By: AMFS Board Certified Neurologist
Reflex sympathetic dystrophy (RSD) is often described as one of the most painful disorders to experience, on par, some would say, with childbirth, bone pain, and trigeminal neuralgia. However, unlike other pain syndromes there are no effective treatments for RSD. Reflex sympathetic dystrophy is actually a condition within a larger group of disorders referred to as complex regional pain syndrome (CRPS), which is divided into types I and II – RSD is considered type I CRPS whereas causalgia (derived from the Greek word referring to burning pain) is referred to as type II CRPS. The term ‘dystrophy” means degeneration which may be reversible. The distinction between these two types of CRPS is that type II is associated with a specific nerve injury whereas this cannot be identified with type I.
The cause of RSD is not known although it is typically triggered by trauma, even seemingly minor such as resulting from injury to an ankle, foot, or hand. Furthermore, RSD may be caused by surgery and as such it is considered to be a possible, sometimes unavoidable, not unexpected outcome. In the vast majority of cases where a nerve is injured, the pain caused by the injury resolves, sometimes over the course of weeks to months, however, in about 5% of cases, the pain becomes persistent, leading to CRPS (RSD or causalgia). This disorder is reported to be more common in women than men and typical age of onset is between 30-60 years.
Reflex sympathetic dystrophy results from trauma to sympathetic nerves controlling the size of very small arteries usually in the distal upper and lower extremities, resulting in impairment of blood flow, i.e., if the vessel constricts too much it may lead to coolness and bluish/whitish discoloration of the hands or feet whereas too much vasodilatation has the opposite effect, i.e., the affected extremity becomes swollen and red, and may lead to excessive sweating. In either case pain, particularly to touch, is a cardinal feature of RSD.
Symptoms associated with RSD are described as burning, sharp, stabbing, or stinging, involving the skin or one or more joints, and often appear out of proportion to the injury itself. These sensory disturbances are called dysesthesias whereas paresthesias refer to nonpainful abnormal sensation such as tingling. Someone with RSD may also experience hyperalgesia, which is defined as increased sensitivity to pain. Another characteristic feature of RSD is allodynia, which refers to a painful response to an otherwise nonpainful stimulus, such as rubbing or touching the affected area lightly. Symptoms from RSD can be debilitating, often to the point where an individual can become incapacitated.
Types I (RSD) and II (causalgia) complex regional pain syndrome are divided into 3 chronologic stages beginning with the initial injury. Stage 1 (referred to as acute) typically lasts up to 3 months and is associated with gradual development of severe pain, changes in temperature and skin color. In stage 2 (called dystrophic), symptoms may reverse spontaneously but for those who don’t see improvement, this stage lasts between 3-6 months and is characterized by worsening pain, changes in skin color, and abnormalities in nail and hair growth. In stage 3 (called atrophic) abnormalities seen in stage 2 may become irreversible and may lead to muscle wasting, contractures of tendons (due to pain caused by even limited movement of the affected body part), and constant pain. It is not known why some individuals recover completely whereas for others the symptoms become irreversible, even though the trauma in either case may be relatively minor.
No diagnostic studies are available to confirm a diagnosis of RSD. Electrodiagnostic evaluation, comprising nerve conduction studies, is not sensitive enough to detect abnormalities involving the sympathetic nerves which are extremely thin. There are no proven treatments for RSD, which includes pain management, e.g., sympathetic nerve blocks, medications (narcotics, antiepileptic medications, antidepressants, and antiinflammatory agents), and sometimes in intractable cases spinal cord stimulator may be an option. Even with treatment someone with RSD can still be severely affected by pain.
Reflex sympathetic dystrophy can be difficult to diagnose because it is not commonly understood, even amongst healthcare providers. Even when promptly diagnosed and treated early some patients may still not respond adequately to therapy. Failure to promptly diagnose RSD and initiate treatment in a timely manner is often considered grounds for malpractice due to negligence against a healthcare provider, even though various medications may have been tried.
There are essentially two, not necessarily mutually exclusive, ways in which medical negligence may be considered in such a situation: either because failure to diagnose RSD early leads to permanent symptoms or failure to treat leads to marked impairment of quality of life. Since even early treatment of RSD may not alter the eventual outcome of disease course development, failure to treat in such a circumstance should not in and of itself be considered medical negligence particularly since in all likelihood the healthcare professional will have already tried treatment with different medications. Furthermore, it is (or should be) the implicit goal of the healthcare provider to provide treatment or to refer the patient to specialists who typically treat RSD (either pain management or neurologist) and in these circumstances the failure to do so may constitute grounds for medical negligence. The most common reason why a patient may not be treated for RSD is because the healthcare provider not familiar with this disorder may instead consider the persistence of pain to be indicative of a psychiatric disorder, notably malingering or drug-seeking, and so may refuse to treat the pain, but instead may opt for psychiatric evaluation and use of psychiatric medications.