michelle troendle case conference august 6, 2014
TRANSCRIPT
DIGITALIS AND YOUMichelle TroendleCase conferenceAugust 6, 2014
Where do you find this in nature?
1) Digitalis purpurea (foxglove) 2) Nereum oleander (oleander) 3) Thevetia peruviana (yellow oleander) 4) Convallaria majalis (lily of the valley) 5) Urginea maritima (red squill) 6) Bufo alvarius (Colorodo River toad)
Digitalis
Purple, pink, white, yellow Grows to about 3 feet Whole plant toxic
Foxglove
Toxin: Digitoxin
Nerium oleander
Common oleander
Toxin: oleandrin
Convallaria majalis
Lily of the valley
Toxin: convallotoxin, convallarin
Thevetia peruviana
Common method of suicide in Sri Lanka Also called Lucky Nut
Yellow oleander
Toxin: thevetin
Urginea maritima
Red squill
Toxin: scillaren
Bufotoxin
Digoxin
Signs of an acute overdose
GI distress – nausea, vomiting, abdominal pain
Lethargy Confusion Atrial and ventricular ectopy (may
progress to VT or VF) Sinus bradycardia Sinus arrest High-degree AV block
Quiz
What is the most common dysrhythmia associated with digoxin toxicity? PVCs
EKG changes – name a pathagnomic dysrhythmia
EKG – another pathagnomic dysrhythmia
When to treat digoxin toxicity
ACUTE CHRONIC
Heart Block K+ > 5 15 ng/mL anytime
after ingestion > 10 ng/mL 6 hrs
after ingestion Ingestion of:
10 mg adult 4 mg child
Dysrhythmia GI symptoms Altered mental status Heart block Hypotension
Dosing of Dig-fab
It blows to calculate 3 general ways to dose:
1) Estimate quantity of digoxin acutely ingested and assume 80% bioavailability
2) Obtain a serum digoxin concentration (SDC) and using a pharmacokinetic formula incorporate the apparent Vd of digoxin using the patient’s body weight (kg)
3) use an empiric dose based on the average requirement for an acute or chronic overdose in an adult or child
Ok let’s go through this – option 1
# of vials = Amount ingested (mg) x 80% .5 (mg/vial)
Limitation – history made be inaccurate, which can cause error in calculating dose
Calculation based on dig level
# vials = SCD (ng/dL) x Weight (kg)100
Empiric
ACUTE CHRONIC
Adults: 10-20 vials Children: 10 vials
*This is a lot easier, but will frequently overestimate or underestimate Fab requirements
Adults: 3-6 vials Children: 1-2 vials
* Each vial of DSFab contains 38 mg (digibind) or 40 mg (digifab) of purified DSFab that will bind approximately .5 mg digoxin or digitoxin
Let’s review this scene
LIKES DISLIKE
Digoxin toxicity can cause ventricular tachycardia
Did they give him digi-fab?
Ipicac – no no no no!!!!!! Patients with ventricular
tachycardia have a heart rate well over 130s
Patients with ventricular tachycardia with a pulse get cardioverted, not defibrillated
Patients generally don’t defibrillate themselves
You do not shock asystole