13 GENERAL INTRODUCTION, AIMS & OUTLINE 1 A General Introduction Imagine you wake up one morning with excruciating pain in your arm and shoulder. No matter what you try, you cannot find any relief for the pain. At first you do not even notice the muscle weakness, but by the end of the next day you can barely lift your arm. While helping you take off your shirt, your partner notices that your shoulder blade is sticking out. When you look in the mirror, you see that your shoulder blade is indeed positioned at a weird angle, as if it is “winging”. Over the coming weeks, the acute pain subsides, but your shoulder and arm remain weak. After some back and forth with your general physician, you are diagnosed with neuralgic amyotrophy. A neurologist explains that you have nerve damage and that recovery will take time. You continue to struggle with daily tasks such as getting dressed and cooking dinner. You miss playing volleyball and picking up your oneyear-old niece. You wonder if you will ever be able to return to your physically demanding job as a nurse in an elderly home. Over time you develop ways to compensate, but that only helps to some extent. Moreover, the extra burden on compensating muscles causes pain and fatigue. You hold out hope that you will regain function of your shoulder and arm as the peripheral nerves recover, but a year and a half later, you are still not anywhere near where you want to be. This fictional scenario reflects the unfortunate reality many patients with neuralgic amyotrophy find themselves in. It was inspired by stories that patients have shared with me, which have been incredible motivators for the work described in this thesis. Neuralgic amyotrophy Neuralgic amyotrophy (NA) is a common (yearly incidence of 1/1000) and disabling peripheral nerve disorder. 3 It is characterized by severe acute pain, caused by an acute auto-immune inflammation of nerves in the brachial plexus territory. The inflammation leads to peripheral nerve damage and subsequent weakness of muscles innervated by the affected nerves. 4-6 The acute phase, in which inflammation is ongoing, typically lasts several weeks, after which affected nerves will show spontaneous recovery over the course of months to years. 5, 6 NA typically affects one upper extremity, but can also occur bilaterally, and may involve nerves outside the brachial plexus, such as lumbar plexus and phrenic nerve. 5-7 To compensate for the initial muscle weakness, many NA patients develop abnormal movement patterns, most notably in the shoulder region. Abnormal positioning of the shoulder blade in rest and during movement is referred to as scapular dyskinesia, and is present in the majority of NA patients. 6-8 While these compensatory movement patterns can be beneficial at first, they often lead to long-term motor dysfunction and subsequent residual complaints such as impaired functional capability, fatigue and pain, which in turn lead to problems with activities of daily living. 6, 8-10 There is no proven effective causative treatment for NA. 6, 9 Standard physical therapy is often ineffective, and can even worsen symptoms. 8 A large proportion of NA patients thus continue to suffer from residual complaints, even when peripheral nerve recovery has taken place and muscle weakness has subsided. 6-8, 10 (Mal)adaptive neuroplasticity The fact that functional problems persist, despite recovery of the peripheral nerves and muscles, “the hardware”, suggests that the problemmay lie within the “software”: the way
RkJQdWJsaXNoZXIy MjY0ODMw