A pet owner’s job is to advocate for their pet, and you can do that by paying close attention to their daily behaviors and habits. Significant changes in eating or drinking habits can be linked to underlying medical issues that can have lasting effects on your pet’s health. The Madison Street Animal Hospital team shares the most common reasons for thirst or appetite changes in pets and how we diagnose and treat each condition.

#1: Diabetes in pets

Diabetes is a disease that impairs the ability of dogs and cats to produce or use the hormone insulin, which is responsible for transporting glucose into body cells to use for fuel. Without this action, the glucose builds up in the blood, the excess blood glucose overwhelms the kidneys and spills over into the urine along with water, and dehydration results. Since pets can’t use the energy from their food, they become ravenously hungry, while simultaneously losing weight and drinking more to compensate for water loss. 

Diabetes is diagnosed with blood tests and diabetic pets are treated with insulin injections and a strict, specialized, individually tailored diet. Common complications include pancreatic inflammation, liver enzyme elevation, and high cholesterol, which are treated separately with additional medications. Pets with diabetes require frequent monitoring to optimize their treatments.

#2: Thyroid disease in pets

The thyroid gland produces several different hormones that regulate metabolism on a cellular level, and has far-reaching effects on every body system. Overactive thyroid (i.e., hyperthyroidism) is one of the most common chronic diseases in older cats, while underactive thyroid (i.e., hypothyroidism) mainly affects middle-aged and older dogs. Appetite and energy levels can significantly increase or decrease with high or low thyroid levels, respectively. Weight, heart rate, blood pressure, and temperature regulation are also commonly affected.

Hyperthyroidism in cats is treated with medications, injection of a radioactive substance that kills the overactive thyroid cells, a special iodine-deficient diet, or surgery. Cats with secondary heart disease or elevated blood pressure require additional medications. Treatment for underactive thyroid in dogs requires a daily synthetic hormone replacement pill. 

#3: Acute or chronic gastrointestinal problems in pets

Any change that results in inflammation or discomfort in the gastrointestinal (GI) tract can potentially decrease a pet’s appetite. In some cases, appetite actually increases because nutrients aren’t properly absorbed, making pets feel hungrier. Inflammatory bowel disease, exocrine pancreatic insufficiency, lymphangiectasia, and gastrointestinal lymphoma are the most common chronic GI diseases in pets. Diagnosis for these conditions usually involves extensive blood testing, followed by a confirmatory endoscopy or exploratory surgery with biopsies. Treatments vary, but often include anti-inflammatories, antibiotics, probiotics, enzymes, and highly specialized diets.

Pets in acute GI distress usually vomit, have diarrhea, and refuse to eat. Some of the more common causes include viral or bacterial infections, parasites, new or unusual foods, pancreatitis, gastric dilatation-volvulus (GDV), and foreign body ingestion. GDV and foreign body ingestion are emergencies and require surgery.

#4: Kidney disease in pets

Kidney disease usually follows a chronic disease course in pets, with kidney damage beginning months to years before pet owners note clinical signs. Most affected pets are middle-aged or older and will begin to drink and urinate excessively as their kidney function declines, and they no longer can properly conserve water. The kidneys have many body functions, including filtering waste products from the blood, regulating blood pressure, and contributing to red blood cell production. When these functions are disrupted, pets may also lose weight, vomit, eat less, and feel generally sick. 

Chronic kidney disease is diagnosed with blood and urine tests and treated with supplemental fluids, a special diet to reduce kidney workload, and medications to control secondary complications, such as high blood pressure, urine protein loss, and nausea. The earlier kidney disease is diagnosed in a pet, the more likely treatments will be effective. Acute kidney dysfunction, which is more common in younger pets, can also occur from toxins, infections, or inherited disorders.

#5: Cushing’s syndrome in dogs

A cream-colored Labrador retriever stands in a kitchen holding a large, shiny metal bowl in its mouth, eyeing the door as if waiting for the veterinarian. The kitchen boasts white cabinets, wooden countertops, and a striped rug on the floor.

Cushing’s syndrome is a disorder in which the adrenal glands produce too much cortisol. Cortisol, which is called the stress hormone, helps prepare the body for fight or flight, but too much hormone can damage the liver, and pets feel hungry and thirsty all the time. They may also develop a pot-bellied appearance, muscle wasting, hair loss, thinned skin, and skin infections, giving “Cushing’s dogs” a characteristic appearance. 

Cushing’s can be tricky to diagnose, because other adrenal hormone excesses, such as estrogen, epinephrine, or certain forms of testosterone, show similar signs. These aren’t easily detected on routine tests, and your pet may require several rounds of blood testing for an accurate diagnosis, as well as additional tests after medical therapy begins, to ensure levels return to the normal range.

This list is by no means exhaustive—therefore, a veterinary examination with our Madison Street Animal Hospital team is crucial if you’re concerned about your pet. Habit or behavior changes may also be caused by dental disease, arthritis pain, cancer, heart disease, and smell loss from aging, as well as any illness where they do not feel their normal self.

Our team recommends annual wellness diagnostic screenings for adult and senior pets, because they help us detect some of the common diseases before you may notice your pet showing signs or changes at home. Early detection ensures more effective treatment and a longer lifespan. Call us or use our online scheduler to schedule your pet’s next wellness and preventive care appointment, or if your pet’s eating or drinking habits have changed.