SGL 5 (Coma)

Coma and Disorders of Consciousness

Overview

  • Coma is defined as a state of unconsciousness with physical and mental inactivity.

  • Patients cannot recall, and all sexes and ages are susceptible to this condition.

  • The term 'coma' comes from the Greek word koma, meaning deep sleep.

Types of Loss of Consciousness

  • Fainting (Syncope): A brief, transient loss of consciousness and postural tone due to diminished blood flow to the brain.

  • Conversion Disorder: A psychological condition that can lead to a temporary loss of consciousness.

Identification of Coma

Symptoms of Coma

  1. Loss of erect posture.

  2. Eyes closed and a sleep-like state.

  3. Lack of responsiveness.

Assessment Tool: AVPU

  • Alert

  • Verbal

  • Painful response

  • Unresponsive

Physiology of Consciousness

Key Physiological Aspects

  • Neurophysiology: Understanding brain function.

  • Cerebral Metabolism: The brain's energy consumption.

  • Cerebral Perfusion: Blood flow management to the brain.

  • Intracranial Pressure: Pressure within the skull and its implications.

Causes of Coma

Primary Causes

  1. Bihemispheric Cortical Dysfunction: Impaired function of both hemispheres of the brain.

  2. Brainstem Suppression: Involves the ascending reticular activating system (ARAS).

Structural Brain Pathologies

  • Acute Stroke: Related to large cortical or brainstem infarctions or hemorrhages.

  • Trauma: Head injury can cause loss of consciousness.

  • Epilepsy: Seizures leading to a comatose state.

  • Infection: Conditions like meningitis or encephalitis.

Cerebral Hypoperfusion

  • Causes: Cardiac arrest, arrhythmias, hypotension.

  • Importance of maintaining adequate ventilation and perfusion for brain oxygenation.

  • The brain typically receives 15-20% of resting cardiac output.

  • Autoregulation of cerebral blood flow occurs between 60-160 mm Hg mean arterial pressure.

Metabolic Causes

  • Hypoglycemia: Resulting from insulin therapy.

  • Hyponatremia: Low sodium levels due to water retention, sodium loss or renal diseases.

  • Drug poisoning: Exposure to toxic substances.

  • Alcohol intoxication: Affects consciousness heavily.

  • Carbon monoxide poisoning: Displaces oxygen in the blood.

  • Uremia: Renal failure causing acid and electrolyte imbalances.

Increased Intracranial Pressure

  • May be caused by space-occupying lesions (SOL), such as brain tumors or abscesses.

  • The total volume of intracranial contents is fixed; an increase in volume leads to dysfunction.

Management of Coma

Initial Assessment

  1. Check airway, breathing, pulses, and blood pressure frequently.

  2. If the patient is breathing, carefully roll them onto their side (if no spinal injury is suspected).

CPR and Resuscitation

  1. If breathing or pulse stops, roll the patient onto their back and commence CPR.

Handling Spinal Injuries

  1. If spinal cord injury is suspected, do not move the patient unless necessary; monitor breathing.

  2. If the patient vomits, roll the body carefully onto the side to prevent aspiration.

General Care

  1. Keep the person warm until medical help arrives.

  2. Do not provide food or drink to a comatose patient.

  3. Do not leave the patient alone.

  4. Avoid placing a pillow under the patient's head.

  5. Do not shake or slap the patient to try to revive them.

Specific Management Strategies

  1. If hypoglycemia is suspected (before coma), administer oral sugars.

  2. If fainting is observed, lay the person flat and raise their feet to improve blood flow.

  3. If a person feels faint, advise them to sit or lay down with their head between their knees.

Seizure Management

  1. For seizure patients, place them on their side and avoid injury while ensuring they do not bite their tongue.

Conclusion

  • Emphasis on immediate assessment, careful management, and understanding the physiological basis of consciousness is crucial for treating patients in comatose states.