Acute Inflammatory Demyelinating Polyneuropathy Concurrent with Evans Syndrome

To the Editor:

The association of autoimmune hemolytic anemia and idiopathic thrombocytopenic purpura (ITP) is known as Evans syndrome. We describe a patient with a relapse of Evans syndrome complicated by acute inflammatory demyelinating polyneuropathy (AIDP), suggesting a relationship between the two disorders.

A 73-year-old black man with a history of positive Coombs test for autoimmune hemolytic anemia and chronic relapsing ITP requiring splenectomy and intermittent treatment with intravenous immunoglobulin (IVIG), presented with a 1-week history of progressive weakness in his lower limbs. Symptoms had begun distally and progressed proximally during the next few days, rendering him incapable of ambulating. Physical examination during this hospital admission was remarkable for markedly decreased muscle strength in both lower limbs, with absent deep tendon reflexes. Sensory examination was unremarkable. Admission laboratory tests revealed a platelet count of 4,000/μl; 2 weeks earlier, his platelet count had been 165,000/μl. Hemoglobin and hematocrit levels were within normal range; however, results of direct Coombs test were strongly positive. Spinal fluid analysis showed elevated protein level without pleocytosis. Results of a nerve conduction study were consistent with demyelinating radiculoneuropathy. The patient was treated with IVIG for both ITP and AIDP. By the fourth day after admission, platelet counts were within normal range. His strength gradually improved during the next 2 weeks.

The cause of these disorders remains unknown. The onset of AIDP in this patient, concordant with relapse of Evans syndrome, supports the notion that these conditions represent manifestations of a common underlying disorder of immune regulation. It has been suggested that they result from immune responses against foreign antigens that are misdirected to the host's hematopoietic or nerve tissue through molecular mimicry. ^1,2

A review of the literature showed only one similar case, reported in 1965. ³ Further review of that case showed the neurologic manifestations to be dominated by a clinical picture suggestive of transverse myelitis rather than AIDP.

Sumit Gaur, MD

Sudhathi Reddy, MD

Michael A. Baumann, MD