Juvenile amyotrophic lateral sclerosis: Classical wine glass sign on magnetic resonance imaging.

Amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig disease, is a chronic degenerative neurologic disease and is characterized by the selective involvement of the motor system. Usually, patients present with upper motor neuron (UMN) and lower motor neuron compromise. Degeneration of the UMN in the cerebral cortex is one of the main pathologic changes in ALS. These changes usually affect corticospinal tracts leading to degeneration of the fibers which show characteristic hyperintensities along the tracts leading to the "wine glass sign." Patients with ALS usually present in the sixth decade of life; presentation in pediatric age in the form of juvenile ALS being rare.

Introduction

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease which affects both motor function and extramotor systems. According to the revised El Escorial criteria for the diagnosis of ALS, the presence of signs for the affection of both upper motor neurons (UMNs) in the primary motor cortex and lower motor neurons (LMNs) in brainstem and spinal cord is mandatory, and the disease must be progressive.[1] Because of varied clinical phenotypes of ALS, it is difficult to differentiate it from other ALS-mimicking conditions. Electromyography can be used for the detection of LMN involvement in addition to the clinical examination. On the other hand, UMN signs must be visible at the clinical examination while electrophysiological transcranial motor stimulation abnormalities are not included in making the diagnosis of ALS according to the El Escorial criteria. Magnetic resonance imaging (MRI) is the radiological investigation of choice with the recent advances of diffusion tensor imaging, presenting a promising technique for early detection of alterations in the motor cortex and pyramidal tracts.

Case Report

Herein, we report a case of a 9-year-old male who presented to the department of neurology with complaints of progressive increase in weakness of bilateral lower limb, poor grip in bilateral upper limb, and difficulty in walking since last 2 years. There was no history of any muscle pain, trauma, fever, recent vaccination, dog bite, respiratory tract or gastrointestinal tract infection. Physical examination demonstrated decreased power in the bilateral lower limb (3/5 in the right lower limb and 2/5 in the left lower limb) and upper limb (4/5 in the right hand and 4/5 in the left hand), no signs of dermal rashes, or hypertrophy of muscles. Muscles were found to be atrophied with exaggerated tendon reflexes and fasciculations. Laboratory findings including serum creatinine phosphokinase were within normal limits. No obvious pathological findings could be documented on plain computed tomography of the brain. MRI of the brain was performed using 1.5 Tesla scanner (GE Signa Excite, USA). T2-weighted imaging and additional fluid attenuating inversion recovery sequence showed hyperintense signals in the posterior limb of internal capsule [Figure 1a and b] involving corticospinal tract (CST) which was found to extending up to midbrain. The coronal images showed classical wine glass sign [Figure 1c].

Figure 1

(a) T1-weighted imaging, black arrow shows hyperintensity in the posterior limb of internal capsule (b) T2-weighted imaging, black arrow shows hyperintensity in the posterior limb of bilateral internal capsule (c) T2-weighted imaging, black arrow shows hyperintensity in the posterior bilateral internal capsule and midbrain (corticospinal tract) with classical wine glass appearance

Discussion

Areas of abnormal signal intensity on T1- and T2-weighted images in the CST have been previously reported in patients with ALS.[23456] Other diseases such as ischemic processes, demyelinating diseases, and infections may involve the pyramidal tracts. However, bilateral symmetrical involvement associated with the characteristic clinical findings clinches the diagnosis of ALS.

The diagnosis of ALS was previously based only on clinical and electromyographic data. The degeneration of motor neurons may result in a cellular loss and axonal edema as previously shown on electronic microscopy.[7] So far, imaging methods had been of limited use because of their unsatisfactory results. Approximately, 90% of ALS are sporadic with 10% having familial predisposition, but majority of the cases of juvenile ALS (JALS) are familial.[1] About 20% of families with familial ALS carry mutation in superoxide dismutase gene 1.[8] Most of the JALS are autosomal recessive, though autosomal dominant inheritance patterns have been described.[9] Recessive forms of JALS have been mapped to chromosome regions 2q33 and 15q12-21.[10] Genetic linkage to the chromosome 9q34 region is seen in the dominantly inherited form. No effective treatment for the disease have been found till date, though thyrotropin-releasing hormone, ganglioside therapy, and plasmapheresis have been tried in adults without much benefit.[19] JALS is a diagnosis that should be suspected in a child presenting with a combination of UMN and LMN signs. MRI facilitates reaching the correct diagnosis by showing the typical involvement of the CST and the wine glass appearance.

Conclusion

JALS is an uncommon disease of the pediatric age group. MRI plays as an important diagnostic tool for reaching up to a diagnosis and for prognosticating the disease.

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Conflicts of interest

There are no conflicts of interest.