Symptoms of Portosystemic (Liver) Shunts in Dogs

Source: PetWave, Updated on July 16, 2015
Portosystemic Shunts

How Congenital Portosystemic Shunts Affect Dogs

It is hard to speculate as to how dogs with congenital portosystemic shunts “feel” differently than they would have if they were not born with this anatomical abnormality. However, the primary effects that we see in dogs with this condition are largely neurological, gastrointestinal and/or urological in nature. Neurological means pertaining to the brain and central nervous system; gastrointestinal means pertaining to the digestive tract (stomach and small and large intestines); and urological refers to the urinary tract.

Symptoms of Liver Shunts

A congenital portosystemic shunt (PSS) can cause a huge variety of clinical signs. About 75% of affected dogs develop signs by the time they reach 1 year of age. Typically, these signs wax and wane over time. Most dogs with PSS only develop a few observable symptoms of their condition. These may include neurological signs that are secondary to a condition called hepatic encephalopathy, which may span a spectrum of severity from mild to extremely severe. Hepatic encephalopathy is a syndrome caused by severe damage to the liver, such as the inadequate blood supply to the liver caused by a PSS. The neurological signs associated with a portosystemic shunt typically are episodic (come and go) and may include one or more of the following:

  • Lethargy
  • Ataxia (lack of coordination)
  • Disorientation
  • Weakness
  • Drooling/hypersalivation (ptyalism)
  • Abnormal vocalization
  • Head pressing
  • Vision disturbances (apparent blindness)
  • Pacing
  • Behavioral changes
  • Circling
  • Tremors
  • Excitability
  • Seizures
  • Coma
  • Collapse

Gastrointestinal (stomach and intestinal) symptoms also often are present in dogs with congenital portosystemic shunts. These may include:

  • Vomiting
  • Diarrhea
  • Constipation
  • Lack of appetite (inappetence; anorexia)
  • Excessive appetite (excessive ingestion of food; polyphasia)
  • Pica (craving for unnatural materials or articles of food; often involves ingestion of feces)

The urinary tract in dogs with portosystemic shunts can be adversely affected as well. If this happens, the signs may include:

  • Blood in the urine (hematuria)
  • Difficulty urinating (dysuria)
  • Abnormally frequent urination (pollakyuria)
  • Abnormally large volume of urine (polyuria)
  • Abnormally large intake of water (polydipsia)
  • Enlarged kidneys (bilaterally)
  • Kidney and/or bladder crystals or stones (ammonium urate or biurate uroliths)

Other assorted signs of a PSS may include:

  • Stunted growth (common)
  • Itchy skin (pruritis; often intense)
  • Slow recovery from anesthesia or tranquilizers
  • Poor/unkempt haircoat

Dogs at Increased Risk

Congenital portosystemic shunts are typically diagnosed in young dogs, on average well before two years of age. Female Bichon Frises are roughly 12 times more likely to be born with a PSS than are males of that breed. The reason for this gender-based association is not known. The Maltese Terrier, Yorkshire Terrier and Irish Wolfhound reportedly have an approximately 20 times greater risk of being born with a congenital PSS than do other breeds. Other breeds reported to have a predisposition to being born with portosystemic shunts include the Golden Retriever, Labrador Retriever, Old English Sheepdog, Samoyed, Australian Shepherd, West Highland White Terrier, Miniature Schnauzer, Australian Cattle Dog, Collie, Poodle, Cairn Terrier, Tibetan Spaniel, Havanese, Shih Tzu and Dachshund.

Disorders Similar to Portosystemic Shunts (Liver Shunts)

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