Sudden Weight Gain

When your pet’s appearance changes suddenly, whether it’s a swollen belly, rapid weight gain, or a bloated look that wasn’t there yesterday, something is going on that goes beyond eating too much. Sudden weight gain or abdominal swelling in pets is often a sign of fluid accumulation, hormonal disease, or other medical conditions that require diagnostic workup to identify and treat.

At Ruby Veterinary Urgent Care in Johns Creek, our ER-trained veterinarians use blood work, X-rays, and ultrasound to pinpoint the underlying cause and get your pet on the path to treatment.

Sudden or unexplained weight gain is rarely just a matter of too many treats. Common medical causes include:

• Fluid accumulation (ascites) in the abdomen, which can result from heart disease, liver disease, or certain cancers
• Cushing’s disease (hyperadrenocorticism) causes the body to produce excess cortisol, leading to a pot-bellied appearance, increased appetite, increased thirst and urination, and skin changes
• Hypothyroidism, more common in dogs, slows the metabolism and causes weight gain, lethargy, and skin and coat changes
• Heart disease can cause fluid retention and a distended abdomen
• Organ enlargement of the liver, spleen, or kidneys from infection, inflammation, or tumors can cause visible abdominal swelling
• Pregnancy, especially if unplanned, presents as rapid abdominal enlargement
• Internal bleeding from trauma or a ruptured mass can cause sudden abdominal distension

Note: Pets experiencing nonproductive retching, restlessness, and a hard distended abdomen should be seen immediately at a 24-hour emergency hospital, as these can be signs of gastric dilatation-volvulus (bloat), a life-threatening surgical emergency.

If you notice these signs, you should have your pet evaluated:

• Rapid change in body shape or abdominal size
• Lethargy or decreased energy that is unusual for your pet
• Increased thirst and urination
• Changes in appetite (increased or decreased)
• Difficulty breathing or exercise intolerance
• Skin and coat changes such as thinning hair or dull coat
• Weakness in the hind legs
• Firm or tense abdomen

We start with a thorough physical exam and a conversation about your pet's history, symptoms, and any changes you've noticed at home.

From there, our in-house diagnostics help us zero in on the cause. Comprehensive bloodwork including a complete blood count, chemistry panel, and thyroid testing can screen for metabolic and hormonal conditions.

If we suspect Cushing's disease, we may recommend specific hormone testing such as a cortisol stimulation test or low-dose dexamethasone suppression test.

Abdominal X-rays let us evaluate organ size, look for masses, and check for fluid buildup. An abdominal ultrasound gives us a detailed look at individual organs, fluid, and masses.

We may also run a urinalysis, which can reveal dilute urine or other abnormalities that point to hormonal disease.

Treatment depends entirely on the underlying diagnosis. Fluid accumulation may require therapeutic drainage (abdominocentesis) for comfort and diagnostic sampling of the fluid. Cushing’s disease is managed with medication through your primary care veterinarian, typically with ongoing monitoring. Hypothyroidism is treated with daily thyroid hormone supplementation, which is very effective. Heart disease management may include diuretics, heart medications, and monitoring. Masses or organ enlargement may require referral for further workup and potential surgical intervention.

A sudden weight gain evaluation at Ruby typically takes 60 to 90 minutes to allow time for bloodwork, imaging, and discussion of results. Our in-house laboratory provides bloodwork results within minutes, and imaging is performed and reviewed during the visit. You’ll leave with a clear understanding of the likely cause, a treatment plan, and coordination with your primary care veterinarian for ongoing management.