Slit Ventricle Syndrome

• Slit ventricle syndrome occurs in minority of patients who have been shunted.
• "Slit ventricle" refers to finding of very small ("slit-like") ventricles on CT or MRI indicating excessive drainage.

Diagnostic criteria: 
An association of  clinical signs of headache, vomiting with signs of  slit like ventricles on CT or MRI. 

• Headache may be intermittent, often postural occurring when standing up and resolving when the patient lies down. Vomiting can be related to visual or auditory disturbance, drowsiness.
• Symptoms usually present years after shunt placement or shunt revision.
• Severe form of slit ventricle syndrome occurs in children. The absence of cerebrospinal fluid (CSF) within the ventricles combined with a growing brain leads to situation in which "the brain is too big for the skull." The intracranial pressure (brain pressure) can be very high. Adults can develop a milder form of slit ventricle syndrome. 
• The diagnosis of slit ventricle syndrome can be difficult and the condition is often misdiagnosed or the diagnosis delayed. The finding of small ventricles in a shunted patient can be misinterpreted as a properly working shunt. Most patients with small ventricles on CT or MRI may not have the slit ventricle syndrome clinically. Patients must be symptomatic to call Slit ventricle Syndrome. 
• Typically, the shunt is nearly blocked but still barely flowing.

A case of  Vp shunt done for Post TB Meningitis Hydrocephalus. Now came for follow up with new onset of headache and nausea. CT Brain plain shows right parietal Vp shunt with collapsed lateral ventricles. Possibility of "Slit Ventricle Syndrome" considered clinically and patient re admitted for further management.  

Treatment: 
The management of slit ventricle syndrome is difficult and challenging.
In general, a neurosurgeon with expertise in the management of hydrocephalus is optimal.
Various treatment options have been proposed, and include:
1. Observation.
Usually limited to minimally symptomatic patients
2. Anti-migraine medicines.
3. Shunt revision.
 Change the ventricular catheter.
 Change the shunt valve.
 Add siphon controlling device (SCD).
 Programmable valve with or without SCD.
 Converting to a lumboperitoneal shunt.
4. Temporarily blocking the flow of the shunt (via "externalization" of the shunt) in order to expand the ventricles.
This should be done with ICP monitoring due to the risk of coma.
Many patients have aqueductal stenosis, and therefore are candidates for endoscopic third ventriculostomy (ETV).
In some cases, a special shunt configuration draining both the ventricles and the cisterns (space around the brain) can equalize the inner and outer brain pressures, thus reducing the chance of producing slit ventricles again. This type of shunt is called a ventriculocisternoperitoneal shunt.
5. Subtemporal decompression.
This procedure is rarely performed because improvements, if any, are typically short-lived.