Pituitary Endocrine Disorders Flashcards
(41 cards)
1
Q
OBJ: Know and understand the clinical signs and pathophysiology of Acromegaly
A
- Unregulated diabetes (PU/PD/PP)
- Broad face, prominent jowls
- Large body size
- thick skin on head, neck, limbs
- heart failure signs
- arthritis/arthropathy
2
Q
OBJ: Know and understand the clinical signs and pathophysiology of Diabetes Insipidus (DI)
A
- excessive thirst
- water-seeking
- increase urine production
- encephalopathy
3
Q
OBJ: Know and understand the key clinical and laboratory features of Acromegaly
A
- Hyperphosphatemia without azotemia
- Hyperglobulinemia
- elevated ALP and ALT
- Proteinuria/Hyposthenuria
- periarticular periosteal proliferation
- Hyperostosis of the skull
- Cardio-, hepato-, and renomegaly
4
Q
OBJ: Know and understand the key clinical and laboratory features of Diabetes Insipidus
A
5
Q
OBJ: Know and understand the diagnostic tests used to confirm Acromegaly
A
- Hormone assessment
- GH - not useful do to fluctuations and availability
- Insulin-like Growth Factor 1
- liver response to GH
- reflects GH 24hr prior - Elevated in Acro
6
Q
OBJ: Know and understand the diagnostic tests used to confirm Diabetes Insipidus
A
- Monitor water intake for 24hr
- obtain serial plasma and urine osmolality
- Determine response to Osmotic stimulus and ADH
- Water deprivation test
- DDAVP response test (ADH analogue)
7
Q
OBJ: Know and understand the treatment options for Acromegaly
A
- Radiation - TOC cats
- Hypophysectomy
- Medical management
- pasireotide
- supportive care
8
Q
OBJ: Know and understand the treatment options for Diabetes Insipidus (DI)
A
- provide water
- intranasal DDAVP
- Monitor for over/under treatment
9
Q
What is Acromegaly?
A
- “Hypersomatotrophism”
- Chronic excess GH secretion
- GH (growth hormone) aka somatotrophin
- Causes overgrowth of soft tissues, bones, and viscera (anabolic) and insulin resistance (catabolic
- RARE
10
Q
What is the etiology of Acromegaly in cats?
A
- ACRO caused by GH producing pituitary tumor
- Macroadenoma of the pituitary somatotrophs
- Functional, benign tumor; locally expansive; rare distal metastasis
11
Q
What is the etiology of Acromegaly in Dogs?
A
- Excess progestin compounds
- Exogenous or endogenous PROG stimulates GH secretion
- Medroxyprogesterone (MPA; Depo-Provera) most commonly implicated
12
Q
What is the common signalment/history of patients with Acromegaly
A
- Geriatric males over-represented (mean age 10yo)
- Unregulated diabetes (PU/PD/PP) - historical or at initial presentation
13
Q
What are the common physical exam findings of a patient with Acromegaly?
A
- Pronounced physical changes
- Broad face, prominent jowls
- Protruding jaw (prognathia), enlarged interdental spaces
- Large body size, distended abdomen
- Thick skin on head, neck, limbs (dogs)
- Weight gain (*despite diabetes mellitus)
- Heart failure signs (tachycardia, dyspnea)
- Arthritis/arthropathy
- Neurological signs (abnormal mentation, depression
14
Q
Which hormones can be assessed for an Acromegaly diagnosis? which is the most useful?
A
- GH
- IGF-1 - MOST useful
15
Q
Why isn’t GH as useful for diagnostics
A
- Should be most useful, but
- GH level fluctuates over the day and disease stage
- GH assays not regularly available
- GH level rarely determined in dogs and cats
16
Q
Why is IGF-1 most useful
A
- IGF-1 is produced in the liver in response to GH
- IGF-1 level reflects GH secretion for 24 hr prior and is ELEVATED in Acromegaly
- Some poorly-regulated diabetic cats have elevated IGF-1 levels that overlap with Acromegaly cats
- very high level strongly suggests Acromegaly
- Feline and Canine IGF-1 assays are offered by several commercial labs
17
Q
What Laboratory Findings are common for patients with Acromegaly?
A
- CBC - erythrocytosis
- CHEM:
- changes caused by diabetes - hyperglycemia, hypercholestrolemia
- Elevations in ALP and ALT
- Hyperglobulinemia
- Hyperphosphatemia without Azotemia
- Renal failure present in some cats: azotemia and hyperphosphotemia
- Urinalysis:
- Proteinuria
- Hyposthenuria
- Ketonuria is uncommon
18
Q
What findings are common during imaging of patients with acromegaly?
A
- Enlarged soft tissues of head and neck
- Periarticular periosteal proliferation
- Elongated mandible
- Hyperostosis of the skull
- Cardio-, hepato- and renomegaly
19
Q
What are the treatment options for Acromegaly?
A
- Radiation - TOC in cats
- mixed results; improvement over months
- Hypophysectomy
- some success w/ surgical removal of tumor; limited experience/availability
- Medical Management
- Pasireotide (somatostatin analogue) - shows promise in European studies $$$
- Others - bromocriptine, octreotide
- Not useful in cats
- Supportive therapy - address diabetes, heart failure, renal insufficiency
20
Q
What is the prognosis for patients with Acromegally?
A
- Guarded to poor
- survival is 18 - 36 monthsd
21
Q
How is Diabetes Mellitus regulated in cats with Acromegally?
A
- Same treatment principles as other diabetic cats
- Ketosis is uncommon
- Large doses of insulin may be needed
- May never get complete control
- Affected cats are at risk for DM complications
22
Q
What is Diabetes Insipidus (DI)?
A
- RARE disorder
- Caused by ADH deficiency
- ADH - Anti-diuretic hormone (aka “AVP”)
- Produced from posterior pituitary
- Main hormone involved in water balance
- ADH deficiency = POLYURIA (increased urine volume)
23
Q
What are the different types of Canine Diabetes Insipidus (CDI)?
A
- Complete - NO ADH secretion
- Partial - Insufficient amounts of ADH
24
Q
What are the causes of Canine Diabetes Insipidus?
A
- Congenital - genetic/developmental
- Acquired - various causes
- intracranial tumor
- Metastatic tumor
- Infiltrative disease
- Infection
- Head trauma
- pituitary surgery
25
What are the clinical signs of CDI?
* Excessive thirst
* water-seeking behavior
* Increased urine production
* Encephalopathy - ill animals
* Signs of primary disease (acquired CDI)
26
What Laboratory findings are common in CDI?
* Hydrated animals:
* Typically normal
* Dilute USG (\<1.008)
* Dehydrated animals:
* Hypernatremia (severe)
* Neurologic impairment
* Azotemia (pre-renal)
* Dilute USG (\<1.008)
27
What are the common differential diagnoses for CDI?
* Primary Polydipsia (PP)
* young, hyperactive, excitable dogs
* Environmental/physical stressors
* Resolution occurs in novel situations
* Nephrogenic Diabetes Insipidus (NDI)
* Acquired water imbalance - secondary to other disorders (e.g. hypercalcemia, renal failure)
* “ADH” resistance
* Normal ADH productions
* Kidney is insensitive to ADH
28
How is CDI diagnosed?
* Quantitate 24-hr water intake
* Obtain serial plasma and urine osmolality
* Determine response to osmotic stimulus and ADH
* water deprivation test
* DDAVP response test (ADH analogue)
29
What is the treatment for CDI?
* Ensure adequate access to water at all times
* Intranasal DDAVP formulation
* 1 drop q12 hors into conjunctival sac
* Monitor to ensure patient is not over/under treated
30
What is the prognosis for CDI?
* Good for congenital CDI
* as long as the owner is aware and willing to treat
* Guarded/Poor for acquired CDI
* depends on primary pathology
31
What is the common signalment in dogs with acromegaly?
* Intact females (mean 7-8yo)
* young dogs receiving MPA
32
What history is common to dogs with Acromegaly
* Respiratory stridor, panting, fatigue
* Hx of MPA administration or estrus cycling
* Occasionally diabetes is present
* Less common: vaginitis, pyometra, skin and joint changes
33
How is acromegaly diagnosed in dogs?
* Based on history of progesterone exposure
34
What is the treatment for canine Acromegaly?
* Medical management (TOC)
* Discontinue exogenous progestin or perform ovariohysterectomy
* All organ and tissue changes are expected to resolve over time
* Diabetes in dogs with ACRO can resolve
* Diabetes never resolves in some dogs and insulin is needed for life
* Prognosis - good with appropriate therapy
35
What is Pituitary Dwarfism?
* “Hypopituitarism”
* Extremely Rare
* German shepherd dogs are most commonly affected
36
What is the etiology and pathology of Pituitary Dwarfism?
* Genetic defect - genes unknown
* Autosomal recessive in GSD - unknown in other breeds
* Histology:
* pituitary hypoplasia (anterior lobe)
* Pituitary cysts - may be cause for consequence of hypoplasia
37
What clinical signs are common in Pituitary dwarfism dogs?
* Growth retardation - noticed at a young age, concern about poor growth
* Hair/coat abnormalities - retained puppy coat; alopecia may occur over time
* Determatopathy - hyperpigmentation and dry skin/scaling
* Reproductive abnormalities - cryptorchidism and anestrus
* Normal activity with lethargy developing later in life
38
How is Hypopituitarism diagnosed?
* Requires measurement of abnormal GH secretion
* Basal GH level test - typically low but inconsistent (NOT recommended)
* GH stimulation test:
* assess GH secretion after injection of GH secretogogue
* Normal dogs = 2-4x increase
* Not widely available
* Ancillary Testing - needed for full patient evaluation
* Assess thyroid, adrenal, and reproductive function
* Pituitary imaging - Brain CT/MRI
* small pituitary/cystic structures
39
How is Hypopituitarism treated?
* Optimal = GH replacement
* Canine/Feline GH is not commercially available for hormone replacement
* Porcine GH has bee used for dogs
* Hypoglycemia and diabetes are potential side effects
* Progestins may provide alternative therapy - not studied
40
What responses are expected from treatment of hypopituitarism?
* Growth may occur - depending on the status of the growth plates
* Improvement in skin and coat
41
What is the prognosis of Hypopituitarism?
* Poor w/out treatment
* Guarded w/ treatment
