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EMSWORLD.com | JANUARY 2018 45 CONTINUING EDUCATION Y ou are called to a shelter in the downtown core at 2 a.m. on a cold Februar y evening for a 57-year-old man found uncon- scious in the rear alley. When you arrive police officers have secured the scene. You see no drug or alcohol paraphernalia. The shelter manager tells you there is a strict curfew of midnight, and that the man, whom he knows well, often arrives back after midnight and sleeps in the alley until the doors open at 6 a.m. The man- ager says the man has many medical and psychiatric problems, but the shelter does not provide medications or healthcare. Your partner is at the man's head and reports he is protecting his own airway— no snoring or secretions—and breathing at a rate of 10, full, with a strong but irregular pulse at a rate of 55. He moans and with- draws to deep painful stimulus but does not open his eyes. His pupils are equal and reactive at 3 mm. Some pertinent questions to consider: 1. What is this man's GCS? 2. Which narcotics do not cause pupil constriction? 3. List 10 potential diagnoses for this patient's altered level of con- sciousness. 4. How do you determine if the airway is patent? Decreased Level of Consciousness Consciousness is the awareness of one's own self. It includes arousal (a scale from alert to comatose) and cognition (levels of awareness and orientation). The brain stem is responsible for arousal and is also sensitive to metabolic, toxic, and mechani- cal insults. Causes of decreased level of conscious- ness are divided into two main catego- ries: structural and metabolic. Structural abnormalities are anatomic events that affect the contents of the cranial space and include: • Hemorrhage (epidural, subdural, sub- arachnoid, intraparenchymal) • Clot (embolus, thrombus) • Fluid (encephalopathy—hepatic, ure- mic, or high altitude; hydrocephalus) • Infection (brain abscess, bacterial meningitis, viral encephalitis) • Tumor/malignancy • Foreign body More questions to consider: 5. Which two of the above conditions present with neck stiffness and photophobia? 6. What is the difference between an embolus and a thrombus? 7. Which type of intracranial hemor- rhage is almost always secondary to trauma? Metabolic abnormalities are often remembered using the AEIOU TIPS mne- monic. There are several variations of this mnemonic, many of which include struc- tural causes. This version is for strictly non- structural causes. The list is not exhaustive but meant to represent common causes that should be considered prehospitally. • Alcohol and drugs o Ethanol and toxic alcohols (ethylene glycol, methanol) o Anticholinergics, opiates, barbiturates, benzodiaz- epines, anticonvulsants, antipsychotics o Carbon monoxide, cyanide • Electrolytes and endocrine abnormalities o Hyponatremia (low sodium) o Myxedema coma (hypothyroid) o Addison's crisis (low cortisol) • Insulin (diabetic problems) o Diabetic ketoacidosis o Hyperosmolar, hyperglyce- mic nonketotic states o Hypoglycemia • Oxygen levels low o Hypoxia secondary to respi- ratory or cardiac failure o Pulmonary embolism o Hypotension • Uremia • Temperature extremes (hypother- mia, hyperthermia) • Infection (sepsis, meningitis) This CE activity is approved by EMS World, an organization accredited by the Commission on Accreditation for Pre-Hospital Continuing Education (CAPCE), for 1 CEU upon successful completion of the post-test available at EMSWorldCE.com . Test costs $6.95. Questions? E-mail editor@EMSWorld.com. • List structural and metabolic causes of decreased level of consciousness • Identify key assessments to differentiate causes of decreased level of consciousness • Discuss treatment of the undifferentiated unconscious patient OBJECTIVES Decreased LOC: An Approach To Common Causes Many patients present as unconscious or confused, and the cause is oen overlooked By Blair Bigham, MD, MSc, EMT-P