TOC |  STAT | Neuro

STUPOR & COMA (I)

A.  Normal Brainstem Reflexes with No Lateralizing Signs

Brainstem Reflexes:
*Pupillary reaction to light for midbrain & 3rd nerve function
*Spontaneous & reflex eye movements & corneal responses - pontine function
*Respiratory & pharyngeal responses - medullary function

1. Abnormal Head CT Scan
a. Subarachnoid hemorrhage
b. Bilateral contusions, edema, or axonal shearing of hemispheres due to closed head trauma
c. Bilateral subdural hematomas
d. Hydrocephalus

2. Normal or Unhelpful Head CT Scan
a. Drug toxin ingestion (toxicologic analysis)
b. Endogenous metabolic encephalopathy (glucose, pO2, pCO2, Na+, BUN, Ca++, osmolarity, ammonia)
c. Shock or hypertensive encephalopathy (BP)
d. Meningitis or nonherpetic viral encephalitis (CSF analysis)
e. Acute disseminated encephalomyelitis (CSF analysis)
f. Subarachnoid hemorrhage with normal CT (CSF analysis)
g. Epilepsy (EEG)
h. Conversion reaction, catatonia
i. Advanced Alzheimer's disease & Creutzfelt Jakob disease
j. Reye's syndrome (ammonia, > intracranial pressure)

B. Normal Brainstem Reflexes with Lateralizing Motor Signs

1. Abnormal Head CT Scan
   a. Cerebral hemorrhage (basal ganglia, thalamus)
   b. Large infarction with surrounding brain edema
   c. Subdural or epidural hematoma
   d. Tumor or brain abscess with edema
   e. Vasculitis with multiple infarctions
   f. Herpes virus encephalitis
   g. Pituitary apoplexy
   h. Metabolic encephalopathy superimposed on preexisting focal lesions (i.e. stroke)
   
2. Normal or Unhelpful Head CT Scan
   a. Metabolic encephalopathies with asymmetrical signs
   b. Isodense subdural hematoma (brain scan, angiogram)
   c. Epilepsy with focal seizures or postictal state (EEG)
   d. TTP (CBC with platelet counts)

C. Multiple brainstem reflex abnormalities

1. Abnormal Head CT Scan
   a. Pontine, midbrain hemorrhage
   b. Cerebellar hemorrhage, tumor, abscess
   c. Cerebellar infarction with brainstem compression
   d. Mass in hemisphere causing advanced bilateral brainstem compression
   e. Brainstem tumor or demyelination
2. Normal or Unhelpful Head CT Scan
   a. Basilar artery thrombosis causing brainstem stroke (clinical signs, angiogram)
   b. Severe drug overdose (toxicologic analysis)
   c. Traumatic brainstem contusion hemorrhage (clinical signs, auditory evoked potentials)
   d. Basilar artery migraine
   e. Brain death

A. No focal/lateralizing neuro deficit or no CSF abnormality:

1. Drug/toxin: heroin, barbiturate, antidepressant, alcohol, tranquilizers, etc.
2. Metabolic disorders: diabetic ketoacidosis, diabetic hyperosmolar coma, alcoholic ketoacidosis, renal failure, liver failure, hypoxemia, hypotensive encephalopathy, hypoglycemia, hypercapnia, hyponatremia, hypernatremia, hypokalemia, myxedema coma
3. Severe systemic infections
4. Cardiovascular: cardiac failure, shock, hypertensive encephalopathy
5. Epilepsy, post ictal states

B. Focal/laterilizing neuro deficit, +/ CSF abnormality:

1. Stroke (CVA): hemorrhage, thrombosis, embolism, hematoma
2. Mass lesions: brain tumor, abscess

C. Meningeal irritation with CSF blood or pleocytosis:

1. Subarachnoid hemorrhage: trauma, AV malformation, ruptured aneurysm
2. Meningitis: bacterial, fungal, viral
3. Encephalitis                                                                                         

EVALUATING THE COMATOSE PATIENT:
Rapid neurologic assessment is key to appropriate management
by Khalid Malik, MBBS, David C. Hess, MD
Postgraduate Medicine  Feb 2002

Table 1. Causes of structural or surgical coma

Trauma

• Subdural injury
• Epidural injury
• Diffuse axonal injury
• Brain contusions
• Penetrating head injury

Intracranial hemorrhage

• Subarachnoid hemorrhage
• Intracerebral hemorrhage: Posterior fossa (pontine, cerebellar), Supratentorial (basal ganglia, lobar)

Ischemic stroke

• Large middle cerebral artery infarction with brain herniation
• Brainstem stroke involving bilateral rostral pons or midbrain
• "Top of the basilar" syndrome with bilateral infarction of thalami and rostral midbrain

Diffuse microvascular abnormality

• Thrombotic thrombocytopenic purpura
• Rocky Mountain spotted fever
• Cerebral malaria

Tumor

• Glioblastoma multiforme with herniation
• Multiple metastatic lesions

Other disorders

• Osmotic demyelination syndrome (central pontine myelinolysis)

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Table 2. Causes of metabolic or medical coma

Drug overdose

• Benzodiazepines, barbiturates, opioids, tricyclic agents

Infectious disease

• Sepsis
• Bacterial meningitis
• Encephalitis (eg, herpes simplex, arboviral infection)

Endocrine disorders

• Hypoglycemic reaction
• Diabetic ketoacidosis
• Hyperosmolar coma
• Myxedema
• Hyperthyroidism

Metabolic abnormalities

• Hyponatremia
• Hypernatremia
• Uremia
• Hepatic encephalopathy
• Hypertensive encephalopathy
• Hypomagnesemic pseudocoma

Toxic reactions

• Carbon monoxide poisoning
• Alcohol poisoning
• Acetaminophen overdose
• Ethylene glycol poisoning

Medication side effects

• Reye's syndrome
• Neuroleptic malignant syndrome
• Central anticholinergic syndrome
• Serotonin syndrome
• Isoniazid intoxication

Deficiency states

• Thiamine deficiency (Wernicke's encephalopathy)
• Niacin deficiency (pellagra)

Hypothermia

Psychogenic coma

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03202002