
    • Hormone release is regulated through negative feedback loops, ensuring hormone levels remain stable.

    Pituitary Disorders

    • Pituitary Pars Intermedia Dysfunction (PPID):

      • Common in older horses; excess POMC-derived peptide production leads to symptoms like hirsutism and weight gain.
      • Diagnosis often requires ACTH levels and can be complicated by seasonal increases.

    • ACTH-Secreting Tumors:

      • Benign adenomas that cause adrenal hyperplasia and Cushing’s syndrome in dogs.

    • Acromegaly:

      • Caused by growth hormone overproduction via pituitary adenoma in cats, leading to distinctive physical features and insulin resistance.

    Adrenal Gland Overview

    • The adrenal gland, located atop the kidneys, is divided into the medulla (catecholamines) and cortex (steroid hormones).
    • Cortex zones include:
      • Zona Glomerulosa: Produces aldosterone; regulates sodium and potassium.
      • Zona Fasciculata: Produces cortisol; involved in metabolism and immune response regulation.
      • Zona Reticularis: Produces minor amounts of sex steroids.

    Adrenal Disorders

    • Adrenal Hyperplasia and Neoplasia:

      • Chronic ACTH stimulation, often from pituitary adenomas, leads to adrenal cortex enlargement.
      • Adrenal tumors can be functional (excess cortisol) or non-functional (cause pressure effects).

    • Cushing’s Syndrome (Hyperadrenocorticism):

      • Caused by adrenal tumors, accounting for 15-20% of cases in dogs.

    Diagnostic Approaches

    • Diagnosing endocrine disorders can involve various hormonal assays and imaging techniques.
    • ACTH tests, TRH stimulation, and dexamethasone suppression tests are pivotal in assessing pituitary and adrenal function.
    • Accurate interpretation of results is critical due to physiological variations and potential cross-interferences.

    Clinical Signs of Endocrine Disorders

    • Common signs include changes in coat appearance, thirst, urination, weight fluctuations, and altered appetite.
    • Recognizing overlapping clinical signs amongst different conditions (e.g., PPID vs. equine metabolic syndrome) is essential for accurate diagnosis.
    • Clinical pathology aids diagnosis but should be complemented with hormonal testing and imaging for comprehensive evaluation.### Hyperadrenocorticism Overview
    • Secondary hyperadrenocorticism, primarily caused by an ACTH-producing pituitary adenoma, accounts for 80-85% of Cushing’s cases in dogs.
    • Corticosteroid administration can induce iatrogenic hyperadrenocorticism.

    Clinical Signs of Cushing’s Syndrome

    • Common symptoms include polyuria (PU), polydipsia (PD), polyphagia, weakness leading to a pot-bellied appearance, and hepatomegaly due to glycogen accumulation.
    • Alopecia affects over 90% of dogs with Cushing’s; calcinosis cutis is present in approximately 40% of cases.
    • Affected dogs exhibit increased susceptibility to skin, urinary tract, and respiratory infections.

    Clinical Pathology Findings

    Haematology

    • Leukocytosis with stress leukogram: mature neutrophilia, lymphopenia, eosinopenia, monocytosis.
    • Neutrophilia and monocytosis arise from reduced margination and emigration; lymphopenia from steroid-induced lymphocytolysis.

    Biochemistry

    • Significant increase in alkaline phosphatase (ALP) seen in ~95% of patients; levels can be 5-40 times normal.
    • Mild elevation of ALT due to hepatomegaly; increased cholesterol and triglycerides from glucocorticoid effects on fat metabolism.
    • Elevated glucose levels result from increased gluconeogenesis and insulin antagonism.

    Urinalysis

    • Urine specific gravity (SG) varies but is typically less than 1.007; urinary tract infections are common.
    • Collect urine before hospitalization to minimize stress-related changes.

    Screening Tests for Hyperadrenocorticism

    • Testing should be postponed if an animal is seriously ill due to confounding results from concurrent diseases.
    • Candidates for testing include dogs with suggestive history, physical exam findings, pituitary tumors, and those with difficult-to-manage diabetes.

    Diagnostic Tests

    Urinary Cortisol:Creatinine Ratio (UCCR)

    • Simple screening test; sensitivity improves with home-collected urine samples.
    • A positive result requires further confirmation with LDDST or ACTH stimulation test.

    Low Dose Dexamethasone Suppression Test (LDDST)

    • First-choice screening test, unless iatrogenic Cushing’s suspected; involves blood sampling before and after dexamethasone administration.
    • Normal dogs suppress cortisol; dogs with Cushing’s do not exhibit expected suppression.

    ACTH Stimulation Test (ACTH stim)

    • Gold standard for diagnosing iatrogenic hyperadrenocorticism; measures adrenal cortex response to synthetic ACTH.
    • Sensitivity ranges from 57-95%, lower in dogs with adrenal tumors.

    Discriminatory Tests

    • Important to differentiate between pituitary-dependent hyperadrenocorticism (PDH) and adrenal-dependent hyperadrenocorticism (ADH).
    • High Dose Dexamethasone Suppression Test (HDDST), ACTH concentration, and ultrasonography are utilized for differentiation.

    High Dose Dexamethasone Suppression Test (HDDST)

    • High doses suppress ACTH secretion from pituitary microadenomas; non-functioning adrenal tumors do not show suppression.

    ACTH Measurement

    • Accurate differentiating test, but currently unavailable in some regions; requires precise sample handling and storage.

    Ultrasound

    • Useful for distinguishing PDH and ADH; in PDH, adrenal glands are symmetrical; ADH presents asymmetrical glands with possible tumor invasion.

    Hyperadrenocorticism in Cats

    • Mostly pituitary-dependent (approximately 80%); common clinical signs include PU/PD, abdominal enlargement, polyphagia, and skin atrophy.
    • Clinical pathology shows unremarkable haematology or stress leukogram; hyperglycaemia is prevalent.

    Adrenal Neoplasia in Ferrets

    • Commonly caused by adrenocortical adenomas leading to progressive alopecia; excess estrogen may cause bone marrow suppression.

    Phaeochromocytoma

    • Tumors of the adrenal medulla, often non-functional; when functional, they can result in severe cardiovascular symptoms.
    • Malignant forms may invade local structures including the caudal vena cava.

    Adrenocortical Atrophy and Hypoadrenocorticism

    • Caused by destructive lesions in the pituitary or idiopathic atrophy in dogs; results in glucocorticoid and mineralocorticoid deficiencies.
    • Addison’s disease presents with numerous clinical signs including weakness and dehydration.

    Hypoadrenocorticism Clinical Pathology

    Haematology

    • May show mild non-regenerative anemia and an atypical leukogram with lymphocytosis.

    Biochemistry

    • Prerenal azotaemia due to low sodium retention; electrolyte imbalances commonly include hyperkalaemia and hyponatraemia.
    • A Na:K ratio of less than 25:1 strongly suggests hypoadrenocorticism.

    Screening Tests

    • Basal cortisol is typically decreased; the ACTH stimulation test confirms diagnosis by demonstrating lack of cortisol response.

    Atypical Addison’s Disease

    • Some dogs present with nonspecific signs without classic electrolyte abnormalities; may eventually develop classical Addison’s with time.

    Other Adrenal Lesions

    • Nodular cortical hyperplasia is a common incidental finding in older dogs, often non-pathological and not requiring treatment.

    Lipids, Cholesterol, and Endocrine Diseases

    • Plasma lipids include triglycerides and cholesterol; important for energy metabolism and cell structure.
    • Hyperlipidaemia refers to increased circulating lipids; lipaemia indicates visible turbidity in blood samples.### Lipaemia and Lab Tests
    • Lipaemia affects spectrophotometric lab tests, leading to falsely elevated glucose, albumin, phosphorus, and bilirubin levels, while total protein and albumin results may appear decreased.

    Causes of Hyperlipidaemia

    • Postprandial hyperlipidaemia is common in cats and dogs, resulting in increased triglycerides 1-2 hours post-meal, peaking at 6-8 hours; fasting for 12 hours before a blood sample can prevent this.
    • Endocrine diseases such as hypothyroidism, diabetes mellitus, hyperadrenocorticism, and acromegaly cause hyperlipidaemia due to reduced LDL receptor activity, decreased biliary cholesterol excretion, and insulin resistance.
    • Cholestasis results in reduced hepatic cholesterol uptake and impaired bile cholesterol excretion.
    • Pancreatitis increases cholesterol synthesis and causes cholestasis, affecting lipid metabolism.
    • Nephrotic syndrome leads to proteinuria and hypoalbuminaemia, causing hypercholesterolaemia through urinary loss of enzymes and impaired hepatic function.
    • Primary hyperlipidaemia occasionally seen in certain dog breeds (e.g., miniature schnauzers) linked to genetic defects in lipid metabolism.
    • Anorexia, particularly in horses and cats, can cause hyperlipidaemia and hepatic lipidosis due to negative energy balance and increased free fatty acid mobilization.

    Thyroid Glands Anatomy and Function

    • The thyroid gland typically has two lobes on either side of the trachea in most animals; dogs typically have the right gland cranial to the left.
    • Histology reveals cells lining large colloid-filled follicles; hormone synthesis occurs mainly in these follicles.
    • Thyroglobulin synthesizes T3 (triiodothyronine) and T4 (thyroxine); T4 production is about 20 times higher than T3.

    Thyroid Hormone Regulation

    • The hypothalamic-pituitary-thyroid axis regulates thyroid hormone production; low levels trigger TRH release, stimulating TSH from the pituitary, thereby stimulating thyroid hormone synthesis.
    • T4 is mainly bound to proteins like albumin, with about 1% of T4 being 'free' T4; T3 is primarily bound to albumin.

    Physiological Effects of Thyroid Hormones

    • Thyroid hormones increase basal metabolic rate, protein synthesis, glucose metabolism, lipid breakdown, cholesterol conversion to bile acids, and cardiac function.

    Parafollicular Cells

    • Parafollicular or C cells produce calcitonin which, in response to high blood calcium levels, promotes calcium excretion and inhibits osteoclast activity.

    Hypothyroidism in Dogs

    • Most common endocrinopathy in dogs, often over-diagnosed; true prevalence uncertain.
    • Primary hypothyroidism (95% cases) mainly results from lymphocytic thyroiditis or idiopathic thyroid atrophy; secondary hypothyroidism occurs due to pituitary tumors.
    • Commonly observed in purebred dogs (e.g., Golden Retrievers, Boxers).

    Primary Hypothyroidism Pathophysiology

    • Lymphocytic thyroiditis involves lymphocyte infiltration and cell destruction; clinical signs appear after 75% gland destruction.
    • Idiopathic thyroid atrophy results in thyroid follicle degeneration; often appears unrelated to lymphocytic thyroiditis.

    Clinical Signs of Hypothyroidism

    • Symptoms include lethargy, weight gain, cold intolerance, skin issues, hair loss, and variable combinations of these signs; can mimic aging.

    Clinical Pathology in Hypothyroidism

    • Normocytic normochromic anaemia present in ~40% of cases.
    • Common biochemistry findings include hypercholesterolaemia and hypertriglyceridaemia due to decreased hepatic lipoprotein metabolism.

    Testing and Diagnosis

    • Total T4 is a key parameter for thyroid function assessment; it is sensitive but not specific for hypothyroidism.
    • Low T4 may occur in non-thyroidal illnesses (euthyroid sick syndrome) and various medications must be considered.

    Confirmatory Testing

    • TSH levels increase in primary hypothyroidism due to reduced negative feedback; concurrent non-thyroidal illness can suppress TSH levels.
    • Free T4 is the active hormone and is less affected by external factors; it is typically low in hypothyroid dogs but may be impacted by some medications.

    Treatment Monitoring

    • Serum TT4 is monitored at specific intervals after starting therapy or adjusting doses to assess treatment efficacy.

    Goitre and Thyroid Hyperplasia

    • Goitre refers to thyroid enlargement from nutritional deficiency or goitrogenic substances, particularly common in animals with iodine deficiency.
    • Multifocal nodular hyperplasia occurs mostly in older cats, dogs, and horses, with cats being prone to hyperthyroidism.

    Hyperthyroidism in Cats

    • Most common endocrinopathy, affecting mainly elderly cats; often undetermined if due to hyperplasia or adenoma formation.
    • Clinical signs include weight loss, increased appetite, hyperactivity, and potential complications like systemic hypertension and cardiac issues.

    Importance of Laboratory Testing

    • Laboratory tests are critical for accurate diagnosis, as many clinical signs are non-specific and may overlap with other diseases.

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    Description

    This quiz provides an overview of endocrine glands, focusing on their structure, function, and the role of hormones in the body. Learn how these specialized cells release hormones into the bloodstream and their effects on target organs. Test your understanding of the mechanisms that maintain hormonal balance in the body.

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