Other common findings include episodic weakness, ataxia, head-pressing, disorientation, circling, pacing, behavioral changes, amaurotic blindness, seizures, and coma. Hypersalivation is a prominent sign in cats but also occurs in dogs. Bizarre aggressive behavior appears more likely in cats. Clinical signs of HE tend to wax and wane, and often are interspersed with normal periods. Gastrointestinal signs of intermittent anorexia, vomiting, and diarrhea are common.
Many affected animals have a history of stunted growth, failure to gain weight, or weight loss.
Polydipsia and polyuria are common. If urolithiasis is a complicating feature, pollakiuria, dysuria, and hematuria may occur. Physical examination may be unremarkable except for small body stature or weight loss. The neurologic examination is normal, or if overt signs of HE are present, neurologic findings are consistent with diffuse cerebral disease. Although a congenital PSS may be highly suspected based on historical , physical. laboratory, and radiographic findings, a definitive diagnosis requires identification of a shunt by contrast radiography, rectal portal scintigraphy, ultrasonography, or exploratory laparotomy.