Importance of Joint Aspiration in Identifying the Cause of Acute Monoarthropathy

When a patient presents with acute monoarthropathy, it is important to identify the cause of their symptoms. The most important investigation in this case is joint aspiration. This procedure involves taking a sample of fluid from the affected joint and examining it under a microscope to identify any infective organisms. This is crucial in cases where septic arthritis is suspected, as appropriate therapy can be guided based on the results. On the other hand, if the cause is gout, joint aspiration can reveal the presence of crystals in the fluid. X-rays are of no value in septic arthritis as they only become abnormal following joint destruction. Therefore, joint aspiration is the most important investigation in identifying the cause of acute monoarthropathy.

Treatment Options for Severe Rheumatoid Arthritis

Severe rheumatoid arthritis can be a challenging condition to manage, especially when conventional disease-modifying anti-rheumatic drugs (DMARDs) fail to provide relief. In such cases, biological therapies may be recommended. Here are some treatment options for severe rheumatoid arthritis:

Enrol in Biological Therapy Programme
Patients with highly active disease despite trying three previous agents for a therapeutic treatment duration may be candidates for biological treatments. TNF-alpha inhibitors and anti-CD20 are examples of biological treatments that are routinely used in the UK.

Maintain on Steroids and Add a Bisphosphonate
Short-term treatment with glucocorticoids may be offered to manage flares in people with recent-onset or established disease. However, long-term treatment with glucocorticoids should only be continued when the long-term complications of glucocorticoid therapy have been fully discussed and all other treatment options have been offered.

Commence Leflunomide
Severe disease that has not responded to intensive therapy with a combination of conventional DMARDs should be treated with biological agents. Leflunomide is one of the DMARDs that can be used in combination therapy.

Use Methotrexate/Leflunomide Combination
Patients who have not responded to intensive DMARD therapy may be prescribed a biological agent, as per NICE guidelines. Methotrexate and leflunomide are two DMARDs that can be used in combination therapy.

Avoid Commencing Penicillamine
DMARD monotherapy is only recommended if combination DMARD therapy is not appropriate. Patients without contraindications to combination therapy should not be prescribed penicillamine.

The woman in the picture appears to have osteoarthritis, which is commonly seen in overweight individuals affecting weight-bearing joints like the knees. The changes in her hands also suggest osteoarthritis. Treatment options include weight reduction, pain relief medication like paracetamol or non-steroidal anti-inflammatory drugs (NSAIDs), physiotherapy, or knee replacement surgery. Rheumatoid arthritis is unlikely as her ESR and rheumatoid factor are normal. Seronegative arthritis is also unlikely as it is associated with raised inflammatory markers, which are not present in this case. Enteropathic arthropathy is unlikely as there are no recent symptoms of inflammatory bowel disease. Osteoporosis is not a likely diagnosis as it does not cause knee or finger pain, but rather presents following a fracture.

Differentiating Systemic Lupus Erythematosus from Other Connective Tissue Diseases

Systemic lupus erythematosus (SLE) is a complex autoimmune disease that can present with a variety of symptoms. Patients may experience pleuritic chest pain, arthralgia, and a typical rash, which are all indicative of SLE. Anti-nuclear antibodies are typically positive, although they are not specific to lupus. Treatment for SLE involves glucocorticoids as the mainstay, with second-line agents including cyclophosphamide, hydroxychloroquine, and azathioprine. BLyS inhibitors are also showing promise in clinical trials.

Other connective tissue diseases, such as granulomatosis with polyangiitis (GPA), rheumatoid arthritis, systemic sclerosis, and mixed connective tissue disease, have distinct features that differentiate them from SLE. GPA is a necrotising small-vessel vasculitis that commonly affects the kidneys and lungs, with palpable purpura on the extremities. Rheumatoid arthritis typically presents with joint pain and swelling, but without a butterfly rash or hypertension. Systemic sclerosis affects the skin on the face, forearms, and lower legs, with Raynaud’s, sclerodactyly, and telangiectasia. Mixed connective tissue disease has features of SLE, but without any other connective tissue disease symptoms.

It is important to differentiate between these diseases to provide appropriate treatment and management for patients.

Seropositive and Seronegative Arthritis: Types and Characteristics

Seropositive arthritis is characterized by the presence of rheumatoid factor, an antibody targeted against the Fc portion of immunoglobulins. While rheumatoid factor can be present in systemic lupus erythematosus (SLE), seropositive SLE generally indicates more severe disease progression. On the other hand, reactive arthritis, psoriatic arthritis, ankylosing spondylitis, and enteropathic arthritis are all seronegative arthritis, meaning that rheumatoid factor is classically not present.

Reactive arthritis is usually precipitated by a gastrointestinal or genitourinary infection occurring before the onset of arthritic symptoms. The classic triad of reactive arthritis is conjunctivitis, asymmetric oligoarthritis, and urethritis. The condition may be self-limiting, but in some patients, it may become chronic or recur frequently.

Psoriatic arthritis is classically found in patients with psoriasis, but in around 1 in 6 people, it may present many years before psoriatic skin symptoms. Ankylosing spondylitis, on the other hand, is a chronic disorder of an inflammatory nature characterized by sacroiliac joint involvement and linked to the HLA-B27 antigen. Enteropathic arthritis is associated with inflammatory bowel disease and can affect any joint, but it most commonly affects the spine and lower limb joints. Approximately 1 in 5 people with inflammatory bowel disease will develop the condition.

The symptoms described suggest a diagnosis of ankylosing spondylitis, a chronic form of seronegative spondyloarthropathy that primarily affects the axial skeleton. Diagnosis is made using the modified New York criteria, which includes clinical and radiological criteria. HLA-B27 and sacroiliitis on MRI play a major role in the recently proposed ASAS diagnostic algorithm. Radiographic sacroiliitis is required for eligibility for anti-TNF treatment. Other conditions, such as pseudogout, Lyme disease, osteoarthritis, and rheumatoid arthritis, are unlikely diagnoses. Timely diagnosis requires a high index of suspicion.

Differentiating Autoantibodies in Connective Tissue Diseases

Connective tissue diseases are a group of autoimmune disorders that affect various parts of the body. Differentiating between these diseases can be challenging, but autoantibodies can provide valuable clues. Here are some common autoantibodies and the connective tissue diseases they are associated with:

1. Anti-centromere antibody: This antibody is most likely to be present in limited systemic sclerosis (CREST).

2. Anti-Scl-70: This antibody is found in diffuse systemic sclerosis.

3. Anti-RNP antibody: This antibody is found in mixed connective tissue disease.

4. Anti-Ro antibody: This antibody is classically positive in Sjögren’s syndrome or systemic lupus erythematosus.

5. Anti-Jo-1 antibody: This antibody is commonly raised in polymyositis.

By identifying the specific autoantibodies present in a patient, healthcare providers can better diagnose and manage connective tissue diseases.

Medication Combinations for Treating Rheumatoid Arthritis

When treating rheumatoid arthritis, the first-line medication is a DMARD monotherapy with methotrexate. Short-term steroids may also be used in combination with DMARD monotherapy to induce remission. Hydroxychloroquine is another medication that can be used, but patients should be closely monitored for visual changes as retinopathy and corneal deposits are common side effects.

Etanercept is not a first-line treatment for rheumatoid arthritis, and methotrexate should not be given in combination with a TNF-alpha inhibitor like etanercept. Methotrexate plus sulfasalazine is an appropriate medication combination for treating rheumatoid arthritis, but regular eye checks are not required as neither medication affects vision.

If a patient has failed treatment with methotrexate, sulfasalazine plus hydroxychloroquine may be a regimen to consider trialling. However, it is important to note that new-onset rheumatoid arthritis should be treated with a DMARD monotherapy first line, with the addition of another DMARD like methotrexate as the first-line option.

Ocular Manifestations of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory polyarthropathy that primarily affects small joints, causing symmetrical joint tenderness and swelling. It is an autoimmune disease with genetic and environmental risk factors. RA can result in marked physical disability, and extra-articular features are more common in rheumatoid factor-positive patients with long-standing disease. Ocular manifestations of RA include keratoconjunctivitis sicca, also known as dry eye syndrome, which is the most common ocular extra-articular manifestation. Scleromalacia perforans, a thinning of the sclera, is associated with RA but presents less often than keratoconjunctivitis sicca. Episcleritis and scleritis are also associated with RA but are less common than keratoconjunctivitis sicca. Orbital apex syndrome may involve the optic nerve, causing a palsy, but this is very rare. It is important for healthcare providers to be aware of these ocular manifestations and monitor patients with RA for any changes in their vision or eye health.

Differentiating Knee Conditions: A Case-Based Approach

A patient presents with a red, tender, and inflamed knee. The differential diagnosis includes prepatellar bursitis, osteoarthritis, localised cellulitis, rheumatoid arthritis, and gout.

prepatellar bursitis, also known as housemaid’s knee, carpet layer’s knee, or nun’s knee, is often caused by repetitive knee trauma. Treatment involves non-steroidal anti-inflammatory agents and local corticosteroid injection. Septic bursitis requires appropriate antibiotic cover and drainage.

Osteoarthritis is a diagnosis of exclusion and does not typically cause a red, tender, inflamed knee. Knee aspirate in this case would not show white cells.

Localised cellulitis may result in erythema but is unlikely to cause knee swelling. Knee aspirate in this case would not show white cells.

Rheumatoid arthritis is unlikely to present in men of this age and typically affects small joints of the fingers, thumbs, wrists, feet, and ankles.

Gout can be diagnosed through the presence of negatively birefringent crystals seen on joint microscopy.

In conclusion, a thorough evaluation of the patient’s symptoms and appropriate diagnostic tests are necessary to differentiate between these knee conditions.