How do I know if my dog has ascites?

The most visible sign is a distended, tense abdomen that may feel fluid-filled when gently pressed. Your dog may also show laboured breathing, lethargy, and loss of appetite. If the belly grows noticeably within a few days, seek veterinary attention immediately.

Is ascites in dogs treatable?

It depends on the underlying cause. Heart disease can often be managed with medication, significantly improving quality of life. Some tumours carry a poorer prognosis. Early treatment always leads to better outcomes, so prompt diagnosis is key.

Is ascites painful for dogs?

The fluid itself creates pressure, especially when it compresses the diaphragm and makes breathing harder. Secondary peritonitis can cause intense abdominal pain. Dogs typically seem apathetic and reluctant to move.

Can I drain the fluid at home?

No. Abdominocentesis must only be performed by a vet under sterile conditions. Attempting it at home risks serious infection, bleeding, and dangerous electrolyte imbalances.

Dog Ascites: Symptoms, Causes and Treatment

What is ascites in dogs?

Ascites (also called abdominal dropsy or hydroperitoneum) is the pathological accumulation of free fluid in the peritoneal cavity. It is not a disease in itself but a sign that something is disrupting the normal balance between fluid production and absorption in the abdomen.

Ascites can affect dogs of any age and breed, though the most common underlying diseases are more prevalent in older animals.

Main causes

Heart failure

When the heart fails to pump efficiently, venous pressure rises and fluid leaks into the abdominal cavity. Right-sided heart failure — from dilated cardiomyopathy or constrictive pericarditis — is a classic cause of ascites in dogs.

Liver disease

Cirrhosis and other chronic liver conditions reduce albumin synthesis and raise portal vein pressure, allowing fluid to seep into the peritoneum.

Hypoalbuminaemia

Low albumin levels in the blood — from liver disease, protein-losing enteropathy, or nephropathy — reduce oncotic pressure and allow fluid to leak out of blood vessels into body cavities.

Peritonitis

Inflammation of the peritoneum, whether infectious or chemical, generates an accumulation of inflammatory exudate. This form is usually more urgent and painful than other types of ascites.

Tumours

A ruptured splenic or hepatic haemangiosarcoma can bleed into the abdomen (haemoabdomen). Lymphomas and other abdominal tumours may obstruct lymphatic flow or produce a neoplastic effusion.

Symptoms to watch for

Distended, tense abdomen that may feel fluid-filled (fluid wave sign) on palpation.
Laboured or rapid breathing due to diaphragm compression.
Marked lethargy and weakness.
Loss of appetite and weight loss despite the enlarged belly.
Exercise intolerance.
Vomiting or nausea.
In some cases, pale or jaundiced (yellowish) mucous membranes.

Diagnosis

Physical examination and ultrasound

The vet will palpate the abdomen and test for a fluid wave. Abdominal ultrasound confirms the presence of free fluid, estimates the volume, and allows evaluation of organs (liver, spleen, heart, kidneys) to guide the diagnosis.

Abdominocentesis and fluid analysis

A fine needle is used to withdraw a fluid sample. Analysis (cytology, protein level, glucose, bacterial culture) classifies the fluid as transudate, modified transudate, or exudate — which strongly narrows the differential diagnosis.

Blood tests

Complete blood count, biochemistry (albumin, liver enzymes, creatinine), clotting profile, and if appropriate, cardiac troponin to assess overall health and guide diagnosis.

Treatment

Therapeutic abdominocentesis

In severe ascites compromising breathing, the first step is draining some fluid to give immediate relief. This does not treat the underlying cause but improves the dog's comfort while definitive therapy is started.

Treating the underlying cause

Heart failure: diuretics (furosemide, spironolactone), ACE inhibitors, digoxin if indicated.
Liver disease: hepatic diet, lactulose, SAMe, protein restriction in encephalopathy cases.
Hypoalbuminaemia from enteropathy: corticosteroids, hypoallergenic diet, vitamin B12.
Infectious peritonitis: intensive antibiotic therapy, sometimes emergency surgery.
Tumours: surgery (splenectomy for haemangiosarcoma), chemotherapy depending on type.

Outlook and quality of life

Dogs with chronic ascites (cardiac or hepatic) can live months or even years with good quality of life if treatment is maintained consistently and regular check-ups are kept. At home, monitor body weight and abdominal girth, report changes to your vet promptly, and never skip follow-up appointments.

How Purzi can help

If your dog has a condition that predisposes to ascites, Purzi lets you log daily symptoms (appetite, energy level, abdominal appearance), store lab results and ultrasound reports, and consult the assistant whenever you notice changes. A clear, organised health record helps your vet make better decisions at every visit.