Internal Medicine: Endocrine: Endocrine Disorders Flashcards
What are the differential diganoses of PUPD?
- Diabetes insipidus- central, primary, secondary
- Iatrogenic- glucocorticoids, diuretics
- Renal medullary washout
- Primary polydipsia
- Osmotic diuresis- diabetes, primary renal glucosuria, fanconi’s syndrome, post-obstructive diuresis
What are the different causes of diabetes insipidus?
- Central diabetes insipidus
- Primary nephrogenic diabetes
- Secondary nephrogenic diabetes insipidus- pyometra, renal failure, hypercalcaemia, cushing’s, hyperthyroidism, addison’s, pyelonephritis, liver failure, acromegaly, hypokalaemia
What are the different causes of osmotic diuresis?
- Diabetes mellitus
- Primary renal glucosuria
- Fanconi’s syndrome
- Post-obstructive diuresis
What iatrogenic causes can cause PUPD?
- Glucocorticoids
- Diuretics
- Phenobarbitone
- High salt diet
- Levothyroxine
- Vitamin D toxicity
- What causes renal medullary washout?
- What causes primary polydipsia?
- Loss of hypertonicity of medulla because of long term PUPD
- Problem of thirst centre in brain ‘psychogenic’ or behavioural
What is the definition of polydipsia in terms of values?
over 100ml/kg/day
How should PUPD be initially worked up?
If after the initial work up what diseases must it be?
- History- rule out iatrogenic
- Physical examination- renal disease, pyo
- Haematology- pyo/pyelonephritis
- Biochemistry- hyperCa, hypo Na, renal disease, diabetes
- Bile acids- liver disease
- T4- hyperthyroidism
- Urinalysis
If none of the above it must be:
* Hyperadrenocorticism
* Central diabetes insipidus
* Primary nephrogenic diabetes insipidus
* Primary polydipsia
- Following an initial work up to PUPD what needs to be excluded next?
- Following the above step what are the final tests done?
- Exclude Hyperadrenocorticism
- Water deprivation test, followed by response to exogenous DDAVP (synthetic vasopressin)
Vasopressin = ADH
What are the common pitfalls in workup of PUPD?
- Failure to confirm true PU/PD
- Disorganised approach
- Water deprivation test performed too early
Remember CDI and primary NDI are rare, HAC is common
How is central diabetes insipidus treated?
- DDAVP nasal drops applies into conjuntiva
- 1-4 drops once or twice daily
- Titrate to clinical signs
What are the different causes of poor growth?
- Nutritional- underfed/poor diet
- Physiological- mismate, breed variation
- GI- paratism, megaoeosphagus, EPI, chronic obstruction
- Cardiac- congenital, endocarditis
- Renal- dysplasia, polycystic
- Liver- shunts, hepatitis
- Lysosomal storage disease
What are the different endocrine causes of poor growth?
- GH deficiency
- Hypothyroidism
- Hypoadrenocorticsm
- Diabetes mellitus
Rare pituitary endocrinopathies
* Pituitary dwarfism
* Acromegaly
* Diabetes insipidus
Parathyroid
* Hyperpatathyroidism
* Hypoparathyroidism
What is the function of ACTH?
ACTH is adrenocortitropic hormone
responsible for controlling the production of cortisol by the adrenal glands
What hormones does the pituirary gland produce?
FLAT PEG
* FSH
* LH
* ACTH
* TSH
* Prolactin
* Endorphins
* GH
What causes pituirary dwarfism?
What are the clinical features?
How is it diagnosed?
- Rare congenital lesion
- Almost exclusive GSDs
- Failure of GH secretion
- Isolated GH deficiency or combined (FSH, LH, TSH)
Clinical features
* Proportionate dwarfism
* Failure to develop adult coat
* Delayed dental eruption
* Delayed growth plate closure
* Thin, fragile, hyperpigmented skin
* Pyoderma
* Immature gonads
Diagnosis:
* Routine testing notmal
* Rule out other causes
* Definitive: dynamic test to assay GH, IGF-1
How is pituitary dwarfism treated?
Progestagens
* Induced GH secretion from mammary tissue
* Adverse effects
GH
* Results usually disapointing
* Skin signs may improve
* Adverve effects
Check thyroid status
Do Not Breed
How is pituitary dwarfism treated?
Progestagens
* Induced GH secretion from mammary tissue
* Adverse effects
GH
* Results usually disapointing
* Skin signs may improve
* Adverve effects
Check thyroid status
Do Not Breed
- What is acromegaly?
- What is the source in Dogs
- What is the source in Cats
- What is the signlament in dogs/cats
- Excess growth hormone
- Cats- pituitary tumour
- Mammary tissue in response to progesterone/prostagens
- Cats- older males, Dogs- intact females (luteal phase)
What is the pathogenesis of acromegaly?
- Chronic excess GH leads to insulin antagonism and anabolic effects (IGF-1)
- Insulin antagnoism leads to diabetes mellitus
- Anabolic effects on organs, cartilage and bone
What are the clinical features of acromegaly?
- Insulin resistant DM
- Excessive growth of the extremities
- Prognathism, wide interdental spaces
- Soft tissue proliferation
How is acromegaly diagnosed and treated?
Diagnosis
* Diabetes mellitus
* Liver enzyme elevation
* Elevated IGF-1
* MRI/CT
Treatment
* Bitch- OVH (spay) or stop progestagens (Bony changes irreversible)
* Cat- attempt to control DM, surgery, radiation of pituitary mass
- What controls the secretion of parathyroid?
- What are the functions of parathyroid?
- Calcium controls the secretion
- Parathryoid increased Ca and PO4 by affecting osteoblasts, increases calcium reabsorption and decreases PO4, and causes calcitriol (active vitamin D) to increase absorption of Ca and PO4 from GI
- What causes primary hyperparathyroidism?
- What symptoms does it cause?
- Functional tumour producing PTH
- Causes hypercalcaemia- PUPD, dehydration, dystrophic calcification, renal damage (acute renal failure)
How can hyperparathyroidism be diagnosed?
- High total calcium and iCA (ionised calcium)
- Normal to low PO4
- High PTH
- Detect mass in thyroid/parathyroid area
How is hyperparathroid treated?
Restore normal calcium
* Fluids (0.9% NaCl)
* Frusemide (after rehy)
* Prednisilone
* Calcitonin
Surgical removal of parathyroid tumour- monitor Ca post-op
What can cause secondary hyperparathyroidism?
- Renal secondary hyperparathyroidism
- Nutritional secondary hyperparathyroidism- unbalanced diet
What is pseudo-hyperparathyroidism
Caused a tumour secreting parathyroid hormone related protein
What are the causes of primary and secondary hypoparathyroidism?
Primary- immune mediated
Secondary- surgery
Other then hypoparathyroidism what can cause low Ca2+?
- Hypoalbuminaemia
- CKD
- Puerperal tetany
- AKI
- Acute pancreatitis
What are the clinical signs of low calcium from hypoparathyroidism?
How is it diagnosed?
- Anxiety
- Muscle twitching, spasm, tetany
- Weakness, ataxia
- Seizures
- Tachycardia, weak pulses
Diagnosis- Low Ca, High PO4, low PTH
How is hypoparathyroid treated?
Emergency
* IV fluids
* IV/SC calcium gluconate
Maintenance
* Oral calcium
* Oral Vitamin D
