With the rapid onset of the cranial nerves involved, CXR not showing lymphadenopathy, a normal spinal fluid, and normal ACE level, this was unlikely. Lyme disease also can cause bilateral facial weakness. She had not been in an endemic area , had an initial normal spinal fluid, and negative Lyme titers. This diagnosis was unlikely. Acute intermittent porphyria can be confused with Guillain-Barre syndrome as it tends to cause a motor neuropathy.
Patients often have abdominal pain, neuropsychiatric symptoms, and a family history.
As she did not have these findings, this diagnosis was unlikely. Urine screen for porphobilinogens was negative. Repeat lumbar puncture showed an elevated protein. There was no evidence of botulinum toxin in serum or stool, and the culture was also negative. As the diagnosis in this patient was considered to be Miller Fisher syndrome, the patient was treated with intravenous immunoglobulin.