Phenytoin toxicity: Difference between revisions
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*90% protein bound; dialysis ineffective | *90% protein bound; dialysis ineffective | ||
==Clinical Features== | == Clinical Features == | ||
*CV (only with IV form) | |||
**Bradycardia | *CV (only with IV form) | ||
**Hypotension | **Bradycardia | ||
**Hypotension | |||
**Asystole | **Asystole | ||
*Neuro | *Neuro | ||
**Nystagmus | **Nystagmus | ||
***First only with forced lateral gaze; later becomes spontaneous | ***First only with forced lateral gaze; later becomes spontaneous | ||
***May disappear at higher levels | ***May disappear at higher levels | ||
**Ataxia | **Ataxia | ||
**Decreased LOC | **Decreased LOC | ||
*GI | *GI | ||
**N/V | **N/V | ||
*Skin | |||
**tissue infiltration (IV) --> "purple glove syndrome" | |||
**edema, pain, ischemia, tissue necrosis, compartment syndrome | |||
<br> | |||
==Diagnosis== | ==Diagnosis== | ||
Revision as of 19:43, 5 November 2012
Background
- Mortality is extremely rare after intentional overdose if good supportive care is provided
- Rapid IV dosing carries greatest risk (due to propylene glycol constituent of IV form --> myocardia depression & cardiac arrest)
- 90% protein bound; dialysis ineffective
Clinical Features
- CV (only with IV form)
- Bradycardia
- Hypotension
- Asystole
- Neuro
- Nystagmus
- First only with forced lateral gaze; later becomes spontaneous
- May disappear at higher levels
- Ataxia
- Decreased LOC
- Nystagmus
- GI
- N/V
- Skin
- tissue infiltration (IV) --> "purple glove syndrome"
- edema, pain, ischemia, tissue necrosis, compartment syndrome
Diagnosis
- Phenytoin level
- Provides a rough guide only; neither sensitive nor specific
- Level >10: usually no symptoms
- Level 10-20: Occasional mild nystagmus
- Level 20-30: Nystagmus
- Level 30-40: Ataxia, slurred speech, N/V
- Level 40-50: Lethargy, confusion
- Level >50: Coma, seizure (rare)
Treatment
- Detoxification
- Activated charcoal PO
- Bradyarrhythmias
- Atropine, pacing
- Hypotension
- IVF
Disposition
- Cannot base on phenytoin level (erratic absorption after PO overdose)
- Consider discharge if pt has only mild symptoms and serial phenytoin levels decline
Source
Tintinalli