Never Trust a Normal MRI

Case Study: A 16-year-old boy was admitted because of throbbing headache on the right frontal side with additional transient loss of speech and impaired function of the left leg 4 hours before. On admission, neurological investigation was completely normal. He never had headaches before. Because of an additional positive familial anamnesis (mother with migraine), a first migraine attack was supposed. Because of the focal neurological signs, a prompt MRI was performed without any pathological findings.

Six hours later, the patient developed central paresis of the left facial nerve, hemiparesis on the left arm and leg, and a clipped speech without headache. Despite the quite recently normal MRI, we repeated this investigation and found a lacunar infarction of the crus poster of the capsula interna and the ventrolateral part of the thalamus. We started a therapy with ASS and the neurological symptoms disappeared completely within one week. A thorough work-up revealed a heterozygous factor V Leiden mutation (G1691A). The fluctuation of the neurological deficits can be considered rather typical for lacunar infarction.

We recommended the continuous prophylaxis of further thrombotic complications with 100 mg ASS p.o. daily for the next 3 years. The patient currently 1 year later is in well condition and did not have had any other migraine attacks, strokes, or other neurological symptoms. At follow-up, neurophysiological tests showed a normal intelligence and executive functions.

Again, this patient demonstrates the significance of clinical findings. Many patients as well as physicians rather count on laboratory findings and technical investigations but in some instances these tests might be misleading and patients profit from the good feeling of their doctors.

Keywords: migraine attack, hemiparesis, MRI, fluctuation of neurological symptoms, stroke.