189 - Situations that can mimic death

*Hypothermia
*Drug overdose (drugs like opioids, tricyclic antidepressants, barbiturates, alcohol and anaesthetic agents)
*Near drowning, cold water immersion
*Severe hypoglycemia
*Severe hepatic encephalopathy
*Myxedema coma
*Severe catatonic state

------

*These conditions are important and need to be remembered when you are confirming death of a patient. It is also important for everybody to know the PROTOCOL FOR CONFIRMATION OF DEATH :

1. Feel for a major (carotid or femoral) pulse for atleast 1 minute.
2. Listen for heart sounds over the cardiac apex for at least 1 minute.
3. While you are doing this, watch the chest wall for any movement.
4. Listen to the chest for breath sounds for 3 minutes.
5. Watch for any spontaneous movement during your examination.
6. Check there is no motor response to supra-orbital examination.
7. Simultaneously retract both eyelids, shine a bright light into each eye in turn and check that both pupils are fixed and unreactive.
8. Check the corneal reflexes, which should be absent. (The video below shows how you elicit a CORNEAL REFLEX)



*In certain situations, additional investigations may be available and confirmatory: for example, an ECG monitor trace showing asystole, absence of pulsatile flow from an intra-arterial line or absence of contractile motion on echocardiography.

188 - Digitalis toxicity

*Reduced tolerance of digoxin may be seen in (factors predisposing to digitalis toxicity) :
 - Advanced age
- Acute Myocardial Infarction/ Ischemia/ Hypoxemia
- Magnesium depletion (hypomagnesemia)

- Hypercalcemia (Calcium synergises with digitalis and precipitates its toxicity)
- Hypothyroidism (Both hyperthyroidism and hypothyroidism enhance digitalis toxicity. Thyrotoxicosis patients are more prone to develop digitalis arrhythmias and Myxedema enhances responsiveness to digitalis. Myxedema patients eliminate digoxin more slowly)
- Renal insufficiency (Digoxin is mainly excreted by kidneys)

- Electrical cardioversion 

* Digitalis toxicity causes hyperkalemia, but hypokalemia enhances digitalis toxicity (by increasing its binding to Na+/K+ ATPase.

*The administration of the following drugs raises the serum concentration of digoxin :
- Quinidine
- Verapamil
- Procainamide
- Amiodarone

*MANAGEMENT OF DIGITALIS OVERDOSE :

- Withdrawl of the drug
- Potassium (administer cautiously and by oral route whenever possible if hypokalemia is present. Potassium must not be employed in the presence of A-V block or hyperkalemia.
- Phenytoin/Beta blocker or Lidocaine : Lidocaine is effective in treatment of digitalis induced ventricular tachyarrythmias.
- Cardiac pacemaker : may be required in digitalis induced A-V block.
- Electrical conversion : may be life saving in digitalis induced ventricular fibrillation 
- FAB fragments/ digitalis antibodies : are potentially life saving in severe intoxication 
- Hemodialysis is not useful in digoxin toxicity .

(Other conditions where hemodialysis is ineffective is Digoxin poisoning, Kerosene poisoning, Benzodiazepine poisoning and Organophosphate poisoning)

(Remember that Digoxin and Digitoxin are two different drugs, both derived from digitalis, But digitoxin is mainly excreted by liver and digoxin is mainly excreted by kidneys. Hence digoxin dosage need not be adjusted in liver failure and digitoxin dosage need not be adjusted in renal failure)

*The most lipid soluble cardiac glycoside is Digitoxin.
*The most rapidly absorbed oral glycoside is digitoxin.