Causes of FLUTD

Remember, FLUTD itself is not a disease, but rather a group of conditions affecting the lower urinary tract. This means there are many possible causes of FLUTD.

Let’s take a look at these in greater depth.

Click on the possible causes below to expand and read more

Feline Idiopathic Cystitis (FIC)

Idiopathic means unknown cause, and cystitis means inflammation of the bladder. In the majority of cats with FLUTD (57%) the underlying cause can’t actually be identified. These cats are then diagnosed as having FIC, or inflammation of the bladder with no known cause.

Stress is believed to play an important role in the development of FIC. It’s really important to understand- this does not mean that you have done anything wrong! Something as simple as moving some furniture can cause stress in some cats. We’ll learn more about this later in the course.

Bladder stones (Urolithiasis)

Bladder stones are hard accumulations of minerals in the urine, which irritate the bladder lining and cause pain and inflammation. Even more seriously, if they manage to travel into the urethra, they can cause a blockage. This is known as a ‘blocked bladder’, and it is a life threatening emergency. We’ll learn more how to spot the signs of a blocked bladder later in the course.

Bladder stones are the cause of FLUTD symptoms in about 1 in 5 cases. Some types of stone are more likely when cats have a urinary tract infection, meaning the FLUTD can sometimes be caused by both UTI and urinary stones

Urethral plugs

The urethra can become blocked by a build-up of mucous, made up of crystals, inflammatory cells, and debris. Small bladder stones can also form a plug in the urethra. If the urethra becomes completely blocked, this is known as a ‘blocked bladder’, which is a life-threatening emergency. Sometimes the urethra can become blocked by a spasm in the muscles of the urethral sphincter, which can happen when there is severe inflammation. This is known as a ‘functional blockage’.

A very large urethral plug removed from a male cat

Anatomical defect

The most common anatomical defect causing FLUTD in cats is a urethral stricture. This can happen when fibrous scar tissue develops as a result of trauma, or ongoing severe inflammation. Luckily, this is still relatively uncommon.

Neoplasia

Thankfully cancer of the bladder or urethra is relatively rare in cats, affecting less than 1 in 1000 cats, but it is one of the possible causes, especially in older cats with FLUTD.

Urinary Tract Infection (UTI)

Bacterial lower urinary tract infection is relatively rare in cats. One study found it was the cause of FLUTD symptoms in about 8% of cats.

UTI is more common in cats with another condition like diabetes or kidney disease. It’s more common in older cats, probably for this reason.

Summary

The majority of cases of FLUTD in younger cats are due to Feline Idiopathic Cystitis (FIC). This means inflammation of the bladder, of unknown cause. It is thought that stress plays an important role in FIC. Other possible causes include bladder stones (urolithiasis), blockage of the urethra (urethral plugs), an anatomical issue, cancer (neoplasia) or bacterial infection.

Key Takeaway

Feline Idiopathic Cystitis (FIC) is the most common cause of FLUTD in young cats.

Niamh Morgan
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