Carbamazepine Toxicity Differential Diagnoses

Updated: Apr 29, 2020
  • Author: Muhammad Waseem, MS, MBBS, FAAP, FACEP, FAHA; Chief Editor: Stephen L Thornton, MD  more...
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DDx

Diagnostic Considerations

Other problems to consider in the differential diagnosis include the following:

  • Hypersensitivity reactions (eg, dermatitis, eosinophilia, lymphadenopathy, vasculitis, splenomegaly)
  • Pancytopenia (eg, aplastic anemia, leukopenia)
  • Drug-drug interactions

Acute change in mental status

In patients who have a history of seizures despite taking carbamazepine, the postictal state (after an unwitnessed seizure) and an acute mental status change due to carbamazepine overdose are difficult to differentiate.

Child abuse may be a consideration in a pediatric patient with no prior relevant history who presents in coma. Other causes of coma to consider in patients of any age include the following:

  • Trauma
  • Infection
  • Central nervous system (CNS) tumors
  • Other intoxications

Arrhythmias

Although arrhythmias are uncommon in pediatric patients, they may occur in children with underlying cardiac disease and with very large overdoses. Other causes of arrhythmias should be assessed, including electrolyte abnormalities, hypoxia, and overdoses with other drugs known to cause arrhythmias (eg, phenytoin, digoxin, cocaine, tricyclic antidepressants).

Seizures

In patients taking long-term carbamazepine therapy for epilepsy, identifying the cause of the current seizure is important. A seizure could be due to subtherapeutic drug levels, breakthrough seizures with therapeutic drug levels, or carbamazepine toxicity. Other causes that must also be considered include the following:

  • Other drug ingestion
  • Trauma
  • Hypoglycemia
  • Electrolyte disturbances
  • Brain tumors
  • CNS infection
  • New-onset epilepsy

Differential Diagnoses