Medical Appendix – Internal Disorders

Listed in this Appendix are some of the disorders cats may acquire. Some
are very common and others are rare, but being an alert, informed owner
can make a big difference in how quickly symptoms get noticed an
diagnosed and how fast a cat’s pain and suffering will be relieved. The
problem could be minor or it could be life-threatening. Your familiarity with
your cat and how he normally looks, acts, feels, or sounds enables you to
suspect trouble when he just “isn’t his usual self.” Cats’ lives have been
saved because of hunches like this.
The purpose of this book is neither to be a complete medical reference
nor is it meant to replace the personalized care of your veterinarian. If you’d
like to read in more detail about all the disorders that can affect cats, I urge
you to add a veterinary medical reference book to your home library.

“Internal Disorders”


These worms live in the intestines and are probably the most common of
the internal parasites in adult cats.
Tapeworms require an intermediate host during the larval stage before
transmission to the cat. Fleas are common tapeworm hosts and based on the
cat’s fastidious grooming behavior, it’s very likely that at least one flea that
is harboring immature tapeworms will be ingested.
Cats can also acquire tapeworms by eating raw meat or raw freshwater
fish. Outdoor cats who routinely hunt can also be exposed through their
The tapeworm attaches itself to the intestinal wall by way of suckers and
hooks on the head. The body is comprised of segments, each one containing
eggs. These segments break off and pass out of the body in the cat’s feces.
The segments, which are about a ¼” in length, can wriggle by themselves
when freshly separated from the worm. You may notice one or two moving
segments clinging to the hair around your cat’s anus. As the segments dry,
they resemble grains of rice. You may also find these tapeworm segments
on your cat’s bedding.
The cat may also drag his hindquarters along the carpet or lick his anus
frequently due to the itching.
If you notice tapeworm segments, the veterinarian will administer
deworming medication specifically for tapeworms, either in oral or
injectable form.
If there are tapeworms in your cat, most likely there are also fleas on
your cat. Combine the deworming with a comprehensive flea control
program to avoid a reappearance of the parasite. Even if you don’t see little
tapeworm segments on the cat or in the environment, if he has a significant
flea problem, there’s a chance that he also has tapeworms.


A common worm found in kittens and puppies. Roundworm larvae are
transmitted to nursing kittens by way of the mother’s milk. Kittens with
roundworms develop a characteristic pot belly appearance while the rest of
the body remains thin.
Cats acquire roundworms by coming in contact with egg-contaminated
soil, water, feces, or vomit. Roundworm eggs are very hard and can
withstand unfriendly conditions in the soil for a long time, until an
unsuspecting host comes along.
Roundworms, which grow from four to five inches long, live in the cat’s
stomach and intestine. You may notice a roundworm in the cat’s feces or in
vomitus. Roundworms resemble spaghetti (not a pleasant comparison, I
know, but it’s unfortunately accurate). Symptoms include weight loss,
diarrhea, vomiting, pot belly, lethargy, and coughing (coughing occurs when
the worms have reached the cat’s lungs).
Treatment: deworming medication is given to kill mature worms and
larvae. Your veterinarian will also recommend a follow-up visit so the cat’s
feces can be rechecked to ensure all worms and larvae have been
completely killed.
Roundworms are rare in adult cats.
If you’ve adopted a stray cat, in addition to having him tested for diseases
and vaccinated, he should also be checked for worms.

3- Hookworms

These thin worms attach to the intestinal wall to feed. Hookworms are
relatively small, ranging in length from ¼–½”.
Transmission occurs through contact with feces or soil containing the
larvae. Hookworms are shed through feces and end up contaminating soil or
litter. They can then enter another cat’s body through the paws as the animal
steps on the contaminated soil or litter. Transmission to kittens can occur
through nursing contaminated milk from the mother. For kittens,
hookworms can be potentially fatal. Transmission doesn’t occur in utero.
Signs of hookworm can include: diarrhea, constipation, weight loss,
weakness, pale nostrils, and pale lips. Hookworm infection can lead to
anemia with continual loss of blood from the intestine.

4- Heartworm

Heartworm is a disease more commonly associated with dogs. Even though
it’s not as common in cats, it’s important to keep your cat protected.
Heartworm prevention in cats hasn’t received the attention and awareness
needed to alert owners to the danger.
Heartworm is spread by mosquitoes carrying the larvae. Once the
mosquito bites the cat, it injects the larvae from its saliva. When the larvae
mature into worms, they move through the circulatory system and
eventually travel to the heart or lungs. Because of a cat’s small size, the
presence of just a few worms is considered a heavy infection and therefore
Signs of heartworm can include: vomiting and coughing. As the disease
progresses, it leads to breathing difficulty. Diagnosis is confirmed through
blood tests, urinalysis, X-ray, and ECG. It can be easily misdiagnosed as
asthma during a routine exam.
Prevention is the key since there is no medication to kill adult
heartworms (usually surgery is the only option).
There are heartworm preventatives that can be administered. Discuss
these options with your veterinarian. If your cat goes outdoors and you live
in a high-risk area, which is any climate where a mosquito might fly by, it’s
a good idea to protect your cat. Cats living in warm climates may need to
remain on a heartworm preventative year-round. In colder climates the
preventative should be given just before the start of mosquito season and
continue until the season is well over. Your veterinarian will advise you on
whether your cat should remain on a preventative year-round.
Treatment for a heartworm-positive cat is decided on a case-by-case
basis. Prednisone may be given. In acute cases, a cat in shock will need to
be stabilized using oxygen, IV fluids, bronchodilators, and IV steroids.

5- Toxoplasmosis

Toxoplasmosis can cause birth defects in humans by infecting the fetus, and
as such should be a concern for pregnant women. If you’re pregnant or
suspect that you might be, another family member should take over litter
box responsibilities. Refer to Chapter 8 for specific instructions.