Unexplained weight loss in the cat

The “Shrinking Kitty” is a common presentation in the small animal clinic; this article offers a logical approach to the cat with unexplained weight loss.

Introduction

A cat with unexplained weight loss is a familiar scenario within the small animal consult room, and such cases can be both challenging and frustrating for the clinician. This article will outline a logical approach to the situation where no obvious diagnosis is apparent, with an emphasis on a cost-conscious, stepwise approach; a typical scenario is shown in Box 1.

Step 1: revisit the history

Owners can become accustomed to abnormal behaviors and may discount the significance of clinical signs such as vomiting. It is not unusual for an owner to say “Fluffy seems fine” when talking about a cat that vomits on a weekly basis. Similarly, an owner may fail to recognize the importance of a subtle change in stool consistency or an increase in urine output. Occasional coughing may be attributed to hairballs and not reported to the veterinary care team. A careful review of the patient’s history, using open-ended questions to encourage more detailed responses, may highlight issues that could explain the weight loss and merit further investigation.

Step 2: revisit the physical examination

It can often be very useful to repeat the physical examination in a cat with unexplained weight loss, as subtle abnormalities may be initially overlooked or discounted. If the muscle condition score was not initially noted, this should be established and recorded. It can be difficult to examine the oral cavity in an awake cat, but inspection of the teeth and gum line may reveal significant pathology. It is however important to bear in mind that a cursory visual examination does not rule out significant and impactful dental disease; the extent of painful conditions such as tooth resorption may only be determined with radiographic studies (Figure 1) (1). A thorough ophthalmologic examination should be performed, looking for signs of uveitis or chorioretinitis. These are non-specific findings, but are often seen in cats with fungal or protozoal infections (Figure 2) (2). Any skin or subcutaneous nodules should be carefully examined, particularly if noted in proximity to the mammary chain. It is also prudent to watch the cat ambulate to look for signs of joint, spinal, or neurological disease; many of us examine our feline patients on the table and may therefore fail to notice changes in gait, coordination, or muscle strength.
 

[...]