Dirty Game

I remember this patient very distinctly. Thanks for sharing Dr Suad

added comments on TCA

1. If QRS > 110 = predictive of neurotoxicity

2. If QRS > 160 = predictive of cardiac toxicity

3. In cases of ventricular arrhythmias, my preferred approach is synchronised cardioversion. And as mentioned, first line anti arrhythmic is Lidocaine.

4. Indications to give sodium bicarb push doses in TCA (not limited to): QRS>100

5. When treating a patient with TCA with NaHCO3 make sure to watch the serum sodium and ph closely. If you have given 3-4 amps with no resolution of QRS, then re-consider your diagnosis. DO NOT OVER PUSH NaHCO3- without monitoring the serum Na and pH

6. If the pH=7.55, you cannot give any more sodium bicarb, and so the next drug of choice is hypertonic saline 3%

7. In cases of refractory seizures or refractory ventricular arrhythmias, call the poison center ASAP and prepare intralipid. (Do not wait until the patient arrests). Be mindful of the severity of the overdose.

Great blog! Thanks

Dirty Game cont'

Thanks for the comments and the good differential diagnosis, although hyperkalemia was not mention and it could give similar ECG pattern( K level in this patient was 9 in VBG !!)

Yes the ECG showed sodium channel blockage effects, but also there is brugada like pattern with ST elevation in V1,V2 which could be unmasked by TCA

This patient is sick and need to be approach in ABC order , he is not maintaining the airway and need to have definite airway and assisted ventilation specially if he does not response to naloxone ,(which should be on of the medication to be given for this unresponsive , hypoxic patients )

While you are preparing the sodium bicarb IV bolus and antihyperkalemia medications to be given to this patient , he had run of VT

which aborted by sodium bicarb bolus and he was started on infusion and this was his repeat ECG were QRD narrowed and the brugada like pattern is more obvious

Patients labs showed also significant rhabdomyolysis and AKI with hyperkalemia

his urine drug of abuse screening came positive to TCA and morphine

He was treated with Intubation , IV fluid , sodium bicarb , antihyperkamic , norepinephrine and recovered after ICU admission.

TCA is a very dirty drug and the patient had a dirty combination of hyperkalemia in top of sodium channel blockage effect that masked the brugada pattern as well

Mechanism of toxicity is wide due to broad receptors activities

Management:

• Serum alkalinization to be started if f the patient has any ECG signs of sodium channel blocakge effects (prolonged QRS duration, large R in lead aVR, increased R:S ratio)

• Patients should receive 8.4% sodium bicarbonate 1-2 mEq/Kg boluses at 3-5-minute intervals to reverse the abnormality or to a target serum pH less than or equal to 7.55.

• After bolus , a sodium bicarbonate infusion can be administered by mixing 3 ampules(150 mEq) of 8.4% sodium bicarbonate in 1 L of D5W and infusing at a rate of 1-2x maintenance.

• For cardiac arrhythmias refractory to alkalization therapy, the next line drugs are lidocaine 1 mg/kg IV under cardiac monitor control.

• Consult medical toxicology backup as soon as possible for further assistance.

• If hypotension occurs; the patient’s intravascular volume status should be assessed, and if appropriate, rapidly corrected. norepinephrine is initial choices for vasopressor therapy.. (Catecholamine depletion at receptor sites occurs in severe TCA poisoning and may render dopamine and dobutamine ineffective in these situations.).

• If seizures occur while alkalinization is being implemented, then administer a benzodiazepine anticonvulsant, such as diazepam 0.1 mg/kg or 10-20 mg IV. If seizures continue, anticonvulsants (generally including diazepam,lorazepam, and/or barbiturates) should be rapidly given in sufficient quantity to stop the seizure activity. Phenytoin should be avoided as it may worsen cardiovascular toxicity.

• Patient should be referred to cardio if persistent brugada pattern

References:

1- National Guidelines of Poisoning

2. Goldfrank Toxicology

Previously healthy pt came with AMS / CV instability/ Rs depression/ Hyperthermia

The ddx should include both tox and non tox causes :

Non Tox ddx will include :

Sepsis / late CNS bleed with complication/ sever metabolic disturbance. / cardiogenic shock 2ry to MI / aortic dissection

Tox ddx will include :

Clinical pic and ECG findings fit more Anticholinergic toxidrome ( could be TCA / other Na channels blocker e.g carbamazepine)

Other possibility is overdosing more than one agents to have a mixture clinical pic he came with ( e.g sympathomemtic overdose leading to Cardiac event appearing as STEMI leading to cvs instability mixed with other sedative drugs leading to CNS and Rs depression)

I need more hx and laboratory clues to decide the management plan , but empirically I will start with :

Secure airway

Support circulation with Fluids and inotrops as needed . Antibiotics if any clues of infective process

Cooling measures

Whole bowel irrigation

CT head when possible

US: RUSH protocol

Cardiologist to be involved for ECG changes

Toxicologist consult

Empirical antidots:

Boluses of sodium bicarbonate

Magnesium sulfate will help is most of arrhythmia

This patient is very sick and requires immediate attention

- Take to resus bay & hook to a monitor

- Establish two large bore IV line and draw rainbow coloured tubes with VBG.

- Definitive airway (intubation) is a priority (Unable to maintain airway with loc GCS, failure to oxygenate and ventilate with shallow breathing and expected to deteriorate). I will give him IV fluid bolus 1 L then induced him with 1 mg/kg ketamine and rocuronium. Post intubation measures.

- If still hypotensive post 20 mls/kg then start on norepi drip

-CXR, bedside Rush protocol, CT head.

- DD : TCA toxicity (top of my dd , with prolonged QRS, prolong QTc, Brugada like ECG changes, RAD , ?RBBB, along with hypotension and CNS depression) : other tox DD SSRI tox, anticholinergic tox, antihistamine tox, cocaine tox . Non tox DD , CNS insult (trauma,infection , heat stoke), metabolic , cardiac (cardiogenic shock (ischemic, arrhythmias) , respiratory (infection/ aspiratory) , sepsis

## Treatment (if TCA tox is the cause) : Na bicarb to treat cardiac toxicity, given 2 mEq/kg rapid, repeat if needed , stop if QRS < 100ms or pH >7.50. Use lidocaine if NAHCO3 not working. Synch cardioversion if unstable tachyarrhythia. For hypotension IV fluids if refractory then norepi , ? ECMO if above fail. Intralipid therapy if refractory to bicarbs . Dialysis not useful due to large Vd.

Admit to ICU.