Typically develop over several days
Cephalgia, nausea and vomiting, lethargy, ataxia, altered mental status
Paralysis of upward gaze ("sunset eyes"), dilated pupils, cranial nerve palsies
Vomiting, irritability, bulging fontanelle
Often very subtle: a caregiver-reported change in behavior predicts malfunction
Often very subtle: a caregiver-reported change in behavior predicts malfunction
Neither sensitive nor specific
Decreased level of consciousness, erythema along shunt tract, bulging fontanelle, nausea/vomiting, irritability should raise suspicion
Valve chamber abnormality
Gently compress chamber and observe for refill
Difficulty compressing chamber indicates distal flow obstruction
Slow refill (>3s) indicates proximal obstruction
Gently compress chamber and observe for refill
Difficulty compressing chamber indicates distal flow obstruction
Slow refill (>3s) indicates proximal obstruction
Ventriculoperitoneal shunt complications
Ventriculoperitoneal shunt obstruction
Ventriculoperitoneal shunt mechanical failure
Ventriculoperitoneal shunt overdrainage 
Ventriculoperitoneal shunt infection
Ventriculoperitoneal shunt overdrainage
Separate, noncommunicating CSF accumulations may develop within a ventricle
Brain herniation syndromes