Summary about Disease
Flapping tremor, also known as asterixis, is a neurological sign characterized by involuntary jerking movements, primarily affecting the hands and wrists. It's not a disease in itself but rather a symptom of an underlying medical condition. It's most often seen in liver failure (hepatic encephalopathy) and kidney failure (uremic encephalopathy). The tremor appears as a brief, intermittent lapse of sustained posture, causing a flapping motion of the wrist or other body parts.
Symptoms
The main symptom of asterixis is the characteristic "flapping" tremor. Other associated signs and symptoms depend on the underlying cause. Common manifestations include:
Sudden, brief loss of muscle tone followed by rapid recovery, causing a flapping movement.
Most commonly observed in the wrists when the arms are outstretched and the hands are dorsiflexed (cocked back).
Can also occur in other body parts like the tongue or feet, but less frequently.
May be accompanied by other symptoms related to the underlying cause, such as jaundice (yellowing of skin and eyes) in liver disease, or confusion and fatigue in kidney disease.
Causes
Asterixis is usually a result of metabolic encephalopathy, meaning brain dysfunction due to metabolic abnormalities. The most common causes include:
Liver Failure: Hepatic encephalopathy, a condition where toxins build up in the blood due to the liver's inability to remove them.
Kidney Failure: Uremic encephalopathy, where waste products accumulate in the blood due to impaired kidney function.
Other Metabolic Disturbances: Electrolyte imbalances (e.g., hypokalemia, hypomagnesemia), respiratory failure (hypercapnia), drug toxicity (e.g., phenytoin, barbiturates), severe heart failure, Wilson's disease, severe infection, hypoglycemia, hyperthyroidism.
Medicine Used
Treatment of asterixis focuses on addressing the underlying cause. There are no specific medications solely for treating the tremor itself. Common medical interventions include:
Liver Failure: Lactulose and rifaximin to reduce ammonia levels.
Kidney Failure: Dialysis to remove waste products from the blood.
Electrolyte Imbalances: Corrective measures to restore normal electrolyte levels.
Drug Toxicity: Discontinuation of the offending medication.
Other Causes: Management specific to the underlying condition (e.g., thyroid medication for hyperthyroidism).
In some cases, medications such as clonazepam or other anti-seizure medications may be used to help manage the tremor, but these are typically used to treat the underlying cause more so than the tremor itself.
Is Communicable
Asterixis itself is not communicable. It is a symptom of an underlying medical condition, and these conditions are not typically infectious.
Precautions
Precautions depend on the underlying cause and involve preventing or managing the conditions that lead to asterixis. General recommendations include:
Liver Disease: Avoiding alcohol, maintaining a healthy diet, managing viral hepatitis infections, and taking medications as prescribed.
Kidney Disease: Managing diabetes and hypertension, avoiding nephrotoxic drugs, and adhering to dialysis schedules.
Medication Management: Being aware of potential side effects of medications and reporting any unusual symptoms to a doctor.
Overall Health: Maintaining a healthy lifestyle, managing underlying medical conditions, and seeking prompt medical attention for any new or worsening symptoms.
How long does an outbreak last?
Asterixis is not an "outbreak" like an infectious disease. The duration of asterixis depends entirely on how quickly the underlying cause can be identified and effectively treated. It can be temporary (resolving within days or weeks with treatment) or chronic (persistent if the underlying condition is not well-managed).
How is it diagnosed?
Asterixis is diagnosed primarily through clinical examination. The typical diagnostic process includes:
Neurological Examination: The doctor will observe the patient's outstretched arms and hands for the characteristic flapping tremor. This is often provoked by asking the patient to dorsiflex their wrists (extend their hands upward as if stopping traffic).
Medical History and Physical Examination: A thorough evaluation to identify potential underlying causes, such as liver disease, kidney disease, or medication use.
Laboratory Tests: Blood tests to assess liver function (e.g., liver enzymes, bilirubin, ammonia levels), kidney function (e.g., creatinine, BUN), electrolyte levels, and other relevant markers.
Imaging Studies: In some cases, imaging studies like CT scans or MRIs of the brain may be performed to rule out other neurological conditions.
Timeline of Symptoms
The onset and progression of asterixis depend on the underlying cause. Generally, the timeline is as follows:
Gradual Onset: Often develops gradually as the underlying condition worsens. For example, in liver failure, asterixis may appear as liver function declines.
Intermittent: The tremor may be intermittent at first, becoming more frequent and pronounced as the condition progresses.
Variable: The severity of asterixis can vary depending on the degree of metabolic disturbance.
Important Considerations
Asterixis is a sign of a serious underlying medical condition. It should not be ignored.
Prompt diagnosis and treatment of the underlying cause are crucial to prevent complications and improve outcomes.
Patients with asterixis may experience impaired motor coordination and should take precautions to prevent falls and injuries.
Medication management is essential, as some medications can trigger or worsen asterixis.
Regular monitoring of liver function, kidney function, and electrolyte levels is important for patients at risk for asterixis.