Photo: Pxhere

Definition

Rheumatic muscle pain varies from being slightly uncomfortable to causing extreme pain. The pain is chronic when it has lasted daily for more than three months. Rheumatic muscle pain contributes to drug use, long-term sick leave and reduced quality of life. Most often, the symptoms are harmless, such as painful, stiff and tender muscles after unusual physical activity, having slept in an uncomfortable position or when normal aging, but they can also be signs of serious underlying disease.

Causes

Muscle pain is usually not a sign of illness. Painful, stiff and tender muscles are a natural reaction after unusual physical activity or having slept in an uncomfortable position. The symptoms are then expected to gradually subside completely within a few days. In the population is leg cramps among the most common acute muscle pains. The condition is most often without a specific medical cause. With increasing age, the muscles often become more stiff and sore, especially after being at rest. Such age-related rheumatic pain is common and is distinguished from stronger, new symptoms that persist or increase over days and weeks may be signs of muscle disease or another underlying disease.

New-onset and chronic muscle pain without known cause should be further investigated by a doctor (please read more about the medical investigation below on this page).

Muscle pain may be separated in two main groups:

1. Pain due to inflammation (rheumatic inflammation or infection)
2. Pain not related to inflammation

 1. Muscle pain with inflammation (Disease sensation, signs of inflammation in blood tests)

The inflammatory muscle diseases are often characterized by other simultaneous symptoms such as new tiredness, night sweats, a tendency to fever and results in blood tests.

• Medicines. Cancer treatment with checkpoint inhibitors can trigger muscle inflammation.
• Polyarteritis nodosa (PAN) is a very rare form of vasculitis (systemic vasculitis). Symptoms are new, strong, unexplained pains, often in the calves. One feels ill and has clearly affected the general condition, often with night sweats, a tendency to fever and weight loss. Blood tests show high levels of inflammation (CRP, SR). Most are in their 60s.
• Polymyalgia rheumatica is the most common of the rheumatic inflammatory diseases that occur in old age. Most are aged 65-80, never under 50. The symptoms develop within a few days, eventually with severe stiffness in the shoulders, neck, upper arms and pelvis, hips and thighs. Most bothersome at night and in the morning, so that it can be difficult to get out of bed. Blood tests show high CRP and blood lowering reaction (SR). Creatine kinase (CK) is normal. Treatment with Prednisolone 15-20 mg/day has a good effect within a few days, but must be continued in lower doses over 1-2 years.

• Polymyositis / Dermatomyositis is a rare condition that can affect all age groups. The symptoms are diffuse at the start. Increasing muscle weakness can cause difficulty climbing stairs and hills and difficulty getting up from squatting. Not everyone has pain. Blood test shows elevated creatine kinase (CK). If the value is slightly elevated (CK<1000), a new sample is taken after 2-3 days without physical activity. Dermatomyositis has a rash in the form of red or red-violet skin, over the base and middle joints of the fingers, chest, neck or around the eyes. Some people get limescale under the skin (calcinosis). The lungs can also be attacked (heavy breathing, dry cough). See also Antisynthetase syndrome. Inclusion body myositis develops gradually and causes weaker muscles over several years, most often from the age of 50-60. Slightly elevated CK in blood tests.
• Rheumatoid arthritis (RA, arthritis) can attack at any age. Symptoms are mostly from joints, such as joint stiffness, joint swelling and joint pain. When the disease begins in older people, muscle pain is also common. In blood tests, CRP is high. anti-CCP is often detected. Creatine kinase (CK) is normal.
• Tetanus (tetanus) is caused by the bacterium Clostridium tetani and has become extremely rare with only 0-2 cases annually in Norway (Public Health) and is usually prevented by vaccine in the childhood vaccination programme. Among the unvaccinated, symptoms such as muscle cramps and jaw locking (difficulty opening and closing the mouth) can occur a few weeks after an animal bite or other infection.
• Trichinosis is caused by a parasite transmitted via insufficiently cooked or fried infected meat from pigs, wild boars or bears. The disease is very rare in Norway, with fewer than one case per year.
• Tropical disease (infection) can cause severe muscle pain. Dengue Fever also called "Breakbone fever" because of extremely strong muscle pain.
• Viral infections often cause temporary symptoms like the flu, but also with Hepatitis B.
• Vasculitis diseases of various types causes muscle pain. Polyarteritis nodosa (PAN) is mentioned above, but also granulomatosis with polyangiitis (GPA) / Wegener's granulomatosis may begin with symptoms from muscles.

2. Muscular pain without inflammation

The incidence is high. The underlying causes are many, but often not detectable. Night sweats, fever and weight loss are unusual and blood tests are usually normal.

• Depression can intensify rheumatic symptoms, but can also be a consequence of long-term pain.
• Diabetes mellitus can rarely damage the muscles due to reduced blood circulation (muscle infarction)
• Vitamin D deficiency. Muscle pain is a rare symptom, 25-OH vitamin D in a blood test is extremely low and is often due to incorrect nutrition and lack of sunlight over a long period of time.
• Fibromyalgia is a common condition, especially among adult women. Typically, chronically painful muscles throughout the body with increasing symptoms after exertion. The condition is also called generalized chronic muscle pain syndrome.
• Claudication is due to poor blood circulation such as blood clots, atherosclerosis or Vasculitis that Takayasu arteritis). Symptoms are pain in the leg(s) or arm(s) during physical exertion or when the arm/leg is held high.
• Compartment syndrome, muscle lodge syndrome can occur after injury, overload or exercise. The symptoms are severe pain in the damaged muscle due to swelling, pressure and reduced blood circulation.
• Hyper-parathyroidism is hyperfunction of one of the bi-thyroid glands. These are located on the neck and can produce too much of the hormone PTH (parathyroid hormone), which causes too much calcium in the blood. Some people also have too little 25-OH vitamin D (secondary form). The symptoms can be laxity and weak muscles.
• Mitochondrial disease are rare, but serious, muscle diseases that occur in children and young people.
• Multiple Sclerosis (MS) is a disease of the nerves that often also causes muscle pain.
• Muscular Dystrophy is a group of rare, hereditary muscle diseases that most often begin among children and young people.
• Muscle cramps are usually harmless and without an underlying disease. In case of increasing, strong symptoms, further investigations are appropriate.
• Muscle pain syndrome can be chronic and generalized as in Fibromyalgia or located in parts of the body. Symptoms can include the arms, legs, neck, pelvis and back. Normal blood tests are expected.
• Muscle tension is most often felt in the neck with tension headaches or related to back pain. Normal blood tests are expected.
• Parkinson's disease is a nerve disease characterized by stiffness, tremors in the hands, reduced facial expressions and walking with short steps. Muscle pain and stiffness can sometimes be reminiscent of rheumatic disease. Normal blood tests are expected.
• Post-polio syndrome causes chronically painful muscles in people who have had the nerve disease poliomyelitis in the past.
• Rhabdomyolysis is an acute, serious injury in which large numbers of muscle cells die. The cause may be physical overload, injury or poisoning. In the blood, creatine kinase (CK) is very high, often 10.000-100.000. A tissue sample ensures the diagnosis.
• Statins are widely used cholesterol-lowering drugs. Muscle pain is a common side effect, while muscle inflammation is less common.
• Stiff person syndrome is a very rare but dramatic nerve disease
• Metabolic disease in the form of hypothyroidism due to low metabolism. Stiffness and pain in muscles, feeling cold, weight gain and fatigue are typical, most often among women. Blood tests show high TSH, low f-T4
• Fatigue syndrome (CFS / ME) can cause muscle pain in addition to extreme unexplained fatigue.

Symptoms

Muscle pain can be related to stress or constant even at rest. Some of the conditions improve with physical activity, while others worsen. The intensity varies from slight tenderness and irritation to intense pain. The localization can be in the neck, shoulders, pelvis or hips (proximal) or in the forearms and calves (distal). Fever, increased heat over muscles, swelling, objective muscle weakness, paralysis, new neck stiffness combined with a feeling of illness, swallowing or breathing difficulties can be alarm symptoms/red flags that must be clarified quickly.

Examinations

Medical history in the case of muscle pain includes hereditary dispositions, typical symptoms (see above), intensity and duration. Affected physical activity and other chores are of interest.

Clinical examination includes observing the shape and size of the muscles, any spontaneous movements, twitches or signs of tension. Pain on light pressure, loss of strength (getting up from the chair and from squatting without support). Skin symptoms such as eczema or redness and signs of neurogenic outcomes are also of interest.

Laboratory tests may include CRP, SR, Hgb, white blood cells (leukocytes with differential counts), platelets (platelets), liver, kidney and thyroid function tests, electrolytes with potassium and calcium, glucose, CK (creatine kinase), anti-nuclear antibody (ANA). Urine sticks.

Imaging may be relevant if you suspect special conditions. MRI shows signs of damage, infection or inflammation in muscles. In the case of general muscle weakness, the thigh muscles are most often examined. In case of symptoms, a CT scan of the lungs is appropriate.

Tissue sample (biopsy) done in case of suspicion Myositis, non-inflammatory myopathy, rhabdomyolysis or other specific problem where damage to muscle tissue is relevant.

EMG (electromyalgia) may show signs of neurogenic muscle disease.

Diagnosis

Harmless conditions are most common, but certain symptoms indicate the need for further investigation and treatment. The cause of muscle pain is determined on the basis of symptoms, age of onset, duration, location and various examinations (see above).

Treatment

Mild symptoms are expected to resolve spontaneously. If necessary, relieve a limited period of time so that you avoid activity that causes the pain. One can use light pain relievers such as paracetamol or NSAIDs against the symptoms. More extensive muscle pain and increasing symptoms are treated specifically depending on the underlying cause (see above).

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