Phenytoin toxicity: Difference between revisions
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== Background == | == Background == | ||
*Mortality is extremely rare after intentional overdose if good supportive care is provided | *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) | *Rapid IV dosing carries greatest risk (due to propylene glycol constituent of IV form --> myocardia depression & cardiac arrest) | ||
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*CV (only with IV form) | *CV (only with IV form) | ||
**Bradycardia | **Bradycardia | ||
**Hypotension | **[[Hypotension]] | ||
**Vfib | **[[Vfib]] | ||
**[[Asystole]] | **[[Asystole]] | ||
*Neuro | *Neuro | ||
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**Decreased LOC | **Decreased LOC | ||
*GI | *GI | ||
** | **[[Nausea and vomiting]] | ||
*Skin | *Skin | ||
**tissue infiltration (IV) --> "purple glove syndrome" | **tissue infiltration (IV) --> "purple glove syndrome" | ||
**edema, pain, ischemia, tissue necrosis, compartment syndrome | **edema, pain, ischemia, tissue necrosis, compartment syndrome | ||
*Anticonvulsant hypersensitivity syndrome | *Anticonvulsant hypersensitivity syndrome | ||
**Eosinophilia, rash, pseudolymphoma, SLE, pancytopenia, hepatitis, pneumonitis | **Eosinophilia, [[rash]], pseudolymphoma, [[SLE]], pancytopenia, [[hepatitis]], pneumonitis | ||
==Differential Diagnosis== | |||
==Diagnosis== | ==Diagnosis== | ||
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==Treatment== | ==Treatment== | ||
*Detoxification | |||
**[[Activated charcoal]] PO | |||
*Bradyarrhythmias | |||
**[[Atropine]], pacing | |||
*Hypotension | |||
**[[IVF]] | |||
==Disposition== | ==Disposition== | ||
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**Consider discharge if pt has only mild symptoms and serial phenytoin levels decline | **Consider discharge if pt has only mild symptoms and serial phenytoin levels decline | ||
== | ==References== | ||
[[Category:Tox]] | [[Category:Tox]] | ||
Revision as of 06:57, 7 August 2015
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
- Vfib
- Asystole
- Neuro
- Nystagmus
- First only with forced lateral gaze; later becomes spontaneous
- May disappear at higher levels
- Ataxia
- Decreased LOC
- Nystagmus
- GI
- Skin
- tissue infiltration (IV) --> "purple glove syndrome"
- edema, pain, ischemia, tissue necrosis, compartment syndrome
- Anticonvulsant hypersensitivity syndrome
Differential Diagnosis
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
- Bradyarrhythmias
- Atropine, pacing
- Hypotension
Disposition
- Cannot base on phenytoin level (erratic absorption after PO overdose)
- Consider discharge if pt has only mild symptoms and serial phenytoin levels decline