PUPD + other Endocrine disorders

Question 1

What are the main Ddx for PUPD?

Answer 1

• Diabetes insipidus
• Osmotic diuresis
• Iatrogenic
• Renal medullary washout - loss of hypertonicity of medulla because of long term PUPD
• Primary polydipsia - problem of thirst centre of brain

Question 2

What can cause diabetes insipidus?

Answer 2

• Central DI
• Primary NDI
• Secondary NDI =
  -Renal failure
  -Hyperadrenocorticism
  -Pyometra
  -Hypercalcaemia
  -Hyperthyroidism
  -Pyelonephritis
  -Hypoadrenocorticism
  -Liver failure
  -Hypokalaemia
  -Acromegaly

Question 3

What can cause osmotic diuresis?

Answer 3

• Diabetes mellitus
• Primary renal glucosuria
• Fanconi’s syndrome - glucose + amino acids in urine
• Post-obstructive diuresis

Question 4

What are iatrogenic reasons for PUPD?

Answer 4

• Glucocorticoids
• Diuretics
• Phenobarbitone
• High salt diet
• Levothyroxine
• Vitamin D toxicity

Question 5

What classes as polydipsia?

Answer 5

• drinking >100ml/kg/day

Question 6

What would you initial work-up for PUPD be?

Answer 6

• History (rule out iatrogenic)
• Physical examination (evidence of renal dz, pyometra…)
• Haematology (evidence of pyometra / pyelonephritis?)
• Biochemistry (hyperCa? hypoNa? renal disease? diabetes?)
• Bile acids (liver disease?)
• T4 (hyperthyroidism?)
• Urinalysis (diabetes, Fanconi’s, renal glucosuria?. Culture to rule out pyelonephritis
• Rule out cushings = dexamethasone suppression test
• Differentiate CDI, primary NDI + primary polydipsia with DDAVP (desmopressin test)

Question 7

What hormones are release from the hypothalamus?

Answer 7

• TRH
• GnRH
• CRH
• PRH
• Dopamine
• Somatostatin

Question 8

What hormones are released from pituitary gland?

Answer 8

• Anterior lobe = (FLAT PEG)
• TSH
• FSH / LH
• GH
• Prolactin
• Endorphins
• ACTH
• Posterior lobe =
• Oxytocin
• Vasopressin (ADH)

Question 9

What is the pathogenesis of pituitary dwarfism?

Answer 9

• Rare congenital lesion (developmental defect in pituitary gland)
• Almost exclusive GSDs
• Failure of GH secretion
• Isolated GH deficiency or combined deficiency
• FSH, LH, TSH

Question 10

What are clinical features of pituitary dwarfism?

Answer 10

• Proportionate dwarfism
• Failure to develop adult coat
• Delayed dental eruption
• Delayed growth plate closure
• Thin, fragile, hyperpigmented skin
• Pyoderma
• Immature gonads

Question 11

How is pituitary dwarfism diagnosed + treated?

Answer 11

• Dx = rule out other causes of retarded growth,
• Dynamic test to assay GH
• Tx = Progestagens = induce GH secretion - adverse effect
• GH - adverse effects
• Do NOT breed

Question 12

What is pathogenesis of acromegaly?

Answer 12

• Excess growth hormone
• cats = pituitary tumour (Older males)
• dogs = mammary tissue (intact females)

Question 13

What are clinical features of acromegaly?

Answer 13

• Insulin resistant DM
• Excessive growth of the extremities
• Prognathism, wide interdental spaces
• Soft tissue proliferation

Question 14

Dx + Tx of acromegaly?

Answer 14

• Dx =
• Diabetes mellitus
• Liver enzyme elevation
• Elevated IGF-1
• MRI/CT
• Tx = Bitch = OVH / stop progestagens (bony changes irreversible)
• Cat = attempt to control DM, surgery, radiation

Question 15

What is central diabetes insipidus?

Answer 15

• Complete / partial deficiency in ADH
• renal collecting tubules = impermeable to water
• Neoplasia / trauma of hypothalamus / posterior pituitary = cause

Question 16

What does PTH do?

Answer 16

• Increase calcium reabsorption from kidneys
• increase calcium release from bones
• Increase absorption of dietary calcium in SI

Question 17

What is primary hyperparathyroidism? What does it cause? Dx? Tx?

Answer 17

• Functional tumour producing PTH
• Causes hypercalcaemia =
• PUPD
• dehydration
• dystrophic calcification
• Renal damage (AKI)
• Dx =
• High total calcium and iCa
• Normal to low PO4
• High or normal PTH
• Detect mass in thyroid/parathyroid area
• Tx = restore normal calcium level + surgical removal of parathyroid tumour

Question 18

What is secondary hyperparathyroidism?

Answer 18

• Renal secondary hyperparathyroidism
• Nutritional - unbalanced diet

Question 19

What is pseudohyperparathyroidism?

Answer 19

• Caused by tumour secreting PTH-rp
• Anal sac adenocarcinoma

Question 20

What is hypoparathyroidism? CS? Dx? Tx?

Answer 20

• Failure to produce PTH
• CS = hypocalcaemia =
• Anxiety
• Muscle twitching, spasm, tetany
• Weakness, ataxia
• Seizures
• Tachycardia, weak pulses
• Dx = Low calcium + high PO4, Low PTH
• Tx = EMERGENCY = IV fluids + calcium gluconate
• maintenance = oral calcium + Vit. D

Question 21

What are differentials for hypocalcaemia?

Answer 21

• Hypoalbuminemia (low total Ca, ionised Ca normal)
• CKD
• AKI
• Eclampsia (puerperal tetany)
• Acute pancreatitis

Question 22

What are pancreatic endocrine diosrders?

Answer 22

• Insulinoma - functional tumour of pancreatic B-cells producing insulin = hypoglycaemia
• Gastrinoma - tumour producing gastrin = gastric hyperacidity + risk of ulceration + can have severe signs

Question 23

CS, Dx + Tx of insulinoma?

Answer 23

• CS =
• Often episodic (fasting, exercise, excitement)
• Weakness, trembling, ataxia, seizures
• +/- other neurological signs
• May have weight gain
• Dx = Persistent hypoglycaemia, Normal glucose does not exclude, Elevated insulin, Pancreatic mass
• Tx = IV glucose if needed, frequent small meals, prednisolone, surgery

Question 24

Dx + Tx of gastrinomas?

Answer 24

• Dx = Elevated gastrin levels, imaging, endoscopy
• Tx = surgical removal - BUT frequent metastases

Question 25

What are signs of phaechromocytoma? Dx? Tx?

Answer 25

* CS = - anxiety - tachycardia - tachypnoea - vomiting - diarrhoea - weight loss - hypertension (retinal detachment) * Dx = US + urinary / plasma metanephrines * Tx = Radical excision - BUT frequent metastases

Question 26

What are signs of hyperaldosteronism? Tx?

Answer 26

* Adrenal tumour producing aldosterone = CS = * PUPD * weakness * neck ventroflexion (hypokalaemia) * hypertension (sodium retention) * Tx = * restrict sodium and supplement potassium * surgical excision * spironolactone (aldosterone antagonist) Hyperaldosteronism