Neuroscience PHT 5200: Clinical Correlates

Questions and Answers

What is NOT a known cause or contributing factor of the condition discussed?

Smoking

Genetic mutation (correct)

Heavy metal intoxication

History of brain trauma

Which symptom is always present in cases of this condition?

Mental deterioration

Dysarthria

Hyperreflexia (correct)

Sensory loss

In which timeframe is a patient typically expected to become wheelchair dependent?

In 12-18 months (correct)

Within 6 months

Never becomes dependent

After 3 years

Which variant of ALS is characterized by initial symptoms affecting muscles innervated by cranial nerves?

Progressive Bulbar Palsy Signup and view all the answers

What is the prognosis for patients diagnosed with this condition?

Usually fatal within 3 to 5 years Signup and view all the answers

What is a characteristic of Wallerian degeneration in peripheral nerves?

It involves the degeneration of the distal segment of the axon. Signup and view all the answers

What factor reduces the likelihood of a functional connection during nerve regeneration?

Proximity of the injury to the neuron cell body. Signup and view all the answers

Which statement is true regarding the regeneration of nerves in the peripheral nervous system (PNS)?

Regeneration proceeds at a rate of approximately 1 mm per day. Signup and view all the answers

What is a significant difference between the central nervous system (CNS) and peripheral nervous system (PNS) regarding regeneration?

PNS neurons regenerate more effectively due to the presence of Schwann cells. Signup and view all the answers

Which of the following factors does NOT influence regeneration of peripheral nerves?

The presence of surrounding fatty tissue. Signup and view all the answers

What is a symptom associated with cauda equina syndrome?

Saddle sensory loss Signup and view all the answers

What type of sensory loss is seen below the level of impairment in posterior spinal artery syndrome?

Same side loss of DCML modalities Signup and view all the answers

Which of the following conditions is associated with subacute combined degeneration of the spinal cord?

Pernicious anemia Signup and view all the answers

In Friedreich’s ataxia, which tract is primarily responsible for unconscious proprioception?

DSCT Signup and view all the answers

What is a characteristic symptom of Tabes Dorsalis?

Loss of DCML modalities Signup and view all the answers

Which of the following is NOT a symptom of systemic problems affecting the spinal cord?

Improved reflexes Signup and view all the answers

Which symptom indicates a lower motor neuron (LMN) problem?

Clumsy gait Signup and view all the answers

What type of atrophy is observed in Friedreich’s ataxia?

Limb muscle atrophy Signup and view all the answers

What condition is characterized by the defect of the neural arch allowing for extension of the meninges and cerebrospinal fluid?

Meningocele Signup and view all the answers

Which type of spina bifida does not involve the spinal cord and typically presents with no functional deficits?

Spina Bifida Occulta Signup and view all the answers

What is the primary symptom of autonomic dysreflexia in individuals with complete lesions above T6?

Increased blood pressure Signup and view all the answers

Which structure is affected by polio, leading to muscle weakness without sensory changes?

Anterior horn cells Signup and view all the answers

If a patient experiences flaccidity followed by spasticity after a complete transection of the spinal cord, what is the condition likely causing this progression?

Spinal shock Signup and view all the answers

What is the primary defect in myelomeningocele compared to other types of spina bifida?

The spinal cord is involved Signup and view all the answers

What type of spina bifida is characterized as having incidental findings on X-ray, generally presenting with no functional deficits?

Spina Bifida Occulta Signup and view all the answers

In cases of complete spinal cord transection, which symptoms may NOT be experienced?

Normal sensory perception below the lesion Signup and view all the answers

Which of the following is a common treatment for autonomic dysreflexia?

Sit the patient up and relieve noxious stimuli Signup and view all the answers

What is the condition characterized by chronic headaches and high blood pressure due to autonomic dysregulation?

Autonomic Dysreflexia Signup and view all the answers

When might a surgical repair for myelomeningocele occur?

At the time of birth or potentially in utero Signup and view all the answers

What is a typical characteristic of post-polio syndrome?

Initial recovery followed by muscle weakness Signup and view all the answers

What indicates that Lou Gehrig may have suffered from chronic traumatic encephalopathy?

Presence of tau protein (TDP-43) in spinal cord tissue Signup and view all the answers

What is NOT a characteristic of complete transection of the spinal cord?

Restores normal sensorimotor function below the lesion Signup and view all the answers

Which site is primarily affected in diseases such as muscular dystrophy?

Muscle Signup and view all the answers

What characterizes myasthenia gravis at the neuromuscular junction?

Antibodies against nicotinic acetylcholine receptors Signup and view all the answers

In myasthenia gravis, which of the following symptoms is commonly observed?

Weakness in limbs and cranial muscles Signup and view all the answers

What is the role of acetylcholinesterase in relation to myasthenia gravis?

Breaks down acetylcholine at the synapse Signup and view all the answers

Which statement accurately describes the nerve conduction studies in myasthenia gravis?

Typically remain within normal ranges Signup and view all the answers

What is a major characteristic of lower motor neurons?

Control skeletal muscle fibers Signup and view all the answers

How does muscle weakness from myasthenia gravis vary?

It varies from day to day Signup and view all the answers

Which of the following is considered a major site of problems in the context of neuromuscular diseases?

Nerve roots Signup and view all the answers

Study Notes

Major Sites of Neurological Issues

Muscle disorders such as Muscular Dystrophy can occur at various sites including:
- Neuromuscular junction
- Peripheral nerves
- Nerve roots
- Motor neurons
- Spinal cord, with complications including extra-axial and intra-axial lesions, tracts issues, and trauma
- Vascular problems

Motor Unit and Lower Motor Neuron

Definition of a motor unit includes cell body, axon, neuromuscular junction, and all skeletal muscle fibers it innervates.
Lower motor neurons consist of the cell body and axon, crucial in muscle activation.

Myasthenia Gravis

An autoimmune disorder affecting postsynaptic transmission at the NM junction, caused by antibodies against nicotinic acetylcholine receptors.
Symptoms include fluctuating muscle weakness, particularly in cranial and limb muscles, typically not affecting muscle stretch reflexes (MSRs).
Nerve conduction studies often remain normal.

Wallerian Degeneration

Limited regeneration in the PNS compared to the CNS, marked by distal axon atrophy and proximal segment swelling.
Regeneration mechanisms include regenerative (same axon regrows) and collateral sprouting (nearby axon regrows).
Regrowth rates are approximately 1 mm per day, depending on factors such as cell body integrity and lesion location.

CNS vs PNS Regeneration

CNS regeneration is less likely due to factors currently not definitively identified.
Common risk factors include heavy metal toxicity, smoking, military service, and brain trauma.
Typical onset of conditions is in males aged 40 to mid-60s.

Symptoms and Prognosis of ALS

Early symptoms include painless extremity weakness and difficulties with fine motor skills; wasting of hand and foot muscles follows.
Progression leads to rapid weakness spread, hyperreflexia, and atypical sensory conditions.
Life expectancy post-diagnosis generally ranges between 3 to 5 years due to respiratory failure or choking from dysphagia.

Variants of ALS

Progressive Bulbar Palsy: affects muscles innervated by cranial nerves, involving dysarthria and dysphagia.
Spinal Muscular Atrophy: characterized by lower motor neuron involvement leading to muscle weakness and atrophy.

Role of Physical Therapy (PT)

Education and support for patients and families are essential; training in maintaining functionality and transfers.
Use of adaptive devices and wheelchair assistance is advocated; heavy strengthening is not recommended.

Polio and Its Aftereffects

Affects anterior horn cells with no sensory changes but causes muscle weakness.
Post-polio syndrome can arise, with considerations for patient safety and recovery strategies.

Disorders of the Spinal Cord

Conditions include Spina Bifida, complete cord transection, anterior and posterior spinal artery syndromes, and Brown-Sequard syndrome, each having distinct impacts and required treatments.

Types of Spina Bifida

Spina Bifida Occulta: vertebral defect without nerve involvement, generally asymptomatic.
Meningocele: involves a bulge of meninges without cord involvement, typically repaired at birth.
Myelomeningocele: significant involvement of the spinal cord, resulting in severe neurological deficits including paraplegia.

Complete Transection of the Cord

Initial spinal shock presents as flaccid paralysis, later developing UMN signs like spasticity and hyperreflexia.
Results in total loss of sensory modalities below the injury level, impacting respiratory function if occurring above the C3 level.

Autonomic Dysreflexia

A potentially life-threatening condition arising from complete lesions above T6, characterized by exaggerated autonomic responses to noxious stimuli.
Symptoms include severe headache, high blood pressure, flushing above the lesion, and bradycardia; treatment requires removing the stimulus and positioning the patient correctly.

Cauda Equina Syndrome

Symptoms include saddle sensory loss and LMN signs like bowel and bladder difficulties, alongside low back pain.

Systemic Problems Affecting the Spinal Cord

Includes subacute combined degeneration of the spinal cord due to vitamin B12 deficiency, leading to proprioceptive loss, spastic paresis, and urinary incontinence.

Friedreich’s Ataxia

Genetic condition resulting in motor and proprioceptive dysfunction due to affected CNS tracts.
Characterized by gait and coordination impairments, upper motor neuron signs, and preservation of some reflexes.

Questions and Discussion Points

Consideration of case studies or specific patient presentations to further understand the clinical correlates within peripheral and spinal cord contexts.

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Description

Explore the various clinical correlates from the periphery to the spinal cord in this quiz designed for Neuroscience PHT 5200. Understand the major sites where problems occur, including muscular conditions, neuromuscular junctions, and spinal cord issues. Test your knowledge on definitions and key concepts related to motor units and clinical pathologies.