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Difficulty: MediumNeurosurgery

Emergency medical services transport a 32-year-old female to the hospital due to altered mental status and intractable vomiting. According to her husband, she developed a relentless, diffuse headache yesterday, which has progressively worsened. Her past medical history is notable for congenital hydrocephalus secondary to aqueductal stenosis, managed with a ventriculoperitoneal shunt that was last revised 15 years ago. Her temperature is 37.0∘C37.0^\circ\text{C} (98.6∘F98.6^\circ\text{F}), blood pressure is 165/95 mm Hg165/95\text{ mm Hg}, and pulse is 52/min52/\text{min}. On physical examination, the patient is somnolent but arouses to loud verbal stimuli. Pupils are sluggishly reactive to light, and fundoscopy reveals bilateral papilledema. She exhibits an inability to look upward. Which of the following is the most appropriate next step in management?

  1. Non-contrast computed tomography of the headAnswer
  2. B
    Lumbar puncture for cerebrospinal fluid analysis
  3. C
    Intravenous ceftriaxone and vancomycin
  4. D
    Intravenous dexamethasone
  5. E
    Supportive care with intravenous fluids and antiemetics

Answer

Non-contrast computed tomography of the head
This patient presents with classic signs of severely increased intracranial pressure (ICP), including the Cushing reflex (hypertension and bradycardia), altered mental status, papilledema, and Parinaud syndrome (upward gaze palsy resulting from dorsal midbrain compression). Given her history of a ventriculoperitoneal (VP) shunt, mechanical shunt failure causing acute obstructive hydrocephalus is the most likely diagnosis. The most appropriate initial step is a non-contrast computed tomography (CT) scan of the head to rapidly assess ventricular size, evaluate for midline shift, and confirm the diagnosis prior to emergency neurosurgical intervention.

Step-by-Step Solution

1
Analyze the patient's presenting symptoms and vital signs.
The patient exhibits headache, vomiting, somnolence, hypertension (165/95 mm Hg165/95\text{ mm Hg}), and bradycardia (52/min52/\text{min}).
These findings represent the Cushing reflex (hypertension, bradycardia, irregular respirations), which indicates severely elevated intracranial pressure (ICP) and impending herniation.
2
Correlate the physical examination findings with the patient's medical history.
The patient has papilledema and Parinaud syndrome (impaired upward gaze) in the setting of a preexisting ventriculoperitoneal (VP) shunt.
Parinaud syndrome is caused by compression of the dorsal midbrain (superior colliculus) by a dilated third ventricle/suprapineal recess. This strongly points to acute mechanical failure of her VP shunt causing obstructive hydrocephalus.
3
Determine the most appropriate immediate diagnostic intervention.
A non-contrast head CT is selected as the next step.
Rapid neuroimaging with a non-contrast CT scan is required to objectively evaluate ventricular size, identify the extent of hydrocephalus, and plan for emergent neurosurgical intervention.

Key Concept

Diagnosis and acute management of ventriculoperitoneal (VP) shunt malfunction.
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Topics

Neurosurgery

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