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A hidden mesencephalic variant of central pain
Author(s) -
Convers Philippe,
Creac’h Christelle,
Beschet Albert,
Laurent Bernard,
GarciaLarrea Luis,
Peyron Roland
Publication year - 2020
Publication title -
european journal of pain
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.305
H-Index - 109
eISSN - 1532-2149
pISSN - 1090-3801
DOI - 10.1002/ejp.1588
Subject(s) - spinothalamic tract , midbrain , medicine , brainstem , somatosensory system , psychogenic disease , neuroscience , lesion , medial lemniscus , psychology , anesthesia , thalamus , central nervous system , surgery , nociception , radiology , receptor
Background Central post‐stroke pain (CPSP) can arise after lesions anywhere in the central somatosensory pathways, essentially within the spinothalamic system (STS). Although the STS can be selectively injured in the mesencephalon, CPSP has not been described in pure midbrain infarcts. Methods Of more than 300 CPSP consecutive cases, we describe five patients who developed definite neuropathic pain following lesions circumscribed to the postero‐lateral mesencephalon. Results The mesencephalic lesion responsible for pain was always haemorrhagic and always involved the spinothalamic tract (STT), as demonstrated by suppressed laser‐evoked potentials in every case, with or without preserved lemniscal function. In three cases the midbrain injury could be ascribed to trauma, presumably from the cerebellar tentorium. As a result of the paucity of sensory symptoms, the pain was considered as ‘psychogenic’ in two of the patients until electrophysiological testing confirmed STT involvement. Conclusion Postero‐lateral midbrain lesions should be added to potential causes of CPSP. Because pain and spinothalamic deficits may be the only clinical sign, and because small lateral midbrain lesions may be difficult to trail with MRI, mesencephalic CPSP can be misdiagnosed as malingering or psychogenic pain for years. Significance Selective spinothalamic injury caused by small lateral midbrain lesions is a very rare cause of central post‐stroke pain that can remain undiagnosed for years. It appears to obey to haemorrhagic, sometimes post‐traumatic lesions. Sudden development of contralateral burning pain with isolated spinothalamic deficits may be the only localizing sign, which can be easily objectively detected with electrophysiological testing.