Guillain-Barré Syndrome as a Paraneoplastic Manifestation of Small-cell Carcinoma of Lung

Sajid Naveed, MD, MRCP; Kelechi Okoli, MD, MRCP; Jocelyn Hollingsworth, BS; Rahil Kasmani, MD, MRCP

Disclosures

South Med J. 2010;103(2):156-158. 

In This Article

Discussion

Guillain-Barré syndrome (GBS) refers to the heterogeneous group of immune-mediated polyneuropathies, which includes acute inflammatory demyelinating polyradiculoneuropathy (AIDP), acute motor and sensory axonal neuropathy (AMSAN), acute motor axonal neuropathy (AMAN), and the Miller-Fisher syndrome (MFS). GBS is classically triggered by a preceding bacterial or viral infection. The proposed mechanism for GBS is molecular mimicry, ie cross reactivity between the immune responses evoked by an infective agent and components of the peripheral nervous system. The presence of shared antigenic epitopes between peripheral nerve components and the oligosaccharide coat of Campylobacter jejuni, as well as the ability of C jejuni infection to produce anti-ganglioside antibodies, support the hypothesis of molecular mimicry. This immune reaction can be directed against the axon or myelin of the nerves, producing the variants of GBS.

Paraneoplastic syndromes occur in 10–20% of patients with lung malignancies, and occur most frequently with SCLC. Neurologic paraneoplastic syndromes associated with SCLC include Lambert-Eaton myasthenic syndrome (LEMS), subacute sensory neuropathy, necrotizing myelopathy, cerebellar degeneration, cerebral encephalopathy, and opsoclonus. These syndromes are believed to result from immune responses to tumor antigens that share antigenic epitopes with normal nervous tissue. The demonstration of P/Q type calcium-gated voltage channel antibodies in LEMS supports this hypothesis. This mechanism is reminiscent of molecular mimicry described above. Another proposed mechanism is that decreased immune-surveillance induced by cancer allows the emergence of autoimmune T-cell or B-cell clones.

GBS has been previously described in association with other cancers.[1–5] Given the proposed pathogeneses of GBS and neurologic paraneoplastic syndromes, GBS in this patient most likely represents a paraneoplastic manifestation of SCLC. Table 2 summarizes the characteristics of the previously described cases[6–8] of GBS associated with SCLC including our case. The clinical features of GBS associated with cancer do not appear to differ from usual GBS. The mortality observed in these cases is presumably related to the underlying cancer. Theoretically, persistent immune dysregulation from the cancer can worsen the prognosis of the GBS. In our patient, therapy for GBS in the form of intravenous immunoglobulins and remission of the SCLC lead to resolution of his neurologic deficits. It is not possible to determine the relative contributions of both therapies to his recovery.

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