Myoclonus overview

Revision as of 22:52, 29 July 2020 by WikiBot (talk | contribs) (Bot: Removing from Primary care)
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to navigation Jump to search

Myoclonus Microchapters

Home

Patient Information

Overview

Historical Perspective

Classification

Pathophysiology

Causes

Differentiating Myoclonus from other Diseases

Epidemiology and Demographics

Risk Factors

Natural History, Complications and Prognosis

Diagnosis

History and Symptoms

Physical Examination

Laboratory Findings

CT

MRI

Other Imaging Findings

Other Diagnostic Studies

Treatment

Medical Therapy

Surgery

Primary Prevention

Cost-Effectiveness of Therapy

Future or Investigational Therapies

Case Studies

Case #1

Myoclonus overview On the Web

Most recent articles

Most cited articles

Review articles

CME Programs

Powerpoint slides

[1]

American Roentgen Ray Society Images of Myoclonus overview

All Images
X-rays
Echo & Ultrasound
CT Images
MRI

Ongoing Trials at Clinical Trials.gov

US National Guidelines Clearinghouse

NICE Guidance

FDA onMyoclonus overview

CDC on Myoclonus overview

overview in the news

Blogs on Myoclonus overview

Directions to Hospitals Treating Myoclonus

Risk calculators and risk factors for Myoclonus overview

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [2] Associate Editor(s)-in-Chief: Saumya Easaw, M.B.B.S.[3]

Overview

Myoclonus is brief, involuntary twitching of a muscle or a group of muscles. It describes a medical sign (as opposed to symptom) and, generally, is not a diagnosis of a disease. The myoclonic twitches or jerks are usually caused by sudden muscle contractions; they also can result from brief lapses of contraction. Contractions are called positive myoclonus; relaxations are called negative myoclonus. The most common time for people to encounter them is while falling asleep (hypnic jerk), but myoclonic jerks are also a sign of a number of neurological disorders. Hiccups are also a kind of myoclonic jerk specifically affecting the diaphragm.

Myoclonic jerks may occur alone or in sequence, in a pattern or without pattern. They may occur infrequently or many times each minute. Most often, myoclonus is one of several signs in a wide variety of nervous system disorders such as multiple sclerosis, Parkinson's disease, Alzheimer's disease, Subacute sclerosing panencephalitis and Creutzfeldt-Jakob disease and some forms of epilepsy.

In almost all instances in which myoclonus is caused by CNS disease it is preceded by other symptoms; for instance, in CJD it is generally a late-stage clinical feature that appears after the patient has already started to exhibit gross neurological deficits.

Anatomically, myoclonus may originate from lesions of the cortex, subcortex or spinal cord. The presence of myoclonus above the foramen magnumeffectively excludes spinal myoclonus, but further localisation relies on further investigation with electromyography (EMG) and electroencephalography (EEG).

Classification

In juvenile myoclonic epilepsy, seizures usually involve the neck, shoulders, and upper arms. These seizures typically occur shortly after waking up. They normally begin between puberty and early adulthood. They can usually be controlled with medication, but it must be taken for life. In rare cases, myoclonic seizures can be symptomatic of Lennox-Gastaut syndrome, beginning in early childhood and usually involving the face, neck, shoulders, and upper arms. In these cases, the seizures tend to be strong and difficult to control.Progressive myoclonic epilepsy includes both myoclonic and tonic-clonic seizures. Treatment is not normally successful for any extended period of time.

Causes

Myoclonus may develop in response to infection, head or spinal cord injury, stroke, brain tumors, kidney or liver failure, lipid storage disease, chemical or drug poisoning, or other disorders. Benign myoclonic movements are commonly seen during the induction of general anesthesia with intravenous medications such as etomidate and propofol. These are postulated to result from decreased inhibitory signaling from cranial neurons. Prolonged oxygen deprivation to the brain, called hypoxia, may result in posthypoxic myoclonus. Myoclonus can occur by itself, but most often it is one of several symptoms associated with a wide variety of nervous system disorders. For example, myoclonic jerking may develop in patients with multiple sclerosis, Parkinson's disease, Alzheimer's disease, or Creutzfeldt-Jakob disease or Lupus. Myoclonic jerks commonly occur in persons with epilepsy, a disorder in which the electrical activity in the brain becomes disordered leading to seizures.

Natural History, Complications and Prognosis

Although myoclonus is not a life-threatening condition, it may result in serious, debilitating impairments. Action Myoclonus with its positive and negative myoclonus components is generally considered the most serious.

References

Template:WikiDoc Sources