Setting: ED
CC: “Hit in head playing football”
VS: BP: 144/92 mm Hg; P: 54 beats/minute; T: 100.8°F; R: 18 breaths/minute
HPI: A 20-year-old college student was hit in the head when he was tackled in a football game. The patient had just received a thrown ball and was immediately tackled and knocked into a nearby wall striking his head. He lost consciousness. The patient awoke about 10 minutes later and was disoriented when loaded into the ambulance.
Cushing Reflex
• Increased intracranial pressure
• Hypertension
• Bradycardia
PMHX: none
Medications: none
PE:
General: groggy, somewhat lethargic
Neurological examination: no focal deficits detected
HEENT: pupils equally round and reactive
Initial Orders:
Head CT without contrast
What is the mechanism of dilated pupil in intracranial bleeding?
a. Hypertension from any cause
b. Brainstem stroke
c. Compression of third cranial nerve
d. Meningeal irritation
Answer c. Compression of third cranial nerve
Large bleeds that cause uncal herniation will compress the third cranial nerve. The parasympathetic fibers are on the outside of the nerve and will be damaged first. Parasympathetic fibers normally constrict a pupil. If you compress the parasympathetic fibers on the outside of the third cranial nerve, the pupil will dilate.
The dilation of a pupil is on the same side as a bleed.
Advance the clock. The CT scan is performed and you are waiting for the report. Repeat the physical examination after 15 to 30 minutes in severe head trauma.
PE:
General: more lethargic, difficult to arouse
Neurological examination: hard to assess because of altered mental status; some weakness of left side of body
HEENT: dilation of right pupil only
What is the mechanism of the “lucid interval” in which the patient awakens, then loses consciousness?
a. Constriction of cerebral vessels
b. Accumulation of blood in skull decreasing perfusion
c. Cerebellar dysfunction
d. Decreased myocardial contractility
Answer b. Accumulation of blood in skull decreasing perfusion
Both subdural and epidural hematoma can cause a “lucid interval.” The initial loss of consciousness (LOC) is from the shock of head trauma. This is the same as in a concussion. After the patient awakens, there can be an accumulation of blood in the skull. This accumulation of blood increases intracranial pressure and decreases cerebral perfusion. The decrease in perfusion causes a second loss of consciousness. This is the reason we must observe people who have had head trauma. We are observing for an increase in intracranial pressure from blood that subsequently alters mental status.
As soon as the mental status and neurological examination start to deteriorate, you should immediately intubate and hyperventilate the patient. If the CT results are not back, you should still do this.
Indication for Intubation after Head Trauma
• Worsening mental status
• New focal neurological deficits
• Unilateral dilated pupil
Pupil dilates = Herniate = Do not wait = INTUBATE + hyperventilate!
What is the mechanism of a beneficial effect in hyperventilating intracranial hemorrhage?
a. Decreased PCO2 constricts cerebral vessels.
b. Increased oxygen constricts cerebral vessels.
c. Raising pH increases cerebral perfusion.
d. Bicarbonate improves perfusion.
Answer a. Decreased PCO2 constricts cerebral vessels.
Cerebral vasculature is very sensitive to concentrations of carbon dioxide (CO2). When CO2 is high, cerebral vessels dilate to remove this metabolic waste product. When CO2 is low, the blood vessels will constrict and perfusion decreases. In a normal person, this small change in overall intracranial volume will not have a meaningful impact on cerebral perfusion, but when you have a massive increase in intracranial pressure a small change in volume can result in a big drop in pressure. This decrease in pressure is to help slow down uncal herniation until you have time to surgically decompress the skull and drain the blood out. Hyperventilation is a bridge to surgical decompression.
Low compliance creates big changes in pressure with small changes in volume.
The skull has low compliance: Small Decrease in Volume = Big Decrease in Pressure
Move the clock forward to allow the intubation and to get results of the CT scan. Hyperventilation is a temporary bridge to the definitive procedure, which is surgical decompression.
Report:
Head CT: large subdural hematoma on right side, midline shift present (Figure 4-4)
Figure 4-4. Acute subdural hematoma is white. The midline is shifted. (Reproduced with permission from McKean SC, et al. Principles and Practice of Hospital Medicine. New York: McGraw-Hill; 2012.)
Vasoconstriction from hyperventilation wears off rapidly.
Blood in brain causes fever.
Any clot or collection of blood causes fever.
Orders:
Mannitol IV
Neurosurgery evaluation
Craniotomy and drainage
Move to ICU if not already done
ECG
You cannot move the patient to a location called “Operating Room.” Order the procedure the patient needs (e.g., craniology/drainage).
Move the clock only 15 to 30 minutes in a rapidly developing case such as this. Reexamine the neurological system each time.
Report:
ECG: deeply inverted T waves
Target PCO2 25 to 30 mm Hg with hyperventilation
Intracranial bleeding and head trauma are associated with T-wave inversion on ECG.
“Cerebral T waves”
• Massive sympathetic outflow
• Vasoconstriction of coronary arteries
Leave the patient in the ICU after the craniotomy and drainage. Place a ventriculostomy tube for both drainage and pressure monitoring. Do not move the patient out of the ICU until the ventriculostomy is removed and the neurological examination stabilizes. On CCS, a case of massive intracranial bleeding with herniation and the need for emergency surgical decompression will emphasize initial management.
Which of the following is proven to benefit this patient?
a. Methylprednisolone (steroids)
b. Pantoprazole (proton pump inhibitors)
c. Antiepileptic drugs
Answer b. Pantoprazole (proton pump inhibitors)
Stress ulcer prophylaxis with proton pump inhibitors (PPIs) is indicated in head trauma, burns, and those undergoing mechanical ventilation.