susiewabisabi's version from 2015-10-13 22:27

Serotonin syndrome

Question Answer
what scenarios do u see serotonin syndromerecreational, overdose, polypharmacy. Not usual with single agent use or overdose.
which classes and examples of eachanalgesics (fentanyl, tramadol), TCAs, recreational (amphetamines, MDMA), MAOIs (moclobemide, phenelzine), SSRIs (citalopram, sertraline etc), SNRIs (bupropion, venlafaxine)
the classic triad of symptoms is whataltered mental status, autonomic dysfunction, and neuromuscular abnormalities
characteristic manifestations of this includeanxiety, agitation, delirium, coma; mydriasis, diaphoresis, tachycardia, diarrhoea; myoclonus, clonus, hyperreflexia, increased tone
clinical criteria for diagnosisHunter criteria are Spontaneous clonus; OR Inducible clonus + agitation; OR Ocular clonus + agitation/diaphoresis; OR Tremor + hyperreflexia; OR Hypertonic + temperature > 38C + ocular clonus
investigationsscreening para, ECG, CK, UEC, Tn
Management serotonin syndromecease offending agent, resuscitation ABC, T>39.5 intubate with paralysis, sedation with benzos, GTN for hypertension
compare SS and NMSserotonin vs dopamine; onset after hours vs days; tone increased vs lead-pipe rigidity, hyperreflexia vs bradyreflexia; agitation vs mutism, bradykinesia


Question Answer
delirium and agitation tox causesalcohol, anticholinergic syndrome, benzos, cannabis, hallucinogens, NMS, nicotine, salicylates, serotonin syndrome, amphetamines/cocaine, theophylline, withdrawal syndromes
features of deliriumaltered conscious state, decreased cognition, acute onset, fluctuating course
complications of deliriumaspiration, DVT/PE, dehydration, hypoventilation, hyperthermia, physical injury, rhabdomyolysis

Anticholinergic syndrome

Question Answer
agents causing anticholinergic syndromeantihistamines, TCAs, phenothiazine antipsychotics (chlorpromazine, droperidol, haloperidol), atypical antipsychotics (olanzapine, quetiapine), antiparkinsons, carbamazepine, atropine, mushrooms, Datura
clinical features mnemonicBlind as a bat; Mad as a hatter; Red as a beet; Hot as a hare; Dry as a bone; The bowel and bladder lose their tone; And the heart runs alone.
interpret?mydriasis, agitated delirium, flushing, hyperthermia, dry mouth and skin; urine retention; absent bowel sounds; dysrrhythmias
Rx anticholinergic syndromeresuscitation (ABC, glucose, temp), benzos for seizures, ivf, IDC, sedation with diazepam

Cholinergic syndrome

Question Answer
agents causing cholinergic syndromeorganophosphates, carbamates, chemical warfare (sarin), dementia drugs (donepezil, rivastigmine), myasthenia gravis drugs (neostigmine, physostigmine), muscarinics (pilocarpine), nicotine, mushrooms
clinical features mnemonicsSLUDGE - salivation, lacrimation, urination, diarrhoea, gastrointestinal distress, emesis; DUMBELLS - diarrhoea/diaphoresis/decreased BP, urination, miosis, bronchorrhoea/bronchospasm, emesis, lacrimation, lethargy, salivation/seizures.
clinical featuresCNS (agitation, resp depr, seizures); neuromuscular (fasciculations, weakness, paralysis); Autonomic (parasymp muscarinic - bronchospasm, bronchorrhoea, diarrhoea, miosis, salivation, urination; sympathetic nicotinic - HT, sweating)
managementairway managment - pulm secretions, resp depr; atropine for muscarinic effects (bronchorrhoea, bronchospasm, vomiting, diarrhoea, bradycardia); benzos for agitation/seizures; fluid resuscitation; noradr for hypot; organophosphates - pralidoxime 2g iv then infusion
antidotesatropine 1-3g bolus repeat doubling dose q5min until response, organophosphates - pralidoxime 2g iv over 30min then infusion

Neuroleptic malignant syndrome

Question Answer
risk factorshigh doses neuroleptics, increased dose within 5 days, large magnitude dose increase, simultaneous use of 2 or more, young male psych pt, dehydration, medical comorbidities
aetiologydopamine deficiency
clinical featuresCNS ( confusion, stupor); autonomic (hyperthermia, tachycardia, HT); Neuromuscular ('lead-pipe' rigidity, bradykinesia, mutism, dystonia, incontinence)
managementairway (intubate if severe rigidity, temp>39.5, coma); BSL; cool; avoid benzos in severe cases; GTN for HT; bromocriptine
antidotebromocriptine (dopamine agonist) - oral or NG, start at 2.5mg q8h; ECT might increase central dopamine

Alcohol withdrawal

Question Answer
co-morbiditieswernicke's encephalopathy, dehydration, electrolyte abn, gastritis, varices and GIH, pancreatitis, CLD, hepatic encephalopathy, subdural, alcoholic ketoacidosis, cardiomyopathy, coagulopathy, malnutrition
clinical featuresAutonomic (tremor, anxiety, sweating, tachy, HT, hyperthermia); Neuro-excitation (hyperreflexia, hallucinations, seizures); delirium tremens (severe withdrawal leading to resp and CVS collapse, death)
Rx delirium tremensABC, benzos, BSL, electrolytes, phenobarbitone, clonidine (not phenytoin)
Rx alcohol withdrawalAWS, regular diazepam po, thiamine
Rx alcoholic ketoacidosisthiamine, dextrose, fluids
What about benzos withdrawal:pretty much same as alcohol


Question Answer
N acetyl cysteineparacetamol
ethanol, fomepizolethanol, ethylene glycol
oxygen, HBOcarbon monoxide
atropinedigoxin, CCB, BB, organophosphates, carbamates
methylene bluemethHb
succimerlead, mercury
digoxin FABdigoxin, oleander
high dose insulinCCB, BB
sodium bicarbonateNa channel blockers (TCA, propranolol, 1A quinidine, 1C flecainide, local anaesthetics); severe acidosis causing cardiotoxicity; salicylates
clonidineopioid and alcohol withdrawal
calciumCCB, hydrofluoric acid and fluorosis, ethylene glycol causing hypocalcaemia. [C/I digoxin.]

Causes of anion gap, osmolar gap

Question Answer
RAGMACAT MUDPILES CO/cyanide, Alcohol, Toluene, Metformin/methanol, Uraemia, Diabetic ketoacidosis, Paracetamol/paraldehyde, Iron/isoniazid, Lactic acidosis, Ethylene glycol, Salicylates
NAGMA (hyperchloaemic acidosis)USED CARP - Ureterostomy, Small bowel fistula, Extra chloride, Diarrhoea, Carbonic anhydrase inhibitors, Adrenal insufficiency, Renal tubular acidosis, Pancreatic fistula
Increased osmolar gapME DIE - methanol, ethylene glycol, diuretics (mannitol)/diabetic ketoacidosis, isopropyl alcohol, ethanol
Causes of increased lactateType A Inadequate oxygenation - CO, seizure, hyperthermia, shock, hypoxia. Type B Metabolic - salbutamol, cyanide, ethanol, ketoacidosis, metformin, liver failure.


Question Answer
rotten eggssulfur dioxide, hydrogen sulfide


Question Answer
indicationsLA toxicity, propanolol, TCA, verapamil, probably others
dose1.5ml/kg iv bolus, then 0.25ml/kg/min until stable up to 8ml/kg total, can rpt bolus once or twice. Continue ALS throughout.


Question Answer
criteriasmall molecule; small volume of distribution; rapid redistribution from tissues and plasma; slow endogenous elimination
clinical indicationstoxic alcohol (methanol, ethylene glycol); theophylline; severe salicylate; lithium; phenobarbitone; metformin; valproate; carbamazepine; slow K

Activated charcoal

Question Answer
complicationsvomiting, aspiration; misplaced NG tube in lung; impaired absorption of antidotes or drugs given subsequently; corneal abrasions; distraction from other priorities eg resusciitation and supportive care
contraindicationsongoing resuscitation; non toxic ingestion; corrosive ingestion; risk assessment indicates good outcome without AC; decr LOC or delirium or seizures without protected airway; agent doesn't bind
agents that don't bindhydrocarbons, alcohols, metals (lithium, iron, K, lead, arsenic, mercury), corrosives
single dose50g adults, 1g/kg children
multiple dose indicationscarbamazepine, phenobarbitone, quinine, theophylline

Urinary alkalinisation

Question Answer
dose1-2mmol NaHCO bolus, then infusion of 100mmol in 1L D5 at 250ml/hr, maintain normal K.

Local anaesthetic toxicity

Question Answer
maximum doseslignocaine 5mg/kg, bupivacaine 2.5mg/kg (with adrenaline more). Ingestions > 6mg/kg.
toxic mechanismNa channel blocker, metHb (lignocaine)
clinical featuresCNS (seizures, coma); CVS (brady, hypotension, arrhythmias, asystole), Resp (resp depression)
IxECG (long PR, long QRS, large terminal R in aVR), EUC, ABGs, metHb
Rxresus, NaHCO for dysrrhythmias, benzos for seizures, inotropes, intralipid, methylene blue

Paediatric poisonings

Question Answer
2 tablets with severe toxicityamphetamines, CCB, chloroquine, opioids, propranolol, sulfonylureas, theophylline, TCAs
sip or mouthful with severe toxicityorganophosphates, paraquat, hydrocarbons, camphor, naphthalene
management of unknown ingestionadmit for min 12h, BSL, monitor LOC and vitals, d/c only during daylight hours

Poisoning in pregnancy

Question Answer
physiological differencesabsorption (delayed gastric emptying and intestinal transit time); distribution (increased bld vol - increased volume distribution); Elimination (increased renal bld flow and GFR, altered hepatic enzymes)
how does management differdoesn't really, esp paracetamol and iron overdose are treated the same; charcoal and WBI are used when indicated
teratogenicity of paracetamol OD in first trimesterif treated with NAC there is no association with fetal abn
breastfeedingmost drugs are excreted in very low dose, but best to interrupt feeding if possible until resolved
how to minimise risk to fetusexcellent supportive care of mother (avoid hypoxia, hypogylcaemia, hypotension, seizures); lower threshold for treatment of CO, MetHb, lead, salicylates

ECG patterns

Question Answer
Na channel blockadewide QRS, terminal R wave in aVR, R/S ration >0.7 in aVR
agents with Na channel blockTCAs, Class 1a (procainamide, quinidine), Class 1c (flecainide), Local anaesthetics (cocaine, bupivacaine), phenothiazines, propranolol, quinine, diphenhydramine
K channel blockadelong QT, Torsades de pointes
agents with K channel blockantipsychotics (chlorpromazine, droperidol, haloperidol, olanzapine, quetiapine); Class 1a (quinidine); Class 1c (flecainide); Class III (sotalol); TCAs; SSRIs; antihistamines (diphenhydramine, loratadine); macrolides, erythromycin
cardiac glycosides (digoxin, oleander)Na-K-ATPase blockade, increased automaticity; AV block
CCB, BBbradycardia, AV block
hypocalcaemialong QT
tricyclic antidepressantsQRS > 100 (2.5small squares) assocd seizures; > 160 (4 small sq) assocd VT