2007_08_02-Hall - Calgary Emergency Medicine
Download
Report
Transcript 2007_08_02-Hall - Calgary Emergency Medicine
Ethanol Abuse and
Toxic Alcohol Ingestion
Chris Hall, PGY-5
McMaster University
U of C Academic Day
August 2, 2007
Objectives
Approach to the “intoxicated” patient
Pharmacology of alcohols
Common clinical scenarios in EtOH
Diagnostic and management challenges of
toxic alcohols
***Case-based and evidence-centred
Case #1
56 yo male
“Known alcoholic”
Unresponsive on park bench
No witnesses; no apparent trauma
“Smells of alcohol” as per EMS
Case #1
Afebrile, HR 102, BP 140/85, RR 22, O2
sat 91%
CBS: 5.5
Neuro: GCS 11; moves 4 limbs
Sonorous resps; Gag present
Chest: scattered crackles
Abdo, extremities: WNL
Case #1
Any additional information you’d like?
What is your working Dx?
How will you proceed from this point?
The “Intoxicated” Patient
VITAMIN CDE
AEIOU TIPS
“Intracranial” vs. “Extracranial”
The “Intoxicated” Patient
Intracranial
Seizures
Vascular
Infectious
Neoplastic
Traumatic
Extracranial
O2 / CO2
Infectious
Toxins / WD
Metab. / Endo.
Environmental
The “Intoxicated” Patient
Reasonable DDx for Case #1:
–
–
–
–
–
–
Ethanol / other co-ingestions
Head trauma
CNS / other infection
Hypoglycemia / AKA
Wernicke encephalopathy
Alcohol withdrawal (+/- seizures)
Immediate Action
Airway / Breathing
Hemodynamic stability
Reversible causes
– The “Coma Cocktail” (?!)
Further Management
History and P/E
Investigations
– Which ones?
Case #1
TAKE HOME MESSAGE:
– DO NOT assume EtOH to be the cause of the
“intoxicated” patient’s presentation
– Keep the differential broad; systematic
approach to eliminate other DDx
Ethanol: Pharmacology
Alcoholic Trivial Pursuit
What is “100-proof alcohol”?
– 50% EtOH by weight
Alcoholic Trivial Pursuit
What is considered “one alcoholic drink”?
– 15g of EtOH
» 1 oz 50% (liquor)
» 4 oz 12% (wine)
» 10 oz 5% (beer)
Alcoholic Trivial Pursuit
How much EtOH would a 70kg male need
to drink to reach an EtOH level of 30
mmol/L?
a)
b)
c)
d)
e)
3
5
7
9
11
Alcoholic Trivial Pursuit
TRUE OR FALSE:
– Men are less susceptible to acute alcohol
intoxication
– Caffeine masks EtOH intoxication
– Prickly pear is an antidote for veisalgia
– Hydration accelerates metabolism of EtOH
– Intoxication is lessened by co-ingesting food
Pharmacology
EtOH rapidly absorbed
– Stomach and small bowel
– Multifactorial effects on rate
» Food
» GI disease
» Meds (gastric emptying)
» Idiopathic
Pharmacology
EtOH metabolized by ADH and ALDH
– Stomach and liver; 5-10% unchanged via urine
– Gender / ethnic differences in metabolism
– Rate: 3-4mM/h (non-drinker) up to 7.5mM/h
(chronic drinker)
Ethanol: Metabolism
Clinical Presentation
CNS Effects:
– GABA Agonism + NMDA Antagonism
» Inebriation, poor impulse control, ataxia
» “Set-up” for withdrawal
CVS Effects:
– Vasodilation, reduced CO
– Dysrhythmias
Clinical Presentation
GI Effects:
– N/V/D volume loss
– Pancreatitis, gastritis, hepatitis
– GI Bleeding
Metabolic Effects:
– HypoNa, Hypoglycemia
– osmol gap; no anion gap
– Ketonemia after binges
Clinical Presentation
Hematologic Effects:
– Anemia ( MCV)
– Thrombocytopenia
– Lymphopenia
Case #2
46 yo male
CC: “Unwell”
HR: 115, BP 165/100, RR 25, sat 100%
Tremulous
Sweaty
Alert, not confused
Exam otherwise WNL
Case #2
Discuss:
– Your working / differential diagnoses
– Your initial management and approach to this
patient
Alcohol Withdrawal
GABA receptor downregulation + NMDA
receptor upregulation
Anxiety, sweating, tremor, autonomic
overdrive, altered LOC, seizures
Generally in chronic abusers
Spectrum of Illness
Simple Withdrawal
Alcoholic Hallucinosis
Withdrawal Seizures
Delirium Tremens
Alcohol Withdrawal: Rx
Holbrook et al (CMAJ 1999)
– Metaanalysis of WD Rx
– BZD vs placebo or other Rx
– BZD better than placebo
» More successful outcomes
» Less likely to drop out of Rx
– Unable to properly pool results otherwise
Choice of BZD?
Ritson et al, (Drug Alc Dependence 1986)
– RCT; N=40
– Standing lorazepam vs diazepam
– Less anxiety; smoother course with valium
Choice of BZD?
Diazepam is the traditional choice
Lorazepam is preferred in patients with
severe liver disease
Benzodiazepines
Dosing
– Diazepam: 5 mg iv / 10 mg po q 10 min
– Lorazepam: 1-2 mg iv / 2 mg po q 15 min
» NB: longer time of onset; beware dose stacking
– Titrate to effect
» (But how?)
CIWA
10-item scale
Min score = 0, Max score = 67
Score < 8 considered mild withdrawal (Rx
threshold)
Takes 5 min to complete
Symptom-Guided Rx
2002 Arch Int Med & 1994 JAMA:
– 2 RCTs
– CIWA-guided Rx reduces BZD use, length of
Rx vs. standing BZD protocol
Guide therapy with symptoms; avoid
standing dosing schedules
Do not fear huge doses
Adjunctive Rx
Carbamazepine
– 2 RCTs (Am J Psych 1989; J Gen Int Med
2002)
» Similar to BZD in Rx of withdrawal symptoms
Valproate
– 1 RCT (Alc Clin Exp Res 2001)
» Less BZD needed when Rx with VA
Simple Withdrawal: Rx
Adjuncts, cont’:
– Beta Blockers
– Clonidine
– Haldol
– Magnesium
Withdrawal: Disposition
RCT (NEJM, 1989)
– CIWA < 15; no comorbidities
– Outpatient Rx as safe as Inpatient Rx, cost less,
lasted less time
– Inpatients more likely to complete Rx
– Outpatients got daily follow-up and BZD
dosing
Withdrawal: Disposition
Discharge home if:
– Mild withdrawal at time of d/c (CIWA < 8 - 15
after 4-6 h observation)
– Easily controlled w/ BZD
– Not intoxicated
– Responsible supervision preferred
– No prior hx of seizures or DT
Case #2 ,Part 2
BZD sedation is ordered for the patient
60 min later, patient is more tremulous,
agitated
While trying to get out of bed, has
generalized T/C sz
Case #2, Part 2
What are your initial steps?
How will you treat this patient?
Withdrawal Seizures
Usually GTC, self-terminating
15-25% have > 1 seizure
– < 8% go into status
May herald onset of DT
Seizure Management
ABCs
Rule out reversible causes
Lorazepam likely longer anticonvulsant
effect than diazepam
Seizure Management
BZD (e.g. Ativan 2-4 mg iv)
Phenobarbital 15-20 mg/kg
Propofol / Midazolam / Pentobarb
Inhalational Anaesthesia, paralysis, EEG
monitoring
What about Dilantin?
EBM (Ann Emerg Med 1991 & 1994):
– 2 RCTs; 55 & 147 patients
– No difference in relapse of seizures vs placebo
Mechanism of action unlikely to affect
seizures in EtOH withdrawal
Likely to have little impact on Rx
Withdrawal Seizures
Some Questions to ponder:
– Who can be released from the ED?
– When is a CT Head warranted?
– When should patients start an anticonvulsant?
CT Head
New / changed seizures
Focal seizure
Focal examination / meningismus
Failure to recover usual mental status
Mental status out of proportion to EtOH
Recent head trauma
+/- fever (prior to LP?)
Disposition
Normal workup and exam
Single seizure
Withdrawal well-controlled
Not intoxicated
Adequate supervision / follow-up
Starting an Anticonvulsant
Controversial
Seizure may be due to withdrawal or may
represent underlying epileptic d/o
Generally, leave it to neurology!
Case #3
60 yo male
“Alcoholic” by own report
2-week “binge” until yesterday
Since then, N/V, AP, “dizziness & blurred
vision”
Case #3
HR 114, BP 105/60, RR 28, sat 100%
CBS: 3.0
Chest: clear
Neuro: slightly drowsy; no focality; no
tremor
Abdo: tender epigastrium
Urine dip: negative for ketones, blood,
WBC
Case #3
Working diagnosis / differential?
Approach to management?
Metabolic Derangements in
EtOH
Hypoglycemia
Hyponatremia, hypokalemia
Hypomagnesemia, hypocalcemia
Ketoacidosis
Wernicke Encephalopathy / Korsakoff
Amnesia
Ketoacidosis
Pathophysiology
– NADH:NAD ratio
– Loss of EtOH block of ketogenesis
– Starvation
Ketoacidosis
Presentation:
– Recent EtOH binge
– Dehydrated, N/V, abdo pain
– High AG acidosis
– Ketonuria w/o glucosuria
Ketoacidosis
Diagnosis
– Rule out other causes of AG acidosis
– Assess for underlying medical illness
» Infection, AMI
– Beware relying on urine dipstick
Ketoacidosis
Ketoacidosis
Management
– Thiamine replacement
» Needed for pyruvate Krebs Cycle
– Mg replacement
» Cofactor for thiamine
– IVF rehydration
– Dextrose / Glucose replacement
– HCO3 in severe acidosis (e.g. pH < 7.1)
Hypoglycemia
Causes:
– Starvation (during binge)
– Hepatic glycogen depletion
– Impaired gluconeogensis
May be a sentinel phenomenon prior to
onset of AKA
Treated with glucose, thiamine, magnesium
Differential Diagnosis?
Thiamine Deficiency
Chronic Alcoholism
– Malnutrition
– Vomiting
– Malabsorption
Other Chronic Illnesses
– Chronic vomiting (AIDS, hyperthyroidism,
hypermesis gravidarum)
– Dialysis
– Long-term Lasix use
Thiamine Deficiency
“Beri Beri”
– “Dry” beri beri = neurologic disease
» Wernicke encephalopathy
» Korsakoff amnesia
– “Wet” beri beri = cardiovascular disease
» CHF / DCM
» More often in countries w/o thiamine supplements
Wernicke’s Encephalopathy
Classic Presentation
– EOM palsy
– Ataxia
– Altered LOC / cognition
***(only 12% of patients have all 3)
•
Other Sx:
• Hypothermia
• DTRs
Korsakoff’s Amnesia
Presentation
– Memory impairment
– Unable to learn / remember new facts
– Apathy
– Confabulation
***May be abrupt or insidious onset
Treatments
Thiamine
– 100mg iv; repeat prn to 1000mg
– 100-200mg po/day
– Concern for anaphylaxis?
Magnesium
Abstinence
Prognosis
Wernicke’s:
– 25% recover well
– 50% some recovery
– 25% poor recovery
– Almost 80% chance of Korsakoff’s in the
future
Case #4
15 yo female
Recent dispute with parents; last seen 4 hrs
prior
Found unresponsive in garage by father
Brought to a rural ED via EMS with this
container…
Case #4
Afebrile, HR 105, BP 100/40, RR 25, sat
100%
CBS 5.5
Chest, Abdomen WNL
GCS 6; PERL 5mm
Bidirectional nystagmus
No evidence of head trauma or IVDU
Neck supple
Case #4
Electrolytes:
– Na 139, Cl 95, HCO3 14, K 3.9, Glc 5.5
CBC: Normal
Renal: BUN 5.1, CR 115, Osm 320
VBG: pH 7.20 / pCO2 30
Case #4
What is your working diagnosis? Your
differential?
Any additional testing which may be
helpful?
– Any simple tests to help confirm a toxic alcohol
ingestion?
Ethylene Glycol
Sources:
– Radiator antifreeze
Metabolism:
– Sequential oxidation via ADH / ALDH
pathway
– Multiple toxic metabolites
– Glycolic acid causes wide AG acidosis
Ethylene Glycol
Ethylene Glycol
Presentation
–
–
–
–
Renal failure w/ crystalluria
Intoxication, seizures
Hypocalcemia, long QT, dysrhythmias
Opthalmoplegia, nystagmus
Calcium Oxalate Crystals
Approx. 60% Sens
Methanol
Sources:
–
–
–
–
Model airplane fuel
Gas line antifreeze
Windshield washer fluid
Photocopying fluid
Metabolism:
– ADH / ALDH
– Formate is toxic
Methanol
Methanol
Presentation
–
–
–
–
–
–
Visual changes (“snowstorm”)
N/V, AP, Pancreatitis
Hypothermia
Altered LOC, seizures
Acute renal failure
Bilateral basal ganglia lesions (CT Head)
Diagnostic Testing
Toxic Alcohol levels
– Often not available immediately
– May be falsely low
– Use of “Toxic” level is misleading
Diagnostic Testing
Anion Gap
– Na – (HCO3 + Cl)
– “Norm = 7 +/- 4 mEq/l
– Rises as toxic alcohol metabolized
» Due to Glycolate (EG) or Formate (MeOH)
Diagnostic Testing
Anion Gap, cont’
–
–
–
–
Lacks sensitivity (absent early on)
Lacks specificity (MUDPILES CAT)
Cannot rule in / out toxic alcohol poisoning
BUT Very high values highly suggestive of
serious underlying disease / ingestion
Diagnostic Testing
Osmolar Gap
– OG = Osmmeasured – Osmcalculated
– (Osmcalculated = 2 x Na + BUN + Glc)
– “Norm” is disputed
» Classic = 10 +/- 6
» More recent = 5 +/- 10 (or –2 +/- 6, etc…)
– Rises as EG is absorbed; drops as EG
metabolized
Osmolar vs Anion Gap
Diagnostic Testing
Osmolar Gap
– Lacks sensitivity (can be “normal” with fatal
ingestion)
– Lacks specificity
» EtOH, MeOH, EG, Isoprop., Mannitol
– Cannot rule out / in toxic alcohol ingestion
– BUT very high value (> 50) is suggestive
Diagnostic Testing
Evaluate the following:
– Na 135, Bun 6.7, Glc 7.8
– Osm 342
– EtOH 55
Does this add up?
What does this imply?
EtOH and the Osmolar Gap
EtOH : OG ratio is ~ 1.25 : 1
– (Purssell et al Ann Emerg Med, 2001)
Residual difference does not necessarily
mean toxic alcohol
Large discrepancy is suggestive
Lack of discrepancy doesn’t rule out toxic
alcohol
EtOH and the Osmolar Gap
Contribution of EtOH to clinical toxicity:
– Affinity of ADH for EtOH 67x higher than EG
& 15x higher than MeOH
– EtOH is protective
– Levels > 20mmol/L make toxic alcohol
unlikely cause of wide AG acidosis
Management: Overview
ABC
Decontamination
ADH inhibition
Adjunctive measures
Decontamination
Is activated charcoal appropriate in this
patient?
– Why / why not?
Are any decontamination modalities of
value in toxic alcohols?
ADH Inhibition
EtOH
–
–
–
–
“Occupies” ADH
Blocks toxic alcohol metabolism
May be difficult to find / prepare
Requires load and infusion
ADH Inhibition
Indications: (AACT Guidelines)
– Documented level (>7.5 MeOH / >4 EG)
– Documented ingestion and OG > 10
– Suspected ingestion and 2 of:
» pH < 7.3
» HCO3 < 20
» OG > 10
» Urinary oxalate crystals
ADH Inhibition
EtOH
– Adverse Effects:
» Obtundation / inebriation
» Respiratory depression
» Hypotension
» Hyponatremia / glycemia
» Gastritis / pancreatitis
» Phlebitis (infusion site)
ADH Inhibition
EtOH:
– Dosing:
» 5-10% IV solution (preferably CVL)
» Load: 8cc/kg over 30-60 min
» Infusion: ~45cc/hr (70 kg person)
» Goal: EtOH of ~20mmol/L or molar ratio of 1:4
(whichever greater)
» Monitor Glc, Na
ADH Inhibition
Fomepizole
– Inhibits ADH
– Advantages:
» Avoid essentially all S/E of EtOH
» Q12h dosing
– Disadvantages:
» COST
Fomepizole: EBM
Brent et al. (NEJM 1999):
– Case series (N=19) of EG poisoning
» Reduction in acidosis, serum glycolate and urinary
oxaluria
» Preservation of renal function (if normal initially)
» No comparison to EtOH
» 1 patient died
– “Safe and effective”
Fomepizole: EBM
Brent et al. (NEJM 2001):
– Case series (N=11) in MeOH toxicity
» Reduction in formate levels
» Improvement in acidosis
» No patients with significant S/E
» No comparison with EtOH
» 2 patients died
– “Safe and effective”
Fomepizole
Indications:
– Same as for EtOH
– Institutional preference (COST)
Continue dosing until “non-toxic” level and
not acidotic
– MeOH ~ 7.5 mmol/L; EG ~ 4 mmol/L
Hemodialysis
Eliminates toxic alcohols
Can address toxin plus electrolyte or acidbase disturbance
Not always necessary if ADH inhibited;
may serve to shorten duration of Rx
Hemodialysis
Indications (AACT Guidelines)
– Acidosis
– Renal Failure
– End organ damage
» Visual changes, coma, seizures
– Methanol > 15 / EG > 8 (controversial)
– Electrolyte or vital sign disturbance
unresponsive to usual Rx
Hemodialysis
HD may be withheld if
– ADH inhibited
– No acidosis
– No clinical indications for dialysis
(NB: will prolong duration of Rx)
Adjuncts
Methanol:
– Bicarbonate
– Folinic acid
Ethylene glycol:
– Thiamine
– Pyridoxine
Sodium Bicarbonate
Mechanism
– Shifts formic acid to formate (less toxic)
– “Ion trapping” in urine
Indications
– pH < 7.15 (Goldfrank) - 7.3 (AACT)
– May consider in EG and significant acidosis
Folinic Acid
Reduced form of Folic Acid
Mechanism:
– Formic acid metabolism
Indications:
– All MeOH ingestions
Thiamine / Pyridoxine
Mechanism:
– Encourage glycoxylic acid metabolism to nontoxic compounds
Indications:
– Consider in any EG ingestion
Case #5
59 yo male
Found outside homeless shelter
Decreased LOC
Hematemesis / Hemoptysis
Sweet odor on breath
Empty bottle found next to patient
Case #5
HR 105, BP 130/75, RR 10, sat 91%
Chest: scattered crackles
Abdomen: epigastric tenderness
GCS 10, PERL 3mm
Urine:
– dip 3+ RBC, 3+ ketones
– microscopy normal
Case #5
CBC: Hb 100, otherwise WNL
Na 139, Cl 100, HCO3 25, K 3.0
BUN 8.0, CR 129
Glc 8.1
Serum ketones present
Osmolarity 320
Ethanol: undetectable
Case #5:
What is your diagnosis / differential?
What further testing would you like to do?
What is your management at this time?
Isopropanol
Source:
– “Rubbing alcohol”
Clinical:
– Significant inebriation
» NB: IP ~ EG > EtOH > MeOH
– Hemorrhagic gastritis / tracheobronchitis
– Acetone odor
– Rhabdomyolysis
Isopropanol: Metabolism
Isopropanol
Investigations:
–
–
–
–
“Ketosis without acidosis”
No anion gap
Osmolar gap present
Urine may show myoglobinuria
Management
Secure ABC’s
Address complications
– Gastritis, tracheobronchitis, rhabdomyolysis
Usually no specific interventions
– HD shortens half-life
Bonus: Case #6
Case #6
47 yo male
Drinking at a bar, involved in altercation
Struck in side of head with bottle
~ 30 sec LOC
No vomiting, headache, seizure activity
Case #6
All VS WNL
GCS 15; patient slurring speech, slightly
ataxic
No focal neurologic weakness
3 cm laceration on vertex
No spinal tenderness
Patient is requesting to leave the ED
Case #6
Main Issues:
– Does this patient require imaging?
– What is the physician’s obligation regarding the
patient’s request to leave?
Head Trauma and EtOH
Confounding Issues
– Higher risk of brain injury with same
mechanism
– Intoxication clouds assessment
– Direct toxicity of EtOH on injured brain
– Patients often not cooperative
– Time / resource constraints
Head Trauma and EtOH
New Orleans CT Head Rule (NEJM 2000)
– EtOH an independent predictor of risk of
positive CT
– OR = 3.2
– LR(+) = 11.3
– Conclusion: image all “intoxicated” patients
Head Trauma and EtOH
Canadian CT Head Rule (Lancet 2001)
– “Acute intoxication” not included among
variables
– Intoxicated patients not excluded (but unclear
how many included)
– “Suspected chronic alcoholism” not predictive
– Conclusion: “No comment”
Head Trauma and EtOH
Retrospective review of NEXUS II data
(Ann Emerg Med, 2007)
– Suggests over-imaging in intoxicated patients
– “Intoxication” not predictive of positive CT
head
– Conclusion: weak evidence of utility of
NEXUS II CDR in intoxicated patients
Head Trauma and EtOH
Summary of Evidence:
– No strong evidence to guide imaging choice
– Evidence highlights increased risk but likely
overuse of CT Head
– Bottom line: clinical judgment required; CDR
(CCR, NEXUS II) may help
Summary
Ethanol
– Major cause of morbidity / mortality
– Withdrawal may be a medical emergency
– Most of Rx is supportive / directed towards
medical complications
– Never forget to search for other causes of
“intoxication”
Summary
Toxic Alcohols
– Can be difficult to detect
– Have significant direct toxicity (highly lethal)
– Main Rx is directed towards ADH inhibition
and serum clearance
The End
Any questions?