Specific considerations Flashcards
Discuss coma in the poisoned patient
Describes an altered mental status where the patient cannot be roused.
Can be due to
- direct toxic effect on the CNS
- secondary effect of poisoning on the CNS (hypoxaemia, hypoglycaemia, hyopnatraemia, hypotension, seizure or cerebral oedeam.
Toxic agents usually act on the CNS in a global and symmetrical fashio and any focal or unilateral neurological sign is highly suggestive of an alternative cause.
Discuss management of coma in the poisoned patient
Establishment of airway and adequate ventilation is the immediate priority irrespective of the aetiology oc coma. If comatose most patient will require RSI and ETT the excpetion being those with rapidly reversible causes of coma such as hypoglycaemia or opiate toxicity
If requiring intubation and ventilation it is necessary to be aware of required respiratory rate. Many poisoning will results in metabolic or respiratory acidosis and if hyperventilation is not maintained acute acidosis, clinical deterioation and possibly death.
List complications of coma in patient who have been poisoned
1) pulmonary aspiration
2) rhabdo
3) Acute renal failure
4) compartment syndromes
5) pressure areas
6) hypoxic brain injury
Discuss investigation in a comatose patient who has been possibly poisoned
-ECG, paracetamol, BGL –> all tox patients
ABG
- anion gap, lactate
- osmolar gap
Specific drug levels
-carbamezepine, ehtanol, ethyolen glycol, methanol, salicylattes, valproic acid
Discuss agents that cause coma in poisoning that require specific intervention
1) Carbamezepine
- -HD
- - Multi dose activated chracoal
2) isoniazid
- b6
3) opiods
- naloxone
4) organophosphate
- pralidoxime
- atropine
5) phenobarb
- MDAC
- HD
6) salicylates ( severe only)
- HD
7) sulfonylureas
- dextrose
- octreotide
8) Toxic alcohols ( ethylene glycol, methanol)
- Ethanol/fomepizole
- HD
9) Valproic acid
- HD
Discuss toxic seizures
Usually generalised and self limiting - easily controlled with benzo
Most common causes in australia
- venlafaxine, bupropion, tramadol and amphetamines
- common in multiple withdrawal syndromes
In certain poisoning the presence of seizure activity is a herald of grave prognosis if management is not appropriate and rapid. ( chloroquine, propanolol, salicylates, theophylline, TCA)
Discuss management of toxic seizures
- ABC
- check BGL if low correct
- Benzo
- Barbituate as second line
- pyridoxine as third line especially if isonizide poisoning is considered
Define delirium
1) disturbance in attention ( reduced ability to direct, focus, sustain and shift attention) and awareness
2) change in cognition that is not better accounted for by a pre-existing, established or evolving dementia
3) The disturbance develops over a short period ( usually hours to days) and tends to fluctuate throughout the course of the day
4) There is evidence from the history exam or lab finding that the disturbance is caused by a direct physiological conequency of a general medical condition, intoxicating substance, medication use or more than one cause
List common toxicological causes of agitation and delirium
Alcohol Anticholinergic syndrome Antidepressants Atypical antipsychotics Baclofen Benzo and other sedative hypnotic agents cannabis Hallucinogenic agents Neuroleptic malignant syndrome Nicotine Salicylates serotonin syndrome sympathomimetic syndrome synthetic cannabinoids synthetic cathinones theophylline withdrawals syndromes
Discuss agents or syndromes associated with delirium or agitaiton that require specific therapy
Anticholinergic agents – physostigmine
Neuroleptic malignant syndrome - bromocriptine
salicylates – urinary alkinisation, HD
Serotonin syndrome – crypoheptadine, paralysis and I&V
Theophylline - MDA, HD
Discuss serotonin syndrome
Serotonin syndrome is the clinical manifestation of excessive stimulation of serotonin receptors in the CNS
occurs when there is excess serotonin secondary to
- inhibition of serotonin metabolism (MOA)
- prevontion of uptake ( SSRI)
- serotonin release or increase intake of serotonin precursors
Hunter Serotonin toxicity criteria
1) spontaneous clonus
2) inducible clonus and agitation or diaphoresis
3) occular clonus and agitation or diaphoresis
4) tremor and hyper-reflexia
5) hypertonic and ocular or inducible clonus
Discuss clinical features of serotonin syndrome
Mental status change
- apprehension
- anxiety
- agitation, psychomotor acceleration and delirium
- confusion
Autonomic
- diarrhoea
- flushing
- hypertension
- hyperthemia
- mydriasis
- sweating
- tachycardia
Neuromuscular excitation
- rigidity
- hypereflexia
- clonus (esp ocular and ankle)
- increased tone
- tremor
Syndrome will usually resolve within 12 hours up to 24-48 hour in severe cases
Discuss clinical setting in serotonin syndrome may develop
- At the introduction or increase of a single serotonergic agent
- change in therapy from one to another without adequate intervening washout period
- Drug interaction between two serotonergic agents
- INteraction between serotenergic drug and an illicit drug or herbal preparation
- Deliberate self poisoning with serotonergic agents
Discuss management of serotonin syndrome
ABC
Indication for I&V with paralysis include - coma, recurrent seizures, hyperthemia greater than 39.5 or severe rigidity compromising ventilation
If mild to moderate. Can consider cyproheptadine – first gen antihistamine with anticholinergic, antiserotonergic and LA properties. Initial dose is 8mg can be given orally or via NG – airway needs to be uncompromised. TDS dosing
Can consider the use of olanzapine specifically if agitation is a significant issue.
If severe will need to be intubated
Discuss anticholinergic syndrome and its clinical features
Arises due to competitive inhibition of central and peripheral ach muscarinic receptors
Clinical features can be divided into central and peripheral Central -Agitated delirium -- -fluctuating mental state ---confyusion ---restlessness ---hallucinations ---picking at objects in the air ---disruptive behaviour -Tremor -mycoclonus -coma -seizures
Peripheral
- tachycardia
- mydriasis
- dry mouth and skin
- hyperthermia
- urinary retention, consptiation
- flusing
Once established it is difficult to predict the duration of the syndrome – can last up to 5 days
