Difference between revisions of "Phenytoin toxicity"

Revision as of 23:55, 9 May 2017

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

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
GI
- Nausea and vomiting
Skin
- tissue infiltration (IV) → "purple glove syndrome"
- edema, pain, ischemia, tissue necrosis, compartment syndrome
Anticonvulsant hypersensitivity syndrome
- Fever, eosinophilia, rash, pseudolymphoma, SLE, pancytopenia, hepatitis, pneumonitis, pharyngitis, rhabdomyolysis
- Mortality rate of 10%

Level	Sypmtoms
>10	Usually no symptoms
10-20	Occasional mild nystagmus
20-30	Nystagmus
30-40	Ataxia, slurred speech, Nausea/vomiting
40-50	Lethargy, confusion
>50	Coma, seizure (rare)

^Provides a rough guide only; neither sensitive nor specific

Cannot base on phenytoin level (erratic absorption after PO overdose)
- Consider discharge if patient has only mild symptoms and serial phenytoin levels decline

@@ Line 23: / Line 23: @@
 **edema, pain, ischemia, tissue necrosis, compartment syndrome
 *Anticonvulsant hypersensitivity syndrome
-**Eosinophilia, [[rash]], pseudolymphoma, [[SLE]], pancytopenia, [[hepatitis]], pneumonitis
+**Fever, eosinophilia, [[rash]], pseudolymphoma, [[SLE]], pancytopenia, [[hepatitis]], pneumonitis, pharyngitis, [[rhabdomyolysis]]
+**Mortality rate of 10%
 ==Differential Diagnosis==