Malabsorption in Cats

This syndrome might be due to a lack of digestive enzymes, inflammation of the bowel wall, or an overgrowth of bacteria which interfere with digestion. The signs linked to malabsorption are weight loss and diarrhea, however these are general symptoms and not diagnostic in their own right.

Malabsorption is an umbrella term used when a cat is not able to properly absorb all of the nutrition from its food. Most commonly this is linked to disease processes affecting the small intestine, where most of the absorption takes place, but can also affect the large intestine.

The symptoms of malabsorption are quite general and their presence alone is not sufficient to make a diagnosis. A persistent sign, such as long-term weight loss or diarrhea, needs investigation to determine the root cause, of which a form of malabsorption is one of many explanations. Indeed, even when malabsorption is diagnosed there is still a question as to what type of malabsorption the cat is suffering from. 

• Diarrhea
• Weight loss
• Vomiting
• Increased appetite
• Dullness and depression
• Poor coat 
• Flatulence

Poor absorption from the bowel has many causes. Key to treating the condition is to understand why the problem has developed in the first place. Some of the most common causes are: 

• Inflammation: the bowel wall may become swollen as a result of a dietary allergy, food intolerance, or conditions such as eosinophilic enteritis, in which one type of white cell floods the bowel wall.
• Cancer: Bowel cancers such as adenocarcinoma or intestinal lymphosarcoma 
• Infections: Such as campylobacter, cryptosporidia,  giardia, or parasitic worms
• Damage to the gut wall: As a result of viral infections or an overgrowth of unhelpful bacteria.

It is helpful to build up a picture of how frequently the cat has diarrhea and its appearance. This enables the vet to decide if the problem relates to the large or small intestine, which may influence the choice of tests. 

A fecal analysis is useful to detect infection and parasites. When present, the vet may treat these first and see if the problem resolves. If it doesn't, then screening blood tests give information about organ function (of which diarrhea could be a complication). For example, a cat with overactive thyroid glands may develop malabsorption as a result of increased gut motility, and the key to treatment is therapy for the thyroid. 

Bowel function blood tests give a valuable insight into the health of the gut wall, and levels of pancreatic enzymes, which are also causes of malabsorption. 

Ultrasound scans enable the clinician to assess the thickness of individual layers of the gut wall. This can help differentiate between an inflammatory condition (such as inflammatory bowel disease, IBD) and cancer. However, in these cases, the ultimate diagnosis depends on cytology (a sample of cells) or histology (examining a biopsy sample)

If dietary allergy is suspected, then the vet may suggest feeding a hypoallergenic diet for a number of weeks, to see if this brings about a resolution of symptoms.

At first presentation the vet may try to relieve the symptoms using:

• A low fat, highly digestible diet or a high fiber diet
• B Vitamin injections to replenish low levels in the bowel wall
• Deworming and / or an antibiotic such as metronidazole that has an anti-inflammatory effect on the bowel wall.
• Probiotics: To re-establish a healthy population of bacteria in the gut

If the cat does not improve, then successful treatment depends on identifying the underlying reason for the malabsorption and addressing this.

• Hyperthyroidism: Medication, surgery, or radioactive iodine therapy.
• Cancer: Chemotherapy and surgery as necessary. Whilst lymphosarcoma might respond well to chemotherapy, adenocarcinoma carries a much poorer outlook. In addition, bowel surgery to remove any cancerous areas is associated with a risk of complications, such as peritonitis.
• Food allergy: Feed a hypoallergenic diet
• Bacterial overgrowth: Give a course of antibiotics and probiotics that promote the growth of healthy bowel bacteria
• Deworming: Or appropriate parasite control
• Inflammatory bowel disease (IBD) If, despite dietary manipulation, the inflammation refuses to resolve, drugs such as steroids or other immunosuppressive drugs are most likely to be helpful. 

If the cause is an infection, then complete cure may be possible. 

If the cause is disease elsewhere, such as overactive thyroid glands, how well-controlled that condition is will influence how the malabsorption responds. In these cases, close monitoring is needed of the primary condition (eg the thyroid) in order to control the secondary condition (malabsorption).

In cats with dietary allergies or intolerance that leads to malabsorption, feeding a low-allergen diet can bring about a dramatic improvement. However, relapses will occur when the cat eats something they shouldn't.

IBD is one of the more common causes of malabsorption, and also one of the most difficult to control. Affected cats are often subject to relapses or flare ups, so it's important to have a good rapport with your vet so that you have a plan in place to cope with these episodes.