New Nigerian Journal of Clinical Research

CASE REPORT
Year
: 2020  |  Volume : 9  |  Issue : 16  |  Page : 91--93

Cervical spondylotic amyotrophy mimicking amyotrophic lateral sclerosis


S Sheetal, P Byju 
 Department of Neurology, Pushpagiri Institute of Medical Sciences and Research Centre, Thiruvalla, Kerala, India

Correspondence Address:
Dr. S Sheetal
16 FG, The Edge, Skyline Apartments, Thirumoolapuram, Thiruvalla - 689 115, Kerala
India

Abstract

Cervical spondylotic myelopathy refers to compressive myelopathy resulting from degenerative changes of the spine. Some patients present with “myelopathic hand” characterized by loss of motor strength, sensory changes, and spasticity. However, cervical spondylosis with muscle atrophy of the upper extremities without sensory disturbance or pyramidal signs is called cervical spondylotic amyotrophy. Cervical spondylotic amyotrophy is a rare condition, usually reported as unilateral disorder, though occasionally, it may be bilateral. Due to the gross wasting and absence of sensory signs, it may be mistakenly diagnosed as amyotrophic lateral sclerosis. Since cervical spondylotic amyotrophy is similar to motor neuron disease, and yet is treatable, it is important to recognize and treat this condition.



How to cite this article:
Sheetal S, Byju P. Cervical spondylotic amyotrophy mimicking amyotrophic lateral sclerosis.N Niger J Clin Res 2020;9:91-93


How to cite this URL:
Sheetal S, Byju P. Cervical spondylotic amyotrophy mimicking amyotrophic lateral sclerosis. N Niger J Clin Res [serial online] 2020 [cited 2021 Mar 7 ];9:91-93
Available from: https://www.mdcan-uath.org/text.asp?2020/9/16/91/301642


Full Text



 Introduction



The degenerative cascade occurring due to age-related changes in the spinal column is known as spondylosis. These spondylotic changes may result in direct compressive and ischemic dysfunction of the spinal cord known as cervical spondylotic myelopathy (CSM). Cervical spondylosis often manifests with spastic tetraparesis with varying degrees of sensory dysfunction. Myelopathy hand is a finding in patients with CSM in which loss of motor strength, sensory changes, and spasticity may dramatically decrease upper extremity function. However, cervical spondylotic amyotrophy is characterized with weakness and wasting of upper limb muscles, without spasticty.[1] Cervical spondylotic amyotrophy is classified into three types: proximal type (with atrophy of the deltoid, biceps, and triceps), distal type (with atrophy of the muscles of the forearm and intrinsic muscles of the hand), and diffuse type (with atrophy of both proximal and distal muscles). Brain et al. first reported cases of cervical spondylosis with muscle atrophy of the upper extremities without sensory disturbance or pyramidal signs.[2] Dr. Russell Brain recognized that patients in whom the diagnosis of motor neuron disease (amyotrophic lateral sclerosis) had been made were outliving their expected natural history, leading to the hypothesis that they must have another condition affecting the cervical cord, and Brain noticed the association with radiological abnormalities of the cervical spine. Since it is similar to the hand of a patient suffering from motor neuron disease, and yet is treatable, it is important to recognize and treat this condition. We hereby report the case of a 58-year-old male who presented to us with progressively increasing weakness and wasting of both upper limbs and weakness of both lower limbs for the past 4 years, resembling amyotrophic lateral sclerosis, who on evaluation was detected to have severe CSM.

 Case Report



A 58-year-old gentleman, a manual laborer, presented to us with a history of gradually progressive weakness of both upper and lower limbs for the past 4 years. His symptoms started around 4 years back, as repeated falls and difficulty in putting on footwear in both feet. Gradually, he started developing bucking of knees while walking. He had difficulty in climbing up and down the stairs and had difficulty in getting up from the toilet seat. Around 3–6 months later, he noticed that he had weakness of both upper limbs also. He had difficulty in making a bolus of food, tying his dhoti, tand urning keys with his hands. Over the past 2 years, he had noticed thinning of his right hand and forearm. He also noticed the twitching of his right forearm muscles. However, he had no paresthesias of the hands or feet.

On examination, he was conscious and well oriented. Cranial nerve examination was normal. Motor system examination revealed gross wasting of the intrinsic muscles of the right hand, right brachioradialis, biceps, triceps, and deltoid [Figure 1]. Extensive fasciculations were noted in the right forearm. Muscle bulk was normal in the left upper limb and both lower limbs. There was hypotonia in the right upper limb, with normal tone in the left upper limb. There was spasticity of both lower limbs. Right deltoid, infraspinatus, triceps, biceps, brachioradialis, and intrinsic muscles of the hand had MRC grade 3/5 power. There was grade 4/5 power in all muscle groups of the left upper limb and both the lower limbs. Deep tendon reflexes in the right upper limb, namely biceps jerk, triceps jerk, and supinator jerk were absent; however, these were exaggerated in the left upper limb. Bilateral knee jerk and ankle jerk were exaggerated. Plantars were bilaterally extensor. The sensory system examination was normal.{Figure 1}

The clinical examination comprising lower motor neuron (LMN) findings of right upper limb and upper motor neuron findings in the other limbs, without sensory symptoms, was suggestive of amyotrophic lateral sclerosis. Electromyography (EMG) done from the bilateral deltoid, triceps, first dorsal interossei, quadriceps, and tibialis anterior showed increased insertional activity, spontaneous activity in the form of fibrillations and fasciculations, and incomplete interference pattern (suggestive of a neurogenic pattern, consistent with amyotrophic lateral sclerosis). Magnetic resonance imaging of the cervical spine was taken since a close differential is cervical myelopathy and it showed marked spondylotic changes in the cervical vertebrae, with significant compression of the spinal cord at C3, C4, C5, and C6 levels [Figure 2] and [Figure 3]. Hence, the diagnosis of a cervical spondylotic amyotrophy was considered, and the patient was advised to undergo surgical intervention.{Figure 2}{Figure 3}

 Discussion



Cervical myelopathy encompasses a range of symptoms and examination findings including motor and sensory abnormalities related to dysfunction of the cervical spinal cord. The pathophysiology of CSM is now thought to be multifactorial with both static factors causing stenosis and dynamic factors resulting in repetitive injury to the spinal cord playing a role. The term “myelopathy hand” has been used to describe the spastic hand with sensory abnormalities in a patient with cervical compressive myelopathy.[3] There have been case reports of a different type of myelopathy hand characterized by muscle wasting and motor dysfunction in patients with cervical spondylosis. This type of myelopathy hand is termed “amyotrophic type of myelopathy hand.”[4] Amyotrophic lateral sclerosis can closely resemble cervical spondylotic amyotrophy. EMG also does not help in differentiating between the two. It may be difficult to distinguish the clinical manifestations during the early stages of the diseases. Evidence of upper motor neuron degeneration and progressive spread of symptoms and signs are required for the diagnosis of amyotrophic lateral sclerosis.

Different mechanisms have been proposed for the pathophysiology of cervical spondylotic amyotrophy.[5] Lebl et al. demonstrated that selective ventral motor root lesions are the cause in the pathogenesis of cervical spondylotic amyotrophy. Another mechanism proposed is vascular insufficiency to the anterior horn cell at the paramedian compression. Stagnant hypoxia secondary to venous congestion is another mechanism proposed.[5]

Cervical spondylotic amyotrophy is characterized by severe motor weakness and wasting in uni- or bilateral upper extremities that do not progress beyond a few myotomes.[6] Sensory loss and pyramidal signs are typically absent or insignificant. Cervical spondylotic amyotrophy is classified into three types: proximal type (with atrophy of the deltoid, biceps, and triceps), distal type (with atrophy of the muscles of the forearm and intrinsic muscles of the hand), and diffuse type (with atrophy of both proximal and distal muscles). Our patient had a diffuse type of cervical spondylotic amyotrophy. Cervical spondylotic amyotrophy follows a self-limited course. After an initial progressive course, the symptoms usually stabilize for years.[7]

This must be differentiated from Hirayama disease. Hirayama's disease is a very rare variant of amyotrophic lateral sclerosis where the hallmark of diagnosis is the involvement of a single limb with LMN features which are more common in distal muscles than proximal muscles.[8] It is a kind of cervical myelopathy related to flexion movement of the neck. Its characteristic is that it progresses for only 2–4 years and then achieves a plateau with spontaneous stabilization.

To conclude, cervical spondylotic amyotrophy is a rare entity characterized by weakness and atrophy of proximal (scapular, deltoid, and biceps) or distal (forearm and hand) upper extremity muscles, with no sensory deficits.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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