Ex 4 - Pathology of Pit and Adrenal Glands Flashcards Preview

742 - Biology of Disease III > Ex 4 - Pathology of Pit and Adrenal Glands > Flashcards

Flashcards in Ex 4 - Pathology of Pit and Adrenal Glands Deck (24):
1

Adenohypophyseal aplasia (dogs/cattle)

- fetus is unable to produce cortisol --> fetal stress is the signal for parturition to occur

- caused by ingested toxins, e.g. Verratrum californium

- Development/growth ceases in late term pregnancy --> gestation continues well beyond term

2

Hyperadrenocorticism (Cushing's) - Clinical signs

- usually a disease of older dogs
- PU/PD
- alopecia/skin disease
- polyphagia/weight gain
- pot belly
- acute dyspnea --> puimonary thromboembolism

3

Hyperadrenocorticism (Cushing's) - Clin Path

- Stress leukogram
- thrombocytosis
- mild hyperglycemia
- hypercholesterolemia
- marked elevation in ALP

4

Hyperadrenocorticism (Cushing's) - Gross Pathologic Findings

* Adrenal glands
* Kidneys
* Pit gland
* Vessels (arteries)
* Liver
* Dermal condition

* Bilateral enlargement of adrenal glands
- = diffuse adrenocortical hyperplasia
- this means the disease is in the pituitary!

* Kidney capsules may be hemorrhagic, due to thrombotic events
- = acute renal infarction

* Pituitary adenomas are common
- carcinomas are less common
- 85% of dogs with Cushing's are pituitary-dependent
- 15% of dogs are adrenal dependent --> one gland is hypertrophic, the other is atrophied

* Arterial thrombi
- adhered to vessel wall, granular surface, dull, laminar on cross-section
- cortisol prevents production of antithrombins --> hyper coagulable state

* Hepatomegaly

* Multifocal dermal mineralization (Calcinosis cutis)

5

Hypoadrenocorticism (Addison's) - Clinical presentation

* Intermittent or waxing/waning signs
* Lethargy, collapse
* Commonly young adult dogs

6

Hypoadrenocorticism (Addison's) - Clin Path

* Mild, non-regenerative anemia
* lack of a stress leukogram***
* Hypoglycemia
* Hyperkalemia
* Hyponatremia/hypochloremia
* Azotemia + minimally concentrated urine
* Na:K ratio is < 25:1

7

Hypoadrenocorticism (Addison's) - Gross pathologic findings

Adrenocortical atrophy!

8

Hypoadrenocorticism (Addison's) - Pathogenesis

- Suspected immune-mediated process

- adrenocortical atrophy
--> loss of aldosterone & cortisol
--> Na loss and K retention

- Often insidious onset with non-specific clinical signs
--> acute circulatory collapse may be most obvious sign
--> CV manifestations due to hyperkalemia and increased water loss

- Glucocorticoid synthesis decreased/lost
--> Hypoglycemia

- Azotemia due to loss of normal osmotic gradient --> dehydration

- Non-regenerative anemia
--> cortisol promotes erythropoiesis (no cortisol, no RBC production)

9

What is the key feature of hypoadrenocorticism

Lack of stress leukogram

10

Equine PPID - Causes (MD's)

1. Diffuse hypertrichosis

2. Pituitary adenoma of the pars intermedia
- poorly formed sella turcica bone in the horse --> compression of pit gland

3. Laminitis

11

Equine PPID - Pathogenesis

1. Idiopathic, age-related loss of dopamine inhibition

2. Increase secretion of POMC derivatives (MSH, and ACTH to a lesser extent)

3. Cortisol is a counter-regulatory hormone of insulin
- increased cortisol results in insulin resistance --> hyperglycemia

12

Feline acromegaly

* Acquired syndrome - occurs in older cats (usually tumor related)

* Results in widening and/or elongation of bones by appositional growth (physes are closed)

* Severe hyperglycemia
- growth hormone interfere with insulin pathways
- become severely diabetic and ill

13

Feline acromegaly - Clin Path

1. Hyperglycemia
2. Stress leuk + mild erythrocytosis
3. Elevated liver enzymes
4. Hyperphosphatemia w/out renal azotemia, mild proteinuria
5. Marked glucosuria

14

Feline acromegaly - PE findings

* Oval shaped eyes
* Broadening of the maxilla
* large paws

15

Feline acromegaly - MD

* Pituitary acidophil adenoma --> very treatable with tumor irriadiation

* Diffuse islet cell degeneration with amyloidosis --> hyperglycemia

* Proliferative and sclerosing glomerulonephropathy --> proteinuria

16

Feline acromegaly - Pathogenesis

* Acquired excess of GH due to adenoma of the pituitary
* Uncontrolled diabetes is typical presentation
- GH mediated insulin resistance
- Beta cell exhaustion

17

Adrenal associated endocrinopathy - Ferrets

Clinical presentation

* long-term "skin disease"
* palpable abdominal mass
* weak with pale mm
* CBC: non-regenerative anemia, thrombocytopenia and leukopenia

18

Adrenal associated endocrinopathy - Ferrets

Morph Diagnoses

* Adrenal cortical carcinoma/adenoma

* Diffuse myeloid and erythroid aplasia

* Prostatic cysts or diffuse cystic squamous metaplasia

19

Adrenal associated endocrinopathy - Ferrets

Pathogenesis

* Bilateral adrenocortical hyperplasia or neoplasia (carcinoma > adenoma)
- excess production of estradiol

* Clinical signs:
- symmetrical alopecia, vulvar swelling, mammary gland hyperplasia

* Occurs more in animals neutered at an early age (2-4 months)

* Pancytopenia as a result of marrow aplasia (poorly understood)

* High levels of estrogen --> prostatic squamous metaplasia in males
-- dysuria may result from enlarged prostate

20

Pheochromocytoma

Clinical Presentation

* Dyspnea
* acute onset blindness, bilateral mydriasis, hyphema of the eye
* tachyarrhythmias
* mild hyperglycemia (only chem abnormality)

21

Pheochromocytoma

Morphologic Diagnoses

1, Adrenal carcinoma
- very aggressive, invasive
- tumor emboli are common --> lungs = dyspnea

2. Hypertrophic cardiomyopathy --> hypertrophy with dilation --> DCM
- low grade catecholamine release impacts the heart
- myocardial infarctions (small) --> tacchyarrhythmias

22

Pheochromocytoma

Pathogenesis

* seen in cattle and dogs
* invasion into Vena Cave common with potential for tumor emboli
* Ca homeostasis implicated in development
* may result in retinal detachment
* cortisol and ACTH are often normal
(unilateral tumor of the adrenals)

23

Waterhouse-Friderichsen Syndrome

* Defined as adrenal gland failure due to bleeding into the adrenal glands
- occurs with Gram (-) endotoxemia = horses

* Diffuse necrosis of the adrenal glands

* Idiopathic pathogenesis

24

Heart-base tumors

* often endocrine related
* especially in brachycephalic dogs (chronic hypoxic state)
e.g. chemodectoma, hemangiosarcoma, ectopic thyroid tumor