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Upper Motor Neuron Lesion (Pyramidal Insufficiency)[edit]

Upper motor neuron lesion
	File:Gray764.png
Synonyms	Pyramidal tract lesion
Pronounce	N/A
Specialty	Neurology
Symptoms	Spasticity, hyperreflexia, Babinski sign, clonus
Complications	N/A
Onset	N/A
Duration	N/A
Types	N/A
Causes	Stroke, multiple sclerosis, traumatic brain injury, cerebral palsy
Risks	N/A
Diagnosis	Neurological examination, MRI, CT scan
Differential diagnosis	Lower motor neuron lesion, peripheral neuropathy
Prevention	N/A
Treatment	Physical therapy, occupational therapy, medications for spasticity
Medication	N/A
Prognosis	Variable, depends on underlying cause and extent of damage
Frequency	Common in conditions affecting the central nervous system
Deaths	N/A

Introduction[edit]

Upper motor neuron (UMN) lesion, also known as pyramidal insufficiency, refers to damage in the neural pathway above the anterior horn cell of the spinal cord or motor nuclei of the cranial nerves. This contrasts with lower motor neuron (LMN) lesions, which affect nerve fibers traveling from the anterior horn of the spinal cord or cranial motor nuclei to the muscles.

File:Nervous and mental diseases (1911) (14775178011).jpg

Diagram of brain showing areas affected by upper motor neuron lesions

Causes[edit]

UMN lesions can occur due to a variety of conditions including:

Symptoms[edit]

Common symptoms of UMN lesions include:

Muscle weakness
Spasticity (increased muscle tone)
Hyperreflexia (exaggerated reflexes)
Babinski sign (upward response of the big toe when the sole of the foot is stimulated)

Diagnosis[edit]

Diagnosis of UMN lesions involves:

Neurological examination
Imaging studies such as MRI or CT scan
Electromyography (EMG) and nerve conduction studies (in some cases)

Treatment[edit]

Treatment focuses on managing symptoms and may include:

Physical therapy and rehabilitation
Medications to reduce muscle spasticity
Supportive care for associated conditions

UMN vs LMN Lesions[edit]

Differences between UMN and LMN lesions:

UMN Lesions: Spasticity, hyperreflexia, positive Babinski sign.
LMN Lesions: Muscle atrophy, fasciculations, decreased muscle tone and reflexes.

File:ALS subtypes UMN LMN distribution.png

Diagram of spinal cord showing areas affected by lower motor neuron lesions

Prognosis[edit]

The prognosis for UMN lesions varies depending on the underlying cause and the extent of neurological involvement.

Epidemiology[edit]

The prevalence of UMN lesions is closely tied to the conditions causing them, such as stroke or multiple sclerosis.

References[edit]

External Links[edit]

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Upper motor neuron lesion
File:Gray764.png
Synonyms	Pyramidal tract lesion
Pronounce	N/A
Specialty	Neurology
Symptoms	Spasticity, hyperreflexia, Babinski sign, clonus
Complications	N/A
Onset	N/A
Duration	N/A
Types	N/A
Causes	Stroke, multiple sclerosis, traumatic brain injury, cerebral palsy
Risks	N/A
Diagnosis	Neurological examination, MRI, CT scan
Differential diagnosis	Lower motor neuron lesion, peripheral neuropathy
Prevention	N/A
Treatment	Physical therapy, occupational therapy, medications for spasticity
Medication	N/A
Prognosis	Variable, depends on underlying cause and extent of damage
Frequency	Common in conditions affecting the central nervous system
Deaths	N/A

Upper motor neuron lesion