Multiple Sclerosis - Clinical Features, Epidemiology, Pathology, Location of Lesions.docx

**Multiple Sclerosis: Clinical Features, Epidemiology, Pathology, Location of Lesions** A close-up of a black text Description automatically generated **Multiple Sclerosis (MS)** **Initial Presentation** - **Unilateral Visual Impairment**: Typically due to optic neuritis, the patient has d...

**Multiple Sclerosis: Clinical Features, Epidemiology, Pathology, Location of Lesions** A close-up of a black text Description automatically generated **Multiple Sclerosis (MS)** **Initial Presentation** - **Unilateral Visual Impairment**: Typically due to optic neuritis, the patient has difficulty with vision in one eye. - **Retrobulbar Neuritis**: Often the initial manifestation, causing pain and vision problems. **Common Symptoms** - **Cranial Nerve Signs**: - **Ataxia**: Lack of voluntary coordination of muscle movements. - **Nystagmus**: Involuntary eye movement. - **Internuclear Ophthalmoplegia (INO)**: Disorder of conjugate lateral gaze due to interruption of fibers in the medial longitudinal fasciculus (MLF). - **Spinal Cord Lesions**: Spasticity and urinary incontinence. **Clinical Features** - **Lhermitte's Sign**: Shock-like sensation running down the spine with neck flexion or extension. - **Uhthoff's Phenomenon**: Worsening of symptoms with heat exposure (e.g., hot showers). **Epidemiology** - **Causes**: - Environmental factors. - Genetic predisposition. - Immunologic factors. - **Peak Incidence**: - Ages 20-30. - Rare in childhood (\50). - **Higher Risk**: - First-degree relatives. - More common in Caucasians and women. **Pathology** - **White Matter Lesions**: Inflammatory lesions in the white matter of the brain. - **Multiple Lesions**: Plaques form in various locations. - **Well-Circumscribed, Irregular-Shaped Plaques**: Representing neurologic deficits separated in time and space. - **Common Locations**: Around lateral ventricles, brain stem, spinal cord, and optic nerve. - **Dawson's Fingers**: Plaques follow the course of periventricular veins. **Diagnostic Features** - **Initial Presentation**: Often impaired vision due to optic neuritis. - **Imaging**: MRI shows plaques around ventricles and other CNS regions. - **Symptoms**: - **Visual Impairment**: Unilateral optic neuritis. - **Shock-like Sensations**: Lhermitte's sign. - **Heat Sensitivity**: Uhthoff's phenomenon. - **CNS Only**: MS primarily affects the central nervous system (brain and spinal cord). **Clinical Course** - **Variants**: Different clinical courses can occur, but the most common is relapsing-remitting MS. - **Age of Onset**: Can become apparent at any age but most commonly between 20 and 30 years. - **Progression**: Disease may start with mild symptoms and progress over time with varying degrees of severity. \_\_\_\_\_\_ What is the name of the shock-like sensation that passes down the spine in a patient with multiple sclerosis? - Lhermitte sign A 25-year-old woman presents with difficulty in her vision for the past several days. On examination, an impairment in the conjugate lateral gaze is noted. What is the most likely location of the lesion? - Medial longitudinal fasciculus Which of the following is NOT a common feature in multiple sclerosis? - Argyll Robertson pupil (Explanation: - **Argyll Robertson pupil** is typically associated with neurosyphilis, where the pupils constrict with accommodation but do not react to light. It is not a common feature of multiple sclerosis. - **Optic neuritis**, **internuclear ophthalmoplegia**, **nystagmus**, and **retrobulbar neuritis** are all common features of multiple sclerosis: - **Optic neuritis**: Inflammation of the optic nerve, often causing unilateral visual impairment. - **Internuclear ophthalmoplegia (INO)**: Caused by a lesion in the medial longitudinal fasciculus, leading to impaired horizontal eye movements. - **Nystagmus**: Involuntary rhythmic eye movements, commonly seen in MS. - **Retrobulbar neuritis**: Inflammation of the optic nerve behind the eye, leading to vision problems.) Which of the following is NOT a likely area for the formation of plaques in multiple sclerosis? - Pituitary glandTop of Form (Explanation: - Multiple sclerosis (MS) primarily affects the central nervous system, particularly the white matter of the brain and spinal cord. - **T5 to T10 spinal cord segments**: These are commonly affected in MS, contributing to various neurological symptoms. - **Beside lateral ventricles**: Periventricular white matter is a classic location for MS plaques, often seen as \"Dawson\'s fingers\" extending perpendicular to the ventricles. - **Pons**: This is a part of the brainstem and can also be affected by MS plaques. - **Cranial nerve II (Optic nerve)**: MS frequently involves the optic nerve, leading to optic neuritis and visual disturbances. However, the **pituitary gland** is not typically a site where MS plaques form. Plaques in the pituitary gland are linked to **hypophysitis**, an inflammation of the gland. This condition affects hormone production, leading to symptoms like fatigue, weight changes, and hormonal imbalances. Multiple sclerosis primarily affects areas rich in myelin, which are found in the brain\'s white matter and the spinal cord\'s white matter, rather than structures like the pituitary gland.) Plaques that are seen beside lateral ventricles follow the course of which structures? - Paraventricular veinsTop of Form (Explanation: Plaques that are seen beside lateral ventricles in multiple sclerosis follow the course of **paraventricular veins**. These veins are involved in the drainage of the periventricular white matter, where plaques commonly form in multiple sclerosis.) Bottom of Form Bottom of Form