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Critical Care

Critical Care. Coma, Seizures. Coma. Neurologist's favorite consultation History, straightforward Neurologic examination, focused Differential diagnosis, limited. Neurologic examination + battery of tests Initial stabilization → specific causative condition → Tx

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Critical Care

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  1. Critical Care Coma, Seizures

  2. Coma • Neurologist's favorite consultation • History, straightforward • Neurologic examination, focused • Differential diagnosis, limited

  3. Neurologic examination + battery of tests • Initial stabilization → specific causative condition → Tx • Recognition of reversible causes of coma • BAO, nonconvulsive status epilepticus, and herniation

  4. Classification of Levels of Consciousness • 3 A’s of consciousness • awake ( fully roused and thus not asleep ) • alert ( able to pay attention ) • aware ( understanding of oneself ) • 3 A’s = alert • Awake and alert = demeted • Awake = dilirious • -3 A’s = coma • Excellent and easily reproducible way of assessing level of consciousness

  5. Unresponsive Patient • Fully conscious but is unable or unwilling to respond verbally (Aphasia) • Waxing-and-waning level of wakefulness (dilirium) • Comatose

  6. Initial Stabilization • Stabilize the patient by addressing the ABCs of resuscitation • Endotracheal intubation (neuro xm b4 intubation) • Avoid D5W

  7. Clinical Evaluation

  8. Focused Neurologic Examination • Reasons for neurologic examination coma patient • Glasgow Coma Scale (GCS) • yield important diagnostic information • Complete and exhaustive neurologic examination is totally unnecessary

  9. Focused Neurologic Examination • Spontaneous movements (~ 15 seconds) • Papillary response (~ 15 seconds) • Ocular motility (~ 15 seconds), and • Motor response (~ 15 seconds)

  10. Spontaneous movements should be observed • Generalized seizures • Tonic (sustained contractions with upper-extremity flexion and lower-extremity extension) • Tonic-clonic movements (tonic contractures alternating with periods of muscle atonia, resulting in rhythmic contractions)

  11. Pupillary responses distinguishes structural from metabolic coma • Pupils are generally resistant to metabolic insult • Indicate the integrity of the brain stem

  12. Minimal or absent eye movement in conjunction with reactive pupils also typically signifies a metabolic process • Gaze deviation may indicate a stroke: • Cortical stroke will cause the eyes to look toward the damaged side of the brain

  13. Whereas a pontine stroke will cause the eyes to look away from the damaged side of the pons

  14. Vertical disconjugation of the eyes (skew deviation) is indicative of brain stem disease and frequently occurs during basilar artery thrombosis

  15. General Physical Examination • Blood pressure, heart rate, and cardiac rhythm are key to the diagnosis of the various cardiovascular and hemodynamic causes of coma • Hypothermia is noted in cases of exposure, drowning, methanol poisoning, and septic shock • Hyperthermia is obviously suggestive of an ongoing infectious process

  16. Rise in intracranial pressure (ICP) occurs with any space-occupying lesion • Signs of rising ICP include • increasing blood pressure • decreasing heart rate • slowing or periodic respiration (Cushing phenomenon)

  17. General Measures, Triage, and Test Battery • Serum electrolyte, calcium, magnesium, phosphorus, blood urea nitrogen (BUN), and creatinine levels, as well as liver function tests • A complete blood count (CBC), a urinalysis, and a urine toxicity screen should also be obtained • Lumbar puncture should be performed only if meningitis

  18. Coma cocktail • consisting of dextrose • naloxone • thiamine—is administered if the cause of coma is not immediately apparent from the brief history and physical examination

  19. Administering dextrose to a thiamine-depleted patient may precipitate the Wernicke-Korsakoff syndrome. • As a rule, therefore, thiamine should always be given before dextrose.

  20. When drug overdose or toxin ingestion is suspected, activated charcoal, 50 to 100 mg (with or without gastric lavage), should be given to prevent systemic absorption.

  21. Management of Specific Causes of Coma

  22. Basilar Artery Occlusion • Uncommon cause of stroke • Caused by embolism • Intrinsic atherothrombosis • Frequently presents with a stepwise accumulation of neurologic deficits that culminates in a coma.

  23. Comatose patient with BAO usually manifests obvious clinical signs of brain stem injury, such as quadriparesis, skew deviation, and diminished gag reflex • Management of BAO should be aimed at immediate recanalization of the occluded artery

  24. Thrombolysis, either intravenous (with tissue plasminogen activator) or intra-arterial (with urokinase or mechanical clot disruption), may be lifesaving

  25. Seizures • Cause coma in two different ways • coma may be the initial manifestation of the immediate postictal state after a generalized seizure • coma may develop when multiple generalized seizures occur in succession and there is not enough time between seizures to allow patients to recover

  26. Tonic-clonic seizure • begins with a tonic contraction that lasts as long as 30 seconds, followed by several minutes of repeated muscle contractions, loss of pupillary response to light, sweating, tachycardia, excessive bronchial secretion, and marked hypertension

  27. Aim is not to stop the body from convulsing but to stop the abnormal cerebral electrical activity immediately • Lorazepam • Goal of therapy is to achieve a burst-suppression pattern on electroencephalography for 12 to 24 hours before any attempt is made to taper medications

  28. Increased Intracranial Pressure • Head of the patient's bed should be elevated to an angle of 30° to 45° to facilitate venous return from the head • Hyperventilation • Mannitol, 0.25 mg/kg every 4 to 6 hours

  29. Metabolic Derangements • Intoxication • overdose of alcohol, narcotics, sedatives, or some combination • induce depression of respiration and cardiovascular function

  30. Hypoglycemic coma • plasma glucose levels fall below 45 mg/dl • jitteriness with palpitations • diaphoresis • focal neurologic symptoms mimicking ischemic stroke to frank coma • Most common cause is diabetes; other common causes include alcoholism, hepatic failure, and renal failure.

  31. Urgent restoration of the patient to a euglycemic state • Ampule (50 ml) of a 50% solution

  32. Diabetic ketotic coma • Key components of the management of diabetic ketoacidosis • Replacement of fluid losses (the average fluid loss is approximately 7 L). • Normalization of electrolyte levels and careful monitoring of serum potassium. • Restoration of acid-base balance (bicarbonate infusion is reserved for severe cases).

  33. Correction of insulin deficiency (4 to 6 U/hr). • Replenishment of energy stores (e.g., through dextrose infusion with insulin coverage until the patient can resume oral feeding). • Investigation to identify an underlying cause (infection is common

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