More so than any other tissue or organ system, the nervous system is exquisitely sensitive to insults and injuries. The importance of timely recognition, diagnosis, stabilization, and treatment of acute neurologic processes to mitigate or prevent permanent injury, disability, and even death cannot be overemphasized. The most elite resuscitationists will utilize “parallel processing” and ensure that the most time-dependent diagnostics and therapeutics are prioritized.
Neurocritical care (NCC) is a relatively new and rapidly developing subspecialty. Intensive care units (ICUs) dedicated to the care of those with neurologic disorders requiring critical care are rapidly increasing in number. The Neurocritical Care Society (NCS) was established in 1999, and held its first annual meeting in 2003. The United Council for Neurologic Subspecialties, which oversees NCC Fellowship accreditation and NCC certification, hosted its first certification examination in 2007. Most recently, leaders in NCC and Emergency Medicine collaborated to create an educational program establishing guidance on the care for patients during the first critical hours of a neurologic emergency, entitled Emergency Neurologic Life Support (ENLS). Similar to Advance Cardiovascular Life Support offered by the American Heart Association, ENLS Certification is provided to those completing the program.
The expansion in the size and organization of the field has led to advances in the technology available for neuromonitoring and strategies for neurologic resuscitation, making a full introduction to NCC concepts beyond the scope of this chapter, and more appropriately the mission of published textbooks on NCC. This chapter will provide an initial framework for the recognition, diagnosis, stabilization, and treatment of acute neurologic illness, with focused discussion of specific disease processes, including, encephalopathy and coma, acute ischemic stroke (AIS), intracerebral hemorrhage (ICH), subarachnoid hemorrhage (SAH), neuromuscular disease (NMDz), seizures, and status epilepticus. Other NCC diseases and disorders, such as traumatic brain injury (TBI) and/or spinal cord injury, cardiac arrest (CA), intracranial pressure (ICP) management, fulminant hepatic failure, delirium, encephalitis, and meningitis, are covered elsewhere in this textbook.
Consciousness has two components, arousal or wakefulness and content or awareness. Deficits in arousal are the result of either a diffuse, bihemispheric insult to the cerebral cortices or a focal injury to the ascending reticular activating system (ARAS) (see Figure 48A–1). Categories of arousal, in decreasing order, include awake, drowsy, obtunded or lethargic, stuporous, and comatose. Drowsy implies that the patient is prone to long bouts of sleep and hypoactivity during hours when normally expected to be awake and engaged, but they are easily aroused and awake with simple stimulation, such as speaking to them. An obtunded or lethargic patient requires a greater degree of stimulation to maintain their engagement. They often require a loud voice or gentle tactile stimulation to arouse them to participate in conversation or perform requested tasks. Once engaged, they tend to respond slowly and are prone to disengagement once stimulation is no longer maintained. A stuporous...