Hydrocephalus and shunt emergencies: SAQ

This boy has an obstructed ventriculoperitoneal shunt with preterminal features. The early-morning headache and vomiting, the increasing drowsiness, and the shunt pump that does not refill point to a shunt malfunction, and the bradycardia, the hypertension, and the irregular respirations are the Cushing triad, which means the brainstem is herniating now. His glucose is normal, so hypoglycaemia is excluded, and the priority is to bridge him to theatre at once while the workup runs in parallel. [1]

Question 1 (10 marks)

Outline the immediate resuscitation, the investigations, and the operative pathway for this boy, including any drugs and doses you would give and the time frame for each step. [3]

I would treat this as a neurosurgical emergency with impending herniation. My first move is to call for senior paediatric and anaesthetic help and to 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. [3]

Because the boy 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 13.5 grams for a 27 kilogram child, or three percent hypertonic saline at 2 to 5 millilitres per kilogram intravenously, which is 54 to 135 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 investigations would run in parallel. I would order a shunt series, which is anteroposterior and lateral skull, chest, and abdomen radiographs that 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, or a rapid magnetic resonance imaging where available, and I would compare the ventricular size to his baseline scan from the last clinic visit, because an increase confirms the obstruction. [11]

I would perform a shunt tap, by sterile puncture of the reservoir, to measure the opening pressure, to test whether the shunt flows when the reservoir is depressed, and to send the cerebrospinal fluid for cell count, protein, glucose, gram stain, and culture. By allowing fluid to be withdrawn, the tap may also relieve the pressure and buy time on the way to theatre. [11]

The operative pathway is shunt revision in theatre, where the blocked component is cleared or replaced and the system is tested for flow. If the boy is unstable or the infection is suspected, the shunt is externalised and an external ventricular drain is placed. The definitive care is operative, and the hyperosmolar bridge and the shunt tap are the temporising steps that keep him alive until he reaches theatre. [3]