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Advisor(s)
Abstract(s)
Após uma amputação podem surgir diversos sintomas específicos, que incluem a dor somática, originada nas lesões do coto de amputação, a sensação fantasma e a dor fantasma.
A dor fantasma (DF) foi descrita pela primeira vez no século XVI por Ambroise Park. Em 1871, durante a Guerra Civil Americana, surgiu o termo "dor do membro fantasma", criado pelo neurologista Weir Mitchel. A abordagem diagnóstica e terapêutica deste sintoma tem sido um desafio para os clínicos e um campo privilegiado de investigação. Apesar do seu reconhecimento desde essa época, a sua fisiopatologia continua a não ser bem compreendida.
Constatou-se que a sensação fantasma não se restringia aos membros, estendendo-se também à perda de dentes, mama, olho, pénis e língua. Por essa razão, o termo “dor do membro fantasma” foi substituído por “dor fantasma”.
O ponto de partida para se entender o fenómeno do membro fantasma - dolorosa ou não – corresponde ao fato de a amputação de parte do corpo poder causar uma desregulação da rede normal de aferentes nervosos e da transmissão nociceptiva. A aferência normal é substituída por outra ainda desconhecida, mas certamente diferente, que fornece à medula espinhal e ao encéfalo, nomeadamente ao córtex somatossensorial, a informação necessária para criar o “fantasma”.
Existem inúmeras teorias para tentar explicar a fisiopatologia da DF, que podem ser divididas em três categorias principais: periféricas, espinhais e centrais. As primeiras assumem que a causa reside nas terminações nervosas junto à lesão, enquanto as segundas atribuem a causa a alterações na medula espinhal. Para as categorias centrais a DF tem causa encefálica.
Como a DF é um problema com formas de apresentação tão díspares, com elevadas incidência e prevalência, a par da dificuldade de tratamento nalguns casos, tornam-na um problema emergente. Visto que o tratamento da dor pode ser feito sob terapêuticas farmacológicas e não farmacológicas, é essencial ter em conta o seu mecanismo. Deste modo, é imprescindível a permanente atualização sobre a sua fisiopatologia.
Esta tese tem como objetivo realizar uma revisão bibliográfica sobre a DF, dando a conhecer, de forma mais aprofundada, as teorias desenvolvidas até ao momento.
After an amputation, various specific symptoms may occur, which include somatic pain that stems from damage made to the amputation stump, phantom sensation and phantom pain. Phantom pain was first described in the 16th Century, by Ambroise Park. In 1871, during the American Civil War, the term “phantom limb pain” was created by the neurologist Weir Mitchel. The diagnostic approach and the treatment of this symptom has been a challenge for physicians, as well as being a rather privileged field of investigation. Despite its recognition since its discovery, its physiopathology has yet to be fully understood. Phantom sensations have been reported from other body parts besides limbs, namely from the loss of teeth, breasts, eyes, penis and tongue. As such, the term “phantom limb pain” has been swapped out for “phantom pain”. The starting point in order to understand the phenomenon of phantom limb – painful or otherwise – is the fact that amputation of a body part causes disruption in the normal network of afferent nerves as well as in the nociceptive transmission. Normal input is lost and replaced by an unknown afferent system, which in turn supplies the spinal cord and encephalon (namely, the somatosensory cortex) with the input necessary to create the “phantom”. There are several theories that attempt to explain the physiopathology of phantom limbs; these can, however, be divided into three main categories: peripheral, spinal and central. The first group assumes that the cause for phantom pain resides in the nervous ends near the lesion, while the second group attributes the cause to changes that occur in the spinal cord. Lastly, the third group claims that phantom pain is derived from some sort of encephalic mechanism. Since phantom pain has such a disparate etiology and presentation in amputees, alongside with high incidence and prevalence levels as well as being difficult to appropriately treat, it reverts to an emergent issue. Given that the treatment of pain can be done under pharmacological and non-pharmacological therapies, it is essential to take into account its mechanism. Thus, a permanent update on its pathophysiology is essential. This thesis is a literature review about phantom pain, in an attempt to better understand and explain the theories that have been developed until now.
After an amputation, various specific symptoms may occur, which include somatic pain that stems from damage made to the amputation stump, phantom sensation and phantom pain. Phantom pain was first described in the 16th Century, by Ambroise Park. In 1871, during the American Civil War, the term “phantom limb pain” was created by the neurologist Weir Mitchel. The diagnostic approach and the treatment of this symptom has been a challenge for physicians, as well as being a rather privileged field of investigation. Despite its recognition since its discovery, its physiopathology has yet to be fully understood. Phantom sensations have been reported from other body parts besides limbs, namely from the loss of teeth, breasts, eyes, penis and tongue. As such, the term “phantom limb pain” has been swapped out for “phantom pain”. The starting point in order to understand the phenomenon of phantom limb – painful or otherwise – is the fact that amputation of a body part causes disruption in the normal network of afferent nerves as well as in the nociceptive transmission. Normal input is lost and replaced by an unknown afferent system, which in turn supplies the spinal cord and encephalon (namely, the somatosensory cortex) with the input necessary to create the “phantom”. There are several theories that attempt to explain the physiopathology of phantom limbs; these can, however, be divided into three main categories: peripheral, spinal and central. The first group assumes that the cause for phantom pain resides in the nervous ends near the lesion, while the second group attributes the cause to changes that occur in the spinal cord. Lastly, the third group claims that phantom pain is derived from some sort of encephalic mechanism. Since phantom pain has such a disparate etiology and presentation in amputees, alongside with high incidence and prevalence levels as well as being difficult to appropriately treat, it reverts to an emergent issue. Given that the treatment of pain can be done under pharmacological and non-pharmacological therapies, it is essential to take into account its mechanism. Thus, a permanent update on its pathophysiology is essential. This thesis is a literature review about phantom pain, in an attempt to better understand and explain the theories that have been developed until now.
Description
Keywords
Amputado Dor Dor do Membro Fantasma Etiologia Patofisiologia Patogénese