Overview
This lecture clarifies the exam-relevant features of Cushing's response in head injury patients, emphasizing that five key signs—not just three—should be memorized for the CEN exam.
Cushing's Response in Head Injury
- Cushing's response occurs as intracranial pressure (ICP) increases in head injury patients, signaling near-fatal brain injury.
- The classic "Cushing's triad" underrepresents the findings; there are five main clinical features tested on exams.
- Cushing's reflex is a different concept and should not be confused with Cushing's response.
Five Key Signs of Cushing's Response
- Bradycardia: Increased ICP stimulates the vagus nerve, leading to decreased heart rate.
- Hypertension: Systolic blood pressure rises as the brain tries to maintain perfusion.
- Respiratory changes: Abnormal breathing patterns (e.g., Cheyne-Stokes, apneustic, Biot’s) due to brainstem compression; rates are not normal.
- Widened pulse pressure: Systolic pressure increases more than diastolic, expanding the gap between them.
- Pupillary changes: Any alteration in pupil size or reactivity (e.g., fixed, dilated, unequal, sluggish) can occur.
Exam Preparation Tips
- Be prepared to identify all five signs on the CEN or similar emergency exams.
- Knowing only the original triad may not be enough; contemporary exam questions test for the full range.
Key Terms & Definitions
- Cushing's response — A group of clinical findings caused by increased intracranial pressure, indicating impending brain herniation.
- Bradycardia — Abnormally slow heart rate.
- Hypertension — Elevated blood pressure.
- Pulse pressure — Difference between systolic and diastolic blood pressure.
- Pupillary changes — Alterations in size or reactivity of the pupils.
Action Items / Next Steps
- Memorize the five signs of Cushing's response for exam purposes.
- Focus on understanding how increased ICP results in each clinical finding.