neurologic disorders
Weakness
Etiology of Weakness
). Usually, lesions in a given location manifest with similar clinical findings. However, some disorders have characteristics of lesions in more than one location. For example, patients with Amyotrophic Lateral Sclerosis (ALS) and Other Motor Neuron Diseases (MNDs) (ALS) may have findings of both upper and lower motor neuron dysfunction. Disorders of the spinal cord may affect tracts from upper motor neurons, lower motor neurons (anterior horn cells), or both. Common causes offocal weaknessinclude Overview of Stroke (the most common cause of unilateral weakness) Peripheral Neuropathy , including those that are caused by trauma or entrapment (eg, Spinal root entrapment (eg, Cervical Herniated Nucleus Pulposus ) Spinal Cord Compression (eg, cervical spondylosis, epidural cancer metastasis, trauma) Multiple Sclerosis (MS) None may occur as part of postictal (Todd) paralysis, which usually resolves over several hours, or result from a Transient Ischemic Attack (TIA) (TIA). The most common causes ofgeneralized weaknessare Deconditioning due to inactivity (disuse atrophy) resulting from illness or frailty, especially in older patients Generalized muscle wasting due to prolonged immobilization in an intensive care unit (ICU)—a condition called critical illness myopathy Critical illness polyneuropathy (ICU neuropathy) Common myopathies (eg, alcohol myopathy, hypokalemia, corticosteroid myopathy) Use of paralytic agents in a critical care patient Many patients report weakness when their problem is Fatigue . Fatigue can prevent maximal effort and muscle performance during strength testing. Common causes of fatigue include acute severe illness of almost any cause, cancers, chronic infections (eg, Human Immunodeficiency Virus (HIV) Infection , Patients with Fibromyalgia , 