coma dr d v siva kumar asso professor gen medicine

COMA

Dr D V Siva KumarAsso ProfessorGen Medicine

Definitions :

o Consciousness – is a state of Cerebral activity in which patient is aware of both self and environment and able to respond to internal changes

o COMA is a state in which patient makes no Psychologically meaningful response to the external stimulus or inner need

o Dementia- Patient is awake and alert but muddled in time place and person (confusion) and as impaired memory and mental processing

o Delirium – patient is similarly confused but alertness is impaired (drowsy)

o Acute confusional state in which patient alertness is clouded and associated with agitation, fright, and confusion

Causes of COMA

Metabolic

i. Hypoglycaemia

ii. Diabetes mellitus

iii. Renal failure

iv. Hepatic failure

v. Hypothermia

vi. Hypothyroidism

vii. Cardio respiratory failure

viii. Hypoxic encephalopathy

o Drug overdosage (including alcohol)

o Structural

- Diffuse

i) Meningitis

ii) Encephalitis

iii) Other infections (e.g. cerebral malaria)

iv) Subarachnoid haemorrhage

v) Epilepsy

vi) Head Injury

vii) Hypertensive encephalopathy

Focal :

i) Supratentorial Lesions

ii) Cerebral Haemorrhage

iii) Cerebral infarction with oedema

iv) Subdural haematoma

v) Extradural haematoma

vi) Tumour

vii) Cerebral abscess

viii) Pituitary apoplexy

Subtentorial lesions :

i) Cerebellar haemorrhage

ii) Pontine haemorrhage

iii) Brainstem infarction

iv) Tumour

v) Cerebellar abscess

vi) Secondary effects of transtentorial herniation of brain due to cerebral mass lesions

Immediate assessment of coma: seven questionsQuestion Check ActionAirway Blood gases Intubate, clear ? give oxygen

2. Fittings? Blood glucose I.V glucose,I.V diazepam,oxygen

3. Signs of CT scan Neurosurgical

craniofacial opinion

trauma?

Question Check Action

4. Neck broken? Splint neck X-ray neck

5. Major Maintainhaemorrhage? circulation

6. Signs of Check blood Treat Diabetes and urine appropriately Mellitus? glucose

7.Evidence of Pupils / Naloxone? drug overdose ventilation

or misuse?

Basic neurological examination in coma

o Assess level of consciousness

o Signs of head injury

- Local bruising, fractures and penetrating wounds

- Bleeding from nose or ears

o Splint the neck: head injury may be associated with fracture of the cervical spine

o If no neck injury (Clinically & by X-ray) check for neck stiffness

o Check resting pupillary size, and pupillary responses to light

o Ocular movements: spontaneous, following and to “doll’s head” (if no voluntary response)

o Limbs: posture, tone and movement

o Reflexes and plantar responses

o Fundi

Metabolic and drug – induced coma

o Coma without localizing signs is characteristic syndrome

o Full range of ocular movement to “doll’s head” testing

o Pupils may be small, e.g. opiate poisoning

o Altered respiratory pattern may signify metabolic acidosis (consider diabetic coma), or respiratory alkalosis (with hypercapnia)

Decerebrate extension may occur in extremis

o Look for signs of metabolic disorder, e.g. jaundice, uraemia, respiratory failure, hypocalcaemia, endocrine disease (especially hypothyroidism or hypopituitarism)

o Drug-induced coma is associated with access to medication or drugs of abuse, or signs of repeated venous access

o Pre-conditions for considering diagnosis of brain death

o The Patient is deeply comatose

a) There must be no suspicion that coma is due to depressant drugs

E.g. Narcotics, Hypnotics, Transquilisers

b) Hypothermia must be excluded Rectal temperature should exceed 350 C

c) There is no profound abnormality of Serum electrolytes, acid base balance, blood glucose concentration and any endocrine metabolic cause of coma has to be excluded

2) Spontaneous respiration has been inadequate or ceased.

Patient is maintained on ventilator, drugs, including neuromuscular blocking drugs should be excluded as cause of respiratory failure

3) The diagnosis of the disease leading to brain death has been firmly established. They should be no doubt the patient is suffering from irremediable structural brain damage

Test for confirming Brain Death

o The pupils are fixed and unreactive to light.

o The corneal reflexes are absent

o Vestibul ocular reflexes are absent

o No motor responses to adequate stimulation

o There is no gag reflex and no reflex response to suction catheter in the trachea

o The test usually repeated after the interval of 6 to 24 hours depending on clinical circumstances before brain death is confirmed.

o History

o General Examination

o Neurological Examination

Examination of unconscious patient

History :

o Questioning relatives, friends or ambulance teem is an essential part

o As the patient sustain head injury

- Leading to admission (or)

- Preceding weeks

o Did the patient collapse suddenly.

Did limb twitching occurred

o Have symptoms occurred preceding weeks

o Does patient suffered a previous illness.

o Does patient take medication

Neurological Disease can produce systemic signs or a systemic disease may affect nervous system.Temperature evidence of weight loss Septic causeBP breast lumps Skin marksNeck stiffness Lymphadenopathy RashesPulse irregularity Hepatosplenomegaly café – au – lait spotsCarotid bruit Prostatic enlargement angiomataCardiac mumurCyanosisLook :Signs of head injuryNeedle marks on armsEvidence of tongue bitingSmell of alcohol

General Examination

Glasgow coma scale (GCS)

o 1974 Teasdale and Jennett, in Glasgow, developed the system for conscious level assessment. They discarded wage terms such as stupor, semi coma and deep coma, and described conscious level in terms of

- EYE opening

- VERBAL response

- MOTOR response

- GCS serves immediate prognostic guide

Eye opening Verba response Motor response

Spontaneous-4 Orientated – 5 Obeying commands-6

To speech – 3 Confused – 4 Localising - 5

To pain - 2 Words – 3 Normal Flexion – 4

None – 1 Sounds – 2 Spastic Flexion – 3

None – 1 Extension – 2 None – 1

o Always describe the conscious level in terms of the actual responses i.e. no eye opening no verbal response and extending

o Also examine

o Pupil response

o Optic Fundi

o Corneal reflex

Limb :

o Reflexes

- Tone

- Plantar response

Eye Movements

o Observe any spontaneous eye movements

- Elicit the oculocephalic (Doll’s Eye) reflex

- Rotation or flexion / extension of the head in comatose patient produces transient eye movements in a direction opposite to the movement

- Note whether the movements, if present, are conjugate or dysconjugate. These ocular movements assess midbrain and tontine function.

- Elicit the oculovestibular reflex (Calorie testing)

o In a comatose patient, irrigation of the external auditory meatus on one side with at least 20ml of ice cold water induces slow conjugate deviation of the eyes towards the irrigated side after a few seconds delay

o In the awake or drowsy patient this slow tonic deviation is masked by a fast, coarse nystagmus towards the opposite side

o Visual fields

o Facial weakness

o Limb weakness

- If pain produces an asymmetric response, then limb weakness is present