The MG-QOL15 for following the health-related quality of life of patients with myasthenia gravis

The MG-QOL15 is helpful in informing the clinician about the patient's perception of the extent of and dissatisfaction with myasthenia gravis (MG)-related dysfunction. The aims of this study were to determine the usefulness of the MG-QOL15 for following individuals with MG and to guide clinical researchers who plan to use the MG-QOL15. We assessed sensitivity and specificity for detecting clinical change and evaluated test-retest reliability. Sensitivities and specificities of various cut-points of change in scores are presented. Also presented are means and standard deviations of MG-QOL15 scores for all patients and for subgroups of patients. The test-retest reliability coefficient was 98.6%. The MG-QOL15 has an acceptable longitudinal construct validity. We consider this instrument to be most useful for informing the clinician about the patient's perception and tolerance of MG-related dysfunction. More objective measures, such as the MG Composite, should also be used to follow disease severity.

The MG Composite: A valid and reliable outcome measure for myasthenia gravis

OBJECTIVE

To study the concurrent and construct validity and test-retest reliability in the practice setting of an outcome measure for myasthenia gravis (MG).

METHODS

Eleven centers participated in the validation study of the Myasthenia Gravis Composite (MGC) scale. Patients with MG were evaluated at 2 consecutive visits. Concurrent and construct validities of the MGC were assessed by evaluating MGC scores in the context of other MG-specific outcome measures. We used numerous potential indicators of clinical improvement to assess the sensitivity and specificity of the MGC for detecting clinical improvement. Test-retest reliability was performed on patients at the University of Virginia.

RESULTS

A total of 175 patients with MG were enrolled at 11 sites from July 1, 2008, to January 31, 2009. A total of 151 patients were seen in follow-up. Total MGC scores showed excellent concurrent validity with other MG-specific scales. Analyses of sensitivities and specificities of the MGC revealed that a 3-point improvement in total MGC score was optimal for signifying clinical improvement. A 3-point improvement in the MGC also appears to represent a meaningful improvement to most patients, as indicated by improved 15-item myasthenia gravis quality of life scale (MG-QOL15) scores. The psychometric properties were no better for an individualized subscore made up of the 2 functional domains that the patient identified as most important to treat. The test-retest reliability coefficient of the MGC was 98%, with a lower 95% confidence interval of 97%, indicating excellent test-retest reliability.

CONCLUSIONS

The Myasthenia Gravis Composite is a reliable and valid instrument for measuring clinical status of patients with myasthenia gravis in the practice setting and in clinical trials.

Construct and concurrent validation of the MG-QOL15 in the practice setting

Health-related quality of life (HRQOL) estimates can play an important role in patient care by providing information about the patient's perception of impairment and disability and the degree to which the patient tolerates disease manifestations. The 15-item myasthenia gravis quality of life scale (MG-QOL15) is an HRQOL evaluative instrument specific to patients with myasthenia gravis (MG) that was designed to be easy to administer and interpret. In this multicenter study we demonstrate the construct validity of the MG-QOL15 in the practice setting. To assess the construct validity, score distributions were examined for test items in different MG patient groups that represent the clinical spectrum of the disease. For example, patients in remission more frequently scored test items as normal than did patients in other groups. Patients with lower (better) MG composite scores also more frequently scored items as normal than did patients with higher (worse) scores. There was also appropriate correlation between the MG-QOL15 and the other MG-specific scales studied. The study findings shed light on what troubles MG patients. The MG-QOL15 has construct validity in the clinical practice setting and represents an efficient and valuable tool for assessing HRQOL for patients with MG.

Neuroleukemiosis: case report of leukemic nerve infiltration in acute lymphoblastic leukemia

We describe a patient in remission from acute lymphoblastic leukemia who developed a painless common peroneal neuropathy. Magnetic resonance imaging (MRI) revealed nerve thickening and enhancement, while a positron emission tomography (PET) scan demonstrated increased fluorodeoxyglucose uptake in a large segment of the neurovascular bundle, suggesting peripheral nerve infiltration. Both findings resolved following treatment with chemotherapy that crossed the blood-nerve barrier. In selected patients presenting with peripheral neuropathy, MRI and PET scan can be helpful in the diagnosis of peripheral nerve infiltration.

Less is more, or almost as much: a 15-item quality-of-life instrument for myasthenia gravis

We describe the process whereby a recently developed myasthenia gravis (MG)-specific quality-of-life (QOL) instrument was reduced from 60 items to 15 items while maintaining potential usefulness in the clinic and in prospective treatment trials. In data from a recently completed prospective trial of mycophenolate mofetil (MMF) in MG, the MG-QOL15 correlated as highly as the 60-item MG-QOL for physical and social domains of the 36-item health survey of the Medical Outcomes Study Short Form (SF-36). Correlation coefficients for the MG-QOL15 were similar to the 60-item MG-QOL for the Quantitative Myasthenia Gravis (QMG), MG-specific Manual Muscle Testing (MG-MMT), and the MG-specific Activities of Daily Living (MG-ADL) scores at week 0 and for change in scores from week 0 to week 12 in the MMF trial. Using the physician global impression at week 12 of the trial as the "gold standard," the MG-QOL15 demonstrated high sensitivity. Because the MG-QOL15 instrument can be quickly and easily administered and interpreted, it is a potential QOL measure for treatment trials and the clinical evaluation of patients with MG.

Guillain-Barré syndrome

Guillain-Barré syndrome (GBS) is an acute-onset, monophasic, immune-mediated polyneuropathy that often follows an antecedent infection. The diagnosis relies heavily on the clinical impression obtained from the history and examination, although cerebrospinal fluid analysis and electrodiagnostic testing usually provide evidence supportive of the diagnosis. The clinician must also be familiar with mimics and variants to promptly and efficiently reach an accurate diagnosis. Intravenous immunoglobulin and plasma exchange are efficacious treatments. Supportive care during and following hospitalization is also crucial.

The evaluation of chronic axonal polyneuropathies

In this article, we present an easy-to-remember method of evaluating neuropathies. Our proposed method is based on asking four questions about the neuropathy and the patient: "What?," "Where?," "When?," and "What setting?" Answering these questions helps characterize the neuropathy, and this characterization enables the clinician to develop a focused differential diagnosis and plan. After presenting this approach to evaluating neuropathy, we discuss many of the most common chronic axonal neuropathies in the context of this paradigm. Acquired demyelinating neuropathies and inherited neuropathies are discussed in other articles in this issue of SEMINARS IN NEUROLOGY.

Stiff-person syndrome

Classic stiff-person syndrome (SPS) is a clinically diagnosed disease characterized by axial and often appendicular rigidity with lumbar hyperlordosis and painful spasms. Supportive data include increased glutamic acid decarboxylase autoantibody titers more than 20 nmol/L, a needle electromyography with continuous motor unit activity in at least one axial muscle, and normal MRI and cerebrospinal fluid studies. Variants of SPS include those with focal limb dysfunction (stiff-limb syndrome), encephalomyelitis ("SPS plus"), and those associated with paraneoplastic autoantibodies. Although the precise mechanism is unknown, an autoimmune etiology for SPS is proposed, based on its association with autoantibodies and other autoimmune diseases and its response to immunomodulatory therapy. The cornerstone of treatment consists of symptomatic care with benzodiazepines and/or baclofen. Other neuromodulators include antiepileptic medications and muscle relaxants. Continued disability despite first-line therapy should prompt consideration of agents aimed at immunomodulation and immunosuppression. Intravenous immunoglobulin is one of the few agents to be evaluated in a double-blind, randomized controlled trial. Other options include steroids, plasma exchange, and chemotherapy agents.

Fatal encephalitis in a patient with refractory celiac disease presenting with myorhythmia and carpal spasm

We report the case of a woman with refractory celiac disease who developed abnormal spontaneous movements of the extremities and face consistent with myorhythmia. Investigation led to a diagnosis of encephalitis, confirmed by postmortem examination. The movements were likely caused by nonparaneoplastic encephalitis associated with refractory celiac disease. Etiologic and diagnostic considerations and treatment options are discussed.

Vasculitic Neuropathies

The classification of vasculitis and the clinical features of vasculitic neuropathy are reviewed. Vasculitic neuropathy usually presents with painful mononeuropathies or an asymmetric polyneuropathy of acute or subacute onset. Neurologists should categorize vasculitic neuropathy in terms of clinical features (eg, systemic or non systemic) and in terms of histopathology (eg, nerve large arteriole vasculitis or nerve microvasculitis). Systemic vasculitis should be classified further into one of the primary and secondary forms. Steroids and cytotoxic agents have been the mainstay of therapy for most forms of vasculitic neuropathy. Dosing, potential side effects, and management recommendations of conventional therapies are provided.

Novel myelin protein zero mutation (Arg36Trp) in a patient with acute onset painful neuropathy

We present a patient with acute onset painful polyneuropathy found to have a novel MPZ mutation (Arg36Trp). The Arg36Trp mutation described in this report occurs at a putative adhesion interface. An alternative explanation for his polyneuropathy was not found and his mother was identified to have polyneuropathy and carry the same mutation. Two hundred normal controls were without this base alteration. The temporal profile of the index case may provide further indirect evidence suggesting an immune mechanism contributing to the pathogenesis of some cases of MPZ mutations. We predict that other rapid symptom onset polyneuropathies will be found to have direct genetic susceptibility.

The natural history and long-term outcome of 57 limb sarcoidosis neuropathy cases

Fifty-seven patients with biopsy-proven sarcoidosis causing limb neuropathy were reviewed in order to delineate the characteristic symptoms, impairments, disability, course, outcome and response to corticosteroid treatment of limb sarcoid neuropathy. Typically the neuropathy had a definite date of symptomatic onset. Prominent were positive neuropathic sensory symptoms (P-NSS), especially pain, overshadowing weakness and sensory loss. P-NSS were the main cause of disability. Almost always the pattern was asymmetric and not length-dependent (unlike distal polyneuropathy). We inferred (from kind and distribution of symptoms, signs and electrophysiologic and other test results) that the pathologic process was focal or multifocal, involving most classes of nerve fibers and variable levels of proximal to distal levels of roots and peripheral nerves. Additional features aiding in diagnosis were: systemic symptoms such as fatigue, malaise, arthralgia, fever and weight loss; involvement of multiple tissues (i.e. skin, lymph nodes and eye); the patterns of neuropathy; MRI features; and ultimately tissue diagnosis. Axonal degeneration predominated, although an acquired demyelinating process was observed in 3 patients. For most cases, the disease had a chronic, monophasic course. MRI studies done in later years of affected neural structures were helpful in identifying leptomeningeal thickening, hilar adenopathy; and enlargement and T2 enhancement of nerve roots, plexuses, and limb nerves. Corticosteroid treatment appeared to ameliorate symptoms more than impairments. Several variables were associated with neuropathic improvement: CSF pleocytosis, short duration between symptom onset and treatment, and a higher grade of disability at first evaluation-a possible rationale for future earlier diagnosis and treatment.