Malabsorption in Cats (Felis) | Vetlexicon
felis - Articles


ISSN 2398-2950


  • Poor absorption of nutrients from small intestine.
  • Cause: altered intestinal mucosal or lymphatic function.
  • Signs: diarrhea, weight loss, vomiting, lethargy, anorexia or polyphagia.
  • Diagnosis: history, physical examination, laboratory tests, abdominal ultrasound, gastrointestinal histopathology.
  • Treatment: dependent on underlying cause.
  • Prognosis: can be guarded.

Presenting signs

  • Chronic diarrhea.
  • Weight loss.
  • Anorexia or polyphagia.
  • Lethargy.
  • Vomiting.



  • Mucosal damage often due to inflammatory response or neoplasia.



  • Reduced nutrient absorption due to:
    • Villous atrophy  →  decreased surface area  →  decreased absorptive capacity.
    • Mucosal damage  →  loss of mucosal integrity  →  increased intestinal permeability.
    • Mucosal damage  → loss of brush border enzymes Brush border membrane disease  → decreased digestion and absorption.
    • Infiltration of lamina propria with inflammatory or neoplastic cells  →  reduced absorption and altered motility.
    • Lymphangiectasia  →  malabsorption of lipoproteins and fats.


Presenting problems

  • Chronic diarrhea.
  • Weight loss.
  • Anorexia or polyphagia.
  • Vomiting.

Client history

  • Chronic diarrhea.
  • Weight loss.
  • Increased fecal volume.
  • Polyphagia/anorexia Anorexia.
  • Flatulence/borborygmi.
  • Lethargy.
  • Vomiting Vomiting - often present in IBD cases which is probably most common in patients with malabsorption.

Clinical signs

  • Poor body condition/coat condition.
  • Muscle atrophy.

Diagnostic investigation

  • See also chronic diarrhea.

Biochemistry/Laboratory tests

Abdominal ultrasound

  • Assess intestinal wall thickness and layering Ultrasonography: GI system.
  • Asses for focal or diffuse intestinal lesions.
  • Assess mesenteric and colonic lymph nodes.
  • Assess liver and pancreas to concurrent disease.


  • Gastrointestinal biopsy.
    Endoscopic biopsies may give false negative results due to inadequate depth of sample collected, however is less invasive than exploratory laparotomy.

Confirmation of diagnosis

Discriminatory diagnostic features

Definitive diagnostic features

  • Histopathology of gastrointestinal biopsies.

Gross autopsy findings

  • Rapid intestinal autolysis. Therefore, prompt examination and fixation of multiple regions of gastrointestinal tract required.
  • Examine for other causes of weight loss, eg liver, kidney, thyroid, pancreas, neoplasia, chronic inflammation etc.

Histopathology findings

  • Handle tissue with great care to avoid mucosal damage. Open and fix serosal side down on card (avoids curling). Include stomach, duodenum, jejunum, ileum, colon, liver, kidney, pancreas, mesenteric nodes. Include multiple sites of small intestine.
  • Diagnosis of inflammatory bowel disease often requires abnormal villus morphology in addition to inflammatory infiltrate, so good villus preservation critical.

Differential diagnosis


Initial symptomatic treatment

  • Modify diet (commercial therapeutic gastrointestinal diet, commercial therapeutic hydrolyzed diet or commercial therapeutic limited-ingredient novel protein diet).
  • Anti-inflammatory or immunosuppressive dose of corticosteroids if IBD.
  • Gastroprotectants (omeprazole Omeprazole, sucralfate Sucralfate) and anti-nausea medication (eg maropitant Maropitant citrate).
  • Fenbendazole Fenbendazole at 50 mg/kg once per day for 5 consecutive days.
  • Supplement cobalamin Vitamin B12, 250 mcg SC weekly for 1-3 months, however one study suggests daily oral supplementation may normalize levels.
  • Supplement vitamin K Vitamin K, if required, based on PIVKA/OSPT PIVKA.

Standard treatment

  • Treat underlying small intestinal disease if identified.




  • Dependent on underlying disease.

Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Toresson L, Steiner J M, Olmedal G (2017) Oral cobalamin supplementation in cats with hypocobalaminaemia : a retrospective study. J Feline Med Surg 19 (12), 1302-1306 PubMed.
  • Jergens A E (2012) Feline idiopathic inflammatory bowel disease: what we know and what remains to be unraveled. J Feline Med Surg 14 (7), 445-458 PubMed.
  • Willard M D (1999) Feline inflammatory bowel disease: a review. J Feline Med Surg 1 (3), 155-164 PubMed.

Further Reading