Saturday, March 15, 2008

Seizures in Pets

Seizures are due to abnormal electrical conduction within the brain that results in a loss of consciousness (in most cases), and various physical signs that can be associated with the seizure. These physical signs can manifest as any one of the following:

Falling over to one side
Legs "paddling" or generalized trembling/twitching
Jaw "chomping"
Eyes "rolled back"

Most pets will seem anxious and even seek out the owner prior to the actual seizure, when the above signs can be seen. The actual seizure usually lasts from 30 seconds to 2 - 3 minutes. Afterwards the pet may seem disorientated, or "drunk" in appearance, sometimes behaving blind, stumbling about and being poorly responsive to his/her environment. This last phase of disorientation can last for as little as 10 minutes to several hours.

When your pet has a seizure, be sure to place thick cushions, blanket, etc. between your pet's head and any hard furniture. Be very careful to avoid handling your pet's head directly, since this has often resulted in a biting injury to owner's hands. Your pet is unaware of his/her surroundings when seizuring, and may bite down very hard on your hand and not even realize it. Make sure to pay close attention to what you are witnessing, since your veterinarian will want you to keep a journal of the seizure events. Record in notebook the following:

Date, time and length of the seizure

Time the length of the "disoriented" phase that follows the seizure - document exactly what signs were seen (from above list), was it associated with any events eg: exercise, eating, drinking, etc?

By keeping a journal, it helps you to know how often your pet is seizuring, and whether the seizures are getting longer or more violent. This helps your veterinarian to counsel you on when is the appropriate time to start anticonvulsant medications, or see a neurologist.

The first time your pet has a seizure, most vets will advise you to do nothing. Many seizures are one-off occurrences and in these cases, investigation is not required. If a seizure occurs more than once, then blood work (standard biochemistry to check liver function) is the first diagnostic test done, alongside a thorough general clinical exam and a more specific neurological exam.


When your pet's seizure is going on to 5 minutes in duration. By definition, this is turning into "status epilepticus" which essentially means a constant state of seizure activity, and if the seizures are not stopped, this can lead to life threatening consequences. Status epilepticus can result in a overheating of the body, essentially a "heat stroke". This also can cause some temporary or permanent damage of the brain tissue. Once a seizure is climbing towards 5 minutes, get your pet immediately in the car and start driving to the closest veterinary clinic.

Once an anticonvulsant has been administered, the pet should be monitored for any more seizure activity for at least 24 hrs, usually accomplished through an emergency (24 hr) center.

If your pet has more than one seizure in a 24 hour period, this is considered a "cluster" of seizure activity. You need to seek veterinary care once he or she has the second seizure, since this indicates a rapid succession of seizures, and may require anticonvulsants be started to control these. A "cluster" will often precede "status epilepticus", as indicated above.


Some pets have been known to have one seizure in their lives, while others develop serious repeated seizure activity. With a first time occurrence of seizure activity, we do not yet have a pattern of seizure activity established. Without a pattern, it is impossible to predict future seizure activity. Your pet may never seizure again, or may continue to have seizures. You play an important role in the diagnosis and proper treatment of your pet's seizures, by providing us with an accurate history, and seeking veterinary help when indicated.

This article was donated by the Columbia Animal Hospital. For further information please visit
Televets is an online Q&A service connecting pet owners with certified pet advisors 24/7. Visit them today with your pet concerns!

Wednesday, March 5, 2008

Portosystemic Shunts

Congenital Portal Shunts are due to a defect in the blood circulation around the liver. Instead of blood entering the liver to be detoxified, the liver is bypassed. The liver usually eliminates toxins derived from the gut. With a porto-systemic shunt, there is a bridging between the veins around the liver and so the toxic material bypasses the liver, causing an elevation of ammonia in the circulation.

This defect may be within the liver (intrahepatic) or occur outside of the liver (extrahepatic) - most are single vessels.

Shunts can be congenital (present at birth) or acquired. Acquired shunts can develop subsequent to portal hypertension (high blood pressure); typically they are multiple in nature. This occurs due to a lack of valves in the portal vein, permitting circulatory accommodation through the shunt. Portal hypertension is usually associated with liver scarring or cirrhosis.

The shunt may lead to episodic development of hepatic encephalopathy (seizures or bizarre behavior) associated with ingestion of high protein food, and administration of certain drugs.

Another effect of the shunt is the development of bladder stones due to inability of the liver to metabolise uric acid from the blood.


Nervous system signs include episodic hepatic encephalopathy (seizures).
Gastrointestinal signs are intermittent inappetence; vomiting; diarrhea; pica; drooling in cats.
Urogenital signs bladder stones and or large kidneys


Basis unknown
Breeds predisposed include miniature schnauzers; Irish wolfhounds; Old English sheepdogs; cairn terriers; Yorkshire terriers


Incidence is greatest in purebred dogs and mixed breed cats
Especially common in Yorkshire terriers


Episodic seizures or disorientation (hepatic encephalopathy) may be noted.
Affected cats may drool. This may be initially confused with an upper respiratory infection based on the display of increased salivation.
Initial signs usually noted at initial feeding of puppy or kitten food and stunted growth is common


CNS Signs: Episodic weakness, pacing, disorientation, head pressing, blindness, behavioral changes (aggression, vocalization, hallucinations), seizures, coma
Gastrointestinal Signs: inappetence, vomiting, diarrhea
Urinary Signs: bladder stones
Congenital disease –The pets may have a normal appearance or have stunted stature, hepatic encephalopathy, golden or copper irises in non- blue-eyed and non-Persian cats.


CNS signs -Other rule outs include infectious disorders (e.g., FIP, canine distemper, toxoplasmosis, FeLV-related infections); toxicities (e.g., lead, mushrooms, recreational drugs); hydrocephalus; epilepsy; metabolic disorders (e.g., severe low blood sugar).
Gastrointestinal signs—bowel obstruction; dietary indiscretion; foreign body ingestion; inflammatory bowel disease
Urinary tract signs—bacterial urinary tract infection; stones


Lab Work

CBC/Biochemistry: low BUN, creatinine, glucose, and cholesterol common; liver enzyme activity variable (ALP usually high in young patients owing to bone isoenzyme); bilirubin normal with congenital but may be high with acquired shunts.
Urinalysis: Decreased urine specific gravity (inability of kidneys to work properly) and crystals in the urine.
Total serum bile acids—sensitive indicators; random fasting values may be within normal reference range; 2-hr postprandial (post feeding) values markedly high (usually > 100 mmol/L)
Blood ammonia values—sensitive indicators; less reliable than total serum bile acids because of analytic problems
Ammonia tolerance testing—more reliable than random ammonia values; samples cannot be stored, frozen, or mailed for analysis.


Abdominal Radiography: Small liver, Large kidneys, Bladder stones
Injecting radiographic contrast media into a mesenteric or spleenic vein. This is the test of choice, but is technically difficult.
Abdominal Ultrasonography: Subjective estimation of small liver, hypervascularity, and observation of the shunting vessel. Color-flow Doppler—assists in shunt localization. Intrahepatic shunts are most easily imaged.

Acquired Shunts

Liver size depends on underlying cause.
Abdominal fluid is easily detected.
Ammonium urate calculi (stones) in the kidney or bladder


Eliminate causal factors—dehydration; elevated kidney toxins; gastrointestinal bleeding; high- protein foods; infection (urinary tract, other); treatment with certain drugs

Protein-restricted diet—dogs: dairy and soy protein may perform better than meat and fish proteins; cats: require balanced, meat-based protein.

Increase dietary protein tolerance by concurrent treatment with lactulose (0.5–1 mL/kg PO q8–12h; dose based on production of two to three soft stools daily), metronidazole (7.5 mg/kg PO q8– 12h), and/or neomycin (22 mg/kg PO q12h).

Cleansing enemas with warmed isotonic fluids— until free of feces
Retention enemas—15 mL/kg; with lactulose (1:2 dilution with water) and neomycin (10–15 mg/kg)


Surgical ligation with congenital disease

Goal: total ligation vessel; often only partial ligation can be performed safely and surgical assessment of extent of ligation may be inaccurate.

Hepatic encephalopathy signs must be resolved before surgery. Intrahepatic shunts are most difficult to ligate.

This article was donated by the Columbia Animal Hospital. For further information please visit

Tuesday, March 4, 2008

Kidney Disease in Cats

The kidneys are organs which maintain the balance of certain chemicals in your cat's blood, while filtering out the body's waste as urine. The kidneys also help regulate blood pressure, help regulate calcium and phosphorus metabolism, and produce a hormone that stimulates red blood-cell production called erythropoietin. As you can imagine, a malfunctioning kidney can cause many problems.

Let us picture the kidneys filtering mechanism. There are tens of thousands of microscopic funnel shaped tubes called nephrons. These tiny structures are responsible for filtering and reabsorbing the fluids that balance the body. These nephrons are susceptible to damage due to many causes such as poisons, aging, infection, trauma, cancer, auto-immune diseases, and genetic predisposition. If any of these occur the entire nephron stops functioning. Fortunately, due to both the reserve capacity of the kidney and the ability of the nephrons to grow larger, the kidney can still function. If damage to nephrons occurs gradually and the surviving nephrons have enough time to hypertrophy, a kidney can continue to function with as few as 25 percent of its original nephrons.

When the number of functioning nephrons drops below 25 percent or when damage occurs too suddenly for the remaining nephrons to compensate, kidney failure occurs. There are two types of kidney failure. Acute kidney failure is a sudden loss of function that is sometimes but not always reversible. Chronic kidney failure is an irreversible loss of function that occurs gradually over months or years.

Failing kidneys can't adequately clear the blood of certain toxins. These include urea (a nitrogen- containing byproduct of protein metabolism) and creatinine (a chemical byproduct of muscle exertion). As a result, when the kidneys fail, there is an abnormally high levels of these wastes products. Other blood components normally regulated by the kidneys - such as phosphorus, calcium, sodium, potassium, and chloride - may also rise or fall abnormally.

Failing kidneys may also produce extremely dilute urine or urine that contains too much protein. Healthy kidneys produce concentrated urine that is relatively protein-free.

To determine the prognosis of kidney disease, blood and urine tests are performed frequently during treatment to evaluate how well the kidneys are responding. A complete blood count looks at the numbers of red and white blood cells and a blood chemistry panel will examine the levels of waste products and electrolytes, indications of whether the kidneys are functioning properly. It's a good sign if test results swing back toward normal within the first 48 to 72 hours of therapy.

The blood tests will determine if your cat is suffering from anemia (a lower than normal number of red blood cells, RBC). This is significant because it often indicates a drop in erythropoietin, a hormone secreted by the kidneys that stimulates RBC production. The blood chemistries will determine levels of blood urea nitrogen (BUN) and creatinine, both are indicators of the amounts of waste products in the blood. Elevations of these levels result from kidney failure.

Urinalysis measures a number of factors, including how well the kidneys are concentrating the urine. In kidney failure, urine becomes dilute. Urine may also be checked for the presence of bacteria, protein, and blood. If the kidneys are normal urine should be concentrated and there should be no blood or protein in the urine.

X-rays, ultrasound and possible kidney biopsies are also very useful in assessing kidney disease.

Acute renal Failure:

The causes of acute renal failure are many. Toxins, antifreeze, cancer, intestinal disease and dehydration are just a few. Management of acute renal failure requires hospitalization, intravenous fluid therapy, and medications to help offset the affects of toxemia associated with renal failure. Intensive therapy is essential to attempt to reverse the process.

One hopes to see positive changes within 48-72 hours of treatment. The prognosis worsens if there is no reduction in the abnormal kidney values.

Chronic renal failure (CRF):

Chronic renal failure is the result of one of several different diseases, including chronic interstitial nephritis, glomerulonephritis, and amyloidosis. Some of these are autoimmune diseases; the body's immune system actually turns on itself and attacks organs and tissues. In addition, pyelonephritis, a bacterial infection that usually starts in the bladder, is often a complicating factor that precipitates CRF.

Other causes such as polycystic kidney disease (PKD) can affect younger cats, especially Himalayans and Persians, and also lead to CRF. Cysts develop in the kidneys and grow, destroying normal tissue.

Renal amyloidosis, is another form of hereditary kidney disease that affect Abyssinian and Somali cats, and may also lead to CRF.

There is no way to prevent or stop chronic renal failure. Cats can only live with one healthy kidney, but because CRF affects both kidneys, over time it is fatal.

Severely affected cats may need hospitalization. They are first rehydrated. This is best done via intravenous fluids, and therefore must be done in a hospital or veterinary clinic. Some clinicians will allow cat owners to give subcutaneous fluids at home, though this is also frowned upon by others. It involves purchasing bags of sterile fluids and injecting the prescribed amount of fluid beneath the cat's skin on a regular basis.

Dietary management is also potentially helpful. A low protein diet is generally recommended. By decreasing the protein intake, waste products of protein digestion in the blood stream decrease. This reduces the work load of the kidneys. Some cats will eat this diet while others will refuse it.

These diets are also low in phosphorus, which is usually retained in the blood stream in cats with CRF. Chronic retention of phosphorus can lead to a mineral imbalance, resulting in calcium being leached out of the bones. Increases in phosphorus also cause severe irritation of the stomach, causing nausea. Decreasing the phosphate in the diet helps to prevent these problems.

Other therapies include:

Administration of antacids such as Alternagel, this acts as a phosphorus binding agent. This will also help control phosphorus levels. This product is available at most pharmacies, located where the antacids are kept.

Calcitriol at a dose of 2.5ug/kg/day is also sometimes recommended to help control phosphorous toxicity. This drug should not be administered if phosphorus levels are over 6.

If urine cultures are positive or on ultrasound there is indication of disease in the kidney pelvis, antibiotics should be administered for 4-6 weeks.

H2 blockers such as pepsid at a dose of 5mg every day, help with the nausea of kidney disease.
If hypertension (high blood pressure) develops amylodipine (Norvasc) is given at a dose of 0.625mg per day.

Epogen or Procrit is an injectable which may help replenish the loss of erythropoiten and help control the anemia. The use of these products is somewhat controversial.

Appetite stimulants-by prescription

Potassium supplements

Kidney Transplant-this procedure is available at about 10 clinics nationwide. Cornell University and the University of Pennsylvania in the East offer this procedure. Please consult with your veterinarian for a facility near you. As of this writing the cost is $4,000-$5,000. Kidney transplant recipients need to take medication daily to avoid organ rejection, and there are ethical considerations regarding the donor cat as well.