- **Arousal** enables **awareness**, leading to **consciousness** - coordinated by the ascending RAS + thalamic arousal centers (that project to the cortex) - The initial coma exam can help localize injury and potential cause of the coma. Serial exams help identify acute deterioration such as ischemic stroke, hemorrhage, hydrocephalus, ↗ ICP, or seizure. ## Glasgow Coma Scale | Test | Not Testable (NT): Examples | 1 | 2 | 3 | 4 | 5 | 6 | | ------ | ------------------------------------------- | -------------- | -------------------------------- | ------------------------------ | --------------------- | -------------- | -------------- | | Eye | Severe trauma to eyes, enucleation | No eye opening | Opens to pain | Opens to voice | Opens spontaneously | --- | --- | | Verbal | Intubation, **aphasic**, linguistic barrier | No sounds | Incomprehensible sounds | Inappropriate words | Confused, disoriented | Oriented | --- | | Motor | Paralysis/hemiparesis | No movements | Abnormal extension (decerebrate) | Abnormal flexion (decorticate) | Withdrawal from pain | Localizes pain | Obeys commands | ## Specific steps - aim to examine mental status, cranial nerves, motors, tones, and reflexes #### Motor - If not responding to commands, induce noxious stimuli and observe response: - Noxious stimuli: sternal rub > supraorbital ridge pressure > nailbed pressure - Responses: localize > withdraw > flex UE (decorticate above the red nucleus) > extend UE (decerebrate below the red nucleus) ± grimaces > In the LE, a lack of upper motor neuron inhibition (e.g. brain damage) may lead to the **triple flexion spinal reflex** when stimulated, where flexion of the hip, knee, and ankle may be confused as withdrawal from pain - post anoxic mayoclonus is common after cardiac arrest, may indicate ongoing seizure #### Tone and reflexes - Symmetric hyperreflexia may normal in young patients, differentiate it from upper motor neurons damage by checking for a Babinski reflex #### Respiratory Patterns - Cheyne-Stokes - Kussmal - Apneustic - Biot's - Cluster