CHAPTER 2 Regional musculoskeletal conditions 140 mandatory. Bone scan may be nonspeci \201 c in this setting, but can be useful to diagnose complex regional pain syndrome. MR of the whole foot or swollen area is the quickest way to an advanced differential diagnosis. Where swelling, pain, and tenderness coexist, infection must be ruled out using imaging. If it cannot and suspicion remains, tissue or \202 uid sampling should be undertaken. In mo st cases it is appropriate to do this under general anesthesia. Complex regional pain syndr ome should be excluded before any intervention. Laboratory tests Any possibility of joint synovitis (most likely at the ankle), enthesitis, ten- donitis, or infection requires investigation with laboratory tests: \200 ESR and CR P are likely to be raised in cases of in \202 ammatory arthritis and infection, and are more likely to be normal or only slightly increased in oligoarticula r JIA and juvenile ERA compared with polyarticular and systemic JIA or infection. Normochromic anemia ( mild microcytosis) is a nonspeci \201 c sign of a systemic conditi on. CBC may be normal in oligoarticular JIA. Leukocytosis is typical with infection, with s teroids and in systemic JIA. Thrombocytosis can be seen in all forms of JIA. If the ESR and CRP are elevated, but the pl atelet count is low, malignancy should be considered. Moderately elevated titers of ANA may be present in 40 \200\22375% of patients with oligoar ticular JIA; a positive ANA is a risk factor for associated uveitis. Even minimally symptom atic uveitis can threaten vision if not treated. Check for circulating rheumatoid factor (RF) and anti-citrullinated protein antibodies (ACP A) in cases of synovitis. High titers are expected in (RF+) polyarticular JIA. Treatment Lower leg disorders \200 Anterior shin pain should be treated according to caus e. \200 Treat foot alignment problems with appropriate orthotics. \200 Review diagnosis if conservative treatment fails, e.g., is there an underlying stress fracture or periostitis? Consider obtaining a bone scan. Ankle and foot disorders \200 The management of bony anomalies/deformities should be disc ussed with an orthopedic surgeon and physical therapist early, to avoid missing an opportun ity to prevent growth abnormalities. Be aware that soft-tissue steroid injection of a presumed local lesion may impair healing/g rowth at apophyses and may aggravate the symptoms of (missed) complex regional pain syndrom e. \200 Consider intra-articular steroid injection of speci \201 c joints in oligoarticular JIA if joints can be clearly identi \201 ed by bone scan or MR. Use of seda tion (adolescents) or light general anesthesia (toddlers/ children) may be appropriate. This page intentionally left blank CHAPTER 2 Regional musculoskeletal conditions 142 Corticosteroid injection therapy Background \200 Local anesthetic and steroid injection i nto joints or soft tissues is a very effective treatment for localized pain. Injection offers a local maximal anti-in \202 ammatory effect with minimal systemic absorption. The indications for local steroid injection include: to reduce in \202 ammation in joints, entheses, tendon sheaths and bursa; to relieve pain from in \202 ammatory ligament lesions; to relieve in \202 ammation at sites of nerve compression; to attempt to reduce the size of nodules and ganglia; to relieve pain at trigger points; a nd as part of epidurals. The contraindications are: Absolute: \200\224 septic arthritis/septicemia \200\224 febrile patient, cause unknown \200\224 se rious allergy to previous injection \200\224 sickle cell disease Relative: \200\224 neutropenia, thrombocytopenia \200\224 anticoagulation or bleeding disorder. Hydrocortisone acetate is a short-acting, weak anti-in \202 ammatory, useful for super \201 cial lesions such as tendons and bursae. A dose of 25 mg is typical. Methylprednisolone acetate (40 mg/ml), prednisolone acetate (25 mg/ ml), and triamcinolone acetonide (10 and 40 mg/ml) are long-acting synthetic agents suitable for joint injections. Small joints accept only a small volume; thus, for IPs, MCPs, MTPs, ACs, and TMs, 0.5 ml of triamcinolone acetate (10 mg) is appropriate. All other joints shou ld accept at least 1ml. Choice of strength of steroid remains empiric. There may be merit i n diluting the steroid in sterile saline, to increase volume for better distribution in lar ger joints. The patient should be warned of potential, though uncommon, side- effects: \200 exacerbation of pain for 24 \200\22348 h \200 septic arthritis and reacti vation of TB \200 tissue atrophy (less likely with hydrocortisone than others) \200 dep igmentation \200 anaphylaxis \200 nerve damage \200 tendon rupture \200 avascular n ecrosis \200 cartilage damage \200 soft-tissue calci \201 cation \200 temporary exac erbation of hyperglycemia in diabetes. As a general rule it is recommended that any one joint should not be injected more than fou r times in 12 months and there are at least 6 weeks between injections. Children and some adolescents usually require a light general anesthetic for most joint injections given the procedure can be quite CORTICOSTEROID INJECTION THERAPY 143 traumatic. An alternative for older children or those who have had many injections done bef ore is to use local anesthetic gel pads (e.g., EMLA patch) to numb skin adequately befor e the injection. Principles of injection techniques The procedure need not necessarily be done in a sterile environment. Some steps below illustrate the need to maintain relatively aseptic conditions : \200 Mark the exact spot of needle insertion. \200 Wash hands. Use sterile gloves for procedure. \200 Clean the skin with povidone-iodine and allow to dry. \200 Anesthetize the skin (either with local anesthetic or refrigerant alcohol spray). Insert clean needle with empty syringe and aspirate back. \200 Leave needle in place, det ach syringe, and place syringe containing drug onto end of needle. Pull back syringe plunger again before injecting to con \201 rm placement. \200 Introduc tion of steroid should be effortless. Resistance implies that the needle is in the wrong space. On completion, remove syringe and needle and throw away \200\234sharps \200\235. \200 Co ver the injection site with clean gauze or bandage. \200 Re-emphasize possible side effec ts and bene \201 ts. The glenohumeral joint \200 The anterior route gives reliable acces s in patients with adhesive capsulitis. It is also better suited for aspiration of joint ef fusions. Palpate the coracoid process anteriorly and the acromion posteriorly. The injection is made just lateral to the coracoid with the needle pointing toward the acromion. The posterior route requires the clinician to palpate the spine of the scapula with the thu mb to its lateral end where it bends forward as the acromion. With the fore \201 nger then palpate the coracoid anteriorly. The line between \201 nger and thumb then marks the pos ition of the joint line. The needle is advanced from behind, 1 cm below the acromion, and t oward the coracoid. There should be no resistance. \200 Withdrawing the needle slightly, and redirecting 30 upward will allow you to reach the rotator cuff with the same procedure! Subacromial articulation and acromioclavicular joint \200 The subacromial bursa is approa ched from the lateral side. To inject this space, the arm is placed in a neutral position, hanging to the side, and the gap between the acromion and the humeral head is palpated. The needle is directed medially and slightly posterior and not too deep (see Plate 13). The AC joint is located by following the clavicle laterally. The joint is often tender to p alpate. The patient lies supine and a small gauge needle with 0.5 ml of steroid is directed into the joint at about 45 anteriorly. The elbow joint and periarticular elbow structures \200 Lateral humeral epicondylitis is injected with the elbow resting on the examination table and \202 exed at 90 . This supe r \201 cial injection is CHAPTER 2 Regional musculoskeletal conditions 144 directed at 45 to the end of the common extensor tendon origin. A fair amount of pressure is required for this injection. It is often painful (see Plate 14). The medial humeral epicondylitis is managed similarly. The needle is directed to the \202 exor tendon origin. However, care should be taken to avoid the groove just behind the medi al epicondyle \200\224the site of the ulnar nerve. An olecranon bursa can be aspirated and injected super \201 cially with minimal effort. Needle position is con \201 rmed by the aspiration of \202 uid. The elbow joint is most easily reached by a posterior approach. Place the thumb on the lateral epicondyle and the third \201 nger on the olecranon. The g roove between the two \201 ngers identi \201 es the joint line. Inject at 90 to the sk in, just above and lateral to the olecranon. Alternatively the radial head can be palpated (with forearm pronation/ supination) and the needle sited tangentially just under the capsu le (anterolateral approach). Lesions of the wrist \200 The radiocarpal joint is best felt with the patient \200\231s h and held palm down and the wrist in slight \202 exion. A triangular gap is felt between the radius and the carpal bones. The needle is pointed proximally and at 60 . The carpal tunnel is injected on the palmar surface of the wrist in the \201 rst crease. If the palmaris tendon is present the injection should be sited just medial (i.e., closer to the \200\234little \201 nger \200\235) to the midline, by about 1 cm, and toward the palm at 45 . There should be no resistance on injection or nerve pai n (see Plate 15). De Quervain \200\231s tenosynovitis should be injected at the point of maximal tenderness, tangentially along the line of the tendon sheath. The hand \200 The small joints of the hand will normally only accept 0.5 \200\2231 ml of injected \202 uid. It is important to remember that the joint line of an MCP is about 1 cm distal to the crest of the knuckle. The approach to a PIP is from the lateral side. PIPs and DIPs are often dif \201 cult to inject. Accuracy of needle placement within a joi nt space might be improved by using US guidance. Ef \201 cacy may be greater using US-guided injection though as yet this is unproved. Hip joint and periarticular hip lesions \200 Hip injection is not a routine outpatient pr ocedure and aspiration and injection under US or \202 uoroscopic guidance is recommended. \200 Meralgia parestheti ca occurs as a consequence of lateral cutaneous nerve entrapment as it traverses the fascia 10cm below and medial to the anterior superior iliac spine. If this spot can be clearly demarcated because of localized tenderness, steroi d injection has a greater chance of success. The ischial tuberosities are located deep in the medial side of the buttocks. The overlying bursae can become in \202 amed, causing pain on CORTICOSTEROID INJECTION THERAPY 145 sitting. These tender points can be injected. The differential diagnosis is enthesitis or p ossibly coccydynia. The coccyx can be palpated centrally (with the patient prone or lying on their side). This site is also amenable to local anesthetic and steroid injections. Adductor apophysitis occurring from a sports injury can be injected simply although it can be dif \201 cult to access. An in \202 amed symphysis pubis is best injected under US gui dance. Trochanteric bursitis or enthesitis at the greater trochanter can be injected with the pati ent lying on their good side. The injection site can be very deep and to reduce the risk of fat atrophy from a \200\234blind approach \200\235, it is reasonable to try using hydroco rtisone \201 rst. The site of injection should be chosen based on the point of maximal te nderness. Injection failure should raise the possibility of poor needle position or a diffe rent diagnosis, e.g., gluteus medius muscle tear at its insertion or pain referred from a l umbosacral disorder. The knee joint and periarticular lesions \200 The most common technique for injection of the knee joint is either the lateral or medial retropatellar approach. From the lateral side, the joint line is marked between the upper and middle third of the p atella. Access to the joint space may be improved by depressing the medial aspect of the pa tella, tipping it up laterally. The needle is advanced tangentially between the patella and the femoral condyle. The entry site for the medial approach is below the midline of the patella, with the needle advanced tangentially toward the suprapatellar pouch. \200 In both techniques, aspiratio n as the needle is inserted will reveal \202 uid as soon as the capsule is entered, so re ducing the risk of forcing the needle too far forward causing cartilage damage. Prepatellar bursitis, painful ligaments, and trigger points around the knee may all respond to local steroid and anesthetic. Popliteal cysts can be directly aspirated and injected but due to the risk of damaging super \201 cial neurovascular structures, should be done under US guidanc e. Ankle and foot disorders \200 The ankle joint is located most easily with the patient sup ine on a couch. The joint line can be palpated just lateral to the extensor digitorum tendo n as it crosses the ankle crease. The needle is initially advanced downwards over the talus . Tendon sheaths and the tarsal tunnel can all be injected; the latter is injected under the \202 exor retinaculum between the calcaneum and the medial malleolus. Painful points under the heel should be injected from the medial side after carefully local izing the position of maximal pain. Never inject through the sole of the foot. Some clinici ans will numb the area by local anesthetic to the posterior tibial nerve, in the tarsal tun nel. \200 The MTPs are injected from the lateral side. Care should be taken as these join ts have a greater than normal risk of infection after the procedure. CHAPTER 2 Regional musculoskeletal conditions 146 Principles of rehabilitation Adults \200 It is beyond the scope of this book to address t he many techniques employed in rehabilitation. The reader is encouraged to discuss and obse rve the management of patients with arthritis with the rehabilitation team. In the last decade, the development of a multidisciplinary approach to rehabilitation has transformed the way most rheumatologists think about disability. Two main types of measurement exist for assessing outcome in rehabilitation (beyond the various scoring systems for particular diseases). Generic measures take a global view of disability and afford later comparison. Generic meas ures also help in assessing different programs, populations, and practices. Speci \201 c m easures deal with the individual patient and their function in their own environment. No one instrument will suf \201 ce and there are now many well-validated disability scores: \200 Ritchie index \200\224impairment \200 Health Assessment Questio nnaire \200\224disability \200 SF36 \200 Beck depression score \200\224depression \200 Spielberg score \200\224anxiety \200 Sickness Impact Pro \201 le (SIP) \200 Multidim ensional pain inventory \200\224psychological response to pain and disability. Important components of rehabilitation for patients with arthritis include: \200 a coordinated team \200 problem-solving approach \200 functionally rele vant program \200 education \200 community orientated \200 cognitive and psychologica l behavioral therapy \200 addressing social factors e.g., work, housing etc. \200 acces s to support services \200 commitment to long-term follow-up and reassessment. Ideally, the team will consist of doctors, specialist nurses, physical therapists, occupational therapists, counselors, psychologists, dieticians, physiatrists, a nd social workers. Childhood There are important additional issues to consider in the management of children: \200 A child \200\231s rheumatic disease always has an impact on their family. Many normal activities are impossible or time-consuming, and \201 nancial hardship is common. Siblings may feel neglected and parents are often overburdened with tasks and worries to fo cus completely on the family. The \200\234team \200\235 aims to share that burden and assi st the whole family. PRINCIPLES OF REHABILITATION 147 The child should be integrated in school ( \200\234mainstream \200\235 preferably) and soci al life as much as possible. It is important to achieve the highest level of integration, h opefully ceasing a child \200\231s perception of sickness and difference, acquiring a sense of belonging and purpose. The therapist will spend as much time preventing deformity in early disease as dealing with chronic disability, the aim being to maintain or restore function. For a child with chronic progressive disease, a regular, often daily, therapy program is ne cessary. The best way to guarantee this is to involve the parents or care provider. With ed ucation on the role of splints/exercise and the impact of rehabilitation on disease progres sion, most parents are eager and capable participants in the therapy. \200 Joint protecti on training is important \200\224proper positioning, use of several joints in a task, safe transfer of loads, avoidance of prolonged position, planning of rest breaks, and adapted aids and devices should all be addressed. Chronic diseases may elicit different emotions in different children \200\224 often frustration with lack of mobility in the young, and peer group issues and psychosexua l anxieties in the adolescent. Positive adjustment, focusing on strengths not weakness, is important, as is the constant awareness of such issues in those that make up the support st ructure. Competence comes in many forms, not simply physical ability, and should be praised at every level, building a child \200\231s self- esteem. Many children who have learned to cope with their disease develop a more mature personality earlier than others in their age group. As such, the adolescent may be earlier and better quali \201 ed to bid for an independent life despite physical limitations. It is important to ensure they are not held back. Adolescents At some point in a patient \200\231s development from childhood to adulthood, t he pediatric physician must start to relinquish care to the adult physician. This phase of patient management, the transition, should be handled care- fully. Some important principle s to consider are stated below. \200 Transfer should only occur when a young person feels ready to function in an adult clinic. From an early stage, adolescents should be encouraged to take responsibility for medications. The whole concept of independence should be introduced well ahead of an anticipated transfe r time. This could be introduced at about the age of 11 years and encouraged by trying to s ee the adolescent by themselves for part of their consultation by the time they are 13 \200 \22314 years of age. A schedule of events leading to \200\234transition \200\235 and \201 nally to transfer o f care should be drawn up. Adolescents should be given information on health care rights and taught how to recognize c hanges in their disease (good or bad) and how to seek help from health professionals. This page intentionally left blank 149 Chapter 3 Patterns of disease presentation: making a working diagnosis Monoarticular pains in adults 150 Oligoarticular pains in adults 152 Oligoarticular pains i n children and adolescents 162 Widespread pain in adults 170 Widespread pain in children an d adolescents 186 CHAPTER 3 Patterns of disease presentation 150 Monoarticular pains in adults \200 When evaluating a patient with joint pain, it helps to know the number of joints involved, i.e., monoarticular (one joint), oligoarticular (2 \200\2235 joints), or polyarticular (> 5 joints). Each of these patterns is associated with its own differential diagnosis. The assessment of speci \201 c joints is discussed in detail in chapter 2. However, the evaluation of a single, hot swollen joint \200\224particularly the knee \200 \224comes up so frequently, a few points bear repeating. When evaluating an acute monoarthritis, it is helpful to remember that the most common causes include infection, crystals, and fracture. Diagnosis of fracture may be obvious from the clinical history, but may require a high inde x of suspicion. Stress fractures occur as the result of repetitive loading of bone, and can be found with occupational, recreational, or athletic activities. Stress fractures may be small, and, therefore, can be missed on plain radiographs; MRI may be more sensitive and sh ould be considered if the patient is at risk. The most common cause of an acute monoarthritis in a young adult is gonococcal arthritis. This most frequently affects the knee, although other joints may b e affected as well. Gonococcal arthritis responds rapidly to antibiotic therapy; the speed of the response often helps con \201 rm the diagnosis. Crystalline arthropathies such as gout or pseudogout should be considered in older adults. Gout in particular can lead to a highly in \202 ammatory arthritis; it can be accompanied by a gouty tenosynovitis that can mimic a cellulitis. In addition to causing a monoarticula r arthritis, pseudogout may also mimic rheumatoid arthritis and osteoarthritis. Nongonococcal septic arthritis is particularly important to consider in the elderly, who ma y not present with the signs and symptoms expected with infection. Nongonococcal septic art hritis is a rheumatologic emergency, and should be treated with intravenous antibiotics and joint aspiration. Although S. aureus is the most common culprit, in the elderly, it is pru dent to consider less common infections (e.g., Gram negative). Also remember that the prese nce of crystals does not completely exclude the possibility of a co-existing infection. Finally, remember that rheumatic disease that is destined to evolve into an oligoarticular or polyarticular disorder may initially present as a problem with a single joint. Because l ong-term outcomes of rheumatoid arthritis in particular are improved by early treatment, it is always appropriate to consider at least a serologic screening for this disorder (e.g., RF, ACPA) in a patient with a monoarthritis for whom the underlying etiology is unclear. This page intentionally left blank CHAPTER 3 Patterns of disease presentation 152 Oligoarticular pains in adults Background The assessment of an in \202 amed joint \200 T he clinical features of in \202 ammation and pain at any given synovial joint and the diff erential diagnosis in the context of other possible regional musculoskeletal diagnoses are discussed in Chapter 2. Synovitis is the term g iven to in \202 ammation of the synovial lining. This in \202 amm ation may be a consequence of a range of cellular processes, and is not speci \201 c for a ny one diagnosis. Joint effusions often accompany synovitis. In \202 ammation of periarticular tissues may accompany synovitis. Enthesitis (i.e., in \202 ammation where tendon inserts into bone) or tenosynovitis may be the most prominent feature. The differential diagnosis of synovitis includes hemarthrosis, which can be due to a number of causes, including trauma, bleeding disorder, vitamin C de \201 ciency, synovial hemang ioma, and pigmented villonodular synovitis (PVNS). Table 3.1 lists the most common causes of oligoarticular joint pain. History: general points \200 Pain and stiffness are typical features of synovitis and ent hesitis; both are often worse in the morning, or after other periods of immobility. The pre sence or absence of stiffness does not discriminate between different causes of synovitis. Pain is often severe in acute joint in \202 ammation. In chronic situations, pain may be l ess severe (due to mechanisms that increase physical and psychological tolerance). There ar e no speci \201 c descriptors that discriminate pain from synovitis or enthesitis. Swelling, either due to synovial thickening or effusion, often accompanies synovitis. Enthesitis may be associated with periarticular soft tissue swelling . A patient \200\231s report of swelling is not always reliable. Patients with carpal tunnel syndrome, for example, will frequently report that their hands are swollen, even when no sw elling is visible. Reduced mobility in a joint affected by enthesitis/synovitis is almost universal regardless of its cause. Examination: general points \200 Swelling may be observed or detected by palpation. Its a bsence does not rule out synovitis or enthesitis. Synovial swelling needs to be discriminat ed from bony swelling, fat, and other connective tissue swellings (e.g., ganglia, nodules, etc.). Without imaging or attempting to aspirate joint \202 uid, it may be dif \201 cult to discriminate synovial thickening from effusion. Skin erythema (implying periarticular in \202 ammation) and warmth do not always accompany joint in \202 ammation, but they are common with crystalline and sept ic arthritis. Erythema can also occur in reactive arthritis, rheumatic fever, and with nasc ent Heberden \200\231s/Bouchard \200\231s nodes in OA. OLIGOARTICULAR PAINS IN ADULTS 153 Table 3.1 The most common causes of monoarticular and oligoarticular joint pain and typical patterns of presentation Disease Typical pattern Gout (Chapter 7) Age >40 years. Initially presents as an acute monoarthritis. Strong association with hyperu ricemia, renal impairment, and diuretics. Possible general symptoms mimicking sepsis. Possi ble family history. Acute phase reactants and serum WBC often high. Joint \202 uid urate crystals seen by PLM. Joint erosions (radiographically typical) and tophi occur in chronic disease Spondyloarthritis (Chapter 8) Age <40 years, men more than women. Mostly oligoarticular lower limb joint enthesitis/synov itis. May occur with sacroiliitis, urethritis or cervicitis, uveitis, gut in \202 ammation , psoriasis (scaly or pustular). Possible family history. ESR/CRP may be normal. More sever e course if HLA B27-positive. CPPD arthritis (Chapter 7) Mean age 72 years. Oligoarticular, acute monoarticular (25%) and occasionally polyarticular patterns of synovitis Hemarthrosis Obvious trauma does not always occur. Swelling usually considerable. Causes include trauma (e.g., cruciate rupture or intra-articular fracture), pigmented villonodular synovitis, ble eding diatheses, and chondrocalcinosis Osteoarthritis (Chapter 6) Soft tissue swelling is usually not as obvious as bony hypertrophy (i.e., osteophytes). Typ ical distribution (e.g., \201 rst carpometacarpal and knee joints) Rheumatoid arthritis (Chapter 5) Can initially present with an oligoarthritis that evolves into a symmetric polyarthritis. C an rarely present as an acute monoarthritis. Septic arthritis (excluding N. gonorrhea) (Chapter 17) Most common cause = Staphylococcus aureus. Associated with chronic arthritis, joint prosthe ses, and reduced host immunity. Peak incidence in elderly. Systemic symptoms common and som etimes overt, but may not occur. Synovial \202 uid is Gram stain positive in 50% of cases and culture positive in 90% of cases Gonococcal arthritis (Chapter 17) Age 15 \200\22330 in urban populations and with inherited de \201 ciency of complements C5 to C9. One form presents as an acute septic monoarthritis. Organism detected by Gram stain of joint \202 uid in 25% and by culture in 50% in the second group CHAPTER 3 Patterns of disease presentation 154 Tenderness of thickened synovium is common but is not always present. Severely tender swelling suggests joint infection, hemarthrosis or an acute in \202 ammatory reaction to crystals. In \202 ammation of entheses results in \200\230bony \200\231 tenderness at joint margins and sites of tendon or ligament insertion. Decreased range of motion is almost always demonstrable in a joint affected by synovitis or enthesitis. The degree to which passive and active range of motion is reduced depends on a number of often interdependent factors (e.g., pain, size of effusion, periarticular muscle weakness or pain). Movement of a joint affected by synovitis or enthesitis will induce pain. Affected joints w ill demonstrate reduced range on active or passive range of motion exercises. Taking a history Age, sex, and occupation The age, sex, and occupation of the patient give nonspeci \201 c but important clues in many cases: \200 Oligoarthritis is uncommon in yo ung adults. SpA, especially reactive arthritis, is likely to be the main cause. 75% of pati ents who develop reactive arthritis are less than 40 years old. Gout typically occurs in those more than 40 years old, and is the most common cause of in \202 ammatory arthritis in men (self-reported in 1 in 74 men and 1 in 156 women). The mean age of patients with calcium pyrophosphate dihydrate (CPPD) arthritis is about 72 years (range 63 \200\22393 years). Patients in areas endemic for tick infection with Borrelia are at risk of Lyme arthritis. I n 2003 \200\2232005, 93% of Lyme cases in the United States occurred in 10 endemic states: Connecticut, Delaware, Maryland, Massachusetts, Minnesota, New Jersey, New York, Pennsylvan ia, Rhode Island, and Wisconsin. Which joints are affected? Some processes are more common in certain joints than others: \200 Shoulder synovitis is typical in hydroxyapatite arthritis (Milwaukee shoulder/knee syndrome) and AL amyloidosis. Involvement of a shoulder or hip is extremely unusual in gout. \200 CPPD arthritis (as ps eudogout) occurs rarely in the small \201 nger joints. \200 The knee is the commonly in volved in acute crystalline arthropathy and septic arthritis (both gonococcal and nongonococcal). Large knee effusions are common with Lyme arthritis, but this is a nonspeci \201 c \201 nding. Large effusions can also be seen with septic and psoriatic a rthritis. In theory, there are many causes of synovitis in a single \201 rst MTP joint but the majo rity of cases are due to gout; 50 \200\22370% of \201 rst attacks occur in this joint. Preceding factors Factors preceding swelling of a single joint or oligoarthritis may be hig hly relevant. These include infection and trauma: OLIGOARTICULAR PAINS IN ADULTS 155 Acute nontraumatic monoarticular synovitis is most commonly due to crystal-induced synovitis or synovitis associated with SpA. A preceding history of trauma typically suggests intra-articular fracture (which may cause hemarthrosis), a meniscus tear (knee), or an intrarticular loose body such as an osteochondral fragment (which may cause the patient to complain about a \200\234loc king \200\235 knee). Twinges of joint pain often precede an acute attack of gout. Acute arthritis occurs in 25% of patients with CPPD arthritis. In hydroxyapatite arthritis, synovitis is usually mild-to-moderate, gradual in onset and typically worse at night. An acute monoarthritis with fever in familial Mediterranean fever (FMF) is a mimic of septi c arthritis. Such joint manifestations are present in up to 75% of cases. Septic arthritis should always be considered (and promptly ruled out) as a cause of acute joint swelling (see Chapter 22). Crystal arthritides Crystal arthritides are associated with nonmusculoskeletal conditions: \200 Hyperuricemia, causes of which include obesity, renal insuf \201 ciency, tumor lysi s syndrome, myeloproliferative diseases, and hemolytic anemia, is associated with gout. Saturnine gout, which is associated with lead exposure (e.g., moonshine, welders), is more likely to lead to polyarticular attacks. Hypertension and hypertriglyceridemia are associated with gout. \200 A history of renal s tones (urate) may be a clue to hyperuricemia and associated gout. Attacks of gout and CPPD arthritis can be precipitated by any nonspeci \201 c illness, trauma, or surgery. The most common associated metabolic disorder is hyperparathyroidism (10% of cases). Though uncommon, hypomagnesemia, hypophosphatasia (low alkaline phosphatase activity), hemochromatosis, Wilson \200\231s disease, and ochronosis are all as sociated with CPPD arthritis. Calcium oxalate crystal arthritis can be seen as a rare compl ication of hemodialysis. Link with infection Many types of infection are linked to oligoarticular arthritis. Often a high index of suspicion is needed to make a link: \200 Speci \201 c infections are dire ctly or indirectly associated with arthritis. \200 Viruses, bacteria, protozoa, helminthe s, and fungi can all directly invade joints. The range of systemic features is wide and pat hogens can cause both polyarticular and oligoarticular patterns of joint involvement. \200 The infections recognized to trigger reactive arthritis are Salmonella, Yersinia , Shigel la , Campylobacter and Chlamydia . The development of reactive arthritis in those who acqui re chlamydial (nongonococcal) urethritis is relatively uncommon (about 1 in 30). Acute HIV infection is associated with a subacute oligoarthritis commonly involving knees and ankles. Chronic arthritis, diabetes, immunode \201 ciency, and joint prostheses are all risk factors for septic arthritis. CHAPTER 3 Patterns of disease presentation 156 Lyme disease should be considered a cause of oligoarthritis in patients with a remote histo ry of erythema chronicum migrans (i.e., macule/ papule initially, expanding 0.5 \200\2231 c m/day to a mean diameter of 15 cm (range 3 \200\22368 cm), often fading without treatment i n 3 \200\2234 weeks). \200 Migratory arthritis is typical in untreated rheumatic fever; h owever, persistent monoarthritis is a common \201 nding in treated patients. \200 A his tory of circumcorneal eye redness with pain, photophobia, and blurred vision may be due to anterior uveitis most commonly associated with SpA but als o seen with sarcoid, Beh et \200\231s, and Whipple \200\231s disease. Family and social history There may be important clues from the family and social history: \200 Both gout and SpA have a familial component. Between 6 and 18% of patients with gout also have a family history of gout. There may be a family history of SpA or uveitis in pat ients who have reactive, psoriatic, or enteropathic arthritis or AS. Gout in young adults suggests an inherited abnormality (usually increased urate production from 5-phosphoribosyl-1-pyrophosphate synthetase activity, since the other enzyme de \201 ciencies present in childhood). Excessive alcohol consumption is associated with gout. Alcohol can also contribute to lacti c acidosis that inhibits urate breakdown. \200 Consider Lyme disease if patients live, wo rk, or visit endemic areas. Outside of the United States, this includes Europe, Russia, China, and Japan. Peak incidenc e occurs during the summer. Brucellar arthritis is generally monoarticular and occurs primarily in areas where domestic ated animals are infected and poor methods of animal husbandry, feeding habits, and hygiene standards coexist. Ask about other associated features Associated extra-articular features include previous ey e, gastrointestinal, cardiac, and genitourinary symptoms: \200 Low-grade fever, malaise, and anorexia occur commonly in both septic arthritis and gout. Marked fever can occur in go ut and only occurs in about a third of patients with septic arthritis. Ask about any current or previous features which might suggest SpA: back or buttock pain (e nthesitis or sacroiliitis); swelling of a digit (dactylitis); plantar heel pain (plantar fa sciitis); red eye with irritation (anterior uveitis); urethritis, balanitis, cervicitis or acute diarrhea (reactive arthritis); psoriasis; symptoms of in \202 ammatory bowel disease . Beh et \200\231s disease (see Chapter 18) can cause an oligoarthritis. Other features include painful oral and genital ulcers and uveitis. The involvement of more than one joint does not rule out septic arthritis. In up to 20% of cases, multiple joints can become infected. Examination General \200 Always compare sides, to establish if the changes are symmetric or asymmetric. OLIGOARTICULAR PAINS IN ADULTS 157 It is important to establish from the examination whether there is true synovial swelling. A history of swelling is not always reliable and other, nonsynovial, pathology can present with single or oligoarticular joint pain. Examine the affected joints Examine the affected joints for tenderness. Check passive range of motion for evidence of locking or instability: \200 Acute processes such as crystal a rthritis, infection and post-traumatic effusion often lead to painful swelling, marked tend erness of swollen soft-tissues, and painfully restricted active and passive movement of the joint. These features are usually less overt with chronic arthritis. \200 Instability of an acutely in \202 amed joint or tests for cartilage damage in the knee may be dif \201 cult to demonstrate. Further examination will be necessary after drainage of joint \202 u id. Detection of enthesis tenderness around the affected joints or at other sites is a useful clue to the diagnosis of SpA. Examine other musculoskeletal structures \200 Examine the low back and typical sites of b ony tenderness \200\224sacroiliitis and enthesitis are common features of SpA. Tendonitis is not speci \201 c and can occur in gout, CPPD arthritis, SpA, and gonococcal infection. Look for skin rashes and any in \202 ammation Oligoarthritis may be part of a systemic in \202 ammatory or infectious condition. \200 Fever and tachycardia can occur with some no ninfectious causes of acute arthritis (e.g., crystal arthritis), but their presence in the context of oligoarticu lar joint swelling requires exclusion of joint infection. Gouty tophi may be seen in the pinnae and in other peripheral locations. They can be dif \201 cult to discriminate clinically from rheumatoid nodules. Polarized light microscopy of material obtained by needle aspiration will be diagnostic for tophi. The hallmark of relapsing polychondritis is lobe-sparing, full thickness in \202 ammation of the pinna. Mouth ulcers are common; however, crops or large painful tongue and buccal lesions associat ed with oligoarticular arthritis suggest Beh et \200\231s disease. A typical site for the osteitis (tender swelling of bone) of SAPHO syndrome is around the sternum and clavicles. Skin erythema over a joint suggests crystal arthritis or infection. \200 Associated skin rashes may include erythema nodosum (associated with ankle/knee synovitis in acute sarcoid) , purpuric pustular rashes (Beh et \200\231s, gonococcal infection, and SAPHO syndrome), erythema marginatum (rheumatic fever), or keratoderma blennhorragica (aggressive-looking r ash of the sole of the foot in Reiter \200\231s disease). Psoriasis may be associated with both synovitis and enthesitis. CHAPTER 3 Patterns of disease presentation 158 Diagnostic procedures The presence of synovitis can be con \201 rmed by obtaining US or MR of the joints in question. At larger joints, both are sensitive for the detection of effus ion and synovial thickening. In \202 ammation at periarticular or capsular entheses can al so be seen.