Common signs and symptoms of a serious head injury include all of the following, EXCEPT:

• A. Widening pulse pressure.
• B. Rapid, thready pulse.
• C. Decerebrate posturing.
• D. CSF leakage from the ears.

Answer: (B)

Rapid, thready pulse is not a typical sign of a serious head injury. In serious brain injury, signs reflect increased intracranial pressure and brainstem involvement. Widening pulse pressure can occur as the body attempts to maintain cerebral perfusion amid rising intracranial pressure (the Cushing response). Decerebrate posturing indicates severe brainstem dysfunction, a grave neurologic sign. CSF leakage from the ears points to a basilar skull fracture, a serious complication of head trauma. A rapid, thready pulse suggests shock or poor perfusion from other causes, not the brain injury pattern itself, and in severe brain injury bradycardia is more characteristic due to the Cushing reflex. So the rapid, thready pulse is the exception.