Pituitary Disorders Flashcards
What clinical signs are associated with pituitary disorders?
Neurological signs referable to intracranial dysfunction (RARELY seizures)
Alterations in BCS, size and growth
Altered cycling, libido, fertility
PU/PD
What intracranial effects can pituitary disorders have ?
Various, non-specific rarely seizures
Depression under responsive to external stimuli
Behavioural changes
Symmetrical changes due to central location of pituitary
What is hypersomatotrophism?
What does it cause?
Increased GH production
Increased IGF1
Tissue proliferation -> phenotype changes
insulin resistance -> DM
What causes HST in dogs ?
Ovarian tumour -> Intact females ——now UNCOMMON due to early neutering
History of progestin administration
Describe some phenotype changes associated with HST.
Thick set facial features
Increased interdental spaces
Insulin resistance -> difficult to control DM
PUPD if DM
Does acromegaly always cause phenotypic changes?
NO
What should you do before you measure IGF-1 ?
Why?
Give insulin
Insulin required for liver to make IGF1
What are the clinical characteristics of feline hypersomatotrophism?
PU/PD Increased appetite prognathism Increased body size Organomegaly Insulin resistance DM
What happens if you leave HST untreated?
Develop HCM
What is the best treatment of acromegaly?
If not?
Hypophysectomy and replacement hormone therapy
Aggressive insulin treatment - long term instability
How common is HST in cats?
1 in 4 diabetic cats
How can you increase your index of suspicion for HST?
How can you confirm
Serum IGF
Demonstration of pit mass
What drugs are required after a hypophysecotomy long term?
Most off insulin within a month
Thyroxine SID
Cortisone SID
DDAVP (synthetic AVP)peri-ocularly SID
What is central diabetes insipidus?
Absolute vasopressin deficiency
Primary pituitary problem
What is nephrogenic DI?
Vasopressin “resistance”
A metabolic problem resulting in renal dysfunction
What are the clinical signs of central diabetes diabetes insipidus?
Marked and unrelenting polydipsia
Secondary polyuria
Otherwise unremarkable
What are the possible explanations of a polydipsic patient?
Primary polydipsia due to DI -> polyuria appropriate
Renal dysfunction and reduced concentrating ability
How can you investigate DI?
Hospitalise and observe USG less than 1.008 Urine osmolality and SG fixed and unchanging Water deprivation test Desmopressin response test
How do you perform a water deprivation test
Measure USG/osmolality before
Dehydrate patient - 5% body weight reduction or increased PCV
Measure USG/osmolality
- LOW in DI
Give desmopressin, measure USG/osmolality
- same in normal
- increase in DI
How do you treat central DI?
Conjunctival desmopressin SID/BID
Adjust based on patient response
Describe the appearance of a patient with hyposomatotrophism
Smaller animal with proportional stature
Non-chondrodystrophic
Sometimes have immature hair coat
Persistent oestrus, males infertile
Normal life expectancy
What can cause Hyposomatotrophism?
Adenohypophyseal malformation
GH deficiency
Gonadotropin deficiency
Thyrotrophin deficiency
What diagnostic aids can be used for hyposomatotrophism?
Serum IGF
Radiography- persistent epiphyseal plates
