Understanding Symptoms of Cushing's Disease in Dogs
Cushing's disease, also known as hyperadrenocorticism, is a chronic endocrine disorder caused by an overproduction of cortisol in dogs. This hormone imbalance can stem from tumors in the pituitary or adrenal glands, and it has profound effects on the body’s metabolism and organ systems. One of its common manifestations is proteinuria, which is an elevated level of protein in the urine, signifying kidney involvement or systemic inflammation.
Common Clinical Signs of Cushing's Disease
Dogs with Cushing's disease often exhibit a wide range of symptoms, which can vary in degree and develop gradually over time. Major signs include:
- Excessive drinking and urination (polydipsia and polyuria) – These are hallmark signs as cortisol affects kidney function and water balance.
- Increased appetite (polyphagia) – Elevated cortisol stimulates hunger.
- Lethargy and reduced activity – Dogs may tire easily and show less enthusiasm for walks or play.
- Potbellied appearance – Fat redistribution and muscle wasting lead to a distended abdomen.
- Hair loss and thin skin – Cortisol impairs hair follicles and skin integrity.
- Recurring skin infections – A suppressed immune system contributes to skin problems.
- Panting and respiratory signs – Cortisol increases fat around the chest, impacting breathing.
Proteinuria as a Diagnostic Marker
One of the less overt, yet clinically significant signs associated with Cushing's disease is proteinuria. This condition suggests that the glomeruli of the kidneys—the filtration units—are leaking protein, which should normally remain in the bloodstream. Their compromise often marks kidney involvement, and in dogs with Cushing’s disease, such proteinuria results from hypertension, vascular damage, or a concurrent inflammatory state.
Routine urinalysis and blood testing are essential for identifying proteinuria and uncovering the presence and severity of underlying disease. Persistently elevated urine protein-to-creatinine ratios (UPC) over 0.5 are considered significant and warrant further diagnostic work.
Advanced or Severe Symptoms
As the disease progresses or remains untreated, dogs can develop further complications such as:
- Visual disturbances – Caused by hypertension or hyperviscosity related to high protein levels.
- Seizures or neurological signs – Due to thickened blood (hyperviscosity syndrome) impairing cerebral circulation.
- Edema or swelling – Especially in the legs, abdomen, or chest due to hypoalbuminemia.
- Respiratory trouble – Resulting from fluid accumulation or pulmonary embolism.
- Blood clots – Indicative of vascular damage and seen as painful limbs or sudden collapse.
Associated Disorders and Overlapping Signs
Cushing’s disease can complicate or coexist with other conditions such as:
- Diabetes mellitus – With overlapping symptoms like increased thirst and urination.
- Hypertension – Leading to kidney damage and neurological signs.
- Urinary tract infections or bladder infections – Common in immunosuppressed dogs.
- Autoimmune disorders – May further exacerbate inflammation and protein loss.
Diagnosis and Monitoring
A thorough diagnostic workup for suspected Cushing’s disease includes:
- Blood chemistry and hormone testing – Especially ACTH stimulation and low-dose dexamethasone suppression tests.
- Urinalysis and UPC ratio – To assess kidney function.
- Blood pressure evaluation – To detect vascular strain.
- Abdominal ultrasound – To visualize adrenal glands and other abdominal structures.
Management and Treatment
Treatment of Cushing's disease typically involves:
- Medication – Drugs like trilostane (Vetoryl) or mitotane to inhibit cortisol production.
- Blood pressure management – Amlodipine, ACE inhibitors, or angiotensin-receptor blockers.
- Supportive care – Including dietary changes, regular exercise, and infection prevention.
- Monitoring protein loss – With scheduled urinalysis and bloodwork to adjust treatment as needed.
Prognosis and Long-term Care
With early detection and appropriate therapy, dogs with Cushing's disease can live comfortably for years. It is crucial, however, to perform routine follow-up exams including lab tests, blood pressure checks, and urinalysis to monitor kidney health and systemic impacts of the disease.
Preventive Measures
While Cushing's disease itself cannot be prevented entirely, especially if due to pituitary tumors, dog owners can:
- Ensure annual veterinary wellness checks.
- Monitor for early signs like increased thirst or poor coat.
- Maintain ideal body weight through diet and exercise.
- Catch kidney issues early through routine urine screening.
Awareness of the symptoms and complications associated with Cushing's disease empowers dog owners to seek timely care and improve quality of life for their pets.
