CASE REPORT
Nagoya J. Med. Sci. 83. 877–881, 2021
doi:10.18999/nagjms.83.4.877

Amyotrophic lateral sclerosis mimicking radiculopathy:
a case series
Soyoung Kwak1, Du Hwan Kim2, Mathieu Boudier-Revéret3
and Min Cheol Chang1
Department of Physical Medicine and Rehabilitation, College of Medicine Yeungnam University, Daegu,
Republic of Korea
Department of Physical Medicine and Rehabilitation, College of Medicine, Chung-Ang University, Seoul,
Republic of Korea
3
Department of Physical Medicine and Rehabilitation, Centre Hospitalier de l’Université de Montréal, Montreal, Canada12ABSTRACT
The clinical findings of early stage amyotrophic lateral sclerosis (ALS) are similar to those of cervical or
lumbar radiculopathy. In the current study, we describe 3 cases of ALS that were misdiagnosed as cervicalor lumbar radiculopathy. Three patients (a 48-, a 52-, and an 80-year-old) visited our clinic due to motor
weakness on either the upper or lower extremities. At other clinics or hospitals, they were diagnosed withradiculopathy due to herniated lumbar disc or cervical foraminal stenosis. The motor weakness in thesepatients was ipsilateral or bilateral but dominant on one side. Sensory deficits or bulbar symptoms werenot observed. Of the 3 patients, 2 had neuropathic pain, but it was not dermatome related. We conducted
an electrodiagnostic test and observed a low amplitude of compound motor action potential on the affected nerve and positive sharp waves on muscles of involved segments, including thoracic paraspinalis.
All the patients were diagnosed with probable laboratory-supported ALS or possible ALS based on theestablished diagnostic criteria (El Escorial Criteria). In the present study, we showed three cases of ALS
that were misdiagnosed as radiculopathy. Our study would be helpful for early and accurate diagnosis ofpatients with ALS.
Keywords: amyotrophic lateral sclerosis, mimic disorder, pain clinic, radiculopathy
Abbreviations:
ALS: amyotrophic lateral sclerosis
NRS: numeric rating scale
MRI: magnetic resonance imaging
CMAP: compound motor action potential
SNAP: sensory nerve action potentials
NCS: nerve conduction study
This is an Open Access article distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
License. To view the details of this license, please visit (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Received: December 23, 2020; accepted: March 10, 2021
Corresponding Author: Min Cheol Chang, MD
Department of Physical Medicine and Rehabilitation, College of Medicine, Yeungnam University,
317-1 Daemyungdong, Namku, Daegu 705-717, Republic of Korea
Tel: +82-53-620-4682, E-mail: wheel633@ynu.ac.kr
877

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INTRODUCTION
Amyotrophic lateral sclerosis (ALS), the most common motor neuron disease, is a progressive
and devastating neurodegenerative disorder.1 About 90% of ALS cases are sporadic, without afamily history. The incidence of sporadic ALS is reported to be 1.89 per 100,000/year, and it isestimated that the general risk of ALS for a lifetime is 1:400 for women and 1:350 for men.1
The risk of developing ALS peaks between the ages of 50 and 75 years.2 It involves both theupper and lower motor neuron systems and has high morbidity and mortality.
ALS is diagnosed on the basis of the patients’ clinical features and the results of an electrodiagnostic test. When patients present with bilateral motor weakness, the diagnostic accuracy isabout 95%, but it reduces to 38% in patients with unilateral motor weakness.3 Previous studies
reported that ALS can be misdiagnosed because several neurological disorders have similar
clinical presentations as ALS. Therefore, it is imperative to consider all possible disorders that
can have similar manifestations before confirming the diagnosis of ALS.4
At pain clinics, pain physicians frequently encounter patients with motor weakness because it
often accompanies neuropathic pain.5 Although not frequent, ALS patients occasionally visit pain
clinics without being diagnosed. In pain clinics, ALS can be easily missed or misdiagnosed asanother disorder because pain physicians tend to consider only compressive neural disorders as
differential diagnosis for motor weakness.
In the current study, we presented our experience from a pain clinic where ALS was misdiagnosed as cervical or lumbar radiculopathy. The study protocol was approved by the Institutional
Review Board of a university hospital.

CASE REPORT
Case 1
A 48-year-old woman visited the pain clinic of our university hospital for motor weakness
in the right lower extremity. Her weakness started 1 year ago and had slowly progressed. Theweakness began at the right distal lower limb (ankle and toe dorsiflexors or plantar flexors) andprogressed to the proximal muscles of the right lower limb. Additionally, she had slight pain ofa tingling nature [numeric rating scale (NRS): 1] in the entire right lower extremity, which was
not dermatome related. Prior to visiting our clinic, the patient had visited several clinics with thesame symptoms and had been diagnosed with right L5 and S1 radiculopathy due to a herniatedlumbar disc by clinicians. On lumbar spine magnetic resonance imaging (MRI), a central protrusion on L4-5 and a central extrusion on L5-S1 were observed (Fig. 1a). Cervical and thoracic
spine MRI and brain MRI showed no abnormal lesions. The patient received repeated right L5and S1 selective nerve root injection with corticosteroid, but her symptoms did not improve.
Physical examination at our hospital revealed that her motor strength was 3/5 for her right hip
flexor, knee extensor, and plantar flexor and 0/5 for her right ankle dorsiflexor and extensor
hallucis longus on the Medical Research Council (MRC) scale for muscle strength. Moreover,
we observed that the patient’s left ankle dorsiflexor and extensor hallucis longus were mildly
weakened (4/5 on MRC), but she had not noticed it. No sensory deficits or bulbar symptoms
were observed. Bilateral biceps, triceps, knee, and ankle reflexes were normal. Mild atropy andfasciculation in the right calf muscles were obaserved. Compound motor action potential (CMAP)
showed no response for the right peroneal nerve and decreased amplitudes for the right tibialand left peroneal nerves during the electrophysiological examination. The sensory nerve action
potentials (SNAPs) of the bilateral superficial peroneal and sural nerves were normal. Nerve

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Fig. 1 Spine magnetic resonance imaging (MRI) findings of the 3 included patients
Fig. 1a (case1): On lumbar spine axial MRI, an L4-5 central protrusion (left) and L5-S1 central extrusion(right) are observed.
Fig. 1b (case2): On lumbar spine axial MRI, L4-5 diffuse bulging discs are observed.
Fig. 1c (case3): On cervical spine axial MRI, bilateral C7-T1 foraminal stenoses are observed.

conduction studies (NCSs) performed on the upper extremities were normal. On electromyography,
positive sharp waves (2+~3+) were observed in the bilateral thoracic and lumbar paraspinalis andbilateral lower extremity muscles, including bilateral biceps femoris, tibialis anterior, peroneus
longus, tensor fascia latae, gastrocnemius, and right vastus medialis. On follow-up at 6 months
after the first visit to our department, the bilateral knee and ankle reflexes had increased. The
patient was diagnosed with probable laboratory-supported ALS based on the established diagnostic
criteria (El Escorial Criteria).6 Her neuropathic pain in the entire right lower extremity was also
considered as ALS-related.
Case 2A 52-year-old man visited our pain clinic for weakness and pain in the entire right lower
extremity, which was not dermatome related (dull nature, NRS: 2). His symptoms began 6 months
ago and slowly became aggravated. At another university hospital, he was diagnosed with rightL5 and S1 radiculopathy. On lumbar MRI, diffuse bulging discs were observed on L4-5 (Fig.
1b). Cervical and thoracic MRI and brain MRI showed no abnormality related to the patient’ssymptoms. On physical examination in our clinic, the motor strength of the right ankle dorsiflexor,
ankle plantarflexor, and extensor hallucis longus was MRC 2/5. No sensory deficits and bulbar
symptoms were observed. Bilateral biceps, triceps, knee, and ankle reflexes were normal. Also,
mild atrophy was observed in his right calf muscles, but fasciculation was not found. On theNCS performed in our clinic, CMAP of the right peroneal nerve showed no response, and that of
the right tibial nerve showed low amplitude. The NCS studies of the bilateral upper extremities

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and the left lower extremity were normal. On electromyography, positive sharp waves (2+~3+)
were observed in the bilateral lumbar and thoracic paraspinalis, tibialis anterior, and peroneus
longus. On follow-up at 6 months after the first visit to our department, the muscle tones ofthe bilateral lower limbs had increased. Bialteral biceps and triceps reflexes were normal, butbilateral knee and ankle reflexes had increased. Based on the established diagnostic criteria, wediagnosed him with probable laboratory-supported ALS. Additionally, his pain in the entire rightlower extremity was considered as ALS-related.
Case 3
An 80-year-old man visited our clinic for slowly progressive left distal upper extremity pain
for 8 months without pain. In the previous hospital, he was diagnosed with left C8 radiculopathy
due to C7-T1 foraminal stenosis. On the cervical MRI, foraminal stenosis on bilateral C3-4,C4-5, and C7-T1 was observed (Fig. 1c). On physical examination, his left finger flexor andwrist extensor were MRC 4/5, and sensory deficit was not observed. Bulbar symptoms were alsoabsent. Bilateral biceps, triceps, knee, and ankle reflexes were normal. Slight muscle atrophy wasobserved in the left intrinsic hand muscles. On the other hand, fasciculation and split hand sign
were not observed. On the NCS in our hospital, CMAP of the left median and ulnar nerves
showed low amplitude but that of the right upper and bilateral lower extremities were normal. On
electromyography, positive sharp waves (1+~2+) were observed in the left cervical paraspinalis,
flexor carpi radialis, abductor pollicis brevis, abductor digiti minimi, 1st dorsal interossei, andbilateral thoracic paraspinalis and genioglossus. On follow-up at 6 months after the first visit toour department, the deep tendon reflexes of the bilateral upper limbs and the muscle tones ofthe bilateral upper limbs and trunk had increased. Based on the established diagnostic criteria,
we diagnosed him with possible ALS.

DISCUSSION
In the current study, we presented 3 cases of ALS that were misdiagnosed as cervical or
lumbar radiculopathies.
Early stage ALS and cervical or lumbar radiculopathy have similar clinical presentations. ALS
is characterized by the loss of anterior horn cells.1 When anterior horn cells are involved only
in one or two segments in the early stage of ALS, it can be misdiagnosed as a radiculopathy
due to herniated disc or spinal stenosis, which occurred in our patients who were misdiagnosed
with lumbar or cervical radiculopathies.4,7 Electrodiagnostic examination has an important rolein the diagnoses of ALS and radiculopathy, but its results cannot distinguish between them inthe early stage of ALS, where it can present as a radiculopathy.7However, in the case of radiculopathy, the nerve roots are involved, which can produce bothmotor and sensory symptoms, and neuropathic pain can develop along the distribution of thecorresponding dermatomes.8,9 In contrast, ALS involves the anterior horn cells, affecting only motor fibers; therefore, sensory symptoms are not presented and neuropathic pain does not develop
along the dermatome.1 Hence, when pain physicians observe a patient who has motor weakness
likely induced by radiculopathy without sensory symptoms, dermatomal neuropathic pain, orcorresponding imaging findings, they should consider the possibility of ALS. Also, The incidenceof asymptomatic MRI findings of spinal stenosis and herniated discs is high.10 Accordingly, if
the patients’ radiculopathy symptoms are atypical, it is necessary to distinguish ALS throughdetailed examination and observation, although related lesions may be found on imaging studies.

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CONCLUSION
In summary, by presenting 3 cases of ALS mimicking cervical or lumbar radiculopathy, we
showed that the diagnosis of early stage ALS can be confused with radiculopathy. Our study
would be helpful for early and accurate diagnosis of patients with ALS.

FUNDING
This study was supported by the National Research Foundation of Korea Grant funded by
the Korean government (No. NRF2021R1A2C1013073).

CONFLICT OF INTEREST STATEMENT
The authors declare no conflict of interest.

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