AANP Family Nurse Practitioner (FNP) Certification ExamDiagnosisHard
A 55-year-old male presents with a 3-month history of progressive muscle weakness, particularly in his upper extremities, difficulty swallowing (dysphagia), and fasciculations observed on his tongue and shoulders. He denies sensory changes, pain, or bladder/bowel dysfunction. Neurological examination reveals diffuse muscle atrophy, hyperreflexia, and a positive Babinski sign. What is the most likely diagnosis?
- AMultiple Sclerosis
- BAmyotrophic Lateral Sclerosis (ALS)
- CGuillain-Barré Syndrome
- DMyasthenia Gravis
Show answer & explanationAnswer & explanation
Correct answer: B. Amyotrophic Lateral Sclerosis (ALS)
The patient's progressive onset of combined upper motor neuron (hyperreflexia, positive Babinski) and lower motor neuron (muscle weakness, atrophy, fasciculations) signs, affecting bulbar muscles (dysphagia) and limbs, without sensory involvement, is highly characteristic of Amyotrophic Lateral Sclerosis (ALS).
Why the other options are wrong
- A. Multiple Sclerosis is a demyelinating disease of the CNS, presenting with a variety of neurological symptoms (sensory, motor, visual, cerebellar) that wax and wane, often with relapses and remissions, and does not typically involve fasciculations or progressive atrophy of this nature.
- C. Guillain-Barré Syndrome is an acute, rapidly progressive ascending paralysis, often preceded by an infection, primarily affecting peripheral nerves (lower motor neuron signs) and causing sensory changes, which are absent here.
- D. Myasthenia Gravis is characterized by fluctuating muscle weakness that worsens with activity and improves with rest, often affecting ocular and bulbar muscles, without fasciculations, atrophy, or upper motor neuron signs.
Amyotrophic Lateral Sclerosis (ALS)
A progressive neurodegenerative disease that affects motor neurons in the brain and spinal cord, leading to muscle weakness, atrophy, and eventually paralysis.
- Involves both upper (UMN) and lower motor neuron (LMN) signs.
- Presents with progressive muscle weakness, fasciculations, dysphagia.
- Sensory function, cognition, and sphincter control are typically preserved.
Memory trick: ALS: Atrophy, LMN & UMN signs, Spared sensation.