The Team-Based Approach to Undiagnosed and Rare Diseases.

Patients with undiagnosed or rare diseases often remain without a diagnosis for many years. Many are misdiagnosed or treated symptomatically without having an identified underlying disease process. Health care providers in general practice and subspecialists are equipped to diagnose diseases commonly seen. Most practitioners are unlikely to be familiar with uncommon manifestations of a common disorder and have little or no experience with rare diseases. Multidisciplinary teams are effective in reviewing patients with undiagnosed and rare diseases and in developing a new diagnostic strategy for appropriate evaluation. A medical librarian and an access coordinating navigator are essential members of the team.

Evaluation of the child with acute ataxia: a systematic review.

Evaluation of acute ataxia in a child poses a dilemma for the clinician in determining the extent and timing of initial screening tests. This article reviews the evidence concerning the diagnostic yield of commonly ordered tests in evaluating the child with acute ataxia. The literature revealed the following frequencies of laboratory screening abnormalities in children with acute ataxia: CT (∼2.5%), MRI (∼5%), lumbar puncture (43%), EEG (42%), and toxicology (49%). In most studies, abnormalities detected by these screening tests were nondiagnostic. There are insufficient data to assess yields of testing for autoimmune disorders or inborn errors of metabolism. A toxicology screen should be considered in all children presenting with acute ataxia. Neuroimaging should be considered in all children with new onset ataxia. Cerebrospinal fluid analysis has limited diagnostic specificity unless clinically indicated. Studies to examine neurophysiology testing did have sufficient evidence to support their use. There is insufficient evidence to establish a role for autoantibody testing or for routine screening for inborn error of metabolism in children presenting with acute ataxia. Finally, in a child presenting with ataxia and opsoclonus myoclonus, urine catecholamine testing for occult neuroblastoma is recommended. Nuclear scan may be considered, however, there is insufficient evidence for additional body imaging.