Muscle Pain

Muscle pain (myalgia) is a common symptom accompanying many pathologic conditions. It is usually not a reason to visit physician, short-term muscle pain is a completely natural reaction to physical stress or muscle system overload. In addition, muscle pain can be, however, caused by some serious diseases or dangerous side effect of certain medications.


Physical exercise

Physical stress causes muscle pain, especially by excessive overload of an untrained person. If you wake up with pain in certain muscle groups, it is advisable to remember previous day and realize any activity that may be responsible.

Muscle cramps

Any condition that is associated with longer-term muscle spasms leads to subsequent muscle pain and sometimes event to direct muscle damage. Severe epileptic seizures are typical example.


Most viral infections (flu, other respiratory infections etc.) is associated with general fatigue, fever and muscle and joint pain. When the infection is contained by immune system, these symptoms quickly disappear. Muscle pain accompanies also later stages of Lyme disease, tetanus and some tropical febrile infectious diseases.

Autoimmune diseases

Muscle inflammatory processes are typically by this wide group of systemic illnesses. Main symptoms are muscle pain or muscle weakness. A classic example is disease known as systemic lupus erythematosus that can affect a wide range of tissues and organs in the body. Muscles are usually painful by a rheumatic disease called polymyalgia rheumatica. Some autoimmune disorders are targeted especially against muscles such as so-called polymyositis. Muscle pain can be present but strong muscle weakness is even more typical. Polymyositis occurrence quite often accompanies malignant tumors presence.

Serum levels of minerals changes

Reduced serum potassium level (hypokalemia) can cause damage to muscle fibers and muscle pain. It is usually a severe hypokalemia when a person is most at risk of cardiac arrest and circulation failure. Similarly, muscle pain can be causes by hypocalcemia (low serum calcium level) that increases the risk of irritation and muscle spasms.


Statins belong among hypolipidemic agents and they are often prescribed by doctors of internal medicine. Their not so rare and potentially serious side effect is damage to muscle tissue resulting in pain. In blood serum we find elevated enzyme called creatine kinase (CK) that is release from damaged muscles into the bloodstream. Severe muscle damaged resulting in destruction of muscle fibers (rhabdomyolysis) is luckily very rare. If muscle pain occurs in a statin user, and CK level is elevated it is advisable to at least temporary discontinue the therapy.

Diagnostic approach

Medical history is important as always. we try to find out information about any recent physical exertion, about any present infectious process, and about patient's medication.

Blood tests should be done ito check serum ions concentrations and creatine kinase level. Increased
sedimentation rate or elevated CRP level leads to the suspicion of an inflammatory process including autoimmune disorders. When an autoimmune process is suspected, a rheumatological examination should be performed. Muscle problems are often examined by neurologists who can perform electromyography to assess information about neuromuscular signal conduction.

Jiri Stefanek, MD  Author of texts: Jiri Stefanek, MD
 Sources: basic text sources