Best prognostic factor for head injury is : (AIPG 2010)
|A||Glasgow coma scale|
|C||Mode of injury|
Glasgow coma scale
Definition. Coma is a state in which a patient is unresponsive to environmental stimuli and unable to communicate in any manner. Coma is associated with extensive structural or physiologic damage to both cerebral hemispheres or to the ascending RAS in the diencephalon, mesencephalon, or pons.
Causes of coma
1). Drugs, poisoning, eg carbon monoxide, alcohol. tricyclics
2). Hypoglycemia, hyperglycemia (ketoacidotic, or HONK)
3). Hypoxia, CO2 narcosis
6). Myxoedema, Addisonian crisis
7). Hepatic/uraemic encephalopathy
1). Infection meningitis; encephalitis, eg Herpes simplex: malaria, typhoid, rabies, trypanosomiasis
2). Tumour: cerebral/meningeal tumour
3). Vascular, subdural/subarachnoid haemorrhage, stroke, hypertensive encephalopathy
4). Epilepsy: non-convulsive status or post-ictal state
Verbal response in intubated patients (Ref. Hari- 18th ed., pg 2197)
5 – seems able to talk
3 – Questionable ability to talk
1 – Generally unresponsive
1). Pupils. Pupillary size
a. Large, nonreactive pupils result from the disruption of the parasympathetic portion of the third cranial nerve, but may also be seen with barbiturate overdose.
b. Pinpoint pupils that are nonreactive to light may be seen with narcotic overdose.
2). Ocular motility.
If the eyes are immobile, movement can be elicited through the vestibulo-ocular reflex by moving the patient's head side to side (the "doll's eyes" or oculocephalic maneuver)
a. Failure of an eye to abduct in response to these maneuvers implies dysfunction of pontine structures or sixth nerve compromise.
b. Failure of an eye to adduct implies dysfunction of the medial longitudinal fasciculus or oculomotor nucleus or nerve.
(Extra Edge: Hari-18th ed., pg 2251)
1). Spontaneous eye movements in coma often take the form of conjugate horizontal roving.
2). This finding alone exonerates damage in the midbrain and pons and has the same significance as normal reflex eye movements.
3). Conjugate horizontal ocular deviation to one side indicates damage to the pons on the opposite side or alternatively, to the frontal lobe on the same side.
4). This phenomenon is summarized by the following maxim: The eyes look toward a hemispheral lesion and away from a brainstem lesion.
5). The eyes may occasionally turn paradoxically away from the side of a deep hemispheral lesion ("wrong-way eyes"). The eyes turn down and inward with thalamic and upper midbrain lesions, typically thalamic hemorrhage.
6). "Ocular bobbing" describes brisk downward and slow upward movements of the eyes associated with loss of horizontal eye movements and is diagnostic of bilateral pontine damage, usually from thrombosis of the basilar artery.
7). "Ocular dipping" is a slower, arrhythmic downward movement followed by a faster upward movement in patients with normal reflex horizontal gaze; it indicates diffuse cortical anoxic damage.
8). Thermal, or "caloric," stimulation of the vestibular apparatus (oculovestibular response) provides a more intense stimulus for the oculocephalic reflex but provides essentially the same information.
9). The test is performed by irrigating the external auditory canal with cool water in order to induce convection currents in the labyrinths. After a brief latency, the result is tonic deviation of both eyes to the side of cool-water irrigation and nystagmus in the opposite direction. (The acronym "COWS" has been used to remind generations of medical students of the direction of nystagmus—"cold water opposite, warm water same.")
10). The loss of induced conjugate ocular movements indicates brainstem damage. The presence of corrective nystagmus indicates that the frontal lobes are functioning and connected to the brainstem; thus functional or hysterical coma is likely.
3). Motor functions.
a. Quadriparesis and flaccidity suggests pontine or medullary compromise or a high cervical spinal cord insult.
b. Decorticate posturing (i.e., leg extension with flexion of the arm, wrist, and fingers) can be unilateral or bilateral and suggests a hemisphere or diencephalic lesion.
c. Decerebrate posturing (i.e., leg and arm extension) also can be unilateral or bilateral and suggests midbrain or pontine compromise.
d. Glasgow coma scale is the best prognostic factor head injury.
e. Other poor prognosis indicators:
Hypoxia & Hypotension
CT evidence of compression of cisterns / midline shift
Delayed evacuation of large intracerebral hemorrhage
Carrier status for apolipoprotein E-4 allele