High blood pressure

Hypertension is the medical term for high blood pressure, a silent killer of older cats.

What causes hypertension in cats?

Hypertension is usually secondary to another disease. Kidney disease is the most common cause of hypertension but cats with adrenal gland tumours or treated for hyperthyroidism also develop high blood pressure at times. Sometimes no underlying cause is found.

Most cats with hypertension are older than 9 years of age.

What are the effects of hypertension?

Hypertension damages all body organs but we notice it most in:

• the eyes. The small vessels in the retina break under pressure. The bleeding detaches the retina and the cat becomes blind.
• the brain. Ruptured blood vessels cause ‘strokes’, fits, twitches or unusual behaviour
• the kidneys. Increased blood pressure damages the delicate filtration system of the kidney.
• the heart. The heart has to work harder to push the blood out into the body and the heart muscle thickens and becomes less efficient. Sometimes the heart goes out of rhythm or we hear a murmur with the stethoscope. Affected cats may show signs of heart failure such as breathlessness, lethargy, weakness or fainting.

How do we detect hypertension?

We measure the blood pressure of all cats over 9 years old as part of the regular seniors’ examination. We also check the blood pressure of all cats with kidney disease or hyperthyroidism, or with any signs of eye, brain or heart disease. 

Most cats tolerate the cat sized cuffs we put on their arms. Some don’t like the feel of the gel or the sound of the amplifier we use to hear the pulse. We try to put them at ease so that we get an accurate reading.

How do we treat hypertension?

A daily dose of amlopidine as a fragment of tablet (Norvasc), or as chicken, fish, cheese or beef flavoured drops to put on the food, brings the blood pressure down rapidly.

After a week on amlopidine we recheck the blood pressure to see if it has come down to normal. If all goes well we recheck it every 3 months. 

Sometimes other medications like benazepril (Fortekor or Vetace) are added in, particularly if we detect kidney disease.

Cat FIV and AIDS

Freddy came in last week off his food and drooling a lot. When I looked in his mouth I found a red raw gums and mouth. No wonder he was so flat and uninterested in life. 

Many infectious agents contribute to sore mouths like Freddy's. Freddy tested positive to FIV  (Feline Immunodeficiency Virus), which predisposes infected cats to mouth ulceration.  His owners have 2 other cats and a baby and had lots of questions about FIV and feline AIDS.

FIV is prevalent in Australian cats but testing positive for FIV is not the same as having feline AIDS.

Feline AIDS describes the terminal stages of disease which may not occur for many years - or at all! A positive FIV test means that your cat has been infected by the virus.

Are my family at risk?

No. Although FIV belongs to the same family of viruses as HIV in people, it only infects cats. There is no risk of cross infection of either virus between species.

Are other cats in the household likely to be infected?

The virus is shed in the saliva of infected cats and spread by biting. Cats with a history of cat bite abscesses are more likely to test positive for FIV.

Spread between cats in a household is unlikely unless they fight. Normal social interactions such as grooming rarely transmit FIV.

The best way to minimise the chances of FIV infection is to confine uninfected cats indoors away from aggressive cats.

How is FIV diagnosed?

FIV is diagnosed with a blood test at the surgery which detects an immune response (antibodies) to the virus. If this test is positive your cat is infected.

Kittens with immunity passed on from their mother may test positive until 4 months of age. If a young kitten tests positive we retest them at six months of age.

Will my cat recover?

Once a cat is infected with the virus it remains infected for the rest of its life but not all infected cats  become ill.

What diseases does FIV cause?

Like HIV, FIV suppresses the body’s defences so that the cat is vulnerable to diseases it would normally  defeat. The cat is vulnerable to chronic or recurrent infections that fail to respond to regular treatment.

These include:

1. Inflammation of the mouth and tongue leading to appetite loss, drooling and mouth pain
2. Weight loss
3. Poor appetite
4. Fever
5. Signs of brain dysfunction such as aggression, unequal pupils, convulsions and behavioural changes
6. Swollen lymph glands
7. Unusual infections like toxoplasmosis, cryptococcosis, chronic flu, pneumonia, skin disease
8. Tumours especially those of the lymph system

The non specific signs of weight loss, poor appetite and fever occur in many diseases of cats and are usually unrelated to FIV. Cats with FIV are more likely to suffer from these signs and diseases more often and  be less able to throw them off even with treatment.

FIV positive cats have a shorter life expectancy on average than FIV negative cats.

Is there any treatment?

Secondary infections with bacteria or fungi are treated with antibiotics and anti-fungals but no specific treatment for the virus is available. Trials with anti-HIV drugs such as AZT have reduced mouth inflammation in affected cats but the cost and availability of AZT makes its use in general practice difficult at present.

Anti-inflammatory treatment reduces mouth inflammation and peps up the appetite in many cats.

Should I have my cat euthanased?

Certainly not on the basis of a positive FIV test!  Like humans with HIV, cats with FIV appear healthy and happy for a long time before getting sick.

On the other hand if your cat has succumbed to multiple infections, is no longer responsive to treatment or is suffering from a chronically painful mouth then euthanasia is the kindest solution.

How can I help my cat?

Confinement indoors of an FIV positive cat  reduces the risk of infection with other agents. It also reduces the risk of transmission of the virus to other cats.

A good quality, highly palatable diet as well as worming every 3 months and at least annual health checks will enhance the disease free period.

Infections require prompt and aggressive treatment.

How do we prevent FIV infection?

Desexing and confinement indoors, especially at night, reduces fighting and therefore the risk of infection. We recommend vaccination with FIV vaccine for all cats with access to the outdoors. Cats older than 6 months of age are tested for FIV before the first vaccination. A series of three primary vaccinations is given 2-4 weeks apart and then a booster is given annually.