Osteoarthritis starts as mild joint inflammation, which may initially arouse a suspicion of, for example, recent onset rheumatoid arthritis. It may therefore be confused with proper inflammatory diseases. However, over time the character of osteoarthritis proves to be different.
Characteristic symptoms are pain on exertion, followed by aching.
Morning stiffness can occur, but it lasts for no longer than 15 minutes. The intensity of morning stiffness is also less marked than in inflammatory conditions. Particularly in rheumatoid arthritis morning stiffness lasts for several hours and is of high intensity. Osteoarthritis is associated with joint stiffness at the initiation of movement.
In osteoarthritis of the knee, an early symptom may be minor joint effusion and pain caused by inappropriate joint loading. The overlying skin remains cool to the touch, or at the most slightly warm. Thickened synovium is rare, and it feels flexible on palpation. Only a small number of leucocytes (usually less than 2 000 × 106 /l) are present in the synovial fluid, with a predominance of mononuclear cells.
Osteoarthritis of the fingers causes pain and reduced functioning. Sharp pain occurs during and after use in the affected small joints, occasionally accompanied by aggressive inflammation, the end result being a deterioration in the ability to perform activities of daily living. Hard, bony thickening will gradually form around the joints; at the distal interphalangeal (DIP) joints these are called Heberden's nodes and at the proximal interphalangeal (PIP) joints Bouchard's nodes. Flexion deficit is usually small (usually not more than 20 mm; see Clinical Diagnosis of Joint Inflammation in the Adult), but in some cases the fingers may become crooked and the grip power is diminished. ESR and CRP are normal, and rheumatoid factor (RF) and anti-cyclic citrullinated peptide (anti-CCP) antibodies are usually negative.
One of the typical sites for osteoarthritis is the first carpometacarpal joint (CMC 1). The thumb is turned into adduction and the back of the hand takes a squarish shape.
Osteoarthritis can be roughly divided into two groups: oligoarticular large joint osteoarthritis and osteoarthritis of the small joints of the hand. Moreover, it is possible for osteoarthritis to affect the entire skeleton or any single joint. Unlike rheumatoid arthritis, osteoarthritis seldom affects the radiocarpal joint of the wrist.
Dorsiflexion of the wrists is tested by pressing the palms with straightened fingers against each other (picture 1). The respective test for volar flexion is performed by pressing the backs of the hands against each other (video Restricted Motion of the Wrist in a Patient with Rheumatoid Arthritis).
Rheumatoid arthritis is a systemic inflammatory condition where the joints are the main target organ.
The initial symptoms usually affect the fingers, balls of the feet or wrists, but any joint may be the first one to be affected. Fusiform tight swelling around the PIP joints caused by synovitis is characteristic to rheumatoid arthritis (picture 2 ) but may also be seen in other inflammatory joint diseases, especially in psoriatic arthritis and chronic juvenile arthritis.
The symptoms usually develop fairly slowly as the inflammation becomes more widespread.
The onset may also be acute and fulminant, and the inflammatory joint symptoms may be accompanied by generalised symptoms such as fatigue, loss of appetite or fever.
A symmetric distribution of the inflammatory joint symptoms is characteristic of rheumatoid arthritis.
The inflamed joints are painful when moved, but pain at rest is not characteristic of rheumatoid arthritis.
The more active the inflammation, the longer the duration of morning stiffness, i.e. a limitation of motion at the affected joints. The stiffness may affect the entire body and return during the day after a prolonged period of sitting down.
Approximately two thirds of patients with fresh rheumatoid arthritis are positive for the classic parameter, rheumatoid factor (RF), or have anti-cyclic citrullinated peptide (anti-CCP) antibodies, which are specific for rheumatoid arthritis.Some patients who are negative for RF test positive for anti-CCP antibodies.
These findings in a patient with inflammatory arthritis strongly suggest rheumatoid arthritis but they are not a precondition for the diagnosis.
In the diagnostic work-up of a patient with inflammatory arthritis it is sufficient to perform either one of the tests. Nowadays, the determination of anti-CCP antibodies is the test used in most cases.
Markedly increased RF or anti-CCP antibody concentrations confer a more severe disease type.
With advanced age, RF often turns positive without rheumatoid arthritis. Particularly in elderly patients with inflammatory arthritis, the determination of anti-CCP antibodies is important because aging has not been found to affect their occurrence.
The determination of RF or anti-CCP antibodies is usually not warranted if no inflammatory arthritis has been detected.
ESR and often also CRP are at least slightly elevated.
Erosive osteoarthritis of the PIP and DIP joints in the fingers may greatly resemble chronic rheumatoid arthritis but can be distinguished by its typical localisation (it spares the balls of the feet and wrists), absence of RF and often the relatively low ESR or CRP. It should be borne in mind that rheumatoid arthritis is nowadays encountered in patients around the age of 60, and at that age both conditions may occur concurrently. Particularly in these situations an elevated anti-CCP antibody concentration will assist in the diagnosis of rheumatoid arthritis.
Is often associated with the HLA-B27 antigen, in which case predisposition for the disease is inherited. Family history may reveal cases of reactive arthritis in close family members.
Usually presents as either mono- or oligoarthritis of the lower limbs, and the condition progresses relatively slowly from joint to joint following either a migratory or additive pattern.
In addition to inflammatory joint symptoms, enthesopathy (tenderness at the muscle or fascia attachment sites) and dactylitis (sausage-like swelling of fingers or toes, picture 3) are often seen.
Some patients have ocular inflammations (uveitis) and additionally possibly symptoms of urethritis (Reiter's syndrome). Inflammatory bowel disease (IBD) is also possible.
Reactive arthritis is rarely encountered in elderly individuals.
If the patient presents with clear symptoms and fever, the ESR and/or CRP levels are usually markedly elevated, and reactive monoarthritis may therefore be difficult to distinguish from septic arthritis.
In 15% of cases joint inflammation develops before psoriasis.
There are many different types of psoriatic arthritis.
The most common type is asymmetric oligoarticular arthritis, which affects the knees and other large joints. Asymmetric arthritis can also occur in the sternoclavicular joints, sacroiliac joints and the temporomandibular joints.
The early stages of polyarthritis of the small joints resemble rheumatoid arthritis. In the fingers, it often affects the DIP joints.
Arthritis mutilans causes resorption of bone leading principally to the destruction of small bones in the fingers. The condition is rare.
The type that resembles ankylosing spondylitis is characterised by the asymmetry of signs and symptoms.
The joint inflammation is very often associated with psoriatic nail changes (picture 4), and in these cases the psoriatic skin changes may sometimes be totally absent.
Dactylitis of a finger or toe is often associated with psoriatic arthritis.
Enthesitis is very common in psoriatic arthritis.
Family history may reveal cases of psoriatic arthritis in close family members.
If a patient presents with back pain that has lasted ≥ 3 months there are 5 criteria that may suggest ankylosing spondylitis: the age at onset < 40 years, insidious onset of back pain, back pain wakes the patient in the early morning hours, symptoms improved with exercise, no improvement with rest.
Associated with the HLA-B27 antigen in 95% of cases, in which case predisposition for the disease is inherited. Family history may reveal cases of ankylosing spondylitis in close family members.
HLA-B27 testing has the highest information value in patients whose pretest probability for ankylosing spondylitis is around 50% (e.g. a young man with symptoms at the lower back in the early morning hours, but as yet with normal x-ray findings of the sacroiliac joints). The probability of the disease is 92% if the test result is positive and only 8% if the result is negative. If the pretest probability based on history and clinical findings is near zero, a positive test result does not confirm ankylosing spondylitis; the patient probably belongs to the normal population that tests positive for HLA-B27 but has no diseases associated with this antigen.
The HLA-B27 test should not be used to estimate a patient's general risk of ankylosing spondylitis in the absence of appropriate clinical signs and symptoms, since only less than 1% of those who test positive will go on to develop spondylarthritis.
The classic rheumatoid factor (RF) or anti-CCP antibodies have no significance at all in the diagnostics of the diseases in the ankylosing spondylitis group. They should thus not be determined.
In about one third of the patients the condition is associated with isolated limb arthritis, usually oligo- or monoarthritis. In rare cases, the patient may also have symmetric polyarthritis resembling rheumatoid arthritis.
Usually starts at middle age and is more common among men. Prevalence is on the rise (metabolic syndrome, beer and diuretics). Based on a clinical estimation the incidence of polyarticular gout is also on the rise, and in these cases gout may be confused with early onset rheumatoid arthritis. However, gout usually causes significantly more pain, and anti-CCP antibodies are usually not encountered in gout or their concentrations are lower than in rheumatoid arthritis. It should be borne in mind that it is possible for a patient to have both conditions.
Starts from the first metatarsophalangeal joint in over half of the cases.
Trauma to the joint may elicit an attack of gout.
An attack usually begins at night and peaks within 24 hours. The signs of inflammation, i.e. pain, swelling and redness, are usually prominent.
If the condition remains untreated, the attacks recur with increased frequency and gradually lead to chronic destructive polyarthritis.
During an acute attack, the patient may have fever, ESR and/or CRP may be moderately elevated and the serum urate concentration is usually above the upper limit of normal, but it may also be within the reference values.
Often associated with metabolic syndrome (truncal obesity).
Tenderness and restriction of movement most typically around the shoulders and thighsSynovitis is sometimes seen, particularly at the shoulder joints and hips but also at the more peripheral joints, usually at the knees and wrists.
Stiffness and difficulty moving the joints after rest or staying still is particularly pronounced.
Age over 50 years. Note that rheumatoid arthritis in the elderly may start with shoulder pain that resembles polymyalgia.
ESR > 40-50
Headache, visual disturbances, jaw claudication induced by swallowing or chewing as well as severe general symptoms with elevated CRP levels are suggestive of concurrent temporal arteritis.
Sarcoidosis may be associated with acute arthritis, which most often affects the ankles. A typical finding is diffuse bluish red periarticular swelling.
Knees are the next most commonly affected location.
Joint symptoms are often more severe than a clinical investigation of the joints suggests.
The patient usually presents with symmetrical polyarthritis/arthralgia.
Joint symptoms are associated with general symptoms, fever, various cutaneous manifestations and frequently signs of other organ involvement (headache in central nervous system involvement, proteinuria or haematuria in nephritis, thrombocytopenia, leucopenia, sometimes venous thromboses as well as pleuritis or pericarditis).
ESR is usually elevated, but the CRP may be normal.
The joint symptoms may appear intermittently or they may be sustained, and the clinical picture may therefore resemble that of either gout or osteoarthritis.
X-rays show calcification of the joint cartilage (chondrocalcinosis), and pyrophosphate crystals accumulate in the synovial fluid.
Pyrophosphate arthropathy can manifest as severely symptomatic polyarthritis.
Treatment is symptomatic; no specific treatment exists.
Joint infection (septic arthritis)
Usually an acute onset. The patient has strong general symptoms and septic fever. Fever and other signs of inflammation may, however, be absent in elderly individuals, in patients receiving immunosuppressant therapy and in infections involving prosthetic joints.
Acute monoarthritis with fever should be regarded as bacterial in origin until proven otherwise. Oligoarthritis may also be septic in origin.
CRP and/or ESR are usually markedly elevated, but leucocytosis may be absent.
Crystal-induced arthritis may also be fulminant and resemble septic arthritis (remember to request the analysis of synovial fluid to include an evaluation for crystals!).
Viral arthritis
Viral arthritis usually manifests itself either as acute but mild poly- or oligoarthritis, and it usually resolves spontaneously fairly quickly.
Joint inflammation is particularly associated with rubella, arbovirus arthritis and erythema infectiosum (fifth disease), which can be identified by their characteristic rashes.
Arbovirus arthritis: see Pogosta Disease. The rash is pruritic.
Parvovirus Erythema Infectiosum causes erythema infectiosum in children and is quite often a cause of joint inflammation in adults.
In viral arthritis, ESR and CRP are no more than slightly elevated, and the synovial fluid cell count usually (but not always) reveals a predominance of mononuclear cells.
Lyme disease
A multi-faceted disease caused by the spirochete Borrelia burgdorferi, which is spread by tick bites Lyme Borreliosis (LB).
In the acute phase, a rash, called erythema migrans, usually appears at the site of the tick bite. No rash, however, occurs in a considerable number of people who will go on to develop borrelia arthritis. At the start of the disease, the patient usually develops fever, headache, myalgia and lymphadenopathy.
Late manifestations of the disease include joint inflammation, neurological symptoms and carditis.
Joint inflammation usually presents as recurrent episodes of swelling involving one or a few joints.
For a favourable outcome early diagnosis is essential.
The disease is most commonly associated with rapidly progressing migratory arthritis, but the joint complaints may be limited to pain.
Carditis, which manifests as pancarditis or valvular lesions, is an important prognostic factor.
ESR and CRP are usually markedly elevated, and the same applies to antistreptolysin (AST). Streptococcus can be found in throat culture.
Hypertrophic osteoarthropathy
A paraneoplastic phenomenon that , in addition to possible synovitis, is accompanied by periostitis of the long bones and digital clubbing.
If hypertrophic osteoarthropathy is suspected the patient is referred to specialized care.
HIV infection
Patients infected with HIV HIV Infection often develop reactive arthritis and arthralgia.
The patient should be referred to specialized care.
Trauma
The patient may have forgotten an earlier joint trauma, which may make the diagnostic work-up more difficult. It should be borne in mind that psoriatic arthritis often develops after trauma (note Köbner phenomenon).
References
Lopez-Hoyos M, Ruiz de Alegria C, Blanco R et al. Clinical utility of anti-CCP antibodies in the differential diagnosis of elderly-onset rheumatoid arthritis and polymyalgia rheumatica. Rheumatology (Oxford) 2004;43(5):655-7. [PubMed]
Möttönen T, Paimela L, Leirisalo-Repo M et al. Only high disease activity and positive rheumatoid factor indicate poor prognosis in patients with early rheumatoid arthritis treated with "sawtooth" strategy. Ann Rheum Dis 1998;57(9):533-9. [PubMed]
Sieper J, van der Heijde D, Landewé R et al. New criteria for inflammatory back pain in patients with chronic back pain: a real patient exercise by experts from the Assessment of SpondyloArthritis international Society (ASAS). Ann Rheum Dis 2009;68(6):784-8. [PubMed]
Khan MA, Khan MK. Diagnostic value of HLA-B27 testing ankylosing spondylitis and Reiter's syndrome. Ann Intern Med 1982;96(1):70-6. [PubMed]
Healey LA. Long-term follow-up of polymyalgia rheumatica: evidence for synovitis. Semin Arthritis Rheum 1984;13(4):322-8. [PubMed]
Myklebust G, Gran JT. A prospective study of 287 patients with polymyalgia rheumatica and temporal arteritis: clinical and laboratory manifestations at onset of disease and at the time of diagnosis. Br J Rheumatol 1996;35(11):1161-8. [PubMed]
Schlapbach P, Ambord C, Blöchlinger AM et al. Bacterial arthritis: are fever, rigors, leucocytosis and blood cultures of diagnostic value? Clin Rheumatol 1990;9(1):69-72. [PubMed]
Fawaz-Estrup F. Human parvovirus infection: rheumatic manifestations, angioedema, C1 esterase inhibitor deficiency, ANA positivity, and possible onset of systemic lupus erythematosus. J Rheumatol 1996;23(7):1180-5. [PubMed]
Franssila R, Hedman K. Infection and musculoskeletal conditions: Viral causes of arthritis. Best Pract Res Clin Rheumatol 2006;20(6):1139-57. [PubMed]
Turunen M, Kuusisto P, Uggeldahl PE et al. Pogosta disease: clinical observations during an outbreak in the province of North Karelia, Finland. Br J Rheumatol 1998;37(11):1177-80. [PubMed]
Berglund J, Blomberg I, Hansen BU. Lyme borreliosis in rheumatological practice: identification of Lyme arthritis and diagnostic aspects in a Swedish county with high endemicity. Br J Rheumatol 1996;35(9):853-60. [PubMed]