Intracranial Regulation and Neuro Critical Care Flashcards

Vocabulary flashcards generated from lecture notes covering neuro critical care, intracranial regulation, brain injuries, tumors, surgeries, and spinal cord injury complications.

Brainstem

Structure composed of the midbrain, pons, and medulla oblongata that controls life-sustaining functions such as breathing and heart rate.

Meninges

The protective fluid-covered casing/membrane surrounding the brain and spinal cord.

Cerebrospinal Fluid (CSF)

A clear fluid produced within brain ventricles that acts as a protective layer, with a normal intracranial volume of $150\,mL$ (comprising $10\%$ of cranial volume).

Monro-Kellie Doctrine

Principle stating that the cranial vault contains brain tissue ($80\%$ or $1400\,mL$), CSF ($10\%$ or $150\,mL$), and blood ($10\%$ or $150\,mL$); an increase in one component requires a compensatory decrease in others to maintain normal intracranial pressure.

Normal Intracranial Pressure (ICP)

The normal pressure range within the cranium, defined as $5\text{ to }15\,mmHg$.

Decorticate Posturing

Abnormal posturing characterized by rigid stiffness, bent arms flexed inward to the core, clenched fists, and legs held straight.

Decerebrate Posturing

Abnormal body posture characterized by rigid extension of the arms and legs held straight out, toes pointed downward, and backward arching of the head and neck.

AVPU Scale

A simplified measurement of level of consciousness scoring patient responsiveness as Alert, Voice, Pain, or Unresponsive.

Glasgow Coma Scale (GCS)

A neurological assessment scale evaluating Eye Opening (1-4), Verbal Response (1-5), and Motor Response (1-6), with total scores ranging from 3 (worst) to 15 (best).

Cerebral Perfusion Pressure (CPP)

The pressure gradient driving blood flow to the brain, calculated as $CPP = MAP - ICP$, with normal levels between $60\text{ and }100\,mmHg$.

Mean Arterial Pressure (MAP)

The average pressure in a patient's arteries during one cardiac cycle, calculated using the formula $MAP = \frac{2 \times DBP + SBP}{3}$.

Cushing's Triad

Late, severe manifestation of increased intracranial pressure indicating impending brain herniation consisting of irregular respirations, bradycardia, and a widened pulse pressure (increased systolic BP).

Uncal Transtentorial Herniation

Type of brain herniation caused by inferior displacement of the medial temporal lobe (uncus) past the tentorium cerebelli edge, presenting with ipsilateral oculomotor nerve palsy, PCA infarction, and Kernohan's notch phenomenon.

Epidural Hematoma

Rapid arterial bleeding occurring between the skull and dura mater, classically characterized by an initial loss of consciousness, a lucid interval, and rapid neurological deterioration.

Subdural Hematoma

Venous blood accumulation located between the dura mater and arachnoid mater; classified as acute ($\le 48\text{ hours}$), subacute ($48\text{ hours to }2\text{ weeks}$), or chronic ($>2\text{ weeks}$).

Subarachnoid Hemorrhage

Bleeding into the subarachnoid space near the meninges, classically presenting as the 'worst headache of my life', neck stiffness, photophobia, and risk of severe vasospasm.

Diffuse Axonal Injury (DAI)

Widespread, diffuse brain injury caused by tensional, rotational, or shearing forces that stretch and damage axons throughout the brain tissue.

Acoustic Neuroma

A slow-growing tumor involving cranial nerve VIII (vestibulocochlear) that can compress surrounding facial and trigeminal nerves and the brainstem.

Meningioma

A firm, encapsulated, slow-growing tumor arising from the meninges that carries an excellent prognosis following complete surgical removal.

Supratentorial Approach

Cranial surgical entry located above the tentorium; requires maintaining the head of bed elevated 30 to 45 degrees postoperatively with the neck in neutral alignment.

Infratentorial Approach

Cranial surgical entry located below the tentorium at the nape of the neck; requires keeping the neck in straight alignment without flexion and placing the patient side-to-side (avoiding supine).

Transsphenoidal Hypophysectomy

Surgical removal of a pituitary tumor via an incision beneath the upper lip into the nasal cavity (sella turcica); carries CSF leakage as its primary risk.

Diabetes Insipidus (DI)

Endocrine complication resulting from lack of ADH characterized by polyuria, low urine specific gravity ($<1.010$), high serum sodium, and severe dehydration.

Syndrome of Inappropriate Anti-Diuretic Hormone (SIADH)

Endocrine complication resulting from excess ADH characterized by oliguria, concentrated urine (high specific gravity), fluid overload, and dilutional hyponatremia.

Phenytoin (Dilantin)

Anticonvulsant with a therapeutic index of $10\text{ to }20\,\mu g/mL$ used to prevent seizures; must be diluted ONLY with Normal Saline (NS) and infused at a maximum rate of $50\,mg/min$ to avoid Purple Glove Syndrome.

Fosphenytoin (Cerebyx)

A prodrug that converts to phenytoin in the body, developed as a safer IV alternative dosed in Phenytoin Equivalents (PE) and administered up to $150\,PE/min$.

Spinal Shock

A temporary condition occurring immediately following spinal cord injury marked by loss of all spinal reflex activity (areflexia), motor function, and sensation below the level of injury.

Neurogenic Shock

A form of shock occurring with spinal cord injuries above T6 caused by loss of sympathetic nervous system tone, leading to hemodynamic instability with severe hypotension and bradycardia.

Autonomic Dysreflexia

A massive, uncompensated sympathetic reaction in spinal cord injuries at T6 or higher triggered by sustained noxious stimuli below the lesion (such as a full bladder), causing severe hypertension, headache, and facial flushing above the injury.