Plum and posner’s diagnosis of stupor and coma fourth Edition series editor sid Gilman, md, frcp
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Immediate examination on the radiology table showed that breathing was slow and regular and she was unresponsive except to deep pain, with localizing movements of the right but not the left extremities. The right pupil was 8 mm and unre- active to light, and there was no adduction, ele- vation, or depression of the right eye on oculoce- phalic testing. Muscle tone was increased on the left compared to the right, and the left plantar re- sponse was extensor. She was immediately treated with hyperventi- lation and mannitol and awakened. The radiolo- gist reported that there were fragments of metal embedded in the skull over the right frontal lobe. Figure 3–8. Herniation due to a cerebellar mass lesion. The incisural line (A, B) is defined by a line connecting the dorsum sellae with the inferior point of the confluence of the inferior sagittal and straight sinuses with the great vein of Galen, in a midline sagittal magnetic resonance imaging (MRI) scan, shown by a line in each panel. The iter, or anterior tip of the cerebral aqueduct, should lie along this line; upward herniation of the brainstem is defined by the iter being displaced above the line. The cerebellar tonsils should be above the foramen magnum line (B), connecting the most inferior tip of the clivus and the inferior tip of the occiput, in the midline sagittal plane. Panel (C) shows the MRI of a 31-year-old woman with metastatic thymoma to the cerebellum who developed stupor and loss of upgaze after placement of a ventriculoperitoneal shunt. The cerebellum is swollen, the fourth ventricle is effaced, and the brainstem is compressed. The iter is displaced 4.8 mm above the incisural line, and the anterior tip of the base of the pons is displaced upward toward the mammillary body, which also lies along the incisural line. The cerebellar tonsils have also been forced 11.1 mm below the foramen magnum line (demarcated by thin, long white arrow). Following treatment, the cerebellum and metastases shrank (C), and the iter returned to its normal location, although the cerebellar tonsils remained somewhat displaced. (Modified from Reich et al., 59 with permission.) 104 Plum and Posner’s Diagnosis of Stupor and Coma The patient confirmed that the boyfriend had ac- tually tried to shoot her, but that the bullet had struck her skull with only a glancing blow where it apparently had fragmented. The right frontal lobe was contused and swollen and downward pressure had caused transtentorial herniation of the uncus. Following right frontal lobectomy to decompress her brain, she improved and was discharged. LATE THIRD NERVE STAGE As the foregoing case illustrates, the signs of the late third nerve stage are due to more complete impairment of the oculomotor nerve as well as compression of the midbrain. Pupillary dilation becomes complete and the pupil no longer re- acts to light. Adduction, elevation, and depres- sion of the affected eye are lost, and there is Eupneic
Constricts sluggishly DOLL’S HEAD MANEUVER ICE WATER CALORICS Moderately dilated pupil, usually ipsilateral Present or dysconjugate Full conjugate slow ipsilateral eye movement (impaired nystagmus) or Appropriate motor response to noxious orbital roof pressure. Contralateral paratonic resistance Contralateral extensor plantar reflex Dysconjugate, because contralateral eye does not move medially Respiratory pattern a.
size and reactions b. Oculocephalic and oculovestibular responses c. Motor responses at rest
and to stimulation d. Figure 3–9. Signs of uncal herniation, early third nerve stage. Structural Causes of Stupor and Coma 105
usually ptosis (if indeed the patient opens the eyes at all). The lapse into coma may take place over just a few minutes, as in the patient above who was uncooperative with the x-ray technician and 10 minutes later was found by the neurologist to be deeply comatose. Hemiparesis may be ipsilateral to the herniation (if the midbrain is compressed against the opposite tentorial edge) or may be contralateral (if the paresis is due to the lesion damaging the descending corti- cospinal tract or to a herniating temporal lobe compressing the ipsilateral cerebral peduncle). Breathing is typically normal, or the patient may lapse into a Cheyne-Stokes pattern of respira- tion (Figure 3–10). MIDBRAIN-UPPER PONTINE STAGE If treatment is delayed or unsuccessful, signs of midbrain damage appear and progress caudally, as in central herniation (see below). Both pupils or Regular sustained hyperventilation Rarely, Cheyne-Stokes Does not constrict DOLL’S HEAD MANEUVER ICE WATER CALORICS ipsilateral pupil widely dilated
Decorticate or decerebrate responses Ipsilateral eye doesn’t move medially, but contralateral eye retains full lateral movement Respiratory pattern a.
size and reactions b. Oculocephalic and oculovestibular responses c. Motor responses at rest
and to stimulation d. Figure 3–10. Signs of uncal herniation, late third nerve stage. 106 Plum and Posner’s Diagnosis of Stupor and Coma Yüklə 6,14 Mb. Dostları ilə paylaş:
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