Author: ahac-user

Kidney Disease in Pets


Kidney4The kidneys are remarkable and complex organs that serves many essential functions.

Essential kidney functions:

  • Remove protein wastes and toxins from the body.
  • Balance the body’s fluids.
  • Keep electrolytes at optimal levels.
  • Control pH levels of the blood
  • Release hormones that regulate blood pressure.
  • Maintain the production of red blood cells.

Kidney disease occurs when one or more of these essential functions are compromised or reduced. When kidney function is impaired, body systems become imbalanced. When function is significantly impaired, waste levels can become toxic. Kidney disease can progress to kidney failure.

Causes of Kidney Disease

Infections – Bacterial infections that can cause kidney failure in dogs include Leptospirosis and Lyme disease. Leptospirosis is contacted through urine contaminated drinking water. Lyme disease is acquired through the bite of a deer tick. Both cats in dogs can also acquire ascending infections from the lower urinary system. Untreated bladder infections can cause kidney infections.

Toxicity – The kidney is susceptible to adverse toxicity reactions due to its role in filtering the blood. Common toxins that can cause acute kidney failure include grapes/raisins (dogs), antifreeze, rodenticides, Ibuprofen, and lilies (cats).

Cancers – Renal carcinoma is the most common primary renal tumor in dogs and cats. These tumors have aggressive malignancies with the potential for widespread metastasis. Cancers, including lymphoma, can also originate in other parts of the body and metastasize to the kidneys.

Congenital – Inherited malformation of the kidneys can present in pets under a year of age. The most common condition is polycystic kidney disease in Persian and domestic long-haired cats. The condition causes multiple fluid filled cysts to form within the functional part of the kidney.

Immune Mediated – Glomerulonephritis occurs when a mixture of antibodies and pathogens are filtered out of the bloodstream.  When these compounds are trapped, the body responds by activating its immune defenses, resulting in damage to the kidney tissue.

Urinary Obstruction – Stones may form in the kidneys or bladder. If the stones move from the kidneys into the ureters or from the blader into the urethra, an obstruction that impedes the flow of urine may result. Restricted urine flow can cause a secondary kidney failure.

Chronic Disease – Many senior pets experience a gradual loss of kidney function over time. For older animal populations kidney disease affects up to 10% of dogs and 35% of cats. The exact inciting incident or cause is often not identified in these patients.

Kidney2Clinical Signs

Kidney disease may be detected on routine screening of blood and urine prior to the onset of clinical signs.

A few signs to watch for include:

  • Drinking more water
  • Increase in urine frequency or volume
  • Loss of interest in playing
  • Decrease in appetite
  • Vomiting
  • Weight & muscle loss
  • Poor haircoat
  • Bad breath

Unfortunately, kidney disease typically goes undetected and clinical signs do not appear until the kidneys are functioning at 33% or less of original capacity.

Diagnostic Tests

Diagnosis of kidney disease may require a variety of tests including blood work, urine tests, imaging, and blood pressure.

Blood Tests

Biochemistry Panel – BUN, CREA, and SDMA are measured by a blood chemistry test. Elevations (azotemia) can indicate the kidneys’ declining ability to filter the blood.

Electrolytes & Minerals – Levels of blood electrolytes including potassium, sodium, and chloride may be abnormal. Minerals such as calcium and phosphorous may also be elevated.

CBC – Evaluates levels of red blood cells to look for anemia and white blood cells to identify infection.

Titers – Blood tests for infection including Lyme Disease and Leptospirosis in dogs.

Kidney1Urine Tests

Urinalysis – Analysis of urine by physical, chemical, and microscopic means to test for the presence of disease.

Urine Culture & Susceptibility – The best test to diagnose a urinary tract infection is a culture to grow and identify bacteria present in the urinary tract. The bacteria are then further tested to determine the best antibiotic to use in treatment of the infection.

Urine Protein/Creatinine Ratio – A simple test that measures how much protein is being lost through the kidneys.


X-Rays – Radiographs help to assess the size and shape of the kidneys. Kidney enlargement, atrophy or shrinkage, and abnormal shapes or asymmetry may indicate disease. The presence of masses or tumors that change the shape of the kidney can sometimes be visualized using radiographs. Kidney and bladder stones may also be identified on x-rays.

Ultrasound – Ultrasonography is the best diagnostic imaging modality to evaluate the internal structure of the kidneys. Ultrasound reveals any changes in the internal anatomy of the kidney, including abnormal growths, stones, or blood flow.

Blood Pressure – Monitoring blood pressure in kidney patients is important.  High blood pressure (hypertension) is a very common symptom associated with chronic kidney disease. Hypertension causes further deterioration of kidney function.

Classifications and staging

Kidney disease in pets can be classified as acute or chronic. Acute kidney failure happens quickly over several days, and is often a result of sudden kidney injury caused by a specific event such as toxin, obstruction, or infection. Chronic kidney failure happens slowly over months to years. Chronic kidney disease is more prevalent in senior pets and progresses with age.


Kidney disease is staged based upon results of diagnostic tests including the level of nitrogen waste build up (azotemia), amount of protein in the urine, and blood pressure. The stage of disease helps to guide therapy and to determine prognosis.  

Treatment Options

Although there is no definitive cure for kidney disease, treatment can often improve and prolong the lives of pets with this disease. Therapy is geared toward minimizing the buildup of toxic waste, maintaining hydration, addressing disturbances in electrolytes, supporting appropriate nutrition, controlling blood pressure, and slowing the progression of kidney disease.

Kidney5Nutritional Therapy – Prescription therapeutic foods, such as Science Diet KD or Purina NF, are formulated with low levels of phosphorous and moderate amounts of high quality protein. These diets are highly palatable and calorie dense to support debilitated animals. Prescription renal diets have domonstrated in studies to prolong survival time, slow disease progression, and improved quality of life. 

Hydration – Kidney disease patients are prone to dehydration due to body’s inability to conserve water. Patients must always have free access to water. Severely dehydrated patients may need to be hospitalized for IV fluids. Moderate chronic dehydration may be treated with subcutaneous fluids, which are fluid injections under the skin. Feeding of canned food can naturally increase daily water intake for pets experiencing mild dehydration.

Supplements – Additional potassium supplementation may be needed in some cats with chronic kidney disease. Control of blood phosphorus levels is also necessary. If dietary changes alone do not accomplish this, drugs to bind the phosphorus in the food can be given with each meal.

Detox – With acute toxin exposures, a veterinarian can take steps to minimize absorption of toxins. Depending on the situation, the veterinarian may induce vomiting or pump a pet’s stomach, administer activated charcoal, and administer an appropriate antitoxin.

Medications – Patients with acute infectious causes of kidney disease should be treated with broad-spectrum antibiotics. Ideally, the antibiotic choice should be based on test results including titer and bacterial culture. Pets that have poor appetites or nausea may benefit from antacid and anti-nausea medications, such as famotidine and Cerenia. If hypertension and proteinuria is present, a variety of drugs, such as Ace inhibitors, can be used to control the high blood pressure.


The prognosis for pets with kidney disease varies depending on the inciting cause, timeliness of diagnosis, and therapy provided.

Early diagnosis and intervention are important for successful treatment of dogs and cats with kidney disease.  Pets that have a delayed diagnosis will have a poorer prognosis and may only live weeks to months. Patients that are diagnosed in the early stages of disease can live several years with conscientious management of their disease by the veterinarian and pet owner. On average cats tend to live longer than dogs with kidney disease.

In most cases, kidney disease is a progressive disease that worsens over time, but the rate of progression is highly variable. Regular follow up exams and lab tests help the veterinarian determine the progression of an individual animal’s kidney disease and make tailored changes in medical management.

Successful treatment of kidney disease delays progression, provides greater survival times, and increases patient quality of life.

Chocolate Toxicity

chocolate toxicity

Ingestion of chocolate can be a deadly mistake for dogs and cats. Chocolate (cacao) contains the substances caffeine and theobromine.  These substances can have detrimental effects on the GI system, central nervous system, heart, and kidneys of pets. In dogs and cats the ‘half-life’ (length of time it takes for 50% of the substance to break down in the body) for theobromine is over 17 hours.  This means that after 17 hours, half of the theobromine ingested is still in their systems. Humans can metabolize caffeine and theobromine more efficiently than pets can, which is why chocolate is not toxic to humans.

How much chocolate is considered toxic?

chocolate toxicityNo amount of chocolate is safe for an animal to ingest. The effects of chocolate consumption in pets depends on type of chocolate, quantity consumed, and the size (body weight) of the pet. Some types of chocolate contain higher amounts of caffeine and theobromine.

Reported combined caffeine & theobromine content in different chocolates:

  • Dry cocoa powder contains 800 mg/oz
  • Unsweetened baker’s chocolate contains 450 mg/oz
  • Cocoa Bean hulls (mulch) contains 255 mg/oz
  • Semisweet dark chocolate contains 150-160 mg/oz
  • Milk Chocolate contains 64 mg/oz
  • White chocolate contains an insignificant amount.

The most toxic, cocoa or baker’s chocolate, causes a life-threatening emergency when ingested. The moderately toxic dark chocolates can lead to hospitalization and serious illness in pets when amounts as small as one-tenth of an ounce per pound of body weight are consumed. Even pets that devour less than a half ounce of milk chocolate per pound of body weight are at risk of developing clinical signs. 

Online chocolate toxicity calculator can be helpful for pet owners and veterinarians to calculate the potential toxicity of chocolate ingestion.

Symptoms of Chocolate Ingestion

Clinical signs of chocolate toxicosis usually occur within 6–12 hours of ingestion.

Initial signs may include:

  • Increased thirst
  • Vomiting
  • Diarrhea
  • Restlessness

Signs may progress to:

  • Hyperactivity
  • Increased urination
  • Incoordination or trouble walking
  • Fever
  • Twitches & tremors
  • Rigidity & seizures
  • Racing heart progressing to abnormal rhythms

chocolate toxicityTreatment of Chocolate Toxicity

If you suspect your pet has ingested chocolate, you should immediately contact your veterinarian.

If ingestion has occurred within the past 2 hours, the first step is to recover as much chocolate from the patient as possible by inducing vomiting. For many patients, removing the undigested chocolate converts the toxicity from a life-threatening poisoning to just an upset stomach that is easily managed.  Absorbents, such as activated charcoal, are administered by mouth to bind the chocolate and prevent absorption of theobromine and caffeine through the gut. The patient may be administered SQ fluids to help flush the system. Pets may be treated on an out patient basis if minor quantities of chocolate have been ingested and treatment is started before clinical signs develop.

If a pet has consumed larger quantities of chocolate, has developed clinical symptoms, or treatment has been delayed then hospitalization may be required.  Hospitalized patients receive IV fluids to help flush the kidneys and frequent trips out to go potty are needed to prevent re-absorption of the toxins.  Laboratory blood testing may be required to monitor the kidneys. ECG will be used to monitor the heart for changes in rate and rhythm. A variety of medications are used to help treat symptoms such as seizures and arrythmias. Patients may need intensive care for 24 to 48 hours.

The prognosis after chocolate ingestion can be variable depending on the type and quantity of chocolate consumed, and the timing of treatment.

The prognosis is favorable if decontamination, including induction of vomiting and administration of activated charcoal occurs within 2 hours of ingestion and before clinical signs began, the prognosis is favorable. Patients that receive prompt treatment may be treated as outpatients and their symptoms may not progress beyond mild GI upset.

If treatment is delayed past 4 hours of ingestion, and mild clinical signs have started, the pet will need to be hospitalized for 12 to 36 hours for monitoring and supportive care. Pets that have developed symptoms of toxicity have a more guarded prognosis. If symptoms progress to seizures and cardiac arrhythmias the prognosis is poor, and the toxicity may be fatal.

In the days following chocolate ingestion, patients should be monitored carefully. The high fat content of chocolate products may trigger secondary pancreatitis in some patients.


Corneal Ulceration

A corneal ulcer occurs when the protective surface layer of the eye’s cornea is lost or damaged. Corneal ulcers range from superficial abrasions and small circular lesions to deep craters. The deeper layers of the cornea are exposed and become prone to infection and injury. These deeper layers contain many nerves, and irritation of these nerves is very painful. Ulcers may be complicated by secondary bacterial infections.

There are many causes of corneal ulceration, including:
• Trauma from cat scratches or other foreign objects
• Abnormalities of the eyelids including entropion (eyelids rolled inward) or abnormal ingrown eyelashes
• Decreased blinking due to neurologic problems or from sedation and general anesthesia
• Exposure to irritants such as chemicals, soaps, or smoke
• Infections with bacteria, viruses, or fungal agents
• Chronic dry eyes from poor tear production
• Corneal infiltrates such as calcium, cholesterol, or edema
• Brachycephalic breeds of dogs or cats with flat faces and prominent eyes are very prone to corneal ulcers because their eyes protrude beyond the eyelids.

Clinical Signs
Pain is a hallmark sign of corneal injuries and ulceration. A pet with a painful eye may have increased tearing, squinting, blinking, and pawing at the eye. The animal may also be quiet and withdrawn. The eye is usually red and thick eye discharge may develop with infection. The cornea may be cloudy or have visible irregularities. Other signs, such as swelling of the eyelid, inward rolling of the eyelid, protrusion of the third eyelid, or bruising around the head, may occur depending on the cause of the ulceration. Signs of an upper respiratory tract infection may be noted in cases of herpes virus infection in cats or distemper virus infection in dogs.

Diagnostic Tests
A veterinarian diagnosis a corneal ulcer by performing an ophthalmic exam.

Fluorescein staining of the cornea is used to confirm the presence of a corneal ulcer. The stain adheres to deeper corneal layers that are exposed when the corneal surface is damaged. The damaged area if cornea is visible as apple green under blue light. Other ocular tests such as a Schirmer tear test, testing of reflexes, examination of the eyelids and interior of the eye, and glaucoma testing may also be indicated. If a severe bacterial infection is suspected a culture may need to be submitted.


Treatment Options
Most corneal ulcers in dogs and cats can be treated on an outpatient basis by a general veterinarian.

Medications and treatments prescribed for corneal ulcers:
• Topical antibiotics drops or ointment administered directly to the eye to treat active infections and/or to prevent infections.
• If the ulcer is deep and there is concern about infection within the eye, then oral antibiotics may also be prescribed.
• Topical atropine (pupil dilator) may be administered as an ointment or drop directly to the eye.
• Oral nonsteroidal anti-inflammatory drugs may be considered for marked inflammation and discomfort.
• Administration of the pet’s own blood serum as eye drops to provide nutrients to encourage healing.
• Elizabethan cone collar to prevent self-trauma.
• Debridement of the ulcer with cotton swab to remove dead tissue

Referral to a veterinary ophthalmologist may be recommended if the ulcer is deep or not healing. An ophthalmologist can offer application of soft contact bandage lenses or placement of a third eyelid flap to protect the cornea. An ophthalmologist can also offer treatments for underlying conditions such as entropion correction, removal of foreign materials, or abnormal eye lashes.

Follow-up Care
Recheck exams are needed to assess healing and response to treatment. Visit frequency can range from every 24-48 hours to every 7-14 days, depending on the severity of the corneal ulcer. Fluorescein staining of the cornea is performed at most visits to highlight the ulcer and to determine when it has healed. Brachycephalic breeds such as boxers, bull dogs, and Persians may need more intensive follow-up.

Most superficial corneal ulcers and abrasions caused by trauma respond to treatment quickly and heal with minimal scarring. Pets that have underlying chronic conditions such as entropion or ingrown eye lashes may need to have minor procedures to correct the abnormality. Chronic conditions, such as dry eye, may need lifelong treatment with eye drops to prevent future corneal ulcers. Deep ulcers and ulcers that are infected are more difficult to treat and may leave the cornea scarred and pigmentated resulting in decreased vision. In rare instances corneal ulcers that that do not receive treatment and become infected can result in perforations of the eye and loss of vision, and in severe cases even loss of the eye.