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)
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1
Q

Adenohypophyseal aplasia (dogs/cattle)

A
  • 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
Q

Hyperadrenocorticism (Cushing’s) - Clinical signs

A
  • usually a disease of older dogs
  • PU/PD
  • alopecia/skin disease
  • polyphagia/weight gain
  • pot belly
  • acute dyspnea –> puimonary thromboembolism
3
Q

Hyperadrenocorticism (Cushing’s) - Clin Path

A
  • Stress leukogram
  • thrombocytosis
  • mild hyperglycemia
  • hypercholesterolemia
  • marked elevation in ALP
4
Q

Hyperadrenocorticism (Cushing’s) - Gross Pathologic Findings

  • Adrenal glands
  • Kidneys
  • Pit gland
  • Vessels (arteries)
  • Liver
  • Dermal condition
A
  • 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
Q

Hypoadrenocorticism (Addison’s) - Clinical presentation

A
  • Intermittent or waxing/waning signs
  • Lethargy, collapse
  • Commonly young adult dogs
6
Q

Hypoadrenocorticism (Addison’s) - Clin Path

A
  • Mild, non-regenerative anemia
  • lack of a stress leukogram***
  • Hypoglycemia
  • Hyperkalemia
  • Hyponatremia/hypochloremia
  • Azotemia + minimally concentrated urine
  • Na:K ratio is < 25:1
7
Q

Hypoadrenocorticism (Addison’s) - Gross pathologic findings

A

Adrenocortical atrophy!

8
Q

Hypoadrenocorticism (Addison’s) - Pathogenesis

A
  • 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
Q

What is the key feature of hypoadrenocorticism

A

Lack of stress leukogram

10
Q

Equine PPID - Causes (MD’s)

A
  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
Q

Equine PPID - Pathogenesis

A
  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
Q

Feline acromegaly

A
  • 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
Q

Feline acromegaly - Clin Path

A
  1. Hyperglycemia
  2. Stress leuk + mild erythrocytosis
  3. Elevated liver enzymes
  4. Hyperphosphatemia w/out renal azotemia, mild proteinuria
  5. Marked glucosuria
14
Q

Feline acromegaly - PE findings

A
  • Oval shaped eyes
  • Broadening of the maxilla
  • large paws
15
Q

Feline acromegaly - MD

A
  • Pituitary acidophil adenoma –> very treatable with tumor irriadiation
  • Diffuse islet cell degeneration with amyloidosis –> hyperglycemia
  • Proliferative and sclerosing glomerulonephropathy –> proteinuria
16
Q

Feline acromegaly - Pathogenesis

A
  • Acquired excess of GH due to adenoma of the pituitary
  • Uncontrolled diabetes is typical presentation
  • GH mediated insulin resistance
  • Beta cell exhaustion
17
Q

Adrenal associated endocrinopathy - Ferrets

Clinical presentation

A
  • long-term “skin disease”
  • palpable abdominal mass
  • weak with pale mm
  • CBC: non-regenerative anemia, thrombocytopenia and leukopenia
18
Q

Adrenal associated endocrinopathy - Ferrets

Morph Diagnoses

A
  • Adrenal cortical carcinoma/adenoma
  • Diffuse myeloid and erythroid aplasia
  • Prostatic cysts or diffuse cystic squamous metaplasia
19
Q

Adrenal associated endocrinopathy - Ferrets

Pathogenesis

A
  • 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
Q

Pheochromocytoma

Clinical Presentation

A
  • Dyspnea
  • acute onset blindness, bilateral mydriasis, hyphema of the eye
  • tachyarrhythmias
  • mild hyperglycemia (only chem abnormality)
21
Q

Pheochromocytoma

Morphologic Diagnoses

A

1, Adrenal carcinoma

  • very aggressive, invasive
  • tumor emboli are common –> lungs = dyspnea
  1. Hypertrophic cardiomyopathy –> hypertrophy with dilation –> DCM
    - low grade catecholamine release impacts the heart
    - myocardial infarctions (small) –> tacchyarrhythmias
22
Q

Pheochromocytoma

Pathogenesis

A
  • 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
Q

Waterhouse-Friderichsen Syndrome

A
  • 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
Q

Heart-base tumors

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