septic bursitis Bursas, or small sacs lined with synovial cells close to joints and tendons, can become inflamed as part of most types of inflammatory arthritis but can also become infected with bacteria. Usually bacteria gain access to the bursa through superficial skin abrasions that can occur as part of usual day-to-day activities. The olec ranon (over the elbow) and the prepatellar (in front of the kneecap) bursas become infected most frequently.
The symptoms of warmth, redness, exquisite tenderness, and decreased range of motion of the joint are similar to those that occur with other inflammatory causes of olecranon bursitis such as gout or repetitive trauma. Usually septic bursitis causes more severe symptoms, but infective and inflammatory bursitis can be difficult to distinguish.
Any activity that causes friction or repeated minor trauma to a bursa can cause bursitis and increases the chance of inflammation and infection. For example, patients in nursing homes who cannot walk often develop olecranon bursitis because they rest their weight on their elbows. occupations such as carpet laying or roofing can also cause prepatellar bursitis. if bacteria gain access to the inflamed bursa, this can turn into a septic bursitis.
Because of the difficulty in knowing whether the bursa is infected, a needle is often inserted into the bursa, fluid is aspirated and then sent to the laboratory for culture. Infective bursitis is most often caused by Staphylococcus aureus infection. The infection often responds to a course of oral antibiotics that cover this organism. if the clinical response is delayed, intravenous antibiotics, repeated aspiration of the bursa, or surgical drainage of the pus may be needed. (See also bursitis.)
shingles See herpes zoster.
shoulder pain The shoulder joint is a very complex joint with numerous potential causes of pain. The design of the joint is such as to allow the greatest possible range of movement of the arm. There is a trade-off between stability and range of movement, and the shoulder joint is therefore inherently one of the least stable joints in the body. Strictly speaking, the shoulder joint should be referred to as complex since there are in fact four joints that all move together to allow normal shoulder movement.
The glenohumeral joint This joint exists between the upper arm bone, the humerus, and a shallow saucer-shaped flattening of the shoulder blade or scapula. This is what is commonly called the shoulder joint. The different joints will be referred to by their correct anatomical names to avoid confusion. Although sometimes called a ball-and-socket joint, the scapular saucer (glenoid) is far too flat to be a socket and allows the head of the humerus to slide across the surface to a certain extent during normal movement. The joint has a circular cartilage called the labrum that increases the saucer shape of the rather flat glenoid. The joint capsule that attaches to both bones, surrounding the joint and helping hold it together, has to be quite loose to allow the huge range of movement possible at the shoulder. Without muscles to hold them together the humerus would therefore simply fall away from the scapula.
The scapula To enable a greater range of movement than would exist at the glenohumeral joint itself, the scapula also moves. it does this by sliding and rotating against the back of the chest wall under the guidance of muscles that attach either to the spine or, on the other side, the humerus or upper arm bone. This is not a true joint but functions as one.
The acromioclavicular joint The scapula is joined to the main skeleton by the clavicle. The powerful upper trapezius muscle (felt as a curve when running your hand down from neck to shoulder) comes from the spine in the neck and attaches along the upper surface of the clavicle and the spine of the clavicle. The upper trapezius holds them up in the manner of one-half of a suspension bridge. The joint between the scapula and clavicle is called the acromioclavicular joint and can be felt as a hard lump and groove on top of the shoulder. The acromioclavicular joint does not move very much and has short, powerful ligaments crossing it to give good stability.
The sternoclavicular joint The clavicle (often called the collarbone) attaches to the skeleton of the chest at the sternoclavicular joint that lies just underneath the chin if this is pushed down against the chest wall. The sternoclavicular joint has to rotate quite a bit to allow normal shoulder movements to take place. it too has powerful ligaments holding it in place.
While the shape of the bony glenohumeral joint, the ring of cartilage (labrum) in it, and the surrounding joint capsule and ligaments do provide support and limit the range of movement of the humerus, muscular support is more important at this joint than at any other in the body. The muscle acting on the glenohumeral joint can be seen as being in two layers.
1. An inner ring made up of relatively smaller muscles hold the head of the humerus in place, rotate it, and initiate or counterbalance movements produced primarily by larger muscles. These are known collectively as the rotator cuff muscles.
2. The outer ring comprises a number of larger and longer muscles known as prime movers. Contraction of these muscles produces powerful movement of the arm. They often work in combination to produce the full range of movement and rely on the rotator cuff muscles to control movement of the head of the humerus.
Clearly there are many potential causes of shoulder pain. Many of these can be diagnosed by a skilled physician on examination alone. However, shoulder pain can sometimes be very difficult to diagnose. MRI scans, ultrasound examinations, X rays, and arthroscopy may all be helpful. The main causes of pain are discussed below.
Rotator cuff syndrome rotator cuff syndrome is the most common disorder seen, especially in those of middle age or the elderly. While most commonly seen as an isolated condition, it not infrequently complicates other forms of arthritis, especially rheumatoid arthritis. It is discussed elsewhere.
Calcific tendinitis Calcific tendinitis causes quite different symptoms than rotator cuff syndrome. Although some patients may have had intermittent catching at the shoulder for some time, calcific tendinitis typically presents with sudden severe shoulder pain restricting all movement at the shoulder. This condition usually affects people aged 40 to 60 years, and the supraspinatus tendon is most frequently involved. An X ray will show calcified tissue in the area of the rotator cuff tendons. Note that people may have calcification here without any symptoms, in which case it is best left alone. Ultrasound or MRI scans may show degeneration in the affected tendons. Blood tests are typically normal. Painkillers, NSAIDs, ice, and resting the arm in a sling may all help relieve pain in the early stages. Corticosteroid injections may help if there is an associated rotator cuff syndrome. Exercises to improve the rotator cuff function should be started once the pain has settled. Surgical removal of the calcium and repair of the rotator cuff tendons is occasionally required.
Biceps tendinitis The biceps muscle has two tendons at the shoulder level. One of these (the long head of the biceps) passes through the gleno-humeral joint over the head of the humerus. This, along with the rotator cuff muscles, is very important in controlling the movement of the head of the humerus. For this reason bicipital tendinitis usually occurs when there is an injury to other parts of the shoulder complex or instability of the glenohumeral joint. There are therefore usually other abnormalities as well. Most commonly this is rotator cuff impingement. Athletes performing overhead activities are particularly likely to develop this combination of injuries. Tendinitis of the long head of the biceps can occur by itself, for example as an overuse injury in weight lifters. Pain is felt in front of the shoulder, and the tender, swollen tendon can often be felt as it crosses the front of the head of the humerus in its groove. X rays may show abnormalities of the groove but are seldom done these days. ultrasound is excellent for showing the swelling around the tendon as well as the small tears in it that often set off the inflammation. MRI or arthroscopy are used to examine that part of the tendon lying inside the joint. Rest, NSAIDs, ice, and physical modalities such as ultrasound may help settle tendinitis early on. A corticosteroid injection alongside but not into the tendon is very helpful in resistant or chronic cases. Occasionally surgery is required, usually combined with other procedures such as repair of the rotator cuff. A gradual return to activities with appropriate exercises will prevent recurrence. The most important aspect of treating bicipital tendinitis is to diagnose any other disorders that may have lead to it and address them. The most common are rotator cuff problems and instability.
Biceps tendon rupture Complete rupture of the long head of the biceps occurs occasionally. In this case the muscle will bunch up a few inches below the shoulder, especially when the elbow is bent up (that is, when the biceps is contracted). There may be bruising associated with such a rupture as well.
SLAP lesions This term is used to describe tears in the labrum of the glenohumeral joint. This circular cartilage is particularly susceptible to tears in active young people with minor instability of the glenohumeral joint. SLAP stands for superior labrum anterior posterior lesion, describing the common location of these injuries. They may occur as a result of repeated minor trauma or a single episode of trauma, as when the humerus is driven up against the glenoid. MRI or arthroscopy is required to determine how severe the lesion is since treatment differs for the four grades of injury. pain relief, changes in activity, and rehabilitation may be enough but, especially in grades iii and iV, surgical treatment may be required.
Glenohumeral arthritis Arthritis of the gleno-humeral joint occurs in a various conditions. Longstanding rheumatoid arthritis very frequently causes some secondary osteoarthritis here. gout occasionally occurs, and hydroxyapatite-related arthritis particularly affects the glenohumeral joint (see MILWAUKEE shoulder). infective arthritis, neuropathic ARTHRITIS, and AVASCULAR NECROSIS of the humeral head are all rare but important causes of shoulder pain.
Subacromial bursitis The head of the humerus and glenohumeral joint lie underneath the bony projection at the tip of the shoulder called the acromion. Separating them are the tendons of the rotator cuff and a bursa, the subacromial bursa. This is a thin envelope of tissue containing synovial cells that secrete a lubricating substance into the interior that allows the rotator cuff to move smoothly underneath the bony acromion. This bursa can become inflamed (subacromial bur-sitis) if there is impingement or increased pressure such as occurs in the rotator cuff syndrome. Less commonly bursitis may follow a fall onto the shoulder. A corticosteroid injection into the bursa is very helpful in settling the inflammation but must be combined with correction of the cause. This will most commonly be a rotator cuff syndrome or a disordered scapulohumeral rhythm. The latter indicates that the precise coordination between movement of the humerus and of the scapula has been lost.
Frozen shoulder The condition commonly known as frozen shoulder is a painful limitation of shoulder movement in all directions. it is caused by capsulitis or inflammation of the capsule of the glenohumeral joint. The capsule shows an increase in fibrous tissue and shrinks, thus limiting movement of the joint. It affects about 2 percent of the population but is more common in association with certain other disorders. These include thyroid disease, tuberculosis, lung cancer, after a heart attack or stroke, and especially, diabetes. Some diabetics, 10-20 percent, will develop a frozen shoulder at some stage. Having a frozen shoulder on one side increases the risk of having it on the other side to about 10 percent. The frozen shoulder goes through three stages. The first stage is painful and lasts about three months. The second typically lasts for six months (there is less pain in this stage but worsening limitation of movement). in the third phase there is gradual lessening of pain and increase in movement. This process may take one to three years.
Acromioclavicular joint dislocation The acromioclavicular joint is commonly affected by trauma in young people and osteoarthritis in older people. pain is usually felt in a relatively small area over the joint, which is felt as a small bump and groove on top of the shoulder. pain is usually made worse by bringing the arm across the chest under the chin. The joint may be dislocated by a fall onto the tip of the shoulder. Mountain biking, ice hockey, soccer, and rugby are frequently involved. There are six grades of dislocation. The first three grades reflect varying degrees of damage to the joint ligaments but with the end of the clavicle still either touching or very nearly touching the acromion. These are usually treated conservatively with pain relief and immobilization. Type iii may require surgical treatment occasionally. When severe pain persists the end of the clavicle can be removed, and this often gives good pain relief with relatively little loss of function. in types iV to Vi the end of the clavicle is displaced well away from its original position, and surgical intervention is required to restore the connection to the acromion.
Acromioclavicular joint arthritis osteoarthri-tis is quite common in the acromioclavicular joint. This may follow injury, may occur in isolation, or may be part of a generalized osteoarthritis. pain is felt over the joint, which often develops marked bony swelling and tenderness. The pain is worst when raising the arm above shoulder height and when bringing it across the chest. X rays will confirm the diagnosis. The shoulder complex should be carefully assessed and dysfunction in the rotator cuff scapulohumeral rhythm addressed as far as possible. NSAIDs may help, and local heat and nonsteroidal creams may give temporary relief. Corticosteroid injections into the joint often give longer lasting relief and are particularly helpful before starting a shoulder rehabilitation program. Persistent pain that limits activity may require surgical removal of the end of the clavicle.
Osteolysis of the clavicle occasionally after either an injury or following repeated minor stress, the bone of the end of the clavicle is resorbed. This is termed osteolysis. There is persistent pain and limitation of movement. X rays will reveal the diagnosis by showing loss of bone at the end of the clavicle. Rest or altering shoulder movements may result in considerable improvement and even regrowth of the bone. However, surgical removal of the end of the clavicle is sometimes required.
Glenohumeral joint instability Instability at the glenohumeral joint is increasingly recognized as an underlying cause of pain at the shoulder. It may follow trauma or be due to inherent looseness of the ligaments around the shoulder or widespread laxity as found in the hypermobility syndromes. Dislocation of the joint is the most obvious manifestation but lesser degrees of instability are now more frequently recognized. Instability of the glenohumeral joint is traditionally separated into anterior, posterior, and multidirectional. It can be further classified according to how it occurred and whether it is recurrent since this will impact on the treatment.
Shoulder dislocation Anterior dislocation is often caused by trauma, with the arm held away from the body such as might occur when falling to the side and putting one's hand out to soften the fall. Initial treatment is to relocate the joint and immobilize the arm. This dislocation is often accompanied by damage to the labrum and ligaments in front of and below the joint. Young athletes frequently require surgery to be able to return to their sport, while older, less active individuals do well with conservative treatment. Posterior dislocation is much less common and seldom requires surgery.
Multidirectional instability is not often due to trauma. Although it may first be diagnosed after a traumatic dislocation, multidirectional instability will more frequently cause other painful shoulder conditions. Especially common are rotator cuff syndrome and bicipital tendinitis (see above). Shoulder rehabilitation, usually a three- to four-month intensive exercise program, is the treatment of choice, although surgical techniques which may help if there is recurrent dislocation.
In a four-year study patients with nontraumatic shoulder dislocation had a good or excellent result approximately 90 percent of the time if their dislocation was posterior or multidirectional compared with only 45 percent with anterior dislocation. In traumatic dislocation by contrast only 36 percent of posterior dislocations and 13 percent of anterior dislocations did well without surgery. Recurrent dislocation is much more common in young people when the dislocation is anterior and if it is traumatic.
Scapular pain Pain underneath the scapula or shoulder blade together with a snapping or grinding sound can be very difficult to diagnose accurately. occasionally there may be an obvious localized cause such as a bony outgrowth from an underlying rib. More often, however, it occurs with loss of scapulohumeral rhythm, and the pain comes from the soft tissues between the scapula and ribs. This is often called a bursitis. Because this area is relatively hidden from direct examination and imaging, being sure of the origin of the pain is difficult. Correcting faulty shoulder complex movements is the best treatment. The area underneath the scapula is sometimes injected, but there is a risk of puncturing the lung.
sicca syndrome See sjogren's syndrome.
sickle-cell disease (sickle-cell anemia) A genetic (inherited) disorder that results in an abnormal hemoglobin molecule and causes red blood cells to become fragile and sickle shaped. Sickle-cell disease can cause several musculoskeletal problems.
Sickle-cell disease is an autosomal recessive genetic disease. This means that someone has to inherit two abnormal genes to have the disease. People with only one abnormal gene have sickle-cell trait and usually have no clinical abnormalities. A change in a single base of the DNA code leads to a change in one amino acid of the hemoglobin chain. This hemoglobin S causes the red blood cells to be fragile, rupture easily, and sludge in small blood vessels.
Sickle-cell disease is more common in populations of African or Mediterranean ancestry. Approximately 8 percent of African Americans carry the sickle-cell gene and one in 400 has sickle-cell disease.
The symptoms of sickle-cell disease start in childhood. Because their red blood cells break more easily, affected children are anemic and jaundiced. Jaundice refers to a yellow color of the skin and eyes caused by the accumulation of bilirubin, a pigment that is the end product of hemoglobin breakdown. children with sickle-cell anemia are small and often have delayed puberty. Painful sickle-cell crises occur. These crises are often precipitated by an infection or dehydration and last several days. There is acute pain that is probably the result of an inadequate oxygen supply to deep tissues because sickled red blood cells sludge in small blood vessels.
Several musculoskeletal problems can occur in patients with sickle-cell disease.
Arthritis Acute, reversible arthralgia and arthritis are common during sickle-cell crises. More serious is chronic irreversible arthritis caused by bone infarcts in and around large joints such as the knees and hips. These infarcts cause acute bone pain, and large ones can cause avascular necrosis, particularly of the hip or shoulder.
Osteomyelitis and infective arthritis Patients with sickle-cell disease have a higher risk of developing OSTEOMYELITIS and INFECTIVE ARTHRITIS. Differentiating the symptoms of osteomyelitis from a sickle-cell crisis can be difficult. In many patients with sickle-cell disease the spleen becomes less efficient at eliminating certain bacteria, for example pneumococci and salmonellae, and infections with these organisms are common.
Bony deformities In sickle-cell disease the bone marrow is hyperactive, trying to overcome anemia. The hyperactive marrow can lead to deformities in the bones of the skull and spine. The skull becomes thickened with a prominent forehead. The vertebrae may become deformed, leading to spinal deformities.
Other musculoskeletal complications Acute painful swelling of a finger or toe (dactylitis) or the whole hand or foot can occur in infants. gout is more common in patients with sickle-cell disease because the high turnover of red blood cells leads to increased production of uric acid.
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