Endocrine diseases
Zona glomerulosa -- Aldosterone
Zona fasciculata - Cortisol …
Zona reticularis - Dihydroepiandrosterone
Adrenal medulla
Testosterone
Estradiol
E. Simko WCVM
Endocrine diseases
(Addison’s dz)
Most common in dogs
Clinical signs are predominantly due to lack of
aldosterone Na+ ClHO
2
Glomerular
filtrate
Epithelium of
distal nephron
H+
K+
E. Simko WCVM
Endocrine diseases
(Addison’s dz)
Most common in dogs
Clinical signs are predominantly due to lack of
aldosterone Na+ ClHO
2
Glomerular
filtrate
Epithelium of
distal nephron
H+
K+
E. Simko WCVM
Endocrine diseases - Hypoadrenocorticism
Clinical presentation:
• Hyponatremia, hypochloremia, dehydration
• Hyperkalemia, acidosis
• Weakness, depression
• Bradycardia
• Hypovolemia, shock
• “Great pretender”
E. Simko WCVM
Endocrine diseases - Hypoadrenocorticism
Diagnosis:
• Blood chemistry: Na, Cl, K
• CBC: PCV
• ACTH stimulation – no cortisol response
• Necropsy (if animal died)
E. Simko WCVM
Endocrine diseases
Most common in adult cats
Increased incidence since 1970
Awareness and detection
Change in life style of feline pets
Etiology:
Nodular thyroid hyperplasia
Functional thyroid adenoma
E. Simko WCVM
Endocrine diseases - Hyperthyroidism
Changes
• Palpable mass(es) in one or both glands
• Increased basal metabolism
• Weight loss
• Hyperactivity
• Cardiomyopathy (Usually hypertrophic)
• Tachycardia
• Weakness when stressed
E. Simko WCVM
Endocrine diseases - Hyperthyroidism
Diagnosis
• Clinical signs
• Palpable mass(es) in one or both glands
• Increased T4 & T3 blood concentration
E. Simko WCVM
Endocrine diseases
• Physiology and endocrinology is complex.
(Independent review)
• Pathology is relatively simple resulting in:
Excessive hormonal production
Insufficient hormonal production
• Most commonly these disorders are due to
proliferative lesions that are:
Functional and over produce hormones
Compressive and prevent normal production of
hormones
E. Simko WCVM
Endocrine diseases - Pituitary gland
Pituitary adenomas
• ACTH secreting Most common in dogs – Cushing’s dz
• Adenomas of pars intermedia
Most common in horses
Second most common in dogs
Endocrinologically inactive
ACTH secreting
• Endocrinologically inactive adenomas
Common in dogs, cats, and rodents
Compression
Pituitary dysfunction, CNS signs
E. Simko WCVM
Endocrine diseases - Pituitary gland
Pituitary adenomas in horses
• Pars intermedia origin
• Lesions are secondary to:
Thalamic compression
Production of beta endorphin
Probably due to ACTH
E. Simko WCVM
Endocrine diseases - Pituitary adenomas in horses
Thalamic compression results in:
• Intermittent pyrexia
• Hyperhidrosis (Increased sweating)
• Hirtuism (hypertrichosis)
• Polyphagia with huperglycemia and
glycosuria
• Polyuria/polydipsia
Production of beta endorphin
• Docility
• Diminished responsiveness to pain
E. Simko WCVM
Endocrine diseases - Pituitary gland
Diagnosis
• Clinical signs
• Glycosuria, glycemia
• ACTH / cortisol concentration
• MRI
E. Simko WCVM
Endocrine diseases – Calcium and Phosphorus
Major regulators of Ca and P:
• Parathyroid hormone
• Calcitonin (Thyroid C cells)
• Vitamin D
E. Simko WCVM
Endocrine diseases – Calcium and Phosphorus
Ca
PTH
promotion of:
• Ca reabsorption from bone
• P excretion by kidney
• Formation of active Vit D by kidney
• Ca absorption from gut and reabsorption
from renal tubules (minor)
serum Ca, serum P,
renal excretion of P
E. Simko WCVM
Endocrine diseases – Calcium and Phosphorus
Ca
Calcitonin
:
• Inhibition of PTH stimulated bone
absorption
• Increased P excretion by kidney
serum Ca, serum P
E. Simko WCVM
Endocrine diseases – Calcium and Phosphorus
(1,25-dihydroxycholecalciferol)
• Ca and P absorption by intestines
• May facilitate PTH action
E. Simko WCVM
Endocrine diseases – Calcium and Phosphorus
Extracellular fluid
Renal tubules
Urine
PTH +
Intestinal
Lumen
P
Calcitonin
Ca
Calcitonin
Vit D +
PTH +
Vit D +
PTH +
P
PTH +
Ca
Bone
Ca
E. Simko WCVM
Endocrine diseases – Calcium and Phosphorus
Major clinical conditions:
• Neoplasias
Lymphoma
Anal apocrine gland tumor (PTH-rP)
Tumors metastatic to bone
• Hyperparathyroidism
Parathyroid functional neoplasia
• Vitamin D toxicity
E. Simko WCVM
Endocrine diseases – Calcium and Phosphorus
Major clinical conditions:
• Hypoparathyroidism
Parathyroiditis
Iatrogenic – excision with thyroid glands
• Nutritional hyperphophatemia
• Renal failure
• Milk fever
• C-cell thyroid neoplasia
E. Simko WCVM
Endocrine diseases – Calcium and Phosphorus
Primary: Parathyroid tumors
Secondary:
Renal failure
Nutritional imbalance
E. Simko WCVM
Endocrine diseases – Calcium and Phosphorus
Secondary hyperparathyroidism:
Renal failure
GFR
Vit D
Hyperphosphatemia
Hypocalcemia
Nutritional
imbalance
( P, Ca)
Osteodystrophy
fibrosa
Ca reabsorption
from bone
Parathyroid hyperplasia
Increased production of PTH
E. Simko WCVM
We know NS 1:
• Describe basic structure, function and
response to injury of CNS and PNS
• Define nomenclature of neuropathological
terms and conditions
• Describe pathogenesis of Wallerian
degeneration and axonal regeneration
• Define terminology of CNS traumatic injury
We know NS 2:
You should be able to define, describe pathogenesis,
list lesions and know how to diagnose the following
conditions:
• Cytotoxic, osmotic and vasogenic brain edema)
• Thiamine-responsive polioencephalomalacia of
ruminants
• Thiamine deficiency in carnivores
• Lead Poisoning
• Salt Poisoning
• Toxin-induced vasogenic brain edema
We know NS 3:
You should be able to define, describe pathogenesis,
list lesions and know how to diagnose the following
conditions:
•Meningitis
•Rabies
•ITEME
•Distemper
•Listeriosis
•West Nile Viral encephalitis
•TSE
•Equine protozoal encephalomyelitis
We know Muscle 1:
Describe mechanisms of:
• Muscular regeneration
• Muscular repair
Define following conditions and give examples:
•
•
•
•
•
Denervation atrophy
Disuse atrophy
Malnutrition atrophy
Muscular hypertrophy
Ischemic myopathy
- Occlusion of the vascular system
- External pressure on a muscle
- Swelling of a muscle in a non-expandable
compartment
E. Simko WCVM
We know Muscle 2:
You should be able to define, describe pathogenesis,
list lesions and know how to diagnose the following
conditions/diseases:
•
•
•
•
•
•
•
•
•
Nutritional myopathy (White muscle disease)
Toxic myopathy (Monensin toxicity)
Exertional myopathy
Gas gangrene and malignant edema
Blackleg
Botulism
Tetanus
Myasthenia gravis
Masticatory muscle myositis
E. Simko WCVM
We know Skin dz:
See STUDY GUIDE FOR SKIN
E. Simko WCVM
We know Endocrine dz:
• Endocrine dermatoses – see skin guide
plus Adrenal neoplasms of ferrets
• Hypoadrenocorticism
• Hyperthyroidism
• Pituitary tumors
ACTH secreting in Ca
Pars intermedia in Eq
• Ca & P metabolism
• Hypocalcemia and hypercalcemia
• Hyperparathyroidism
E. Simko WCVM