One of the worst things a pet parent can experience is the sudden loss of their beloved cat. Trying to be aware of sudden cat death is excruciatingly painful. You want to understand what happened, to think about what you could have done differently, and to determine if there were health issues that you didn’t see through. It is most difficult to make sense of sudden cat death when it happens to a young one.

When it comes to illness and death in cats, one thing that is important to remember is that cats are naturally inclined to hide their illness as a survival measure, which let cats be sick for a long time before anyone is aware. What may seem like sudden death is actually the consequence of an ongoing illness in its final stages. This can be especially precise for those who spend every day with their cat but do not notice unremarkable changes like weight loss, shedding, sleeping more, or a dull hair coat. As our cats get older, symptoms such as weight loss, less activity, and/or lethargy are believed to be from them slowing with age rather than from an illness.

Causes of sudden death in cats include:

Hypertrophic Cardiomyopathy

Among kinds of heart disease in cats, cardiomyopathy is the most common. Unlike other forms of heart disease, cardiomyopathy is hereditary and not a result of improper diet or exercise, but of the heart muscles not developing properly and thickening. This causes compromised cardiac function.


There are many foods and plants that are toxic to cats, even though they are non-toxic to human beings. Garlic, onions, and chocolate are three examples of foods without issue for us that can induce toxicosis in cats. Severe cases can cause a cat’s health to rapidly worsen. Without prompt treatment, it may also die. These toxins can be absorbed through the skin as well through sprays, oils, or aerosolized particles. A cat can lick the particles off of its fur as well. Even a tiny amount of this can cause toxicosis.

Feline Asthma

Feline asthma is considered an inflammatory respiratory disease, and it can vary in severity. Cats may only suffer minor coughs when the asthma is present. Others may suffer severe constriction of the airway and respiratory distress, severe enough to lead to death. Depending on the severity of asthma, the symptoms of Feline Asthma are:

  • Shallow breathing
  • Coughing or hacking breaths
  • Inability to exercise
  • Wheezing
  • Strained or labored breathing

Feline asthma is neither preventable nor curable, but its symptoms can be managed with medication.

Urinary Obstruction

Urinary obstructions are more common in male cats than female and can cause death within days of forming. Urinary obstruction occurs when a plug forms in the urethra and prevents the passing of urine. This plug could be mucous, crystals, or bladder stones. Signs of urinary obstruction in cats are:

  • Straining or unable to urinate
  • Frequent trips to the litter box
  • Crying or loud meowing while trying to urinate
  • Urinating outside of the litter box
  • Passing only small amounts of urine
  • Blood in the urine


Trauma is distressing and commonly occurred in outdoor cats, which are exposed to other threats, such as:

  • Other animals
  • Diseases
  • Weather events
  • Parasites
  • Toxic plants and chemicals
  • Cruel people
  • Machinery

Still, indoor cats can suffer sudden death due to trauma. Homes are full of hazards like high shelves and reclining chairs. Even though a cat may be particularly good at landing on its feet, a wrong fall can still lead to severe trauma, even to sudden death, especially when the trauma is to the head or neck.  

Blood Clot

A blood clot, or thrombus, can be a sudden death cause in cats depending on where the clot forms. In such cases, the blood flow in an artery or vein is badly interrupted or blocked or when a blood vessel’s lining is damaged. The break-off of a part of this clot is called an embolus, and this ‘traveling clot’ can become lodged elsewhere in the body.
Blood clots are deadly to cats if the clot occurs in the lungs, heart, or brain, depending on the size of the clot, the general health of the cat, and if it has any underlying illnesses.


Sepsis is said to be one of the most challenging illnesses to treat. Since it is a massive full-body infection that, even with aggressive treatment, has a 20%-68% mortality rate. By the time the infection travels to the blood then induces sepsis, the state is urgent. Right after sepsis has taken hold and evolved into septic shock, the cat may die shortly.

Heart Failure

Cats usually hide their pain or illness as a basic instinct. So by the time symptoms become clear to most owners the cat’s heart failure has progressed to a life-threatening condition. At this state, death can occur quite all of the sudden. Heart failure is caused by a number of other diseases, including hypertrophic cardiomyopathy. A general explanation of heart failure is that the heart, for whatever reason, loses its ability to distribute blood throughout the body properly.

Recognizing heart failure is key for treatment – and, yes, heart failure is curable if caught early on. Symptoms include:

  • Appetite loss
  • Grey or purple gums
  • Labored breathing
  • Panting
  • Coughing
  • Weakness
  • Lethargy


Broadly, shock occurs when the brain is deprived of oxygen and the circulatory system slows down. It can rapidly worsen and cause death if left without treatment. Signs of shock include:

  • Pale or discolored gums
  • Depression
  • Convulsions
  • Disorientation
  • Lethargy and weakness
  • Hypothermia
  • Rapid or shallow breathing
  • Rapid or weak pulse
  • Loss of consciousness


Strokes are not rare in cats. A stroke is a cerebrovascular accident, which is a disturbance of the blood supply to the brain. Its cause varies from high blood pressure to the tumor, cancer, poison, or any number of diseases. Strokes may lead to sudden death.

Signs of a stroke in cats include:

  • Disorientation
  • Incoordination and falling over
  • Head pressing
  • Stumbling or abnormal gait
  • Weakness
  • Partial paralysis on one side of the body
  • Lethargy
  • Seizure
  • Unequal pupil sizes


Cats at any age can suddenly die by choking. The cat suffers choking when swallowing an item, and that item becomes lodged in the larynx or trachea. Choking can cause unconsciousness in minutes, and event death in case the blockage is not removed. Signs that your cat is choking are:

  • Coughing or gagging
  • Panicked behavior
  • Pawing at the mouth
  • Drooling
  • Assuming a hunched position with its neck stretched out
  • Labored or wheezing/rasping breathing
  • Fainting

When your cat is choking, remain calm, put him in a carrier or a towel then take him to the vet as soon as possible. If the cat faints or is seriously struggling to breathe, inspect his mouth. Try to remove it if you can see the blockage.

Venomous Animals

Although venom lethality between species is different, a venomous bite of any kind can be a mortal wound for a cat. Depending on the toxicity of the venom, death could even happen in a few hours. Symptoms of envenomation include:

  • Weakness
  • Collapse
  • A bite site, which may be swollen and discolored
  • Vomiting
  • Shaking or twitching (full body or muscular)
  • Dilated pupils
  • Bloody urine
  • Partial or complete analysis

Low blood Sugar

Low blood sugar, so-called Hypoglycemia, can lead to death in severe cases. It is the result of the cat’s body being deprived of the natural sugars used for energy conversion. This could happen because of inappropriate diet, starvation, intestinal parasites, or other health issues that affect blood sugar levels. Hypoglycemia without treatment can cause: 

  • Lethargy
  • Muscular twitches
  • Trembling
  • Loss of appetite
  • Blindness
  • Lack of coordination
  • Unconsciousness

Diabetic Ketoacidosis

Diabetic ketoacidosis is a condition that arises when diabetes is left untreated. The condition has progressed to the point where there is a lack of insulin in the body. To a point that is so serious that sugar cannot get into the cells. Its result is cell starvation.
A body with cell starvation will try to break down fat as an alternate energy source. Ketones are then produced, which don’t produce energy cleanly. A body depending on ketones for energy will suffer pH and electrolyte imbalances. After that dehydration occurs, causing further metabolic imbalances. From here, the health of the cat can rapidly worsen. Signs of diabetic ketoacidosis include:

  • Weakness
  • Vomiting
  • Excessive thirst
  • Excessive urination
  • Weight loss
  • Flaky skin
  • Odd smelling breath
  • Diarrhea
  • Loss of appetite or anorexia
  • Lethargy
  • Abnormal breathing pattern
  • Jaundice
  • Abdominal pain

In severe cases, the cat will fall into a comatose condition. Even with treatment, it may still die.

Acute Kidney Failure

Acute kidney failure is an out of nowhere decline in kidney function. This results in a buildup of toxins and fluids in the body, eventually death. This can progress rapidly. Even with treatment, the mortality rate is still high.
Acute kidney failure may cause the symptoms of:

  • Disorientation
  • Lethargy
  • Weakness
  • Altered drinking volume and urination
  • Incoordination
  • Strained urination
  • Loss of appetite
  • Vomiting
  • Decreased urine production.


The sudden death of a beloved cat is a heartbreaking event that many pet parents have experienced. It’s unfair, and a dreadful shock. Know when are your cats get sick, and Understanding the causes of sudden death can prevent them from occurring at all. It also helps you recognize the early signs of others and seek treatment in time.
Limiting your cat’s exposure to possible causes of sudden death often depends on keeping up with routine vet check-ins. It also means applying vaccinations and medications that prevent parasites. Having a proper, balanced diet and exercise is also essential.

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