Altered Level of Consciousness/Coma

Drugs

Alcohol

• intoxication
• withdrawal
• Wernicke-Korsakoff syndrome

Anticholinergics

Antidepressants

Anticonvulsants: lithium

Analgesics

• opioids
• NSAIDs
• steroids
• salicylates

Antibiotics: penicillins

Anti-histamines

Benzodiazepines

Cardiac: amiodarone, beta-blockers, digoxin, diuretics

Dopamine

Stimulants

• cocaine
• amphetamine

Infections

A variety of infections can lead to delirium, including:

• pneumonia
• UTI
• abscess
• sepsis

Other infections specifically affecting the central nervous system can lead to direct changes in congition. These include:

• meningitis
• encephalitis

Metabolic

In medical patients electrolyte abnormalities are common causes of altered LOC. These include:

• hypoglycemia
• hyperglycemia
• hyponatremia
• hypocalcemia
• hypomagnesemia
• ketoacidosis

Organ failure, leading to accumulation of toxic metabolic products or affecting perfusion, can also affect cognition:

• hepatic failure
• kidney failure (uremia)
• respiratory failure (hypercapnea, or elevated CO2)
• hypothyroidism
• hypertension
• hypothermia

Structural

Structural insults to the brain can lead to direct changes in brain function. Causes include:

trauma

• brain contusions
• diffuse axonal injury
• blunt or penetrating head injury

stroke

intracranial hemorrhage

• epidural
• subdural
• subarachnoid
• intracerebral

tumor

• glioblastoma

hydrocephalus

epilepsy

cerebral venous thrombosis

History

It is important to get a history from witnesses. Ask about onset, seizure, setting, medical history.

San Francisco Syncope Rules (CHESS)

CHF history

hematocrit <30%

EKG abnormality

shortness of breath history

Systolic BP <90 mmHg at triage?

Syncope can be characterized by the following:

• sudden loss of consciousness, often with brief pre-syncopal symptoms
• absence of postural tone (ie, no seizure)
• rapid spontaneous recovery

Physical Exam

cardiac (postural blood pressure and heart rate), respiratory, and neurological exams

• assess any trauma from fall

General exam

• vital signs
• trauma
• fundi for ICP

Neurological exam to localize

• pupillary reflex: midbrain
• brainstem reflexes
• corneal reflex: CN V and VII pons
• vestibulo-ocular reflex (Doll's eyes): tests widespread brainstem integrity
• cold caloric: eyes should slowly and tonically move towards the

• vital signs
• look for head trauma (Battle's sign, otorrhea, rhinorrhea)
• neck suppleness
• tongue for bite marks
• evidence of alcohol abuse
• evidence of IV drug use

resipratory

• tachypnea
• Cheyne-Stokes respirations - diencephalic cause
• hyperventilation - central neurogenic cause
• apneustic breathing
• ataxic breathing
• apnea

eye exam

pupillary responses:

• midsize, unreactive - midbrain
• pinpoint, reactive - pons or narcotics
• small, reactive - metabolic
• dilated, unreactive - drugs
• unilateral dilated, unreactive - rostro-caudal degeneration, uncal herniation

eye movements:

• full, inducible or spontaneous lateral movements suggest brainstem is ok
  • oculocephalic reflex (Doll's eye maneuver)
  • oculovestibular reflex

fundoscopy

motor exam

asymmetry suggests structural lesion

levels of motor response can help in localization

skin

signs of trauma and rashes

sensory exam

sternal rub

nail bed pressure

decorticate posturing

decerebrate posturing

Brain Death

• non-reactive pupils
• absent corneal reflex

Lab Investigations

fibger stick for glucose

CBC, glucose, lytes, osmolality, Ca2+, PO4-, BUN, creatinine

ABG

drug screen: ASA, tylenol, EtoK

CK, troponin, TSH, Mg, beta-hCG

liver enzymes

serum osmoles

lumbar puncture

Diagnostic Imaging

ECG

CT head, MRI, EEG