Syringomyelia USMLE questions

1st Question on Syringomyelia USMLE

MRI of syringomyelia

A 36-year-old man presents to the physician with weakness of both upper extremities, headaches, and multiple second-degree burns on his hands. The patient has no prior significant medical history and cannot recall any recent episodes of trauma. Physical examination reveals no motor deficits in either upper extremity. The exam also reveals the absence of pain and temperature sensation and reflexes in both upper extremities. The position and vibration sense is intact in the upper extremities, and there are no lower extremity abnormalities.

An MRI of the spinal column shows dilation within the cervical spinal cord. Which diagnosis is consistent with this patient’s findings?
A. Amyotrophic lateral sclerosis
B. Syringomyelia
C. Cervical spondylosis
D. intervertebral disk prolapse

The correct answer to this question is option B

The history, physical exam, and MRI findings are consistent with the diagnosis of syringomyelia, which may be primary (such as with a type I Chiari malformation) or acquired as a result of trauma, tumor, or inflammation. Syringomyelia consists of an enlargement of the central canal of the spinal cord, most commonly occurring at C8-Tl. Crossing fibers of the spinothalamic tract are damaged (loss of pain and temperature sensation) with preserved dorsal column function (intact position and vibration sense). Type I Chiari malformations involve downward herniation of the cerebellar tonsils into the foramen magnum.

Read more about the Caues of syringomyelia

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2nd Question on Syringomyelia USMLE

A 25-year-old female presents with complaints of muscle weakness and sensory loss in her UE(upper extremities). Her medical history is significant for involvement in a MVA (motor vehicle accident) ten years ago in which she sustained a cervical spine injury. A physical examination today reveals moderate wasting of the small hand muscles and impaired pain and temperature sensation in the bilateral upper extremities. Light touch, vibration, and position senses are all intact Which of the following is the most likely diagnosis?
A. Amyotrophic lateral sclerosis
B. Syringomyelia
C. Cervical spondylosis
D. lntervertebral disk prolapse

The correct answer to this question is option B

This patient’s upper extremity sensory deficits and weakness are best explained by syringomyelia, a disease process in which CSF drainage from the central canal of the spinal cord is disrupted, leading to a fluid filled cavity that compresses surrounding neural tissue. Damage most often involves the crossing fibers of the spinothalamic tract (pain and temperature) and upper extremity motor fibers, due to their medial locations within the corticospinal tract The most common causes of syringomyelia are Arnold Chiari malformations and prior spinal cord injuries. Symptoms develop months or years after the initial injury, and progression is gradual.

ALS causes upper and lower motor neuron deficits with no loss of sensory function. Twitching, muscle weakness, and cramping are common symptoms

Read more about the How is syringomyelia diagnosed

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3rd Question on Syringomyelia USMLE

A 33-year-old woman comes to the physician due to weakness in both upper extremities. She recently burned both of her hands while cooking but did not feel any pain The patient has no history of trauma, headache, or neck pain She also has no lower extremity weakness or problems with bowel or bladder function.

Examination reveals absent reflexes in her upper limbs. There is a loss of pain and temperature sensation on the back of the neck, shoulders, and upper arms. Vibration and proprioception are preserved. Which of the following is the most likely cause of this patient’s current symptoms?
A. Degeneration of dorsal and lateral white matter of the spinal cord
B. Ischemic injury of the anterior spinal cord
C. Fluid-filled cavity in the central spinal cord
D. Segmental demyelination, inflammation, and gliosis of the spinal cord

The correct answer to this question is option C

This patient likely has syringomyelia, a fluid-filled cavity in the spinal cord that may represent dilation of the central canal or a separate cavity within the spinal parenchyma. It is usually located within the cervical and thoracic spine but can also involve the brainstem (syringobulbia). Patients typically present with loss of pain/temperature sensation in the dermatomes corresponding to the site of spinal involvement (eg, “cape” distribution).

This is due to the disturbance of the crossing spinothalamic tracts in the anterior commissure. Vibration/proprioception is preserved as the dorsal spinal column is not usually affected (dissociated sensory loss) As the cavity enlarges, there can be an interruption of the anterior horn gray matter, resulting in lower motor neuron signs in the upper limbs (areflexic weakness).

Read more about the Clinical features of syringomyelia

Option A refers to Vit B12 deficiency.
Option B refers to Anterior spinal cord syndrome which typically presents with sudden flaccid paralysis (spinal shock) and loss of pain/temperature sensation below the level of spinal injury.
Option D (Segmental demyelination/inflammation of the spinal cord and gliosis of the spinal cord) refers to multiple sclerosis.

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High Yield facts for Syringomyelia USMLE exams

Syringomyelia USMLE
Syringomyelia USMLE

References:

  1. https://medlineplus.gov/ency/article/001398.htm

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