Nephrotic Syndrome in Dogs
Within the intricate network of the kidney’s glomeruli, essential for waste filtration and urine formation, lies a vulnerability to damage. This damage often stems from immune complexes or amyloid deposits, culminating in nephrotic syndrome. Here, the intricate filtration cells known as podocytes suffer impairment, leading to a cascade effect impacting the kidney’s tubular system.
Nephrotic syndrome manifests as the excessive loss of crucial proteins, notably albumin and antithrombin III, into the urine, a condition termed proteinuria. When protein loss exceeds 3.5g daily, repercussions ensue: blood pressure drops, blood volume decreases, and the kidneys respond by retaining sodium, resulting in limb swelling, hypertension, and abdominal fluid accumulation.
Moreover, the urinary excretion of vital thyroid proteins exacerbates the situation, manifesting as hypothyroidism symptoms. Muscle wasting, decreased cholesterol breakdown, and heightened liver production of proteins and lipids further complicate matters, fostering conditions like arteriosclerosis due to increased cholesterol-rich lipids circulating in the blood. Furthermore, the loss of clotting proteins elevates the risk of blood clot formation, potentially leading to paralysis or stroke.
Progressive glomerular disease amplifies urea nitrogen and creatinine levels in the bloodstream, eventually culminating in chronic kidney failure. Glomerular diseases are not uncommon in dogs and necessitate vigilant management to mitigate their debilitating effects.
Symptoms and Types
- Limb swelling
- Abdominal enlargement caused by fluid buildup in the abdomen
- Retinal issues: hemorrhage or detachment resulting from elevated blood pressure
- Optic nerve swelling (located at the back of the eye) due to high blood pressure
- Heart rhythm irregularities due to left ventricle enlargement
- Breathing difficulties
- Bluish-purple skin discoloration
Causes
Persistent inflammatory conditions increase the likelihood of animals developing glomerulonephritis or amyloidosis. These conditions may result from:
- Infections
- Cancer
- Immune-mediated diseases
Diagnosis
Your veterinarian will conduct a comprehensive physical examination of your dog, coupled with various blood tests such as a chemical blood profile, complete blood count (CBC), electrolyte panel, and urinalysis. Providing a detailed history of your dog’s health and symptoms is crucial as it can offer valuable insights into secondary organ involvement.
Protein electrophoresis may be employed to identify the specific proteins lost through the kidneys into the urine, aiding in prognosis determination. Imaging techniques like X-ray and ultrasound will reveal any abdominal cavity detail loss due to fluid accumulation (effusion). Additionally, if nephrotic syndrome stems from glomerular disease, mild kidney enlargement may be evident on imaging.
Treatment
While most patients can undergo treatment as outpatients, hospitalization may be necessary if your dog exhibits severe azotemia (elevated nitrogenous waste in the bloodstream), hypertension (high blood pressure), or thromboembolic disease (blocked vessels due to clotting). Your veterinarian may prescribe medications to halt protein loss into your dog’s urine and to elevate its blood pressure.
Living and Management
To prevent thromboembolic disease, it’s crucial to limit your dog’s activity. Your veterinarian will recommend a low-protein, low-sodium diet, possibly a commercial kidney diet, tailored to your dog’s needs.
Regular follow-up appointments are necessary, typically starting one month after initial treatment and continuing every three months for the following year. These appointments will involve a chemical blood profile, urinalysis, and electrolyte panel to monitor kidney function and protein loss in the urine. Blood pressure and weight will also be monitored at each visit.
Since glomerulonephritis and amyloidosis are progressive diseases, the prognosis depends on the underlying cause. If the cause cannot be resolved, eventual kidney function loss is inevitable. End-stage kidney disease prognosis is generally poor.