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Hyperardrenocorticism in dogs (Cushing’s syndrome) - Coggle Diagram
Hyperardrenocorticism in dogs
(Cushing’s syndrome)
Types
Pituitary-Depending Hyperadrenocorticism
Most common natural occurring cause in dogs
85% to 90% of cases
Excessive secretion of ACTH from pituitary corticotroph hyperplasia
Microadenoma
Macroadenoma
Adenocarcinoma results in bilateral adrenocortical hyperplasia - very rarely
Cortisol-Secreting Adrenocortical Tumors
Responsible for 10% to 15% of spontaneous Cushing’s syndrome in dogs
About half of adrenocortical tumors are benign and half are malignant
Iatrogenic Hyperadrenocorticism
Excessive or prolonged administration of corticosteroids
Clinical signs and physical examination findings are similar to
those seen in the natural disease
Endogenous ACTH production is suppressed, resulting in atrophy of the adrenal cortices
Clinical signs
General appearance
Pendulous, distended, or “pot-bellied” abdomen
Muscle atrophy and weakness
Intergument
Hair loss
Thin hypotonic skin susceptible to bruising
Hyperpigmentation
Seborrheic changes
Secondary pyoderma and Malassezia dermatitis
Urinary and reproductive system
90% of cases: PU/PD
Glucocorticoids decrease renal tubular reabsorption of water
20 Urinary tract infection due to immunosuppressive effects of cortisol excess
Pollakiuria, haematuria, and stranguria may be minimal as a result of the antiinflammatory action of cortisol
Glomerulopathy and associated proteinuria may occur
Low concentrations of pituitary follicle-stimulating hormone
(FSH) and luteinizing hormone (LH)
Respiratory system
Excessive panting is quite common
Pulmonary thromboembolic disease
Endocrine System
Some dogs develop diabetes mellitus
The hallmark of steroid-induced diabetes is the development of insulin resistance
Cortisol antagonizes the actions of insulin by interfering with its action at the cellular level (receptor and postreceptor effects).
Hypertension may occur
Central Nervous System and Neuromuscular System
Lethargy is the most common sign
CNS signs of circling, seizures, behavior change, and depression to obtundation (mental blunting with mild to
moderate reduction in alertness and a diminished sensation of pain)
Muscle weakness
Gastrointestinal System
Polyphagia is common.
Hepatomegaly is often detected.
Pancreatitis secondary to excess cortisol levels is occasionally seen
Diagnosis
History
Routine laboratory testing
Radiography
Ultrasonography
Computed Tomography and Magnetic Resonance Imaging
Pituitary-Adrenal Function Tests
Treatment
Treatment of Pituitary-Dependent Hyperadrenocorticism
Mitotane Therapy
Trilostane therapy
Ketoconazole
L- Deprenyl therapy
Treatment of Adrenocortical Tumours
Adrenalectomy
Mitotane therapy