Coma - Causes And Management

Saturday, April 8, 2023

Dr. Raj Gopal. V


Dr. Raj Gopal. V

Definition of COMAComa is defined as a sleeplike state with total absence of awareness of self and the environment, even after vigorous external stimulation. Coma is the most severe form of unresponsiveness, and by definition, comatose patients lie with their eyes closed. In general a comatose person is: •Apparently asleep.•Closing the eyes.•Not talking.•Unresponsive to instructions.•Without any voluntary movements.


Dr. Raj Gopal. V

Consciousstate

Drowsy

Alert and oriented

Sleepy but can be woken up

Stupor

Coma

Unconscious but responds to vigorous stimulation

Unconscious and unresponsive(Never lasts more than 2-4 weeks)

PVS(PersistentVegetativeState)

All cognitive functions lost.Maybe awake but totallyunresponsive. Breathing, circulationand internal organ functions intact.May last for years.

The various states of consciousness

For consciousness to be intact the cerebral hemispheres must be activated by the ReticularActivating System in the brainstem.


Dr. Raj Gopal. V

Pathophysiology of coma

Primarily 2 mechanisms:

•A diffuse insult to both cerebral hemispheres.•A focal lesion in the Reticular Activating System (RAS) in the upper Pons, midbrain or the Diencephalon.

•The “Big-3” causes: Stroke, Trauma, Drug overdose (STD!).


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(Diencephalon)

(Pons, Medulla)

RAS

COMA

COMA


Dr. Raj Gopal. V

Causes of COMA

Two broad categories: Structural or surgical and Metabolic or Medical.

Structural/Surgical: Diffuse damage to both cerebral hemispheres due to vascular damage or raised intracranial pressure.

Medical/Metabolic: Diffuse insult to both cerebral hemispheres by toxins, either from within or from outside.


Dr. Raj Gopal. V

Causes of COMARemember AEIOU-TIPS

A: Alcohol.E: Epilepsy or Exposure to heat and coldI: Insulin (Diabetic emergencies)O: Overdose or Oxygen deficiencyU: Uremia (kidney failure)T: Trauma (Shock or head injury)I: Infection or Iatrogenic.P: Psychosis or poisoning.S: Strokes.

There are 424 causes of COMA!


Dr. Raj Gopal. V

Causes of Surgical or Structural COMA

•Trauma: Subdural/Epidural/Penetrating head injuries, brain contusions.•Intracranial Hemorrhage: Subarachnoid or intracerebral.•Ischemic Stroke.•Diffuse microvascular abnormalities like purpura, Cerebral Malaria, Rocky Mountain Spotted Fever.•Tumors, either primary brain tumors or metastasis.


Dr. Raj Gopal. V

Causes of Metabolic or Medical COMA

•Drug overdose: Benzodiazepines, Barbiturates, Opioids, Anti-depressants.•Infections: Bacterial meningitis, Encephalitis, Sepsis.•Endocrine disorders: Diabetic emergencies, Myxedema, hyperthyroidism. •Metabolic causes: Hyponatremia, Hypernatremia, Uraemia, Hypoxia, hepatic coma, Hypertensive encephalopathy.•Toxic: Carbon Monoxide poisoning, Alcohol, Acetaminophen Overdose.•Medication side effects.•Hypothermia or hyperthermia.•Deficiency states: Thiamine (In alcoholics) and Niacin.


Dr. Raj Gopal. V

Differences

Differences between Structural or surgical and Metabolic or Medical.

Structural/Surgical: Focal neurological signs, dilated and unreactive pupils and increased intracranial pressure.

Medical/Metabolic: Reactive pupils, no focal neurological signs and normal intracranial pressures.


Dr. Raj Gopal. V

Diagnosis of COMA

•History from third parties like family, friends and emergency medical personnel. Ask relevant questions. •Clinical Examination: Quick and precise.•Rapid and appropriate investigations: To find cause and institute appropriate treatment.


Dr. Raj Gopal. V

Assessment of COMA

The level of coma is assessed by the Glasgow Coma Scale. A quick assessment is the AVPU scale, used by emergency medical personnel:

•A: Alert.•V: Responds to verbal commands.•P: Responds to pain.•U: Unresponsive - - - - - Proceed to GCS.


Dr. Raj Gopal. V

Assessment of COMA

The level of coma is assessed by the Glasgow Coma Scale. GCS assesses:

•Best verbal response.•Best motor response.•Level of stimulus needed to make the patient open the eyes.


Dr. Raj Gopal. V

The Glasgow Coma ScaleEYE OPENINGSpontaneous 4To speech 3To pain 2No response 1

MOTOR RESPONSEObeys 6Localizes 5Withdraws 4Abnormal flexion 3Extension Posturing 2No response 1

VERBAL RESPONSEOriented 5Confused conversation 4Inappropriate words 3Incomprehensible sounds 2No response 1

Total score: E + M + VRange: 3 – 15.Mild coma: 13 – 15Moderate coma: 9 – 12Severe coma: < 8


Dr. Raj Gopal. V

Examination of a Comatose patient

•Baseline: HR, BP, Rectal temperature, Oxygen saturation and capillary Glucose.•Response to external stimuli: None.•Signs of trauma.•Skin and mucus membranes survey: hyperpigmentation, cherry red color, anaemia, jaundice, rashes, IV drug abuse sites, myxoedema.•Any MedicAlert bracelets or cards?•Breath smell: Ketones, alcohol, Solvents.•Examine RS, CVS, PA. •Neurological examination including meningeal signs.


Dr. Raj Gopal. V

Neurological examination

The neurological examination focuses on 4 components.•Respiratory patterns.•Pupillary responses.•Eye movements.•Motor responses.

The most important examination in coma (to identify thecause) is the examination of the pupillary response

and eye movements.


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Respiratory patternsPattern Lesion Description

Cheyne-Stokes Forebrain to pons

Hyperventilation and

hypoventilation with pauses.

Central Neurogenic

Hyperventilation

Midbrain to pons

Rapid, deep breathing

Apneustic breathing

Pons Prolonged inspiratory gasp followed

by a pause and then expiration

Cluster breathing High medullary lesions

Periodic breathing with irregular frequency

and amplitude, along with variable pauses

Ataxic breathing Medulla Irregular in rate and rhythm


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Pupillary responses

•Most important part of examination.•Pupils that react to light and are equal in size: Metabolic or medical coma.•Unreactive, unequal and dilated pupil: Neurosurgical emergency.•Pinpoint pupils: Pontine lesions or opiate toxicity.•Bilateral dilated, unresponsive pupils: Anoxia, severe midbrain damage or anticholinergic drugs.•No pupillary abnormality: Excludes lesions below pons and above thalamus.


Dr. Raj Gopal. V

Eye movements

•Roving, slow, conjugate, lateral to and fro movements: Metabolic encephalopathies or bilateral lesions above brainstem.•Ocular bobbing: Rapid downward jerk and slow return to midposition of both eyes: Bilateral pontine lesions.•Ocular dipping: Slow downward dipping followed by brisk return: Diffuse cerebral damage.•Skew deviation in horizontal plane; Cerebellar or pontine lesion.•Doll’s eye reflex: Normally when the head is turned in a lateral plane the eyes move in the opposite direction. Absence of this response indicates brainstem lesion.•Caloric testing: 40-60 mL of ice cold water in the ears will cause the eyes to move towards the irrigated ear. Absence indicates brainstem damage.


Dr. Raj Gopal. V

Motor responses

•Spontaneous movements always good sign.•One side paralyzed: Suspect lesion in brain on the side not moving.•Decorticate posturing: Arms flexed and legs extended indicates lesions above brainstem or a metabolic cause.•Decerebrate posturing; Arms extended and legs extended indicates bilateral midbrain or pontine lesion. Worse prognosis. Also seen in metabolic conditions sometimes.•Myoclonus: Non-rhythmic jerking in single or multiple muscle groups suggests metabolic encephalopathies (hepatic chiefly).


Dr. Raj Gopal. V

Investigations

•Full blood counts: Infections.•Biochemistry: Electrolytes, sugar, LFTs, KFTs.•Arterial blood gases: Oxygen, CO2, pH, HCO3.•Blood cultures.•Alcohol levels.•Drug screen (urine and blood)•Lumbar puncture: Infections.•CT Scans in case of trauma, bleeds, hemorrhage.•MRIs where possible.•Thyroid function tests (rarely)•Electroencephalogram (EEG) & ECG.•CXR.•Blood slides for Malaria!!


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Management

Immediate management in hospital:•Never forget ABC: Airway, Breathing, Circulation.•“COMA COCKTAIL”: 50 mL of 50% Dextrose + Thiamine 100 mg + Naloxone 0.4 mg (adults).•Stop seizures with anti-epileptics.•Treat metabolic disturbances.•Lower intracranial pressure.•Treat infections.•Mechanical ventilation, IV lines and Ryle’s tubes.


Dr. Raj Gopal. V

Specific Management

Further management depends on the cause always.•Diabetes, hepatic coma, electrolyte imbalances, endocrine causes etc: Correction of metabolic derangements.•Trauma: Neurosurgery.•Strokes, heart attacks, respiratory failure, hypoxia, hypothermia: Correct underlying causes.•Medication/drug overdose: Specific antidotes.•Meningitis and infections: Antibiotics.•Raised ICP: Mannitol and Dexamethasone.


Dr. Raj Gopal. V

Long-term Management•Intensive nursing care.•Recovery position.•Mechanical ventilation.•Pressure sores prevention.•Care of the eyes.•Airway clearance by bronchial toilet.•Fluid and nutrition.•Catheterization of bladder.•Bowel care – Disposable diapers.•Physio to protect muscles and joints.•DVT prophylaxis?•Vital signs monitoring.•Neurological monitoring.


Dr. Raj Gopal. V

WORST PROGNOSIS:Structural damageSubarachnoid HemorrhageCerebrovascular causes

On Day I:No corneal reflexNo pupillary reflexDecerebrate posture

GOOD PROGNOSIS:Metabolic causes.If no recovery in 4 weeksprogresses to PVS.

INDICATORS OF PROGNOSIS:Depth of coma as by GCSPupillary reflexes.Eye movements.Motor responses.Age.


Dr. Raj Gopal. V

Complications

•Pressure sores.•Bladder infections.•Pneumonia: Hospital acquired or ventilator associated.•Persistent Vegetative State.


Dr. Raj Gopal. V

Persistent Vegetative State

A note on PVS•Permanent condition that emerges after severe brain injury.•Normal sleep-wake cycles and eyes that open to verbal stimuli.•No cognitive function.•Cannot localize pain, or follow verbal commands.•Blood pressure and respiration maintained.•Synonyms: Coma vigil, Cerebral death, Total dementia.•Very slim chances that the individual might recover.


Dr. Raj Gopal. V

Brain death

Brain death is different from coma and PVS•Complete lack of activity anywhere in the brain.•Kept alive through artificial means.•Clinically and legally dead.•Confirmatory EEG for legal purposes: Isoelectric ‘flat’ line.•Tests: Shine a light into eyes, corneal reflex, pain sensation, caloric tests, gag or cough reflex tested and removal from ventilator for short period to see if it stimulates respiration.•Organs for transplantation if there is consent.


Dr. Raj Gopal. V

SUMMARY

•Quick history from relatives and friends.•Quick medical examination.•Immediate transfer to specialized centers.•Assessment of Coma depth.•Detailed neurological evaluation.•Basic Laboratory investigations.•Specialized investigations.•Correct underlying cause where possible.•Refer for specialist care if required.•Ongoing care of the patient.•Recovery --------- Congratulations!•Progression to PVS or brain death.


Dr. Raj Gopal. V

Coma - Causes And Management

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