Learning to use


A 16 April 2009 New England Journal of Medicine case described a 46-year-old man with migraine, aphasia, and hemiparesis and similarly affected family members :

The patient had been well, except for migraine headaches, until 4 years earlier, when right-sided weakness, clumsiness, and slurred speech developed during a period of 24 hours. A neurologist at another hospital found dysarthria and right central facial weakness; decreased muscle tone in the right arm, with strength 4+/5; and normal muscle tone in the right leg, with strength 4+/5. Strength on the left side was normal, with slightly increased tone in the left arm and normal tone in the left leg. Reflexes were brisker on the right side than on the left, with an extensor plantar response on the right and a flexor plantar response on the left. Computed tomography (CT) of the brain after the administration of contrast material showed numerous nonenhancing, hypodense lesions in the bilateral basal ganglia and deep white matter.

He developed dysphagia, and symptoms worsened with recurrent exacerbations and worsening seen on MRI scans.  He was treated with interferon beta-1a and steroids and seen at Massachusetts General Hospital for a fifth opinion.  Two brothers had similar symptoms and carried a diagnosis of multiple sclerosis.  A variety of lab tests were normal or inconclusive, including the absence of CSF oligoclonal bands.

Below is the Diagnose screen in the SimulConsult Phenome analyzer with the pertinent positive and pertinent negative findings from the article. The diagnosis of CADASIL is suggested as having high probability. As expected, clicking on the Add tests tab would rank highest checking the NOTCH3 gene, which was abnormal.

Differential diagnosis screen

Subscribers to the software can load the findings in this case by opening the software and then clicking the share icon at the right of the toolbar and adding the following patient string:


The Assess Diagnosis screen shows how CADASIL is a good fit for this patient. Similar screens for other diseases in the differential diagnosis show that the fit for other diseases is not nearly as good.

Assess diagnosis screen