Differential Diagnosis for a 5-Month-Old Girl with Generalized Tonic-Clonic Seizure
- Single Most Likely Diagnosis
- Maple Syrup Urine Disease (MSUD): The patient's symptoms, such as poor feeding, progressive less interactiveness, and seizure, along with the absence of newborn screening, make MSUD a strong consideration. The disease can cause neurological deterioration and seizures if not treated promptly.
- Other Likely Diagnoses
- Pyridoxine-Dependent Epilepsy: This condition is characterized by seizures that are resistant to conventional antiepileptic medications but respond to pyridoxine (vitamin B6) supplementation. The patient's seizure and lack of response to typical treatments could suggest this diagnosis.
- Inborn Errors of Metabolism (e.g., Organic Acidemias, Urea Cycle Disorders): These disorders can present with nonspecific symptoms such as poor feeding, lethargy, and seizures. The absence of newborn screening increases the likelihood of these conditions.
- Infantile Spasms: Although the patient had a generalized tonic-clonic seizure, infantile spasms could be a consideration, especially given the patient's age and the presence of an eczematous rash, which might suggest a neurocutaneous syndrome.
- Do Not Miss Diagnoses
- Meningitis or Sepsis: Although the patient's temperature is normal, and there are no clear signs of infection, meningitis or sepsis can present subtly in infants and are life-threatening if not promptly treated.
- Hypoglycemia: The patient's glucose level is slightly elevated, but hypoglycemia can cause seizures and is a critical condition to rule out, especially in infants who have been feeding poorly.
- Intracranial Hemorrhage: Despite the normal CT scan, it's essential to consider the possibility of an intracranial hemorrhage, especially if there were any traumatic events or if the patient has a coagulopathy.
- Rare Diagnoses
- Glutaric Aciduria Type 1: This is an inborn error of metabolism that can cause seizures, developmental delay, and macrocephaly, although the patient's head circumference is at the 2nd percentile, making this less likely.
- Neonatal Adrenoleukodystrophy: A rare genetic disorder affecting the breakdown of very long-chain fatty acids, leading to neurological symptoms, including seizures. However, it typically presents later in infancy or early childhood.
- Ketotic Hyperglycinemia: A rare condition characterized by elevated glycine levels in the blood and cerebrospinal fluid, which can cause seizures, developmental delay, and other neurological symptoms.