Central Nervous System - COMA

Question 1

Define COMA

Answer 1

Is a state of Unrousability
ie loss of both
1) Arousal (RAS) - in the midbrain, Pons, Medulla and
2) Content function in the Cerebrum

Question 2

What are the aetiology of COMA

Answer 2

TIPS AEIOU
T- trauma, temperature , Tox
I - Infection
P - Psychiatric, Poisoning
S - SOL
A - Alcohol
E - Epilepsy, electrlyte, encepahalitis
I - Insulin
O - Opioids
U - Uraemia

Question 3

Describe your assesment of patient with COMA

Answer 3

1) Initial life saving management
ABC _ cervical spine if required
2) GCS - <8
if GCS 3 - Cerebral assess brianstem lesion - at what level
3) Pupillary constriction - ansecoria + abscent response
(Midbraine structural lesion)
4) Tonic elevation eye position - seizure or irritant brain lesion
5) Corneal reflex ( CN V or VII ) absent
( Posterior fossa or brainstem lesion)
6) Occulocephalic reflex ( Dolls eye) - no brain stem function
7) Occulovestibular reflex
COWS - cold opposite lesion and warm same side of lesion
- no response - no brain function

Question 4

Describe your management of this patient COMA

Answer 4

Airway Protect and maintain. Use oropharyngeal airway or intubate if unable to maintain airway

Breathing Give oxygen until saturations known, monitor O2 saturation, assess rate and pattern of breathing. Support breathing by hand bagging if required

Circulation Obtain venous access. Assess for signs of shock and treat as indicated (see guidelines on shock)

Dextrose - Check blood glucose level. If low, take blood for hormones (insulin, hGH, cortisol) and ketones and give a bolus of 10% Dextrose 5 ml/kg IV, followed by a 10% Dextrose infusion at 4 ml/kg/hour (7 mg/kg/min). If high, consider diabetes

Drugs If opiates suspected, consider Naloxone 0.1-0.8 mg /kg IV (maximum dose 2 mg). Avoid Flumazenil, which may induce convulsions in mixed overdoses, particularly if tricyclic antidepressants have been taken. Isolated benzodiazepine overdose does not cause significant respiratory depression and children are best managed with simple observation. If you decide to use Flumazenil, the dose is 5 g / kg IV. You can repeat this every minute to a total of 40 g / kg (maximum dose 2 mg)

Question 5

What are the emergency management of raised ICP

Answer 5

i.e. Cushings triad of hypertension, bradycardia, apnoea and / or fixed, dilated pupils and GCS  8)

• Airway - intubate
• Moderate hyperventilation to maintain a pC02 of 4 kpa
• IV Mannitol 0.5 - 1.0 g/kg (with urinary catheter in place)
• General measures including sedation and pain relief e.g. IV Valium or Morphine
• It is important to control fever in a child with raised intracranial pressure. Give Paracetamol intragastrically or rectally 10 -12 mg/kg 4 hrly.

Question 6

Describe your investigations of patient who presentyed with COMA

Answer 6

• FBC - Consider coagulation screen
• Glucose - If hypoglycaemic measure insulin, blood ketones, growth hormone and cortisol
• Urea & electrolytes
• Blood gas
• Urinalysis - Consider toxicology screen of urine and blood
• Liver function tests - Consider serum ammonia
• Lumbar puncture - Contra-indicated in presence of coma (GCS <9), raised intra-cranial pressure or unstable clinical state. If meningitis is suspected but LP is contra-indicated, start antibiotics
• Xray cervical spine - Protect neck until fracture has been excluded by lateral cervical spine films in cases of trauma or possible trauma

Question 7

What are conditons that mimic COMA

Answer 7

1) Locked - in Syndrome -
- Basilar artery occlusion
- Infarction of the ventral pons
both damage the decending motor pathways of the limbs and face
2) Hysterical Coma

Question 8

Neuroleptic Malignant Syndrome

Answer 8

Idiosyncratic reaction to neuroleptic drugs

• haloperidol
• fluphenazine
• chlorpromazine
• Metoclopramide
• prochlorperazine
  1) Must be >37.5 , > 38% C in >90% up to 40 C
  2) Generalised muscle rigidity - Parkinsonian rigidity present in > 90%
  3) Autonomic Instability
• tachycardia, sweating, labile BP
  4) Altered Conscious state
• confusion to coma
• dysphagia, aphonia, dysarthria

Question 9

What are the differential diagnosis for Neuroleptic Malignant Syndrome

Answer 9

1) Heat stroke
- no rigidity
- viriable perspiration
2) Malignant hyperthermia
- exposure to suxamethonium or Halogenated hydrocarbon
3) Serotonin syndrome
4) Infection esp pneumonia
5) lethal catatonia

Question 10

How do you manage Neuroleptic Malignant Syndrome?

Answer 10

1) Suportive
- widrawal responsible agent
- cooling and CVS/ Resp support
- observe and treat for rhabdomyolysis / myoglobinuria
2) Bromocriptine - 2.5mg oral q8hrs ( dopamine agonist)
3) Dantrolene - 2 - 3 mg /kg /day IV up to 10mg/kg maximum total dose

NB mortality up to 30%