Hydrocephalus and shunt emergencies: Case

This girl has an obstructed ventriculoperitoneal shunt with preterminal features of brainstem herniation. The early-morning headache that wakes her, the projectile vomiting, and the increasing drowsiness are the classic triad of raised intracranial pressure, and the shunt pump that does not refill points to a proximal obstruction. The bradycardia, the hypertension, and the irregular respirations are the Cushing triad, which means the brainstem is being squeezed now. Her glucose is normal, so hypoglycaemia is excluded, and the priority is to bridge her to theatre at once. [1]

Clinical findings and assessment

The key findings are the five-day history of progressive raised-pressure symptoms, the shunt pump that does not refill, and the preterminal Cushing triad. The pattern is unmistakable for a shunt malfunction with impending herniation, and the working diagnosis is an obstructed shunt, most likely at the proximal catheter. The bradycardia of 44 and the hypertension of 150 over 95 are not incidental; they are the autonomic response to the rising intracranial pressure, and they signal that the brainstem is under threat. [3]

The differential of a shunted child with vomiting and drowsiness includes gastroenteritis, a viral illness, and migraine, and all three are common. The rule is that vomiting in a shunted child is gastroenteritis only after the shunt series is clear and the ventricles are stable, and this girl's Cushing triad puts her beyond that reassurance. Overdrainage and the slit ventricle syndrome present with a positional headache and small ventricles, which is the opposite of her enlarging-pressure picture, and shunt infection presents with fever and track inflammation, which she does not have. The obstructed shunt is the diagnosis. [10]

Immediate management

The immediate management is the bridge to theatre. I would call for senior paediatric and anaesthetic help and alert the neurosurgical team at once, because the definitive treatment is operative. I would elevate the head of the bed to thirty degrees, secure the airway, and give high-flow oxygen, and I would apply continuous monitoring of the heart rate, the blood pressure, the respiratory rate, and the oxygen saturation. [1]

Because the girl has the Cushing triad, I would give a hyperosmolar bridge now, without waiting for the scan. I would give mannitol at 0.5 grams per kilogram intravenously, which is 16 grams for a 32 kilogram child, or three percent hypertonic saline at 2 to 5 millilitres per kilogram intravenously, which is 64 to 160 millilitres. The bridge lowers the intracranial pressure within minutes and keeps the brain perfused while the team is assembled and the theatre is prepared. [1]

The workup would run in parallel with the bridge. I would order a shunt series of anteroposterior and lateral skull, chest, and abdomen radiographs to trace the shunt from the ventricle to the peritoneum, looking for a disconnection, a fracture, or a migrated distal tip. I would order a computed tomography of the head and compare the ventricular size to her baseline scan from the last clinic visit, because an increase confirms the obstruction. I would perform a shunt tap to measure the opening pressure, to test the flow, and to send the cerebrospinal fluid for cells, gram stain, and culture, and the tap may also relieve the pressure by allowing fluid to be withdrawn. [11]

Operative care and intensive care

The definitive management is shunt revision in theatre, where the blocked component is cleared or replaced and the system is tested for flow. The proximal catheter is the commonest site of blockage, often by choroid plexus tissue or debris, and the surgeon clears or replaces it and confirms the flow before closing. If the girl is unstable or the infection is found, the shunt is externalised and an external ventricular drain is placed, and a fresh shunt is reinserted once the cerebrospinal fluid is sterile. [11]

The girl would be admitted to the paediatric intensive care unit after the revision, because she presented with the Cushing triad and she is at high risk of a prolonged recovery and of a non-convulsive or infectious complication. The intensive care team would manage the airway, the ventilation, and the intracranial pressure, and the paediatric neurosurgical team would monitor the shunt function and the wound. The paediatric neurology team would be involved early to guide the neurodevelopmental follow-up. [3]

Distinguishing obstruction from infection and overdrainage

The distinction of obstruction from infection and overdrainage is the central reasoning of the case. Obstruction presents with the raised-pressure triad and enlarging ventricles on the scan compared to the baseline, and the shunt tap shows a high opening pressure with poor flow. This girl's pattern fits obstruction. [11]

Overdrainage and the slit ventricle syndrome present with a positional headache that is worse on standing and relieved by lying flat, with small or slit ventricles on the scan, and the management is to raise the valve pressure, the opposite of obstruction. Shunt infection presents with fever, track inflammation, abdominal pain, and meningism, usually within months of surgery, and the commonest organism is a coagulase-negative staphylococcus. The shunt tap in infection shows a pleocytosis and a positive culture, and the management is the two-stage removal, external drainage, and antibiotics. This girl has no fever and no track inflammation, but I would still send the cerebrospinal fluid from the tap to exclude an infection that may coexist. [6][10]

Outcome and follow-up

The prognosis of a single shunt malfunction that is promptly recognised and revised is good, and most children return to their baseline within days. This girl presented with the preterminal Cushing triad, so her outcome depends on the speed of the bridge and the revision, and the earlier the obstruction is relieved the better the recovery. The longer-term outlook is shaped by the underlying aqueductal stenosis, the cumulative number of revisions, and any neurological injury sustained before the relief, and she will need structured neurodevelopmental and educational follow-up. [1]

I would counsel the family honestly at every stage. I would explain that their daughter's shunt has blocked so the fluid is building up again, that her slow heart rate and high blood pressure mean the pressure on her brain became dangerous, and that the team gave the medicine that lowers the pressure while the surgeons were called. I would explain that the x-rays and the scan found the block, that the operation fixed the tube, and that she will be watched in the intensive care unit. Before discharge I would give the family a written safety-net that names the red flags, which are headache, vomiting, drowsiness, and a change in the eyes or the conscious level, and that gives the direct line to the neurosurgical service. The school and the respite carers would receive the same plan. [3]