Branching cross-examination

This is a MedVellum formative viva. It is not an official RACP, MRCPCH, ABP, ACGME or RCPSC station, mark scheme, duration or pass standard. Release each update only after the candidate states the failing system, the immediate action and the reassessment endpoint. [1] [2]

Candidate brief

You are the senior paediatric clinician in a rural district emergency department. Speak as you would during resuscitation. Secure immediate threats before the diagnosis is certain, state the change you expect from each action, and say what you will reassess. This is one continuous case. Each escalation branch leads to the next update. [2]

Question 1 — Doorway and the first 60 seconds

Stimulus update. A parent carries a four-year-old who has been feverish and increasingly drowsy for a day. Before you touch the child you see poor tone, little response to voice, marked recession, and mottled limbs. Question: What do you say and do now? [2]

Consultant-level model answer. "I am immediately concerned. The child has an altered conscious level with abnormal appearance, work of breathing and circulation to skin. I call the senior paediatric and resuscitation teams now, name a leader, allocate roles, and bring age- and weight-appropriate equipment and monitoring. I secure the airway, give high-flow oxygen, support ventilation if breathing is ineffective, and treat shock, because upstream hypoxia, hypercapnia and shock are common causes of a falling conscious level. Stabilisation precedes diagnosis." [1] [2]

Probing follow-up. "Why secure A, B and C before the disability detail?" A strong answer is: "Because the brain fails secondarily to upstream failure more often than from a primary brain problem. A hypoxic, hypercapnic or hypoperfused brain cannot stay awake, so protecting it is the first disability intervention." [2]

Common weak answer. "I will take a full history, examine the child and order a CT brain." This delays resuscitation for diagnostic completeness in a visibly critical child. [2]

Escalation branch. If the candidate secures A, B, C and starts the disability assessment, release the survey data in Question 2. If they anchor on imaging first, ask which failing system they will treat while it is arranged. [2]

Question 2 — Measuring the level of consciousness and the glucose

Stimulus update. The airway is patent with oxygen, the saturation is acceptable, and the circulation is being supported. The child now responds to voice only. Question: How do you measure the disability, and what one bedside test do you do now and why? [1] [4]

Consultant-level model answer. "I screen with AVPU: the child responds to Voice, which is below Alert, so I convert to an age-adapted Glasgow Coma Scale. I record best eye opening, best verbal response and best motor response separately, because the motor response and its trend predict the threat to the airway. I examine the pupils for size, equality and reactivity, assess posture and tone, and time any seizure. The one test I do now is a point-of-care glucose: DEFG, don't ever forget glucose. A dangerous low I correct immediately through the age-specific pathway without waiting for the laboratory." [1] [2] [4]

Probing follow-up. "Why not just record an AVPU letter and move on?" A strong answer is: "AVPU screens, but the Glasgow Coma Scale measures and trends. The components that predict airway protection are hidden inside the scale, and any response below Alert must be converted. I never treat an AVPU letter as a number." [1]

Common weak answer. "The child is V on AVPU, so the GCS is about 13." Treating a letter as an exact number hides the components and the trend. [1]

Escalation branch. If the candidate measures the GCS and checks the glucose, release in Question 3 that the child begins to convulse. If they omitted glucose, ask what reversible cause they might be missing. [4]

Question 3 — Convulsive status epilepticus

Stimulus update. The child begins to convulse. The convulsion is still ongoing at five minutes. Question: Define the state and lead the next steps. [6]

Consultant-level model answer. "An ongoing convulsive seizure at five minutes is convulsive status epilepticus, and I activate first-line treatment now; I do not wait for two doses to fail. I give a first-line benzodiazepine by the available route: intravenous lorazepam or diazepam, or buccal or intranasal midazolam if access is delayed. I protect and position the airway, give oxygen, and reassess breathing between doses because respiratory depression is the main risk. If the seizure continues, I give a second-line agent per the local pathway." [6]

Probing follow-up. "What second-line agent, and what evidence informs it?" A strong answer is: "Levetiracetam is commonly preferred. The ESETT trial found levetiracetam, fosphenytoin and valproate broadly comparable for established status across age groups, and the paediatric EcLiPSE trial favoured levetiracetam over phenytoin for safety. I use the weight-appropriate dose from the local cognitive aid." [6] [7]

Common weak answer. "I will wait to see if it stops on its own." Status becomes harder to terminate the longer it runs and carries a rising risk of secondary brain injury. [6]

Escalation branch. If the candidate treats the status correctly and controls the airway, release in Question 4 that after the seizure the child develops new pupillary asymmetry. If they let the seizure run, ask at what point status is defined. [6]

Question 4 — Raised intracranial pressure and impending herniation

Stimulus update. The seizure stops, but the child now has a unilateral dilated unreactive pupil and abnormal posture, with a rising blood pressure and a falling heart rate. Question: Interpret this and act. [9]

Consultant-level model answer. "This is raised intracranial pressure with impending herniation. The unilateral dilated pupil, abnormal posture and Cushing pattern mean a focal lesion under pressure is compressing the brainstem. I raise the head of the bed, keep the midline position, optimise oxygenation and control ventilation to avoid hypercapnia, because hypercapnia raises intracranial pressure, and I arrange urgent neuroimaging and neurosurgical input. I do not perform a lumbar puncture until raised pressure is excluded and the child is stable." [9]

Probing follow-up. "Why is hypercapnia dangerous here?" A strong answer is: "A rising carbon dioxide level causes cerebral vasodilation, increases cerebral blood volume, and worsens the rise in intracranial pressure. Controlling ventilation is both a treatment for the brain and a protection against it." [9]

Common weak answer. "I will do a lumbar puncture to exclude meningitis." A lumbar puncture before raised pressure is excluded can precipitate herniation. [9]

Escalation branch. If the candidate recognises herniation and acts, move to Question 5 on retrieval and handover. [9]

Question 5 — Rural retrieval and structured handover

Stimulus update. The child is stabilised but needs neurocritical care and neurosurgery unavailable in the rural hospital. Question: Describe your escalation and handover. [2]

Consultant-level model answer. "I called retrieval in parallel with resuscitation, before local support was exceeded. I agree the destination, the treatment to continue, the escort and equipment, the expected deterioration, the plan if transfer is delayed, and the monitoring en route. My structured handover transfers identity and working weight, the level of consciousness and its trend, timed actions and response, the prioritised differential and pending tests, local limits, family and safeguarding information, and the next contingency and its named owner. I keep the family informed and document objectively." [2]

Probing follow-up. "What is the one principle you most want the team to carry forward?" A strong answer is: "An altered conscious level is an emergency until proven otherwise: secure A, B, C, measure with AVPU and GCS, check the glucose, treat the seizure at five minutes, recognise raised intracranial pressure, and escalate before local support is exceeded." [1] [4]

Common weak answer. "I will wait for the retrieval team to arrive before doing anything else." The child needs ongoing reassessment and stabilisation during the wait, with a contingency for deterioration. [2]