Upper limb reflex sympathetic dystrophy associated with occult malignancy

Complex Regional Pain Syndrome in Cancer Cases: Current Knowledge and Perspectives

Background

Complex regional pain syndrome (CRPS) is a disabling painful disorder caused by many different and poorly understood mechanisms. It often affects the distal limbs and usually happens as consequence of a trauma. Its severity can remarkably affect patients' quality of life. When this painful complication happens in a cancer patient, the impact may be exponential. To date, there is limited knowledge of the surrounding circumstances of CRPS cases in this population.

Methods

We present two clinical cases of patients diagnosed with cancer-related pain presenting with symptoms and signs compatible with CRPS. In one case, CRPS was attributed to direct tumor nerve compression, and it responded successfully to an interventional pain procedure. The second case was associated with a Zoster infection in an immunocompromised cancer patient. Patient responded to multidisciplinary pain management strategies. Additionally, we conducted a literature review to investigate the coexistence of cancer pain and CRPS and suggest some pathophysiology mechanisms of action.

Results and Discussion

Literature reviewed and potential pathophysiology mechanisms are simultaneously explored in terms of classification, etiopathology, evidence, challenges, and future scientific directions.

Conclusion

Comorbid CRPS can impact negatively in cases of cancer pain by affecting their diagnosis and treatment. Further studies are necessary to elucidate how these two conditions present together and how they can be better addressed.

Underlying Adenocarcinoma of the Lung Metastasizing to the Proximal Phalanx of the Foot Causing Complex Regional Pain SyndromeA Case Report

We report an unusual case of adenocarcinoma of the lung metastasizing to the proximal phalanx of the third digit in a 56-year-old woman with overlying complex regional pain syndrome. The patient was initially treated for neuroma, fracture, and neuropathic pain with no improvement over a 4-month period before presenting to the emergency department for left third digit pain. Radiographic imaging showed substantial osteopenia and mottling; magnetic resonance imaging demonstrated an aggressive lesion to the proximal phalanx. The patient underwent excision of the lesion, revealing metastatic moderately differentiated adenocarcinoma.

The clinical relevance of complex regional pain syndrome type I: The Emperor's New Clothes

The management of patients with chronic pain is a nearly daily challenge to rheumatologists, neurologists, orthopedic surgeons, pain specialists and indeed a issue in nearly every clinical practice. Among the myriad of causes of pain are often included a unique syndrome, generally referred to as complex regional pain syndrome type I (CRPS). Unfortunately CRPS I has become a catch all phase and there are serious questions on whether it exists at all; this has led to an extraordinary number of poorly defined diagnostic criteria. It has also led to an etiologic quagmire that includes features as diverse as autoimmunity to simple trauma. These, in turn, have led to overdiagnosis and often overzealous use of pain medications, including narcotics. In a previous paper, we raised the issue of whether CRPS type I reflected a valid diagnosis. Indeed, the diagnostic criteria for CRPS I, and therefore the diagnosis itself, is unreliable for a number of reasons: 1) the underlying pathophysiology of the signs and symptoms of CPRS I are not biologically plausible; 2) there are no consistent laboratory or imaging testing available; 3) the signs and symptoms fluctuate over time without a medical explanation; 4) the definitions of most studies are derived from statistical analysis with little consideration to required sample size, i.e. power calculations; 5) interobserver reliability in the assessment of the signs and symptoms are often only fair to moderate, and agreement on the diagnosis of "CRPS I" is poor. Even physicians who still believe in the concept of "CRPS I" admit that it is vastly overdiagnosed and has become a diagnosis of last resort, often without a complete differential diagnosis and an alternative explanation. Finally, one of the most convincing arguments that there is no clinical entity as "CRPS I" comes from the enormous heterogeneity in sign and symptom profiles and the heterogeneity of pathophysiological mechanisms postulated. This observation is underscored by the diversity of responses among "CRPS I" patients to essentially all treatment modalities. It has even led to the concept that the signs and symptoms of CRPS can spread throughout the body, as if it is an infectious disease, without any medical plausible explanation. If true progress is to be made in helping patients with pain, it will require entirely new and different concepts and abandoning CRPS I as a legitimate diagnosis.

The Challenge to Manage Reflex Sympathetic Dystrophy/Complex Regional Pain Syndrome

The challenge to understand reflex sympathetic dystrophy/complex regional pain syndrome may require a better understanding of the complex relationship between the central and peripheral nervous systems. There is no comprehensive hypothesis that clearly explains the etiology and no uniformly successful treatment method. This brief summary of the challenge reviews some of what is known, hypothesizes a possible etiologic mechanism, and proposes 10 common-sense principles for management that recognizes the handicap of limited knowledge.

Rheumatic syndromes associated with malignancy

The relation between rheumatic syndromes and an underlying malignancy is a complex one. As a result of autoimmunity, an aberrant immune response, or the use of immunomodulatory drugs, many of the rheumatic diseases appear to pose an increased risk for the development of malignancy. Unfortunately, for many of the same reasons, the presence of an underlying malignancy can result in the development of features of rheumatic disease. Awareness of the associations between rheumatic syndromes and malignancy will aid the clinician in the accurate diagnosis of underlying pathology, more effective treatment of both the symptoms and underlying disease, and appropriate surveillance for the development of later complications.

Complex regional pain syndrome type I in cancer patients

Complex regional pain syndrome type I (CRPS-I) is infrequently associated with various malignancies, and may lead to severe pain in already debilitated patients. The causal relationship between CRPS-I and paraneoplastic syndrome, controversies in diagnosis and treatment, and new treatment modalities are presented.