Clinical Toxicology Case Presentation

1
Clinical Toxicology Case Presentation

• By Dr. Kevin Go,UCH.

2
A woman presenting with numbness and hypotension
after taking herbal medicine.
3
History

• F/ 44
• History of right knee thigh pain for 2 years
• Attended a herbalist on 21/12/2004
• Took some herbal broth in the evening
• Develop perioral numbness, abdominal pain ,watery
  diarrhea and generalised weakness 3 hrs after
  herbal broth

4
In AED

• c/o palpitation and dizziness
• BP 85/49
• P 48/min.,irregular
• Temp 36.5
• Hstix 6.5 mmol/L

5
Physical Examination

• Conscious
• Chest clear
• HS dual
• Abd soft, non tender
• Muscle power 5/5 both sides
• Jerks were normal
• No nystagmus /past-pointing
• Neck soft

6
ECG
7
Investigation

• ECG freq ventricular ectopic beats with
  couplets
• PR 0.11 sec
• QRS 0.075 sec
• QTc 0.448 sec
• Na 143.2 mmol/L
• K 4.03 mmol/L
• Venous pH 7.36

8
Management in AED.

• Oxygen given
• IV NS 500ml FR given
• Put on cardiac monitor
• CCU was consulted
• Possibility of herbal medicine poisoning , the
  prescription traced

9
Prescription
10
Which is the responsible toxic ingredient?

• ?? ( Caowu) or aconitine

11
Progress

• After admission to CCU, BP 108/70
• Put on IVF and cardiac monitor
• Repeated ECG showed SR with no more vent ectopic
  7 hrs after admission
• No antiarrhymic drugs given
• Transfer to cardiac ward next day morning
  (22/12/04) with symptoms subsided
• Remained uneventful

12
Investigation

• Hb 11 g/dL
• L/RFT essentially normal
• Troponin I not raised
• Blood gas normal
• Bedside echocardiogram satisfactory LV function
• Blood and urine was sent to TRL aconitine and
  deoxyaconitine was detected in the urine
  compatible with aconitine poisoning

13
Aconitine

• Aconitine
• Highly poisonous C-19 diterpenoid-ester
  alkaloid.
• Derived from aconite rootstock.
• ?? ,??, ??, ????? in herbal medicine contains
  aconitine alkaloids
• Possess anti-inflammatory, analgesic and
  cardiotonic effect.
• Treatment
• Rheumatism
• Neuralgia
• Fever
• Cardiac complaint.

14

• Raw aconite roots
• Generally toxic
• Need possessing before use
• Possessing
• Soaked in water or saturated lime water and
  boiled until the aconitine white core disappears
• Boiling hydrolysis of aconitine to less toxic
  benzylaconine and aconine derivative

15

• Aconite alkaloid very narrow therapueutic index
• Poisoning can be due to
• Inadequate possessing
• Overdose
• Inappropriate preparation methods

16
Toxicity of aconitine.

• Mechanism
• Activate the voltage sensitive Na channels in the
  heart , nerves and muscles
• Enhance inward Na current during the plateau
  phase of action potential
• Prolong the repolarization
• Premature excitation of cardiac myocites
• Both cardiotoxin and neurotoxin

17
Symptoms of poisoning

• Dizziness
• Nausea and vomiting
• Parasthesia
• Muscle weakness ( interfere neuromuscular
  transmission)
• Hypotension and bradyarrhythmia ( muscarinic
  effect)
• Supravent /vent tachyarrhythmia ( premature
  excitation)
• Death usually due to ventricular arrhythmia
• Symptoms onset a few minutes to 2 hrs

18
Management of aconitine poisoning .

• Clinical experience remained limited
• No antidote available
• Rx mainly supportive
• Gut decontamination by activated charcoal may
  reduce absorption of aconitine
• For hypotension IVF and inotropes

19
Treatment of ventricular arrhythmia due to
aconitine

• Remained a challenge
• Cardioversion and cardiac pacing probably not
  effective
• Lignocaine not useful
• Amiodarone and flecainide may be reasonable
  drugs of first choice

20
Cardiotoxicity after accidental herb induced
aconite poisoning .Y.T.Tai et alLancet 1992
340 1254-56.

• 17 patients with aconitine induced cardiotoxicity
  during 1989-1991 were treated
• All patients Chinese. Median age 56. Only 1 had
  hx of MI.
• 2 had VF
• 13 got VT (sustained and polymorphic)
• 2 had freq VEB
• DC cardioversion unsuccessful in 10 patients
• No single antiarrythmic drugs uniformly effective
• Lignocaine unsuccessful in all patients
• Suppression of VT eventually susccessful in 9
  patients with amiodarone (5), flecainide (2),
  procainamide (1), and mexiletine (1)
• 2 patients died from refractory VF within 6 hrs
  of admission
• Remaining 15 stabilized within 24 hr

21
Other case report.

• 61 yr man with aconitine induced refractory VEB
  successfully treated with amiodarone (150mg
  loading ,then 1300mg in 36 hrs) after failure of
  lignocaine
• DF Yeih, FT Chiang Heart 2000 84(4) E8

22
Other treatment option

• Charcoal haemoperfusion for 4hrs
• Clinical Features and management of herbs induced
  aconitine poisoning.
• Lin CC et al Annals of Emerg Med 2004
  43(5)574-9
• Cardiopulmonary bypass.
• Ohuchi S. Kyobu Geka 200053541-544

23
Thank you.
24
Summary Comments

• Use of TCM is common in Hong Kong
• Aconitine poisoning is most commonly reported
• Consider aconitine poisoning as DDx in patients
  presenting with paresthesia ,muscle weakness ,
  hypotension and vent .dysrrhythmia.
• Treatment is mainly supportive
• IVF Inotropes for hypotension
• Amiodarone for tachyarrthymia
• Symptoms usually subside within 24 hours