A young man in a coma

1. A young man in a coma PBL Neuro Block Week Three

2. A young man is brought into the emergency department by ambulance at 9am.  He was discovered unconscious in bed by his flatmate that morning.He had been seen at about 10pm the previous evening when he had been well.  The flatmate knows of no medical conditions.The man appears to be in his twenties and is dressed in jeans and a t-shirt.  He is still comatose.

3. What are you going to do immediately? Murtagh’s approach to unconscious patient

4. Initial examination: • No response to pain • no gag reflex – accepts Guedel airway without response • RR 14 • not cyanosed  (oxygen saturation 99%  on 8l/min oxygen) • PR 110 bpm • BP 100/60 mm Hg • T 37oC  • BSL 4.9mmol/L (4 – 8) • IV line inserted, infusion isotonic saline, bloods for FBC, ELFTs, blood alcohol and serum paracetamol

5. Outline Glasgow Coma Scale – what is the patient’s score? • Initial examination: • No response to pain • no gag reflex – accepts Guedel airway without response • RR 14 • not cyanosed  (oxygen saturation 99%  on 8l/min oxygen) • PR 110 bpm • BP 100/60 mm Hg • T 37oC  • BSL 4.9mmol/L (4 – 8) • IV line inserted, infusion isotonic saline, bloods for FBC, ELFTs, blood alcohol and serum paracetamol

6. Describe and justify what you should look for on examination? • Why does coma occur? • Damage to reticular formation by a lesion or metabolic abnormality when cortex is diffusely damaged • Check ABC • Posture • Decerebrate (extensor) posture can suggest severe midbrain disease – arms are extended and internally rotated and legs are extended • Decorticate (flexor) posture can suggest a lesion above the brainstem (unilateral or bilateral) – flexion and internal rotation of the arms and extension of the legs • Involuntary movements • May be focal or generalised, suggest status epilepticus • Myoclonic jerks can occur after hypoxic injury or metabolic encephalopathy • Neck • Check for trauma, neck stiffness and Kernig’s Sign • Head and face • Check for trauma, Battle’s Sign, facial asymmetry, jaundice, manifestations of myxoedema • Eyes • Inspect pupils • Small and reactive to light occurs in pontine lesions and narcotic overdoses • One small pupil occurs in Horner’s syndrome • Two midpoint non-reactive pupils suggests midbrain disease, anoxia or anticholinergic drugs • One dilated pupil suggests possible subdural haematoma, raised ICP or subarachnoid hemorrhage • Widely dilated pupils may occur in raised ICP and coning or with anticholinergic drugs • Conjunctival haemorrhage suggests skull fracture • Position of the eyes may suggest underlying lesions of cranial nerves, or also cerebral lesions and brainstem problems • Check ‘dolls eye movement’ to assess vestibular reflexes

7. Describe and justify what you should look for on examination? • Ears/nostrils • Look for trauma • Tongue/mouth • Gum hyperplasia can suggest pt taking phenytoin for epilepsy (also check for bite marks on tongue) • Check breath for alcohol poisoning, diabetic ketosis, hepatic coma or uraemia • Upper/lower limbs • Look for injection marks – drugs/diabetes • Test tone and assess any difference between left/right sides • Reflexes • Test pain sensation – apply firm pressure on nail bed of finger or toe on each limb • if coma is deep (or pain sensation absent) expect no response • If sensation is intact but limb paralysed look for grimacing with movement of other limbs • Body • Look for trauma • Examine heart, lungs and abdomen • Check urine – glucose/ketones/protein/blood • Blood glucose • Temperature (hypothermia in hypohyroidism or fever in meningitis) • Stomach contents

8. What are the common causes of coma? • Coma • (COMA provides a useful mnemonic for four major groups of causes of unconsciousness) • C° CO2 narcosis: respiratory failure • O° Overdose of drugs • alcohol • opioids • tranquillisers and antidepressants • carbon monoxide • analgesics • others • M ° Metabolic • diabetes • hypoglycaemia • ketoacidosis • Hypothyroidism • hypopituitarism • hepatic failure • renal failure (uraemia) • Hypercalcaemia • Adrenal failure • others • A ° Apoplexy (Incapacity resulting from a cerebral hemorrhage or stroke) • Supratentorial • intracerebral haemorrhage • haematoma: subdural or extradural • head injury • cerebral tumour • cerebral abscess • Infratentorial (posterior fossa) • pressure from above • cerebellar tumour • brain-stem infarct/haemorrhage • Wernicke's encephalopathy • Meningismus (neck stiffness) • subarachnoid haemorrhage • meningitis • Other • encephalitis • overwhelming infection • Trauma • Common causes of coma are: • traumatic brain injury (TBI) • hypoxic-ischemic encephalopathy (HIE) • drug overdose • ischemic stroke • intracranial hemorrhage • central nervous system infections • brain tumors • Episodic causes - blackouts • Epilepsy • Syncope • Drop attacks • Cardiac arrhythmias (e.g. Stokes-Adams attacks) • Vertebrobasilar insufficiency • Psychogenic disorders, including hyperventilation • Breath-holding (children)

9. What is your general management plan at this point? • From further history, examination and investigations it is established that the patient has attempted suicide with a cocktail of vodka, temazepam, oxazepam, paracetamol and dothiepin.

10. What is your general management plan at this point? Ring a toxicologist. In general: • Labs • Urine –BZD • serum acetaminophen – relate concentration to time period since amount taken – can use Rumack-Matthew nomogram • ECG • Decontaminate • multiple dose activated charcoal – use only if airway is protected • for TCA, acetaminophen • not for benzodiazepines, not for ethanol • In this case we use it. • Administer any antidotes • N-acetylcysteine • TCA • If QRS duration  > 100 ms: Sodium bicarbonate • If seizures: benzodiazepines – already has…. • Supportive care • Saline – hypotension (TCA’s) • Alpha adrenergic vasopressors – hypotension (TCA’s)

11. Additional info • Paracetamol poisoning • Signs • Mild and non specific – nausea, comiting, diaphoresis, pallor, lethargy, malaise (in first 24 hrs) • 24-72 hrs – clinical and lab. Evidence of hepatotoxcity/nephrotoxicity appear. These peak some 72-96 hrs after ingestion, Following this there is a recovery phase. • Get serum acetaminophen – relate concentration to time period since amount taken – can use Rumack-Matthew nomogram • Management • Activated charcoal – if airway protected • Antidote – acetylcysteine – IV • Alcohol ingestion • Acute Alcohol ingestion may in fact be protective – compete for some metabolising enzyme • Chronic alcohol ingestion depletes glutathione levels – bad – but does not seem to result in an increased risk of hepatotoxicity for a single overdose • Benzodiazepine poisoning • Oral taken in overdose without a coingestant rarely cause significant toxicity • Signs • Slurred speech, ataxia, altered mental status • Respiratory compromise – if taken with ethanol • Oxazepam least sedating, temazepam most sedating • Labs • ECG • BZD urine • Management • Activated charcoal is of no benefit • Antidote – flumazenil – but risks often outweight benefits • May require mechanical ventilation TCA poisoning (dothiepin) • Signs • CNS sedation, confusion ,delirium, hallucinations • Arrhythmias, hypotension • Anticholinergic toxicity • Cardiac toxicity • Widening of QRS interview, TQ and PR prolongation, BBB • VT/VF occur in 4% of overdoses • Mortality due to refractory hypertension • CNS toxicity • Mental status changes, delirium • Seizures may result • Coma • Labs • ECG to assess for cardiac conduction abnormalities • Management • DRSABCD • Isotonic saline – hypotension • Sodium bicardbonate – cardiac toxicity • Frequent ABG’s required – target pH 7.5-7.55 (disrupts TCA effect) • Alpha adrenergic vasopressors – hypotension • Activated charcoal – as long as airway is protected • Antiepileptic (if seizures) • Use benzodiazepines • Contraindications • No flumazenil – even if TCA and benzodiazepine indigestion • Certain anti-arrhythmics

12. Following appropriate medical treatment the patient makes a complete recovery.What is the next step in management? • Refer to psych! • Also, watch for withdrawal symptoms/signs in the possibility that he was chronically taking doses of benzodiazepines

13. Further reading • Epidemiology and prognosis of coma in daytime television dramas