Hypertension (high blood pressure) is fairly common in older cats. The condition can cause serious health problems but is treatable. Senior cats and cats with kidney or thyroid disease benefit from routine blood pressure screening.
 
Symptoms
High blood pressure is silent; it has no symptoms of its own. But high blood pressure damages organs of the body, causing symptoms that cat owners might notice.

• Eyes: Sudden blindness is sometimes the first symptom of hypertension in cats. About half of cats with high blood pressure have eye changes that are visible on an examination of the interior of the eye. These eye changes can be permanent, even if the hypertension is treated.[1,2]
• Kidneys: Hypertension might increase a cat’s risk of developing kidney disease. High blood pressure can also make existing kidney disease worse. The first symptoms of kidney disease are increased thirst and increased urine volume (larger urine clumps in the litter box).
• Heart: In cats, high blood pressure causes the heart muscle to thicken, a condition called ventricular hypertrophy. Cats with ventricular hypertrophy may have an abnormal heart rhythm and eventually develop heart failure. Some symptoms of heart failure are panting, difficulty breathing, and weakness.[3]
• Brain: High blood pressure can cause loss of energy, stumbling, and seizures.

 
Causes
In cats, hypertension is usually caused by another disorder. The most common causes in cats are chronic kidney disease and hyperthyroidism (overactive thyroid). Sometimes high blood pressure in cats seems to develop on its own with no known cause, as can happen in humans. Older cats are more likely than younger cats to have hypertension.
 
Blood pressure measurement
Current guidelines recommend measuring blood pressure in cats in these categories [2,4]:

• Cats with signs of organ damage that could result from hypertension (for example, blindness or seizures)
• Cats with diseases that can cause hypertension
• Senior cats (7 years and older)

 
In cats, blood pressure is usually measured with an inflatable cuff similar to the cuffs used in people (but much smaller!). The cuff is placed around a leg or the tail. During the procedure cats can lie down or sit upright, whichever is more comfortable for them. Most operators try to position the cuff at the level of the heart, but forcing a cat to lie down can cause agitation and raise the blood pressure.
 
Blood pressure readings are most accurate in calm cats. You might be asked to wait with your cat in the examination room for a few minutes to give her time to settle down and get comfortable. Consider bringing a cat bed, blanket, or towel from home so your cat can rest on something familiar during the procedure. Blood pressure is typically measured several times during each session to account for variation from motion or anxiety. Cats tend to tolerate the procedure well.
 
A systolic blood pressure below 140 mm Hg is considered normal in cats. (In blood pressure readings like “110/70 mm Hg,” systolic pressure is the first number and diastolic pressure is the second number). A systolic blood pressure of 160 mm Hg or higher indicates hypertension and an increased risk of organ damage.[4]
 
Veterinarians often measure blood pressure on more than 1 clinic visit before making a definite diagnosis of hypertension. Cats’ blood pressures can vary from visit to visit depending on their stress levels. However, signs of organ damage can confirm the diagnosis and justify starting treatment after only 1 measurement session. Cats with hypertension (or at risk for hypertension) should have blood pressure checks every few months.
 
Treatment
The goal of treatment is to reduce the risk and extent of organ damage. The underlying problem causing the high blood pressure is treated at the same time. Most cats with hypertension receive daily oral medication. The dose is adjusted as needed after blood pressure rechecks. Medication is usually effective in reducing the blood pressure, especially if the underlying disease is also controlled.
 
References
1. Syme H. Systemic hypertension: World Small Animal Veterinary Association World Congress Proceedings, 2013. VIN website. https://www.vin.com/doc/?id=5709837. Accessed March 25, 2019.
2. Taylor SS, Sparkes AH, Briscoe K, et al. ISFM consensus guidelines on the diagnosis and management of hypertension in cats. J Feline Med Surg. 2017;19(3):288-303.
3. Quinn R. Cardiovascular effects of systemic hypertension in cats. MSPCA Angell website. https://www.mspca.org/angell_services/cardiovascular-effects-of-systemic-hypertension-in-cats/. Accessed March 25, 2019.
4. Acierno MJ, Brown S, Coleman AE, et al. ACVIM consensus statement: guidelines for the identification, evaluation, and management of systemic hypertension in dogs and cats. J Vet Intern Med. 2018;32(6):1803-1822.
 
Photo by Hunt Han

Antifreeze is toxic to animals and people. Even a small amount of antifreeze licked from a paw or lapped from a puddle could kill a cat or dog. If you think your pet has been exposed to antifreeze, contact a veterinarian immediately.
 
The main ingredient of most types of antifreeze is ethylene glycol, a type of alcohol. Ethylene glycol has a naturally sweet taste.
 
Protect your pets by keeping them away from fluids that have leaked out of cars. Store antifreeze in sealed containers out of the reach of animals and children. Consider using antifreeze made of propylene glycol instead of ethylene glycol; it’s safer for pets.
 
Sources of ethylene glycol
Antifreeze (radiator coolant) is used in the engines of cars and other motor vehicles. The risk of exposure might be higher when seasons change and people change the antifreeze in their cars. Dogs have also been poisoned by drinking toilet water that has had antifreeze added to keep it from freezing.[1]
 
Although antifreeze is the most common source of ethylene glycol poisoning in dogs and cats, ethylene glycol can be present in other products:

• Brake fluid
• Windshield deicing solution
• Motor oil
• Solvents
• Rust removers
• Paint
• Snow globes
• Ink in stamp pads and ballpoint pens[1-3]

 
Signs of poisoning
The earliest symptoms are caused by the ethylene glycol itself. Symptoms that appear later are caused by toxic substances produced when ethylene glycol is broken down in the liver. The symptoms of poisoning occur in 3 stages.[4]
 
Stage 1: During the first 12 hours, symptoms are similar to those of alcohol intoxication:

• Vomiting
• Depression
• Stumbling and loss of balance
• Weakness
• Excessive thirst and urination

 
Stage 2: From about 12 to 24 hours after ingestion, the animal may seem to improve as “drunken” symptoms go away. But toxic products of ethylene glycol begin to alter the body’s acid-base balance and damage the kidneys. Signs include the following:

• Rapid heart rate
• Rapid or labored breathing

 
Stage 3: Between 12 and 24 hours after exposure (cats) or 36 and 72 hours (dogs), the kidneys stop working. The patient shows symptoms of acute kidney failure and other problems:

• Loss of appetite
• Vomiting and diarrhea
• Little or no urine produced
• Seizures
• Coma
• Death

 
Diagnosis and treatment
A blood test can detect ethylene glycol in the first few hours after ingestion. After a few hours, blood and urine tests begin to show evidence of acid-base disturbances and kidney damage. Diagnosing ethylene glycol poisoning can be tricky if no one saw the pet swallow antifreeze and the pet doesn’t arrive at the veterinary clinic until it is showing signs of kidney failure.
 
The sooner treatment begins, the better the prognosis. An antidote to ethylene glycol is available and should be given soon after exposure. This drug stops ethylene glycol from being converted to toxic substances. After most of the ethylene glycol has been metabolized by the liver, the antidote is less likely to be effective.
 
Other treatment is given to correct the body’s acid-base balance and support kidney function. Pets with ethylene glycol poisoning will probably need to stay in the hospital for a few days, even if the poisoning is caught early.
 
Prognosis
The prognosis is good for animals that begin treatment soon after ingesting antifreeze. For those that develop kidney failure, the prognosis is guarded to poor.
 
References
1. Antifreeze poisoning in dogs & cats (ethylene glycol poisoning). Pet Poison Helpline website. https://www.petpoisonhelpline.com/pet-safety-tips/antifreeze-poisoning-in-dogs-cats-ethylene-glycol-poisoning/. Accessed March 11, 2019.
2. Grauer GF. Overview of ethylene glycol toxicity. Merck Veterinary Manual website. https://www.merckvetmanual.com/toxicology/ethylene-glycol-toxicity/overview-of-ethylene-glycol-toxicity. Accessed March 11, 2019.
3. ToxFAQs for ethylene glycol. Agency for Toxic Substances and Disease Registry website. https://www.atsdr.cdc.gov/toxfaqs/tf.asp?id=85&tid=21. Published November 2010. Accessed March 11, 2019.
4. Brownie CF. Managing ethylene glycol toxicity (proceedings). DVM360 website. http://veterinarycalendar.dvm360.com/managing-ethylene-glycol-toxicity-proceedings. Published August 1, 2010. Accessed March 11, 2019.
 
Photo by Ana Silva on Unsplash