An 8-year-old boy with a diagnosis of relapsing-remitting CIDP was admitted to our outpatient clinic for the first time at the age of 4 months due to diarrhea and lower extremity immobility after routine vaccination. He was born after uneventful pregnancy and delivery, with non-consanguineous marriage. At this age, on neurologic examination, he had symmetrical absent deep tendon reflexes and reduced muscle strength in the bilateral lower extremities. Cranial magnetic resonance imaging (MRI) was normal. Spinal MRI demonstrated T2 and fluid-attenuated inversion recovery (FLAIR) hyperintensity in the spinal nerve roots. Cerebrospinal fluid (CSF) evaluation revealed increased protein level (92 mg/dl, normal range: 15–45 mg/dl). With these clinical and laboratory findings, he was misdiagnosed with GBS due to rapidly progressive course. He was treated with intravenous immunoglobulin (IVIg, total: 2gr/kg, 5 days). At 9 months of age, significant improvement in his motor developmental milestones was observed. At 12 months of age, he gradually lost sitting, and was diagnosed with CIDP by nerve conduction study, which was compatible with demyelinating motor-weighted polyneuropathy. The similar clinical relapse occured seven times at the age of 1-year, 1-year and 6-month, 1-year and 10-month, 2-year and 6-month, 4-year and 7-month, 5-year and 10-month, and 8-year and 4-month.
Despite multiple pharmacological combinations such as monthly IVIg (total: 1–2 g/kg, 2–5 days), monthly intravenous (IV) methylprednisolone (MP) (20–30 mg/kg/day, 3–5 days), oral MP (1–2 mg/kg/day, 3–12 months), azathioprine (1–2 mg/kg/day), and rituximab (375 mg/m2 weekly for 4 weeks), clinical relapse and recovery periods were observed. However, slowly progressive distal muscle weakness and mild distal muscle atrophy occurred in bilateral lower extremities. Moreover, gabapentin was added to the treatment for neuropathic pain.
After an relapse-free period of 2 years, the patient was admitted to our outpatient clinic due to drooling, facial asymmetry, and increased distal lower extremity weakness. Neurological examination revealed mild unilateral facial weakness, tongue deviation on protrusion, and mild asymmetric hemiatrophy without tongue fasciculation (Fig. 1). Significant muscle atrophy and weakness, and loss of pinprick sensations were observed in the bilateral distal lower extremities. Deep tendon reflexes were decreased bilaterally in the upper extremities and absent in the lower extremities. Moreover, dysarthria and dysphagia were noticed.
In laboratory tests, blood samples were analyzed for autoimmune processes (including antinuclear antibody, anti-double stranded DNA, thyroid function tests and autoantibodies, anti-Ro/La, rheumatoid factor, anti-ganglioside antibodies, and anti-neurofascin 155/186) and infectious agents (including serology of cytomegalovirus and hepatic viruses), and all were found negative. CD-59 expression on flow cytometry was normal. CSF analysis was not repeated at the last relapse. According to the final nerve conduction study (Table 1), in the upper extremity, the distal latencies of the motor nerve were found prolonged, the amplitudes were found decreased, and the nerve conduction velocities were found at the lower limit. In the upper extremity, the distal latencies of the sensory nerve were found normal, the amplitudes were found decreased, and the nerve conduction velocities were found at the lower limit. Right median nerve F response was found prolonged. The lower extremity motor nerve conductions could not be obtained. In the lower extremity, the amplitudes of the sensory nerve were found decreased, the distal latencies were found prolonged, and the conduction velocities were found at the lower limit. These findings were compatible with motor-weighted demyelinating chronic polyneuropathy, accompanied by axonal involvement. Cranial MRI was also normal in the last attack. The patient was treated with monthly IVIg (total 2 g/kg, 4 days) and soon after weekly rituximab (375 mg/m2 weekly for 4 weeks). In the 3rd month of immunotherapy, hypoglossal nerve involvement improved significantly (Fig. 2).
Table 1
Nerve conduction study findings
Nerve | Left | Right |
Motor Nerve | MCV (m/s) | CMAP (mV) | Distal latency (ms) | MCV (m/s) | CMAP (mV) | Distal latency (ms) |
Median nerve | | | | 46.7 | 0,00 | 4 |
Ulnar nerve | | | | 45 | 0,870 | 4 |
Peroneal nerve | no response | no response | no response | no response | no response | no response |
Sensory nerve | SCV (m/s) | SNAP (µV) | Distal latency (ms) | SCV (m/s) | SNAP (µV) | Distal latency (ms) |
Median nerve | | | | 41.3 | 27.5 | 2.3 |
Ulnar nerve | | | | 44.2 | 11.8 | 2.26 |
Sural nerve | 41.7 | 4.5 | 3.6 | 47,6 | 9.1 | 2.94 |
F wave conduction velocity | | |
Median nerve | | 35.75 |