cat died suddenly
Cat Health and Wellness

9 Causes of Sudden Death in Cats

It’s difficult to cope with the sudden or unexpected death of a cat, especially when it happens to a young adult cat or kitten. Cats regularly reach 16 to 22 years of age, with indoor-only cats living the longest. Outdoor cats lifespan can be reduced by trauma, infectious diseases, and predators.

What are the causes of sudden death in cats? Trauma from road traffic accidents is the most common cause of death in cats that spend time outdoors. Heart disease and poisoning are also leading causes of death in cats of all ages. Older cats are more likely to die as a result of undetected renal failure or urinary tract disease.

Pet owners must note that cats are good at hiding the signs of pain and illness. A cat may be sick for a long time before an owner identifies the symptoms. This is the case with cats that undergo changes in their coat and weight loss as a result of an undetected health condition.

What Causes a Cat to Die Suddenly?

When an indoor or outdoor cat goes missing, it often means that something has happened to the cat that has prevented it from returning home.

This can include illness, injury, and death. By the nature of their survival, cats usually hide when they’re sick or injured and die if not found on time. Furthermore, it can difficult to detect the symptoms of illness in cats. They’re so good at hiding the signs.

It’s easy to believe that symptoms, such as lethargy and weight loss, are from just old age. But it’s more likely to be an underlying medical condition. There are many reasons for sudden death in cats, each affecting certain groups more than others.

For example, it could be that your cat died suddenly due to physical trauma. This is common in outdoor-access cats and death from kidney disease occurs mainly in senior pets. Heart disease can occur in any cat, with few warning signs.

1) Trauma

Examples of trauma include road traffic accidents, animal attacks, falls, and gunshot wounds. 

According to the Canadian Veterinary Journal, of the 79 cats that were brought in for autopsies due to sudden and unexpected death, 34% of the deaths were caused by road traffic accidents.

Researchers noticed that the majority of the road traffic accident cases were attributed to outdoor-access cats only. There were 49 outdoor cats in the study, out of which 25 had died from road traffic accidents. Other trauma-related deaths were caused by gunshots and dog bites.

2) Feline Cardiomyopathy (Heart Disease)

According to Cardiology Research, heart disease affects 10 to 15% of the cat population worldwide.

If left untreated, heart disease can cause congestive heart failure in cats. Heart disease is a condition that occurs due to abnormalities in the heart muscle and can be acquired or congenital:

  • Adult-onset heart disease typically occurs in middle-aged or older cats as a result of wear and tear on the heart structures. Acquired heart disease can also occur from an infection or injury. Hypertrophic cardiomyopathy is the most common form of the disease.
  • Congenital heart disease is present at birth and can be passed down from the parents. Malformations of the heart valve, or the wall that divides the left and right halves of the heart, are common causes for congenital heart disease. These defects can cause blood to flow abnormally, resulting in a heart murmur in cats.

There are many stages of heart disease that can be used by veterinarians to determine the severity of the condition. These include:

  • Asymptomatic. Although heart disease is detected, there are no noticeable signs yet. Arrhythmia or a heart murmur may be present.
  • Mild-to-moderate heart failure. Signs and symptoms of congestive heart failure are obvious during rest and when the cat is active.
  • Advanced heart failure. The affected cat shows severe and obvious clinical signs, such as respiratory distress, significant exercise intolerance, and fluid in the body cavity.

Signs And Symptoms

Heart disease may not present any noticeable signs until it has progressed significantly. A cat with heart disease may hide its symptoms and appear completely normal.

However, as the disease progresses, the signs of illness become increasingly obvious. Some cats with heart disease may have difficulty moving their back legs or have trouble breathing.

Others may be found dead by their owners, with no apparent reason.

Some symptoms of heart problems in cats include:

  • Weakness, lethargy, and inactivity
  • Exercise intolerance
  • Difficulty breathing with fluid buildup in the lungs and chest
  • Fainting or collapsing
  • Rapid breathing during rest
  • Inability to move the back legs
  • Chronic coughing
  • High heart rate

Feline Heart Disease Complications

Hypertrophic cardiomyopathy is the most common form of heart disease in cats that occurs due to an increase in the thickness of the walls of the heart. This prevents the heart muscle from relaxing sufficiently between contractions and also reduces the blood volume in the heart.

Many cats with hypertrophic cardiomyopathy develop congestive heart failure. The condition also increases a cat’s risk of developing blood clots that move out of the heart muscle and obstruct narrowed blood vessels. This is called thromboembolism.

most common cause of death in cats

Thromboembolism occurs in the hindquarters region of an affected cat, thereby resulting in paralysis and severe pain in that region. This causes owners to mistake hypertrophic myopathy for a leg injury.

Although hypertrophic cardiomyopathy is an incurable disease, early detection and treatment can allow a cat to live a normal life for years to come. However, each case is different, and the form and severity of the disease will determine a cat’s prognosis.

It’s also important to note that hypertrophic myopathy can progress slowly or rapidly over a period of years. The condition can remain unnoticed in cats until they reach the advanced stages of the disease, after which death can occur within a few weeks or months.

3) Heart Attack

Heart attacks in cats are due to an obstruction in the blood flow to the heart wall (the myocardium). This causes that portion of the myocardium to die prematurely.

The blockage generally occurs due to the formation of a blood clot, or a thrombus in the heart or the blood vessels, cutting off the blood supply to the myocardium.

Common causes for heart attacks in cats include cardiomyopathy and thromboembolism. The severity of the condition may mean that you may find that your cat died in sleep with its eyes open. It can be hard to cope with the sudden loss of a cat because it’s so unexpected.

Did My Cat Have A Heart Attack?

Heart attacks are rare in cats. Furthermore, the term “heart attack” is typically misunderstood when it comes to animals. The term is often used to describe a collapsing episode or sudden death of an animal, which can be caused by a seizure or syncope (a condition related to poor heart function).

However, myocardial infarctions (heart attacks) are extremely rare in cats, primarily because of the way fats are metabolized in their bodies. Some scientists believe that cats with diabetes may have a higher chance of having a coronary artery blockage, but the risk in such cases is still very small.

Some cats with cardiomyopathy have been suspected to have undergone a heart attack due to the thinning of the heart wall in certain regions of the heart. There’s a higher chance that a blockage that occurs in a cat’s blood vessels may be associated with blood clots from cardiomyopathy, compared to any dietary factors.

4) Feline Heartworm Disease

Feline heartworm disease is caused by the infestation of a parasitic nematode named Dirofilaria immitis, also called the heartworm.

The severity of the condition is directly related to the number of worms existing in the body, as well as the response of the cat’s immune system and the duration of the infestation. Heartworms that infect cats are often smaller and have a shorter lifespan than the heartworms that infect dogs.

Many cats with heartworms do not have any adult worms. Moreover, outdoor cats are twice as likely to be infested by heartworms as indoor cats.

Because most cats have smaller and younger heartworms present in them, their symptoms often go undiagnosed. However, even young worms can lead to severe damage via a condition called heartworm associated respiratory disease (HARD).

Cats cannot be treated with the same medication used to treat heartworm in dogs. Therefore, prevention is the only method of protecting cats from heartworm disease.

How Is Heartworm Disease Transmitted?

Mosquitos are vectors for heartworm disease. Infected animals, such as dogs, coyotes, foxes, and wolves carry adult heartworms that produce microfilaria, or baby worms that circulate in the animal’s bloodstream.

When a mosquito bites an infected animal, the blood meal it collects will also contain these microscopic worms that mature into infective stage larvae within 10 to 14 days.

Following this period, when the infected mosquito bites another susceptible animal (the host), such as a cat or a dog, it will deposit the infective larvae onto the animal’s skin.

The larvae enter the new host via the bite wound created by the mosquito, and once inside, they mature into adult heartworms over a period of 6 months.

After reaching maturation, heartworms can survive within their host for up 2 to 3 years in cats and 5 to 7 years in dogs. Due to their long lifespan, the number of heartworms inside a host can accumulate with each mosquito season.

Signs and Symptoms

Some obvious signs include coughing, lack of appetite, weight loss, asthma-like attacks, and vomiting. On rare occasions, the condition may cause seizures, difficulty walking, fainting or fluid accumulation in the abdominal region.

However, in some cases, cats don’t show any signs or symptoms of the disease and experience a sudden collapse or death.

It’s critical to understand that heartworm disease can affect any cat, whether it is an indoors-only cat or an outdoor-access cat because infected mosquitos can easily come inside a house.

There are numerous variables, including the prevalence of wildlife in your area and climate differences that can cause infection rates to vary every year.

The American Heartworm Society recommends owners to “think 12.” This means getting your pet tested every 12 months and giving your pet a heartworm preventive 12 months a year.

5) Exposure To Toxins

Despite their finicky nature, cats are susceptible to intoxication due to their demanding grooming routine and their curious personalities.

A cat’s body lacks certain liver enzymes, which can affect its liver metabolism. This makes cats more sensitive to environmental chemicals and drugs.

Death caused by toxin exposure is more common in outdoor-access cats, but it can occur in indoor-only cats as well.

Many factors make cats more prone to getting sick after being exposed to a particular toxin. This includes the size of the cat’s body and its habit of hiding, where the effects of toxin exposure may not be immediately evident to the owner.

Contamination of a cat’s digestive system with an environmental toxin often occurs when a cat ingests a toxic substance from grooming contaminated fur or consuming a contaminated animal.

Some toxins can also be absorbed directly into the cat’s skin, especially through the paws. Certain toxins are also hazardous when inhaled.

According to the Pet Poison Helpline, the top 5 cat toxins include:

  • Human drugs (for example, those containing acetaminophen) and veterinary drugs
  • Toxic plants, such as Easter lilies
  • Insecticides
  • Household detergents and cleaners
  • Others, such as liquid potpourri, rat poison, and glow sticks

Signs And Symptoms

Signs and symptoms of poisoning may vary according to the type of toxin concerned. In general, exposure to a toxin may lead to the following effects:

  • Redness, inflammation, swelling and itching of the skin
  • Gastrointestinal signs, such as lack of appetite, diarrhea, vomiting, and drooling
  • Neurological signs, such as lethargy, disorientation, increased hiding, excitability or coma
  • Respiratory signs, such as sneezing, difficulty breathing or coughing

Poisoning can also result in liver failure, which may lead to dehydration, vomiting, diarrhea, loss of appetite and weight loss.

Another detrimental outcome from poisoning is kidney failure, which may result in signs and symptoms such as bad breath, increased thirst, and urination, decreased drinking and urination, vomiting, loss of appetite and weight loss.

Certain toxins have an immediate effect on the body’s system, resulting in a combination of the above signs and symptoms. Although many cases lead to acute or sudden symptoms, others may be affected by chronic, delayed poisoning, which is more difficult to recognize.

causes of sudden death in cats

6) Chronic Kidney Disease

Chronic kidney disease is a common condition that affects about 3 in 10 geriatric cats. Kidneys play a vital role in eliminating protein wastes, producing quality urine and balancing body water, acids and salts.

When a cat develops kidney failure, its kidneys are no longer able to eliminate waste products or perform any of these functions adequately, thereby resulting in the accumulation of toxins in the blood.

This leads to clinical signs, such as loss of appetite, vomiting, weight loss, lethargy, increased thirst, and increased urination. 

Kidney disease in cats can either be chronic or acute:

  • Chronic kidney disease. Occurs when kidney function deteriorates gradually, leading to subtle signs of illness as the condition worsens.
  • Acute kidney disease. Occurs when a severe or sudden injury to the kidneys leads to intense sickness and the cessation of urine production. This often results in death in cats.

7) Feline Urinary Obstruction

Feline urinary obstruction is an acute blockage of the urinary tract that is most common in male cats. Also referred to as “blocked cat,” the condition can lead to death in cats within 72 hours, if left untreated. Common signs for urinary obstruction in cats include crying and straining while urinating.

The urethra is the tube that carries urine from the urinary bladder and takes it out of the body. A urinary obstruction occurs when there is a blockage in the urethra, making it difficult to empty the bladder. Therefore, urinary obstruction is considered as a life-threatening medical emergency.

Signs and Symptoms

Urinary blockages are mainly common in male cats because of their notably narrower that must be able to pass through the penis. However, both male and female cats can develop a urethral blockage, which may lead to symptoms such as:

  • Continuous straining is mistaken for constipation
  • Produce little to no urine
  • Licking around the base of the tail or the genitals
  • Crying or howling, especially in or around the litter box
  • Lethargy
  • Hiding
  • Vomiting
  • Decreased appetite
  • Not tolerating being touched, especially around the stomach area

Signs and symptoms can vary significantly from one case to another as the urethral blockage can be partial or complete. A partial urinary blockage may cause discomfort or pain, or may cause your cat to spend more time inside or around the litter box.

You may notice urine puddles outside the litter box or in unusual areas of the house. Sometimes the urine is also bloody.

As the condition progresses to a complete urinary blockage, the affected cat may not be able to pass any urine. This can lead to severer symptoms and more life-threatening complications.

Profound lethargy, vomiting, and loss of appetite are some common symptoms of a full urinary blockage. If left untreated, the blockage can progress to kidney failure and lead to death within 24 to 48 hours.

8) Stroke

A stroke occurs when the blood supply to the brain is disrupted, leading to failed nerve impulses from the brain to other regions of the body.

The most common age for stroke in cats is approximately nine years. Symptoms for stroke are quick and lead to sudden death in cats.

Numerous underlying health conditions can increase a cat’s risk of a stroke. Some of them include:

  • Cancer within the brain or cancer that has spread to the brain
  • Heart disease
  • Diabetes
  • Hyperthyroidism
  • High blood pressure
  • Liver disease
  • Conditions that contribute to blood clots
  • Parasites
  • Lung disease
  • Infections
  • Trauma

However, in many cases, the cause for stroke cannot be identified. Signs of a stroke may include seizures, falling to one side or having difficulty walking.

9) Sepsis

Sepsis is a deadly infection that leads to severe inflammation in the body. If left untreated, the condition will get severer, resulting in multi-organ failure, including liver failure, acute kidney failure, and acute respiratory distress syndrome.

As the infection becomes severer, it overwhelms the body and causes septic shock. Septic shock is life-threatening for cats and has a high mortality rate even with aggressive treatment.

Septic shock in cats is commonly caused by intestinal cancer or ruptured intestines from a linear foreign body obstruction, which can occur when a cat ingests a string.

Kidney infection, a severely infected wound, feline infectious peritonitis and pyothorax (pus in the chest cavity) are other causes for septic shock in cats.

Occasionally, septic shock may occur as a result of a dental disease that leads to a blood infection, or conditions such as pneumonia, uterine infection and ruptured organs.

Sign and Symptoms

Unfortunately, cats show signs of septic shock only after the condition has reached a moderate-to-advanced state. Some cats may show visible signs of sepsis, such as:

  • Refusal to eat
  • Drooling
  • Vomiting
  • Anorexia
  • Hiding
  • Pale pink gums
  • Increased respiratory rate
  • Dehydration
  • Diarrhea
  • Vaginal discharge
  • Fever
  • Collapse
  • Straining to defecate or urinate
  • Distended abdomen
  • Foul odor from the back
  • Excessively licking the back
  • Collapsing

During a physical examination, your vet may detect additional signs of septic shock, such as abdominal pain, jaundice, slow heart rate, and low blood pressure. In many cases, death is the first sign owners notice when a cat suffers from septic shock.

Always keep a lookout for unusual behavioral changes, such as increased hiding as this indicates that something is wrong with your cat. This could be crucial to avoiding sudden death in cats.