Pain in neurologic disease: Guillain-Barré, multiple sclerosis and Parkinson

Pain is common in neurologic disease and often follows the disease's own pattern: Guillain-Barré pain can come before weakness, multiple sclerosis can cause secondary trigeminal neuralgia, and Parkinson pain often tracks levodopa off periods.

1. Guillain-Barré pain is frequent and early. Weakness usually starts in the legs with reduced reflexes; pain is frequent, can be muscular, radicular or neuropathic, and severe diffuse pain can precede the onset of weakness ¹.
2. Pain persists through the course. In a prospective cohort of 156 patients, 36% had pain in the 2 weeks before weakness, 66% in the acute phase and 38% after 1 year ².
3. Watch breathing in the first week. Up to 22% of patients need mechanical ventilation within the first week, so those at risk of respiratory failure must be identified early ¹.
4. Image every trigeminal neuralgia. The European Academy of Neurology recommends MRI with three high-resolution sequences because no clinical characteristic can exclude secondary trigeminal neuralgia ³.
5. Multiple sclerosis is a classified cause. ICHD-3 lists trigeminal neuralgia attributed to multiple sclerosis among the secondary forms ⁴.
6. Parkinson pain follows motor fluctuations. Classifications include off-period pain and painful dystonia, such as early-morning dystonia, in patients with fluctuating responses to levodopa ⁵.

Severe back or limb pain with progressive bilateral weakness and reduced or absent reflexes suggests Guillain-Barré syndrome; monitor for respiratory insufficiency rather than treating it as radiculopathy ¹.

• Guillain-Barré weakness typically starts in the legs; reflexes are reduced or absent in most patients at presentation and in almost all at nadir ¹.
• Maximum disability is typically reached within 2 weeks; reaching it within 24 hours or after 4 weeks suggests another diagnosis ¹.
• Young children with Guillain-Barré syndrome may present with poorly localized pain, refusal to bear weight or an unsteady gait ¹.
• Signs of imminent respiratory insufficiency include breathlessness at rest or while talking, inability to count to 15 in one breath and accessory muscle use ¹.
• Mean pain intensity was highest in patients with sensory disturbances and in severely affected patients ².
• Secondary trigeminal neuralgia is generally treated like primary, with carbamazepine or oxcarbazepine as first-choice drugs ³.
• Pain affects 68–85% of people with Parkinson disease and is underdiagnosed and undertreated ⁵.
• Levodopa reversed the lower pain threshold of the off state, and rotigotine gave a 2-fold improvement in fluctuation-related pain versus placebo ⁵.

• Attributing back and leg pain with areflexic weakness to disc disease ¹.
• Skipping MRI because trigeminal attacks look typical ³.
• Adding neuropathic drugs for Parkinson pain that tracks the timing of levodopa doses ⁵.
• Assuming Guillain-Barré pain ends as strength returns; over a third still have pain at 1 year ².