DEFINITION
Myopathy means muscular disease, and generally refers to a disorder in which muscle weakness develops due to some malfunction of the actual muscle fibers.
EPIDEMIOLOGY
One third of heavy long-term alcohol consumption (of any beverage type), aka alcoholics, in both sexes and all races, develop skeletal myopathy. The acute form is four times more common in males than females.
- Alcohol-Related Neurologic Disease, Laurie Barclay MDThe Gale Group Inc. The Gale Encyclopedia of Public Health states, 2002
- Alcoholic cardiomyopathy: incidence, clinical characteristics, and pathophysiology, Piano MR., 2002
SYMPTOMS
Alcoholic myopathy can have serious symptoms and side effects.
There are usually no symptoms until the disease is in an advanced stage. At that point, the symptoms occur due to heart failure and may include:
- Ankle, feet, and leg swelling
- Awakening during the night with shortness of breath (paroxysmal nocturnal dyspnea)
- Breathing difficulty while lying down (orthopnea)
- Cough containing mucus, or pink, frothy material
- Decreased alertness or concentration
- Decreased urine output (oliguria)
- Fatigue, weakness, faintness
- Irregular or rapid pulse
- Loss of appetite
- Need to urinate at night (nocturia)
- Overall swelling
- Sensation of feeling the heart beat (palpitations)
- Shortness of breath, especially with activity (dyspnea)
Muscle Symptoms
In the acute form of alcoholic myopathy, muscle pain, tenderness, swelling and weakness may be the first symptoms noted after waking from an alcoholic stupor after binge drinking. Pain in the calf similar to the pain of deep vein thrombosis may occur. In severe cases of acute alcoholic myopathy, muscles of the throat, diaphragm and upper chest may also begin to break down. Muscle breakdown in acute disease may be exacerbated by crush or compression injuries that occur when muscles groups are compressed for long periods of time after an alcoholic passes out. Painless proximal muscle atrophy, with a striking decrease in muscle bulk and weakness develop in chronic myopathy, with the hips, shoulders, thighs and upper arms most notably affected.
- Alcoholic myopathy, Thomas Klopstock, M.D.,1994, last updated 2011
- Acute alcoholic myopathy, rhabdomyolysis and acute renal failure : a case report, S. Singh,2000
Renal Symptoms
The breakdown of muscle tissue releases myoglobin, which is excreted in the urine. Urine may turn red from myoglobin. Myoglobin release, along with other enzymes such as creatine kinase, can also cause acute renal, or kidney, failure, Singh warns. Acute renal failure may require temporary dialysis until the kidneys recover.
Cardiac Symptoms
Alcoholic myopathy can weaken the heart muscles, leading to cardiomyopathy. Severe disease can lead to increased serum potassium levels from muscle breakdown, which can cause heart arrhythmias and irregular beats. Abnormal heart rhythms can cause death in some cases.
- Alcoholic cardiomyopathy: incidence, clinical characteristics, and pathophysiology, Piano MR., 2002
- Alcoholic cardiomyopathy, Iacovoni A., De Maria R., Gavazzi A., 2010
DIAGNOSIS
In case of alcoholic cardiomyopathy the diagnosis includes the detection of abnormal heart sounds, murmurs, ECG abnormalities, and enlarged heart on chest x-ray may lead to the diagnosis. Echocardiogram abnormalities and cardiac catheterization or angiogram to rule out coronary artery blockages, along with a history of alcohol abuse can confirm the diagnosis.
Type 2 muscle atrophy
- Alcoholic myopathy, Thomas Klopstock, M.D.,1994, last updated 2011
PATHOGENESIS
Acute Alcoholic Myopathy
Acute alcoholic myopathy develops suddenly, during an episode of binge drinking or immediately following during withdrawal. Acute alcoholic myopathy is also called “alcoholic rhabdomyolysis”. It can come on rapidly over the course of a few hours and can advance over a few days before receding over the week, given the individual abstains from alcohol. Acute myopathy can present mild to severe symptoms as a result of myonecrosis, the breakdown of muscle tissue.
Symptoms of acute alcoholic myopathy may include muscle pain and swelling in addition to the classic weakness. Often the acute symptoms are reported upon awakening from an alcoholic stupor; they may also accompany withdrawal symptoms and delirium tremens. Tests have revealed that acute alcoholic myopathy affects type I muscle fibers, which can heal rapidly; however type II muscle fibers are involved in chronic alcoholic myopathy.
Typically, full recovery from acute alcoholic myopathy occurs in a matter of days or weeks; however, in extreme cases when kidney failure or hyperkalemia (abnormal potassium level in the blood) occur, the alcoholic may actually die during the episode of acute myopathy. Otherwise, research has shown it takes about 7 to 10 days for the serum creatine kinase levels (reflecting the health of the muscle) to return to normal range.
Chronic Alcoholic Myopathy
In contrast to the acute form, chronic alcoholic myopathy develops much more gradually and lasts far longer. While the acute version may include muscle pain, chronic alcoholic myopathy is usually painless. The absence of pain and gradual onset may explain why it is frequently overlooked and not diagnosed until the symptoms have been present for several years. The recovery time for chronic myopathy is slower and can take many months.
Chronic alcoholic myopathy is associated with long term alcohol abuse (years of daily alcoholic drinking). It evolves slowly, over weeks or months as opposed to its acute counterpart which can develop in a matter of hours or days. The main symptom of chronic alcoholic myopathy is muscle weakness and atrophy. It affects proximal muscles, and type 2 muscle fibers. Interestingly, long term corticosteroid use can lead to similar type 2 atrophy as well, a.k.a. “steroid myopathy”.
Other disorders which may co-occur with chronic alcoholic myopathy include peripheral neuropathy. While with myopathy the primary dysfunction exists within the muscle itself, with neuropathy the dysfunction pertains to the nervous system (nerves or brain).
- Alcoholic myopathy, Thomas Klopstock, M.D.,1994, last updated 2011
HOW ALCOHOL AFFECTS MUSCLE CELLS
Alcohol inhibits smooth muscle cell proliferation via regulation of the Notch signaling pathway: treatment of human coronary artery SMCs with ethanol (EtOH) decreased Notch 1 mRNA and Notch 1 intracellular domain protein levels, in the absence of any effect on Notch 3. EtOH treatment also decreased C-promoter binding factor-1 (CBF-1)/recombination signal-binding protein (RBP)-jk promoter activity and Notch target gene (hairy related transcription factor [HRT-1] or HRT-2) expression. These effects were concomitant with an inhibitory effect of EtOH on SMC proliferation. Overexpression of constitutively active Notch 1 intracellular domain or human hairy related transcription factor-1 (hHRT-1) prevented the EtOH-induced inhibition of SMC proliferation. In vivo, Notch 1 and HRT-1 mRNA expression was increased after ligation-induced carotid artery remodeling. The vessel remodeling response was inhibited in mice that received "moderate" amounts of alcohol by gavage daily; intimal-medial thickening was markedly reduced, and medial and neointimal SMC proliferating cell nuclear antigen expression was decreased. Moreover, Notch 1 and HRT-1 expression, induced after ligation injury, was inhibited by moderate alcohol consumption. Moreover Alcohol impairs protein synthesis: the incubation of human myocytes with different doses of ethanol showed a decrease in basal protein synthesis after 24 hr, but not at earlier time points. Other effects:
- EtOH Inhibits SMC Proliferation
- EtOH Inhibits Notch Signaling in HCASMCs
- EtOH Feeding Inhibits Vessel Remodeling and Notch 1 mRNA Induction After Carotid Ligation.
Effect of EtOH on cell proliferation: the experiments were performed during the first 4 days of culture. Thymidine incorporation showed a tendency to increase for the first 3 days. Exposure of cells to EtOH for only 1 day produced a significant inhibition of proliferation at all EtOH concentrations. This inhibition increased with increasing EtOH concentration (from 10 mM to 100mM). After 2 days of EtOH exposure, the inhibitory effect of EtOH was only significant for the highest concentration (100 mM).
Effect of EtOH on cell differentiation: to determine the effects of EtOH on cell differentiation researchers measured the percentage of the three CK isozymes, which are known to change depending on the state of differentiation. EtOH (in different concentrations) was added on day 5 of the culture, as differentiation began, and the percentage of each isoform was then found to be 31.8% (MM), 14.8% (MB), and 53.5% (BB). As differentiation progressed, the percentage of MM increased to 61% and BB decreased significantly to 12.7% on day 12. Because there was no EtOH dose-dependent effect (results not shown), researchers analysed the pooled results obtained with different concentrations. MM and MB activities both decreased, whereas that of BB increased significantly after EtOH treatment. Although total CK activity did not change in the presence of EtOH, the percentage of isoforms did. The result suggests that EtOH delays cell differentiation. EtOH exerted no significant effects on DNA or protein concentrations. The effect of EtOH on these two parameters was also studied when cells were completely differentiated. As occurred during differentiation, EtOH did not affect the protein or DNA levels, and there were therefore no significant changes in protein/DNA ratio when the cells grew in the presence of EtOH.
- Alcohol Inhibits Smooth Muscle Cell Proliferation via Regulation of the Notch Signaling Pathway,David Morrow, John P. Cullen, Weimin Liu, Paul A. Cahill, Eileen M. Redmond., 2010
- Ethanol inhibits skeletal muscle cell proliferation and delays its differentiation in cell culture, J. Garriga, E. Adanero, J. Fernandez-Solà, A. Urbano-Marquez and R. Cussò, 2000
THERAPY FOR ALCOHOLIC MYOPATHY AND ALCOHOLIC CARDIOMYOPATHY
Treatment for alcoholic myopathy involves lifestyle changes, including complete abstinence from alcohol use, a low sodium diet, and fluid restriction, as well as medications. Medications for alcoholic cardiomyopathy may include ACE inhibitors, beta blockers, and diuretics which are commonly used with other forms of cardiomyopathy to reduce the strain on the heart. Persons with congestive heart failure may be considered for surgical insertion of an ICD or a pacemaker which can improve heart function. In cases where the heart failure is irreversible and worsening, heart transplant may be considered.
- Alcoholic cardiomyopathy: incidence, clinical characteristics, and pathophysiology, Piano MR., 2002
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