Neurosurgical Emergencies

Chapter 45 Neurosurgical Emergencies



Fred A. Fow, MD



1 What is the basic pathophysiology of increased intracranial pressure?


The theory is: The skull is a rigid compartment of fixed volume. Its three constituent parts are brain tissue, blood, and cerebrospinal fluid (CSF). Any increase in the volume of one of these constituents without a decrease in the volume of one or both of the other constituents must result in an increase in intracranial pressure (ICP) (modified Monro-Kelli hypothesis).


Greenes DS: Neurotrauma. In Fleisher GR, Ludwig S, Henretig F (eds): Textbook of Pediatric Emergency Medicine, 5th ed. Philadelphia, Lippincott Williams & Wilkins, 2006, pp 1361–1388.



2 How does increased ICP affect cellular survival?


Cellular survival depends on cerebral blood flow delivering oxygen to meet cellular metabolic demand. Cerebral blood flow is related to cerebral perfusion pressure. Cerebral perfusion pressure (CPP) in turn is affected by changes in mean arterial pressure (MAP) or intracranial pressure ICP (CPP = MAP − ICP). Cerebrovascular autoregulation (reflex vasoconstriction/vasodilatation) allows cerebral blood flow to be maintained despite changes in cerebral perfusion pressure. Autoregulation prevents decreases in cerebral blood flow while MAP is greater than 60 mmHg and while ICP is < 40 mmHg. Outside these ranges, cerebral blood flow and oxygen delivery drop in a passively dependent fashion, resulting in cellular injury.


Greenes DS: Neurotrauma. In Fleisher GR, Ludwig S, Henretig F (eds): Textbook of Pediatric Emergency Medicine, 5th ed. Philadelphia, Lippincott Williams & Wilkins, 2006, pp 1361–1388.



3 What are the symptoms of increased ICP?




image Headache


image Intellectual impairment


image Stiff neck


image Diplopia


image Visual loss


image Irritability


image Vomiting


Steele DW: Neurosurgical emergencies, nontraumatic. In Fleisher GR, Ludwig S, Henretig F (eds): Textbook of Pediatric Emergency Medicine, 5th ed. Philadelphia, Lippincott Williams & Wilkins, 2006, pp 1717–1725.



4 What are the signs of increased ICP?




image Papilledema


image Hyperresonance to percussion (cracked pot sound or MacEwen’s sign)


image Optic nerve atrophy


image Cranial nerve palsies


image Scalp vein enlargement, increased head size, suture separation, bulging fontanel


image Cranial nerve IV: head tilt


image Cranial nerve VI: sunset eyes


image Decorticate or decerebrate posturing


image Altered mental status or level of consciousness


image Meningismus


image Hemiparesis


image Retinal hemorrhage


image Bradycardia, systemic hypertension, and irregular respirations (Cushing’s triad)


Steele DW: Neurosurgical emergencies, nontraumatic. In Fleisher GR, Ludwig S, Henretig F (eds): Textbook of Pediatric Emergency Medicine, 5th ed. Philadelphia, Lippincott Williams & Wilkins, 2006, pp 1717–1725.



5 What are the causes of increased ICP?




1 Increased CSF volume (hydrocephalus)


Decreased absorption (communicating and noncommunicating hydrocephalus)


image Congenital—Arnold-Chiari malformation, Dandy-Walker cyst, vein of Galen arteriovenous malformation

image Acquired—Meningitis, tumor, leukemia, inflammatory response to intracranial hemorrhage

Increased production


image Choroid plexus papilloma—Rare

2 Increased brain volume (cerebral edema)


image Vasogenic—Tumor, abscess, hemorrhage

image Cytotoxic—Hypoxia, ischemia, infection

image Interstitial—Blockages in CSF absorption

3 Mass lesions


image Tumor

image Abscess

image Arteriovenous malformation

4 Idiopathic (pseudotumor cerebri)


Madikians A, Conway EE: Cerebrospinal fluid shunt problems in pediatric patients. Pediatr Neurosurg 26:613–620, 1997.



6 Describe the initial management of increased ICP.




image Maintenance of airway, breathing, and circulation (ABCs) is paramount.


image In the patient with suspected cervical spine trauma, immobilization is mandatory until cervical spine injury and spinal cord injury can be ruled out clinically and radiographically.



7 What are the relevant features of airway management in patients with increased ICP?




image Endotracheal intubation allows for airway maintenance, protection from aspiration, maximal oxygenation, and control over ventilation. Rapid sequence induction (RSI) may help to prevent elevations in ICP and aspiration during intubation. The physician should be experienced in endotracheal intubation and have familiarity with RSI and with the specific indications and contraindications to the use of any of the agents used in RSI.


image Hyperventilation causes cerebrovascular constriction, reducing cerebral blood volume and hence reducing ICP. Hyperventilation should be reserved for cases of impending herniation, as evidenced by severe alterations in mental status and vital signs changes or cases of increased ICP resistant to other modalities of treatment. Excessive or prolonged hyperventilation may result in cerebral ischemia and should be avoided.



8 Which medications are recommended in the treatment of increased ICP?




image Mannitol may be used acutely to draw fluid from brain tissue in cases of impending herniation or cases of increased ICP resistant to other treatment modalities.


image Hypertonic saline has been demonstrated to be an acceptable alternative to mannitol.


image Dexamethasone acts more slowly, but may be employed to reduce tissue edema, such as that accompanying tumor, brain abscess, and nontraumatic hemorrhage.


image Acetazolamide can be given to reduce CSF production but also has limited acute effect.


Adelson PD: Guidelines for the acute medical management of severe traumatic brain injury in infants, children and adolescents. Chapter 17. Critical pathway for the treatment of established intracranial hypertension in pediatric traumatic brain injury. Crit Care Med 4(3 Suppl):565–567, 2003.


Greenes DS: Neurotrauma. In Fleisher GR, Ludwig S, Henretig F (eds): Textbook of Pediatric Emergency Medicine, 5th ed. Philadelphia, Lippincott Williams & Wilkins, 2006, pp 1361–1388.


Steele DW: Neurosurgical emergencies, nontraumatic. In Fleisher GR, Ludwig S, Henretig F (eds): Textbook of Pediatric Emergency Medicine, 5th ed. Philadelphia, Lippincott Williams & Wilkins, 2006, pp 1717–1725.



9 What steps can be taken to reduce metabolic demand?




image Adequate sedation helps to reduce oxygen demand and avoid any unwanted increases in ICP due to agitation.


image Benzodiazepines, narcotics, and propofol should be used with caution because they may lower blood pressure and adversely affect cerebral perfusion pressure.


image Barbiturate coma with pentobarbital reduces cerebral metabolic demand and ICP but requires aggressive pulmonary and hemodynamic management. As such, it is reserved for patients in whom other methods of ICP reduction have failed.


image Paralysis may decrease oxygen consumption; however, this makes neurologic assessment, including recognition of seizures, problematic. Adequate sedation can obviate the need for paralysis. Avoidance of hyperthermia and of stimulation is also indicated.


Adelson PD: Guidelines for the acute medical management of severe traumatic brain injury in infants, children and adolescents. Chapter 17. Critical pathway for the treatment of established intracranial hypertension in pediatric traumatic brain injury. Crit Care Med 4(3 suppl):565–567, 2003.


Greenes DS: Neurotrauma. In Fleisher GR, Ludwig S, Henretig F (eds): Textbook of Pediatric Emergency Medicine, 5th ed. Philadelphia, Lippincott Williams & Wilkins, 2006, pp 1361–1388.



KEY POINTS: INCREASED INTRACRANIAL PRESSURE




1 The first and most important step in the treatment of increased ICP, regardless of its cause, is maintenance of the ABCs.


2 Rapid sequence induction and endotracheal intubation allow for airway protection and help prevent elevation of ICP during intubation.


3 Hyperventilation should be reserved for cases of impending herniation.


4 Avoid excessive or prolonged hyperventilation.


5 Early recognition of signs and symptoms of increased ICP is very important if serious complications are to be avoided.

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Sep 1, 2016 | Posted by in EMERGENCY MEDICINE | Comments Off on Neurosurgical Emergencies

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