Overview
Definition:
Intracranial hypertension (ICH) is a significant elevation of the intracranial pressure (ICP) above normal physiological limits, typically >20 mmHg in children
It is a critical condition that can lead to secondary brain injury, herniation, and death
Management aims to reduce ICP and restore cerebral perfusion pressure.
Epidemiology:
ICH can occur in various pediatric conditions including traumatic brain injury (TBI), hydrocephalus, brain tumors, stroke, meningitis, encephalitis, and congenital malformations
The incidence varies widely depending on the underlying etiology and patient population.
Clinical Significance:
Prompt and effective management of pediatric ICH is paramount to prevent irreversible neurological damage and improve patient outcomes
Understanding the nuances of different osmotic agents like hypertonic saline and mannitol is crucial for pediatric residents and specialists preparing for DNB and NEET SS examinations.
Clinical Presentation
Symptoms:
Infants may present with irritability, poor feeding, bulging fontanelle, and increased head circumference
Older children may experience headache (often worse in the morning or with Valsalva), vomiting (projectile), visual disturbances (diplopia, blurred vision), lethargy, confusion, and in severe cases, seizures or decreased consciousness.
Signs:
Cushing's triad (hypertension, bradycardia, irregular respirations) is a late sign of impending herniation
Papilledema on fundoscopy, focal neurological deficits, cranial nerve palsies (especially VI nerve), and posturing (decerebrate or decorticate) may be observed
Increased ICP can also lead to GCS score reduction.
Diagnostic Criteria:
Diagnosis is primarily based on clinical suspicion and confirmed by direct ICP monitoring
While no specific set of criteria defines ICH, a sustained ICP >20 mmHg is generally considered elevated
Imaging (CT/MRI) is essential to identify underlying causes.
Diagnostic Approach
History Taking:
Detailed history of presenting illness, including onset and progression of symptoms, recent trauma, fever, infections, or exposure to toxins
Past medical history, including neurological conditions and surgeries, is important
Family history of neurological disorders should also be considered.
Physical Examination:
Complete neurological examination, including assessment of mental status (GCS), cranial nerves (especially visual acuity and eye movements), motor and sensory function, reflexes, and coordination
Examination for signs of head trauma, meningeal irritation, and fontanelle tension in infants.
Investigations:
Neuroimaging: Non-contrast CT scan of the head is the initial imaging modality of choice to assess for mass lesions, edema, hemorrhage, and hydrocephalus
MRI provides more detailed anatomical information
EEG may be useful in cases of suspected seizures
Direct ICP monitoring (ventricular catheter, subdural bolt, intraparenchymal probe) is the gold standard for confirming elevated ICP and guiding management.
Differential Diagnosis:
Conditions mimicking ICH include severe dehydration, metabolic encephalopathy, intoxications, sepsis, and certain types of seizures
Distinguishing ICH from these conditions often relies on a thorough history, physical exam, and appropriate investigations, particularly neuroimaging and ICP monitoring.
Management
Initial Management:
Elevate the head of the bed to 30 degrees
Ensure adequate oxygenation and ventilation (avoid hypoxia and hypercapnia)
Maintain normothermia
Control blood pressure to ensure adequate cerebral perfusion pressure (CPP = MAP - ICP)
Sedation and analgesia may be required to reduce agitation and metabolic demand.
Medical Management:
Osmotic therapy is a cornerstone of medical management
Hypertonic saline (3% or 7.5%) and mannitol are commonly used
Both reduce ICP by drawing water out of the brain parenchyma into the vascular space
Hypertonic saline is often preferred due to its vasopressor-sparing effect and potential benefit in improving CPP, especially in TBI
Mannitol has a faster onset but can cause rebound ICP elevation and osmotic diuresis leading to dehydration
Doses vary: Mannitol (0.25-1 g/kg IV bolus), Hypertonic Saline (2-5 mL/kg of 3% NaCl IV).
Surgical Management:
Surgical interventions are reserved for specific etiologies or when medical management fails
Options include ventriculostomy for CSF drainage, craniotomy for decompression or removal of mass lesions (hematoma, tumor), and decompressive craniectomy in select cases of refractory ICH.
Supportive Care:
Continuous ICP monitoring is essential
Maintain euvolemia and electrolyte balance
Prophylaxis against seizures and stress ulcers should be considered
Nutritional support should be initiated early
Multidisciplinary team approach involving neurologists, neurosurgeons, intensivists, and nurses is critical.
Complications
Early Complications:
Rebound ICP elevation after osmotic therapy, dehydration, electrolyte imbalances (hyponatremia with hypertonic saline, hypernatremia with mannitol), cerebral edema, herniation syndromes, seizures, and acute kidney injury.
Late Complications:
Hydrocephalus, focal neurological deficits, cognitive and behavioral impairments, developmental delays, epilepsy, and post-traumatic vision impairment.
Prevention Strategies:
Judicious use of osmotic agents with careful monitoring of electrolytes and fluid balance
Maintaining adequate CPP
Prompt treatment of underlying causes
Close neurological monitoring and timely escalation of care.
Prognosis
Factors Affecting Prognosis:
The underlying cause of ICH, severity and duration of elevated ICP, promptness and effectiveness of treatment, and the patient's age and neurological status at the time of injury are key prognostic factors
Secondary insults like hypoxia and hypotension worsen outcomes.
Outcomes:
Outcomes are highly variable
With timely and effective management, many children can achieve good neurological recovery
However, severe ICH can lead to permanent disability or death
Early recognition and intervention are critical for improving prognosis.
Follow Up:
Long-term follow-up is essential to monitor for developmental progress, cognitive function, behavioral changes, and the development of late complications such as epilepsy or hydrocephalus
Neurorehabilitation services may be required.
Key Points
Exam Focus:
Understanding the mechanisms of action, indications, contraindications, dosing, and side effects of hypertonic saline and mannitol for pediatric ICH is crucial for DNB and NEET SS exams
Differentiating when to use which agent is a common exam theme
Remember that hypertonic saline may be preferred in TBI for its hemodynamic stability.
Clinical Pearls:
Always monitor serum sodium and osmolality when using hypertonic saline
Be cautious of fluid shifts and electrolyte imbalances with both agents
Mannitol can cause a temporary increase in cerebral blood volume, potentially worsening ICP if not managed carefully
Consider the patient's renal function
For infants with open fontanelles, subarachnoid hypertonic saline infusion can be an alternative route
Always aim for adequate CPP (usually 40-50 mmHg in children).
Common Mistakes:
Over-reliance on a single agent without considering the etiology of ICH
Inadequate ICP monitoring
Failure to address reversible causes of elevated ICP
Inappropriate fluid management leading to hyponatremia or hypernatremia
Delaying neurosurgical consultation when indicated
Forgetting to titrate therapy based on ICP response.