CBL: Progressive Weakness in a Middle-Aged Man

A 54-year-old with painless progressive leg weakness and fasciculations.

Topic: ALS Level: Resident

Vignette

TL is a 54-year-old supply manager who presents with 4–5 weeks of painless left leg weakness. He noticed dragging of the left foot during walks and difficulty lifting it while lying down. He denies numbness, falls, tremor, pain, dysphagia, dyspnea, or fasciculations.

Exam: BP 122/74, pulse 67, afebrile. Tongue fasciculations present. Arm strength normal. Left hip flexion and ankle dorsiflexion 4/5. Atrophy of left tibialis anterior. Fasciculations in quadriceps bilaterally. Reflexes brisk in arms and legs, with sustained left ankle clonus and bilateral Babinski signs. Sensation intact. Gait shows mild left foot drop.

Question 1

Which finding best supports ALS as the diagnosis?

  • A. Sensory loss and pain
  • B. Combination of upper and lower motor neuron signs
  • C. Single nerve distribution weakness
  • D. Fatiguable weakness with diurnal variation

Question 2

Which test is most helpful in supporting the diagnosis after exclusion of mimics?

  • A. MRI brain with contrast
  • B. EMG with denervation in ≥3 spinal segments
  • C. Serum CK, B12, Lyme titers
  • D. Lumbar puncture

Question 3

Which of the following is the best management strategy for ALS?

  • A. Natalizumab
  • B. Riluzole
  • C. Supportive care with PT/OT, speech, nutrition, and respiratory support
  • D. B and C

Teaching Points

  • ALS presents with both UMN and LMN findings in multiple regions, without sensory loss.
  • It is a diagnosis of exclusion; EMG helps confirm denervation in ≥3 regions.
  • Riluzole and edaravone may slow progression but do not cure ALS.
  • Multidisciplinary supportive care (nutrition, respiratory support, PT/OT, speech) is essential for quality of life.
  • Disease course is highly variable, ranging from months to years.

References

  1. Brown RH, Al-Chalabi A. Amyotrophic Lateral Sclerosis. N Engl J Med. 2017;377:162–172.
  2. Chiò A, Logroscino G, Hardiman O, et al. Prognostic factors in ALS: A critical review. ALS Frontotemporal Degener. 2013;14(1):1–10.
  3. NICE. Motor neurone disease: assessment and management. 2019.