Slit ventricle syndrome and subdural haemorrhage due to suspected overshunting in a dog with hydrocephalus internus

Abstract

A 1.5-year-old Chihuahua was presented with clinical signs consistent with multifocal localisation. MRI revealed hydrocephalus internus. Following placement of a ventriculoperitoneal (VP) shunt with a low-pressure valve, improvement was noted. Clinical signs returned one month later. A second MRI revealed subdural haematoma, meningeal reaction and slit-like ventricles, and was interpreted as overshunting. Saline solution was injected in the ventricles via the shunt, which was then ligated. Clinical improvement was noted, followed again by relapse three months later. A third MRI revealed recurrence of hydrocephalus internus. The VP shunt was reconnected and, additionally, the valve was positioned and fixed in a vertical position. A disconnection of the valve occurred two weeks later, and the owners elected euthanasia. Complications following VP shunting in this case reveal many similarities to those described in overshunting in people and should be considered as a possible complication.

Complications associated with ventriculoperitoneal shunts in dogs and cats with idiopathic hydrocephalus: A systematic review

“…One dog had revision surgery after 2 months because of overshunting and, after a further 3 months, the shunt system was reconnected. Disconnections of the valve led to euthanasia in this case …”

“…In dogs described in case reports, the complications were disconnections (1/10; 10%), obstruction (1/10; 10%), overshunting with slit‐like ventricle (1/10; 10%), and postoperative seizures in combination with breakage of the tube (1/10; 10%) . Subdural fluid on postoperative magnetic resonance imaging (MRI) (2/10; 20%) was not clinically relevant .…”

“…Median follow‐up time was 11 months (range, 2‐42 months) with 2 nonsurvivors (Table ). One dog died as a consequence of seizures 32 months after the 1st surgery; 1 dog was euthanized because of overshunting after 2 surgeries 5 months after the initial surgery …”

“…The second dog developed overshunting within the mid‐term period and was treated by a slow injection of saline solution and disconnection of the shunt. Neurological signs did not improve and the dog was euthanized . In 2 dogs (11 days and 6 months after surgery) and 1 cat (immediately after surgery), a subdural hematoma could be found on the initial MRI (n = 3; 4.1%).…”

“…The opening pressure (ie, if it was 4/14 or 4/24) was not described in 1 case series . In the described case report, a 4/24 valve was used and sutured to the long axis of the dog in a horizontal direction . This may be crucial for the mechanism used in this type of shunt designed for humans.…”