steps of clinical approach to patient with unknown drug overdose including diagnosis and management

1. Approach To Patient With Unknown
Overdose
Diagnostic Work up
By: Dr. Hanan Fathy Abdelaziz
Consultant of Clinical Toxicology
P.C.C. Al qassim – King Fahd Specialized Hospital

2. Basic Concepts

3. • Case of poisoning is a medical case so emergency
management will be the same except for the use of
the specific antidote in certain limited conditions.
Consequently diagnosis of the causative agent is
not a must to start treatment.
• Prognosis of poisoning cases is good especially with the
early intervention . Deaths are usually due to either
wrong interference, delayed presentation or very large
dose.
• Most cases presented to the ER have no specific
antidote and management is mainly symptomatic.

4. Intended learning outcomes (ILOs)
By the end of this lecture you should
be able to:
• Determine steps of approach to patient with
unknown overdose.
• Arrange steps of approach to patient with
unknown overdose according to priority.

5. Classification of Cases Of Unknown
Overdose

6. Cases of unknown overdose
Emergency case
((Shock & R.F.
Stable case

7. Diagnostic work up is only
considered in stable cases
Immediate
correction
Emergency case

8. Stable Cases
Fully
conscious
Symptomatic
Asymptomatic
Altered
consciousness
Altered level
Altered
content

9. Fully Conscious Cases

10. Classification of fully conscious cases
Fully conscious
cases
Symptomatic
Toxidrome Not toxidrome
Asymptomatic

11. D.D. Conscious Symptomatic Case With
Specific Toxidrome

12. The Most Common Toxidromes
Cholinergic Syndrome
• DUMBLS: defecation,
urination, miosis,
bronchospasm,
fasciculation, paralysis,
lacrimation, salivation.
Causes:
• Carbamate , OPC.
Anticholinergic Syndrome
• Dry skin, flushing, dilated
unreactive pupils, urinary
retention, decreased
peristalsis, tachycardia,
hyperthermia, hallucinations.
Causes:
• Atropine and drugs with
atropine like action.

13. Adrenergic Syndrome
• Hyperthermia,
hypertension,
tachycardia, tachypnea,
mydriasis, increase
peristalsis and sweating.
Causes:
• Sympathomimetics.
Opioid Syndrome
• Miosis, bradycardia ,
hypothermia and decrease
peristalsis.
Causes:
• Opiates and opioids.

14. Anticholinergic Vs Adrenergic Syndrome
Anticholinergic syndrome
• Dry skin.
• Diminished or inhibited
bowel sounds.
• Urine retention.
• Pupil is dilated and
unreactive
Adrenergic syndrome
• Diaphoresis.
• Bowel sounds are
increased.
• No urine retention.
• Pupils are dilated
reactive.

15. Opiate Withdrawal Syndrome
• Diarrhea.
• Mydriasis.
• Goose skin.
• Tachycardia and hypertension.
• Lacrimation and yawning.
• Muscle cramps.
• Hallucinations.
• Seizures.

16. Approach to Conscious Symptomatic
Case Without Specific Toxidrome

17. Steps of
Approach
History Examination Investigations Treatment

18. STEP I : HISTORY

19. The following points are helpful for clinical
approach
For diagnosis
• All available drugs at
home.
• Empty containers.
• History of convulsions
or attacks or diminished
consciousness
For management
• History of liver, renal ,
cardiac disease.
• History of convulsions
or attacks or
diminished
consciousness

20. STEP II: EXAMINATION

21. Examination
work up
Vital signs
General
examination

22. D.D. Of Vital signs:
I. Pulse:
Bradycardia
• Organophosphorus.
• Opiates.
• Digoxin.
• B.Bs.
• CCBs.
• Sedative hypnotics.
Tachycardia
• All adrenergic agents.
• All anticholinergics
agents.
• Digoxin.
• Theophylline.

23. II. Respiration:
Bradypnea
• Respiratory depressants.
• Neuromuscular blockers
and muscle relaxants.
• Agents causing
metabolic acidosis e.g.
methanol and late
salicylate toxicity.
Tachypnea
• Early salicylate toxicity.
• Irritant gas inhalation.
• Toxic hypoxia e.g. CO.
Pay attention to psychological
state because tachypnea may
be hysterical reaction
especially in intended
poisoning.

24. III. Temperature
Hypothermia
• Carbon monoxide.
• Opiates.
• Oral hypoglycemics/insulin.
• Ethanol.
Pay special attention to
hypoglycemia.
Hyperthermia
• Excess muscle activity in
repeated convulsions.
• Impaired thermoregulation
as in anticholinergics.
• hyper metabolic state as in
salicylates.
• Neuroleptic malignant
syndrome.

25. IV. Blood Pressure:
Hypotension
• Any considerable
poisoning can ↓↓ B.P.
• Diarrhea as in food
poisoning and OPC or
Severe sweating as in
salicylates or excess
diuresis in diuretics
• Hypotension with
bradycardia: as in B-B,
CCB and digoxin.
Hypertension
• Sympathomimetics.
• Anticholinergics.
• Scorpion venom.

26. D.D. By Examination

27. For time concern we will discuss
only clue diagnostic signs for the
most common drugs
PAY ATTENTION

28. Skin
Sweating
Diaphoresis:
• OPC.
• Scorpion.
• Salicylates.
Dry skin:
• Sympathomimetics and
anticholinergics.
Color
Cyanosis :
• Respiratory depressants.
Flushing:
• Atropine and drugs of
atropine like action.
• Ethyl alcohol (acute and
chronic).
Redness.
• Carbon monoxide.
How to differentiate redness
from flushing????

29. Gastrointestinal Tract
Vomiting
• Digoxin.
• Theophylline.
• Opiates and opioids.
• Food poisoning.
• Iron.
• Paracetamol.
• Hematemesis: iron and
corrosives.
Diarrhea
• OPC and carbamates.
• Food poisoning.

30. Neurological Examination:
Pupil size and reactivity
Miosis
• Opiates.
• OPC and carbamates.
• Nicotine.
• Pin point pupil may
occur in pontine
hemorrhage.
• Unequal pupils: Usually
points to neurosurgical
disease.
Mydriasis
SHAW:
• S= Sympathomimetics.
• H= Hallucinogens.
• A= Anticholinergics.
• W=Withdrawal from
opiates. Only
anticholinergics produce
dilated unreactive pupils.

31. Motor System
Toxic paralytic syndromes
• Botulism.
• Elapidae venom.
• Delayed neuropathy of
OPC.
• Ciguatera poisoning.
• C.V. accidents in
sympathomimetics
overdose
Tremors
• Chronic alcoholism.
• Sympathomimetics.
• Anticholinergics.

32. Sensory System
Common D.D.Sensory manifestation
• Ciguatera (circumoral)Numbness
• Alcoholism
• Cerebrovascular accidents in
sympathomimetics overdose
Diminished sensation
• CocaineIntense itching
• Salicylates
• CO
Tinnitus

33. Cranial Nerve Deficit
Common D.D.Cranial nerve affection
MethanolOptic atrophy
BotulismSquint
BotulismDysphagia
Elapidae snake bitePtosis
Elapidae snake biteHorsiness of voice

34. III. INVESTIGATIONS
Lab. Work up

35. Lab work up aims to:
• Evaluate vital case of the patient.
• Exclude substances need antidotes i.e. paracetamol ,
iron , OPC etc…
• Diagnosis of specific drug based on history, symptoms
and results of your examination.
These are classified into:
• Emergency investigations.
• Diagnostic investigations.
• Prognostic investigations.

36. Results InterpretationThe testType of
investigation
Cases with altered
consciousness
ABG, Osmolality and
anion gap
Emergency
investigations
↑↑ K : acute digitalis
toxicity
↓↓ K: K loosing
diuretics and
theophylline.
Potassium level (K+)
Cases with altered
consciousness
Blood sugar, liver and
R.F. tests.

37. Results InterpretationThe testType of
investigation
Hemolysis:
Carbolic acid and
naphthalene.
↑↑INR: Oral
anticoagulants(super
warfarin)
CBC , HB% and
coagulation profile.
Emergency
investigations
Substances of abuseUrine screeningDiagnostic
investigations
Examples ????Levels of specific
drugs based on
history and clinical
exam.

38. Results interpretationThe testType of
investigation
• AV block of digitalis.
• Prolonged QT and
Wide QRS of TCA.
• Depressed ST and
inverted T of ischemia
in CO , scorpion and
sympathomimetics
ECGPrognostic
investigations
(investigate for
complications)
Aspiration pneumonia
In hydrocarbons and
infection in corrosives
Plain chest
X-ray

39. Results
interpretation
The testType of investigation
Gastric perforation
in battery ingestion
or corrosives.
Abdominal X-
ray
Prognostic
investigations
(investigate for
complications)
Neurological
complication of CO
CT or MRI
In corrosive
ingestion.
Endoscopy

40. IV.MANAGEMENT

41. After previous work up
If you reach diagnosis
Manage
accordingly
If you don’t reach
diagnosis
Consider the
delay
Less than one
hour
Gastric lavage
A.C.+ observation
6-12 h
More than one
hour
A.C. + observation
6-12h

42. To Summarize Work Up For Stable
Fully Conscious Case

43. stable symptomatic
conscious
case
toxidrome?
Manage
accordingly
Not toxidrome
Start lab and
examination
work up
Reach diagnosis?
Manage
accordingly
Don’t reach diagnosis?
Consider delay
< one hour
G.L. and A.C. +
Observation6-12h
> one hour
A.C. +
observation 6-12h

44. Asymptomatic Cases

45. Asymptomatic Case
In these case you have to exclude the following:
• Iron toxicity.
• Paracetamol toxicity.
• Methanol toxicity.
• Zinc phosphide.
How ??????

46. • For paracetamol and iron investigate for the level 4
hours post ingestion.
• For methanol the patient should be observed for 36
hours with serial ABG and osmolar gap and
investigate for methanol.
• For zinc phosphide investigate for liver enzymes
and ECG and observe the patient for 48 hours in
case of suspicious history.
• Other cases : Investigate for liver , kidney and heart
+ gastric emptying according to delay + observation
for 6- 12 hours according to your evaluation.

47. Stable Cases
Fully
conscious
Symptomatic
Asymptomatic
Altered
consciousness
Altered level
Altered
content

48. Altered Consciousness Cases

49. Altered
consciousness
Altered level
Stimulation Depression
Altered
content
Hallucination
Disorientation

50. Altered level
Depression
• Opiates and sedative
hypnotics
• Alcohols.
• Anti convulsants.
• Anti depressants.
Hypoglycemia:
• Oral hypoglycemics
• Ethanol and salicylates.
Stimulation
• Sympathomimetics.
• Withdrawal syndrome.
• Anti cholinergic drugs.
• Some anti histaminics.
• OPC.

51. Altered Content
Hallucinations
• Anti cholinergics
• Sympathomimetics
• LSD.
• Synthetic cannabis.
• Toxic alcohols
Disorientation
• Disorientation to time and
place : cannabis or
sedatives.

52. D.D. of Coma According to Pupil Size
Coma
Constricted pupil
Opiates
OPC
phenothiazines
Dilated pupil
Alcohols
Anti cholinergics
Barbiturates
Opiate withdrawal
Mid way pupil
Barbiturates
Benzodiazepines
phenothiazines

53. D.D. of Coma According to Etiology
Toxicological coma
• History of drug
ingestion
• Mostly stationary or
regressive.
• Mostly symmetrical.
• Brain imaging are
mostly free.
Structural coma
• Mostly progressive.
• Mostly with lateralizing
signs.
• Brain imaging may
show structural lesion.

54. Lab. Work Up For Unknown Toxicological
Coma

55. Results interpretationThe testType of
investigation
• Metabolic acidosis +↑↑
anion gap and ↑↑ osmolality
= methanol.
• Respiratory acidosis: any
Respiratory depressant
(central or peripheral )
ABG and
osmolality
Emergency
investigations
Hypoglycemia : oral
hypoglycemics , alcohol or
less common salicylates
Blood glucose
level

56. Results
interpretation
The testType of
investigation
↑↑ K :
Rhabdomyolysis
in prolonged coma
K levelEmergency
investigations
Hepatic coma:
paracetamol or
zinc phosphide
Liver enzymes
Coma due to :
Salicylates ,
phenol ,
rhabdomyolysis in
prolonged coma
Renal function

57. Data Interpretation

58. Diagnosis of the case depends on :
• History and circumstances
• Clinical examination from which you select the
appropriate lab test.

59. Investigation to
prove diagnosis
Most likely
diagnosis
The available
data
Urine screening
for abuse
Serum ethanol.
Cannabis
Amphetamine or
combination
Ethanol
Young man +
dilated pupil ±
disturbed
consciousness
Serum level of
carbamazepine)
Tegretol ingestion
(carbamazepine)
Child + sudden
drowsiness +
presence of
tegretol at home
Paracetamol and
iron level
Exclude
paracetamol and
iron
Child + full
consciousness +
ingestion of
unknown drug

60. How to Approach The Unknown Case?

61. Assess respiration
and B.P.
Unstable
Immediate
correction
Stable
Assess
consciousness
Fully
conscious
Examine for toxidromes
&symptoms
and investigate
accordingly
Disturbed level
Start Lab work
up for toxic
coma
Disturbed
content
Investigate
for substance
abuse

62. Undiagnosed Cases

63. Although all this thorough work up still
some cases may be undiagnosed.
Is the exact diagnosis of these cases
is important????????????????????

65. As a rule
If you excluded substances need antidote
management of unknown case will be

66. Management of
unknown case
Stabilize vital signs
Investigate for liver,
kidney & heart
Symptomatic
treatment
Gastric emptying
according to delay
Activated charcoal

67. Thank You