Case 12

22 year old female brought in semi-conscious by boyfriend.

BP 90/60, HR 150/min.
Hypocount : 5.2 mmol

10 minutes later she developed a generalized tonic-clonic seizure.

What does the ECG show?
What is the likely underlying cause?


Answer : Tricyclic Antidepressant (TCA) Overdose

The ECG shows a broad-complex tachycardia which raises the suspicion of a VT (ventricular tachycardia). This is unusual in a young female patient, as VT usually occurs in the setting of more elderly patients with underlying cardiac disease.

Involvement of the cardiovascular and neurological systems in a young patient who presents with in this manner (brought in by boyfriend) should alert us to the possibility of a drug-overdose, especially that of tricyclic antidepressants (TCA) such as amitriptyline.

Presenting features of TCA toxicity may include:

Cardiovascular : Palpitation, Chest pain,  Hypotension

CNS : Convulsion, Decrease mental status, Respiratory depression, Drowsiness, Coma

Peripheral autonomic system : Dry mouth, Dry skin, Urinary retention, Blurred vision

Treatment

·        ICU management

·        Support airway and vital signs

·        Activated charcoal for GI decontamination

·        IV Sodium Bicarbonate esp. in prolonged QRS

·        Benzodiazepines for seizures

·        Consider hemodialysis

Case 8

78 year old female

Brought in by SCDF ambulance. Acutely unwell.
BP 85/50, Temp 37.8. Drowsy and unresponsive.
No family members around to give more history.

What is the diagnosis?
Which drug would you give first in her management?

Answer : Hyperkalemia

On first look, the ECG looks bizarre and not like something which we can fit a pattern to. This in itself should already remind you to think of hyperkalemia. On closer inspection we can see that the QRS complexes are widened and there is also suggestion of tall T waves.

Management

• Immediate management in P1 area. Full monitoring.
• Supplemental oxygen
• IV access; take blood form FBC/ UE/ ABG/ cardiac enzymes & Troponin/ blood cultures; consider IV fluids but need to exclude fluid overload first
• Drugs

1. IV Calcium gluconate/ chloride (10 mls stat) - first drug to be given in treatment of hyperkalemia; to stabilise the myocardium
2. IV Insulin 10 units with IV Dextrose 50% 40 mls - shifts ECF potassium into ICF
3. IV Sodium Bicarbonate (1 meq/kg BW ) IV bolus over 5 mins - also to shift ECF potassium into ICF. Limited use if patient is non-acidotic, and carries risk of fluid overload/ cerebral oedema.

Other drugs which can be considered include Salbutamol nebulisation (be careful in patients with IHD because of resultant tachycardia), as well as Resornium (K-binding resin) but it's not much use in A&E because of relatively longer onset of action (about 1-2 hrs).

This lady has a history of chronic renal impairment on dialysis. Her acute presentation is probably exacerbated by a concomitant infection (chest/ urine).

Remember :

• Consider non-cardiac pathologies when intepreting ECG
• When confronted with bizarre-looking ECG, consider severe hyperkalemia

Case 1

80 year old female

Past medical hx : hyperlipidemia, diabetes
Chief complaint : giddiness and breathless for 2 days
BP 100/60, HR 40

(1) What is the diagnosis?
(2) How would you manage this patient?


Answer : Complete (Third Degree) Heart Block

• Complete dissociation of P waves with QRS complexes
• P-P interval regular; R-R interval also regular

Causes

• Myocardial infarction - in 10% of inferior MI (usually benign); more serious if associated with anterior MI
• Cardiomyopathy (e.g. Lyme disease), acute rheumatic fever
• Overdose of meds (e.g. calcium-channel blocker; beta-blockers)
  

Approach

• Manage as P1 case
• Immediate support of ABC and cardiac monitoring

1. High-flow oxygen
2. IV access - take blood for FBC/ UE/ cardiac enzymes & troponin

• Atropine - 0.6 mg IV every 5 mins up to total of 3 mg
• Consider dopamine
• Transcutaneous pacing if medications ineffective (with analgesia/ sedation)
• Transvenous pacing (by cardiologist) if transcutaneous pacing unsuccessful, or as a definitive procedure after stabilized with transcutaneous pacing
  
• Treat underlying cause (e.g. MI, overdose) and complications (heart failure, shock)