Thalamic Pain Syndrome

Thalamic pain syndrome (Dejerine-Roussy syndrome) is central neuropathic pain after a thalamic lesion, usually infarction or haemorrhage in the ventral posterolateral thalamus. It is a form of central post-stroke pain and is characterised by contralateral hemisensory loss followed weeks to months later by intractable pain.

Pathophysiology. Injury to thalamic relay nuclei disrupts spinothalamic and lemniscal input, causing thalamocortical dysrhythmia and central sensitisation.

Contralateral sensory loss, transient hemiparesis, ataxia and choreoathetosis (the full syndrome), followed after weeks or months by severe, persistent burning or aching pain with allodynia and hyperpathia, worsened by touch, temperature, emotion and movement. Mood disorder is common.

Clinical diagnosis with MRI showing a thalamic lesion. Sensory examination shows impaired temperature and pain sensation. Exclude other pain causes and depression. Assess for other lesions that may cause pain (brainstem, parietal cortex).

Differential diagnosis.

• Central post-stroke pain from other sites, and complex regional pain syndrome.
• Hemiplegic shoulder pain and spasticity.
• Peripheral neuropathic pain.

Management follows that for central post-stroke pain.

Drugs. Amitriptyline 10 mg at night, increased to 75 mg, lamotrigine 25 mg daily titrated to 200 to 400 mg, pregabalin 75 to 300 mg twice daily, or gabapentin up to 2400 mg daily (adjust to eGFR). Carbamazepine or duloxetine as alternatives. Opioids are of limited benefit.

Interventional. Repetitive transcranial magnetic stimulation, epidural motor cortex stimulation or deep brain stimulation (periventricular grey matter, ventral posterolateral nucleus) for refractory pain.

Supportive. Treat depression and anxiety, cognitive behavioural therapy, sleep hygiene, physiotherapy and occupational therapy.

Monitoring. Pain scores, mood, and adverse effects.

Referral and escalation. Refer to pain services and neurosurgery for refractory pain.