Published on March 16, 2014
General Approach And Differential Diagnosis of Coma
OBJECTIVES • Objective: Able to stabilize, evaluate, and treat the comatose patient in the emergent setting. • To understand this involves an organized, sequential, prioritized approach.
The Comatose Patient Objectives • Airway • Breathing • Circulation • Treatment of rapidly progressive, dangerous metabolic causes of coma (hypoglycemia) • Evaluation as to whether there is significant increased ICP or mass lesions. • Treatment of ICP to temporize until surgical intervention is possible.
Why Coma management • Common medical emergency 3-5% • Large proportion of comatose patient recover • Untreated coma may lead to further brain damage
Is it Coma ? Coma is prolonged Unconsciousness Or Unarousible Unresponsiveness. Quantify using the Glasgow coma scale.
Causes/Differential Diagnosis of Coma • Traumatic - head injury • Vascular - Cerebral thrombosis Cerebral Haemorrhage (ICH/SAH) Hypertensive encephalopathy • Meningitis,encephalitis,brain abscess,cerebral malaria • Brain tumor & other SOL • Epilepsy & postictal states • Psychiatric problems (Hysteria,depression,catatonia) • Organ failure - hepatic coma,respiratory coma,uraemic coma
• Metabolic Hyperglycemia , hypoglycemia Hypernatraemia , hyponatracemia Hyperthermia , hypothermia Hypercalcaemia , Water intoxication (SIADH) Diabetic coma Myxodemic coma • Endogenous Intoxication / drugs - sedative,morphine,pethidine Alcohol intoxication : alcohol withdrawl $
Consciousness • Perception • Reaction • Wakefulness
Level of consciousness Spontaneous 4 To Speech 3 To Pain 2 Absent 1 Converses/Oriented 5 Converses/Desoriented 4 Inapropriate 3 Incomprehensible 2 Absent 1 Obeys 6 Localizes Pain 5 Withdraws(flexion) 4 Decorticate(flexion) Rigidity 3 Decerebrate(extension) Rigidity 2 Absent 1 Eyes Open Verbal Motor The sum obtained in this scale is used to the assess Coma and Impaired consciousness Mild is 13 through 15 points Moderate is 9 to 12 points Severe 3 through 8 points Patients with score less than 8 are in Coma GCS
Coma - Aetiology Metabolic:- – Ischemic hypoxic – Hypoglycaemic – Organ failure – Electrolyte disturbance – Toxic Structural:- – Supratentorial bilateral – Unilateral large lesion with transtentorial herniation – Infratentorial
Metabolic encephalopathy • Confusional state -> coma , fluctuation • No focal neurological sign • No neck stiffness • Normal brainstem reflexes • Coarse tremor • Multifocal myoclonus • Asterixis • Generalized/periodic myoclonus
History • Circumstances and temporal profile • Of the onset of coma • Details of preceding neurological symptoms headache, weakness and seizure • Any head injury • Use of drug (e.g. Steroid) and alcohol • Previous medical illness liver, kidney • Previous psychiatric illness
Examination • General physical examination • Evidence of external injury • Colour of skin and mucosa • Odour of breath • Evidence of systemic illness • Heart and lung
Neurological examination • Fundoscopy • Pupil size and response to light • Ocular movements • Posture and limb movement • Reflexes
Cushing Triad Kocher-Cushing response - rise in BP- >bradycardia due to rise in ICP -> compression of floor of the 4th ventricle Stimulation to respiratory center- increase respiratory rate fall in BP and tachycardia usually terminal event due to medullary failure
Pupil • Diencephalic (metabolic) Small reactive • Midbrain tectal Midsize,fixed • Midbrain nuclear Irregular pear shaped • 3rd nerve Fixed widely dilated • Pontine haemorrhage Pinpoint reactive Opiate Pinpoint • Organophosphorus Small • Atropine Wide dilated
Motor Exam Key Points: • Assess tone, presence of asterixis • Response to painful stimuli – none – abnormal flexor – abnormal extensor – normal localization/withdrawal • Symmetric responses seen with metabolic or structural causes • Asymmetric responses seen with structural causes
Posture • Cerebral hemisphere – Decorticate posture • Diencephalon supratentorial – Diagonal posture • Upper brain stem – Decerebrate posture • Pontine – Abnormal ext arm – Weak flexion leg • Medullary – Flaccidity
Investigation • Complete blood count, MP, B.sugar • Blood urea, s. creatinine, s.electrolyte • Blood gases, ALT, AST • CSF examination • CT scan/ MRI • X-ray chest, ECG
Management • Check vital signs - BP,HR,RR Patent airway Adequate breathing Adequate circulation • Correct the reversible cause Rapid history taking & rapid and through P.E 50% glucose Nalosone, Nalophine (Narcotic overdose) Vit B1 for Wernicke’s encephalopathy Flumazenil if coma due to diazepam overdose • GCS assessment
Treatment 1. Turn the patient frequently to prevent aspiration,sore,hypostasis – Skin care – Bladder care – Bowel care Continue treatment 2. If the General condition stablilized, do CT head scan to detect organic lesion – Infract can’t be seen immediately,can see at least 6-8 hr – Haemorrhage can be seen immediately-do CT scan immediately – Tumour-can see as SOL
3. CT head - Normal -do LP – If infection present - treat 4. CT & LP - normal - treat metabolic (if consider metabolic) – If deteriorate ,consider expansion of disease, new lesion and metabolic 5. Increased ICP - osmotic diuresis – Mannitol - 20% in 200cc N/S within 20min. 6. Evaculation of Haemorrhage - refer to neurosurgery 7. Infract - symptomatic treatment • Prognosis – Can be determined by GCS & Head injury – If there is no improvement within 48 hr, prognosis is bad.
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