Mycophenolate mofetil (MMF) is a prodrug that converts to mycophenolic acid (MPA), an inhibitor of inosine-5′-monophosphate dehydrogenase. MPA selectively reduces guanosine nucleotides in T and B lymphocytes, thereby inhibiting their proliferation. In cases of proteinuric renal disease associated with systemic lupus erythematosus, mycophenolate is the preferred treatment.

Cyclophosphamide is not recommended for lupus nephritis due to similar renal outcomes as mycophenolate, but with higher infection rates. While corticosteroids are used alongside second-line agents, mycophenolate is more crucial for long-term renal outcomes. Anti-B cell agents like rituximab are used in lupus treatment, but typically in combination with a conventional second-line agent such as mycophenolate. Methotrexate is primarily used for rheumatoid arthritis treatment.

Understanding Systemic Lupus Erythematosus: A Multisystem Autoimmune Disorder

Systemic lupus erythematosus (SLE) is a complex autoimmune disorder that affects multiple systems in the body. It typically develops in early adulthood and is more common in women and individuals of Afro-Caribbean descent. The condition is characterized by a range of symptoms, including fatigue, fever, mouth ulcers, and lymphadenopathy.

SLE can also affect the skin, causing a malar (butterfly) rash that spares the nasolabial folds, as well as a discoid rash that is scaly, erythematous, and well-demarcated in sun-exposed areas. Other skin symptoms may include photosensitivity, Raynaud’s phenomenon, livedo reticularis, and non-scarring alopecia.

Musculoskeletal symptoms of SLE may include arthralgia and non-erosive arthritis, while cardiovascular symptoms may include pericarditis and myocarditis. Respiratory symptoms may include pleurisy and fibrosing alveolitis, and renal symptoms may include proteinuria and glomerulonephritis, with diffuse proliferative glomerulonephritis being the most common type.

Finally, neuropsychiatric symptoms of SLE may include anxiety and depression, psychosis, and seizures. Overall, SLE is a complex and challenging condition that requires careful management and ongoing support.

Assessing Paget’s Disease: Skeletal Survey vs. Isotope Bone Scan

Paget’s disease is a condition that affects around 2% of the population over 55 years old, with a higher prevalence in men. Symptoms may include bone pain, deformities, and hearing loss in skull base Paget’s. Osteogenic sarcoma is a rare complication. The mainstay of treatment is bisphosphonates.

When assessing for Paget’s disease, a limited skeletal survey is preferred over an isotope bone scan. This is because bone scanning underestimates the extent of disease activity when there is significant osteoclastic resorption of bone. Immunoglobulin electrophoresis is most useful in evaluating multiple myeloma, while an ultrasound scan of the liver is not necessary in the absence of other abnormal liver function tests. A chest X-ray may be considered if respiratory symptoms are present, but in this case, the patient’s lack of significant symptoms makes bronchial carcinoma less likely.

Anti-Ro/SSA Antibodies and Congenital Heart Block

Congenital heart block is mostly caused by the presence of anti-Ro/SSA antibodies in the mother’s serum, even if she does not have any connective tissue disorder. Although the risk of congenital heart block in mothers with anti-Ro/SSA antibodies is low (less than 3%), the correlation between the two is strong. Unlike other symptoms of neonatal lupus, the heart block is usually permanent, and a permanent pacemaker may be necessary.

Immediate hospital admission and prompt administration of corticosteroids are crucial in cases of giant cell arteritis accompanied by visual impairment. Delay in treatment can result in permanent loss of vision. Although there may be concerns about a possible transient ischemic attack or stroke, the patient’s medical history, physical examination, and laboratory results suggest a diagnosis of giant cell arteritis. Therefore, urgent CT of the head may not be necessary at this time.

Temporal arteritis is a type of large vessel vasculitis that often occurs in patients over the age of 60 and is commonly associated with polymyalgia rheumatica. This condition is characterized by changes in the affected artery that skip certain sections while damaging others. Symptoms of temporal arteritis include headache, jaw claudication, and visual disturbances, with anterior ischemic optic neuropathy being the most common ocular complication. A tender, palpable temporal artery is also often present, and around 50% of patients may experience symptoms of PMR, such as muscle aches and morning stiffness.

To diagnose temporal arteritis, doctors will typically look for elevated inflammatory markers, such as an ESR greater than 50 mm/hr or elevated CRP levels. A temporal artery biopsy may also be performed to confirm the diagnosis, with skip lesions often being present. Treatment for temporal arteritis involves urgent high-dose glucocorticoids, which should be given as soon as the diagnosis is suspected and before the temporal artery biopsy. If there is no visual loss, high-dose prednisolone is typically used, while IV methylprednisolone is usually given if there is evolving visual loss. Patients with visual symptoms should be seen by an ophthalmologist on the same day, as visual damage is often irreversible. Other treatments may include bone protection with bisphosphonates and low-dose aspirin, although the evidence supporting the latter is weak.

Differential Diagnosis for a Patient with Arthritis and Recent Travel History to the Far East

A patient presents with arthritis and a recent travel history to the Far East with episodes of unprotected sexual encounters. The differential diagnosis includes reactive arthropathy, septic arthritis, ankylosing spondylitis, rheumatoid arthritis, and Still’s disease.

Reactive arthropathy is the most likely diagnosis due to the presence of oligoarthritis, urethritis/dysuria, and conjunctivitis. A penile swab should be taken, and treatment should include addressing the probable underlying sexually transmitted infection. Septic arthritis is less likely due to the sterile synovial fluid aspirate and concurrent symptom of sore eyes. Ankylosing spondylitis is unlikely due to the absence of back or buttock pain. Rheumatoid arthritis is less likely due to the presence of conjunctivitis and evidence of urethritis. Still’s disease is unlikely due to the absence of high spiking fevers and oligoarthritis over a few weeks/months, which is not typical for this age group.

Systemic Still’s disease is a type of juvenile rheumatoid arthritis that typically presents before the age of 16. It is characterized by systemic features such as high fever, rashes, lymphadenopathy, and splenomegaly, with minor arthritis symptoms. In contrast, pauciarticular Still’s disease affects large joints and often leads to seronegative spondyloarthritis. Antinuclear antibodies are present in this type of JRA. Acute rheumatic fever is another possible diagnosis, but it typically presents with carditis and a positive ASO titre, which is not the case here. Juvenile systemic lupus erythematosus is also a consideration, but the absence of antinuclear antibodies and the presence of significant systemic features make it less likely. Reactive arthritis is unlikely due to the absence of an infective precipitant and the atypical lymphadenopathy and splenomegaly. In summary, a child presenting with systemic features and arthritis may have Systemic Still’s disease or pauciarticular Still’s disease, and other diagnoses such as acute rheumatic fever, juvenile systemic lupus erythematosus, and reactive arthritis should be ruled out.

The simultaneous administration of methotrexate and antibiotics containing trimethoprim can lead to bone marrow suppression and potentially fatal pancytopenia.

Methotrexate interferes with the cell cycle by acting as a folic acid antagonist. Similarly, trimethoprim also acts as a folic acid antagonist. When used together, the risk of myelosuppression is heightened, particularly since trimethoprim reduces the rate at which methotrexate is excreted by the kidneys.

Methotrexate is an antimetabolite that hinders the activity of dihydrofolate reductase, an enzyme that is crucial for the synthesis of purines and pyrimidines. It is a significant drug that can effectively control diseases, but its side-effects can be life-threatening. Therefore, careful prescribing and close monitoring are essential. Methotrexate is commonly used to treat inflammatory arthritis, especially rheumatoid arthritis, psoriasis, and acute lymphoblastic leukaemia. However, it can cause adverse effects such as mucositis, myelosuppression, pneumonitis, pulmonary fibrosis, and liver fibrosis.

Women should avoid pregnancy for at least six months after stopping methotrexate treatment, and men using methotrexate should use effective contraception for at least six months after treatment. Prescribing methotrexate requires familiarity with guidelines relating to its use. It is taken weekly, and FBC, U&E, and LFTs need to be regularly monitored. Folic acid 5mg once weekly should be co-prescribed, taken more than 24 hours after methotrexate dose. The starting dose of methotrexate is 7.5 mg weekly, and only one strength of methotrexate tablet should be prescribed.

It is important to avoid prescribing trimethoprim or co-trimoxazole concurrently as it increases the risk of marrow aplasia. High-dose aspirin also increases the risk of methotrexate toxicity due to reduced excretion. In case of methotrexate toxicity, the treatment of choice is folinic acid. Overall, methotrexate is a potent drug that requires careful prescribing and monitoring to ensure its effectiveness and safety.

Febuxostat is a viable option for preventing gout in patients who cannot tolerate the side effects of allopurinol or have reduced renal function that prevents effective dose escalation. According to NICE and the British Society of Rheumatology, febuxostat can be used as an alternative to allopurinol in such cases. Unlike allopurinol, febuxostat is a non-purine selective xanthine oxidase inhibitor that inhibits both oxidized and reduced versions of the enzyme without affecting purine or pyrimidine metabolism. Although recent studies suggest an increased risk of cardiovascular events with febuxostat use, no changes have been made to the guidelines. While indomethacin, prednisolone, and colchicine are effective in treating acute gout, their preventive use is limited. Colchicine can be used as a temporary measure while a xanthine oxidase inhibitor is being prescribed to prevent acute gout attacks.

Gout is caused by chronic hyperuricaemia and is managed acutely with NSAIDs or colchicine. Urate-lowering therapy (ULT) is recommended for patients with >= 2 attacks in 12 months, tophi, renal disease, uric acid renal stones, or prophylaxis if on cytotoxics or diuretics. Allopurinol is first-line ULT, with a delayed start recommended until inflammation has settled. Lifestyle modifications include reducing alcohol intake, losing weight if obese, and avoiding high-purine foods. Other options for refractory cases include febuxostat, uricase, and pegloticase.

Start alendronate in patients >= 75 years with fragility fracture without waiting for DEXA scan.

Osteoporosis is a condition that weakens bones, making them more prone to fractures. When a patient experiences a fragility fracture, which is a fracture that occurs from a low-impact injury or fall, it is important to assess their risk for osteoporosis and subsequent fractures. The management of patients following a fragility fracture depends on their age.

For patients who are 75 years of age or older, they are presumed to have underlying osteoporosis and should be started on first-line therapy, such as an oral bisphosphonate, without the need for a DEXA scan. However, the 2014 NOGG guidelines suggest that treatment should be started in all women over the age of 50 years who’ve had a fragility fracture, although BMD measurement may sometimes be appropriate, particularly in younger postmenopausal women.

For patients who are under the age of 75 years, a DEXA scan should be arranged to assess their bone mineral density. These results can then be entered into a FRAX assessment, along with the fact that they’ve had a fracture, to determine their ongoing fracture risk. Based on this assessment, appropriate treatment can be initiated to prevent future fractures.

If a patient experiences increased pain or weakness when extending or supinating their wrist during elbow extension, it may be a sign of lateral epicondylitis, also known as tennis elbow. This condition is often caused or worsened by repetitive movements in work or recreational activities, such as plumbing. Cubital tunnel syndrome, which results from ulnar nerve entrapment, typically causes medial elbow pain and ulnar nerve distribution paraesthesia, making it an incorrect answer. Medial epicondylitis, or golfer’s elbow, is also caused by repetitive activities and is characterized by pain that worsens with resisted wrist flexion and pronation, which is the opposite of lateral epicondylitis. Olecranon bursitis, which presents as a soft, painless swelling over the olecranon after trauma, is an incorrect answer as there was no evidence of swelling or effusion and no history of trauma.

Understanding Lateral Epicondylitis

Lateral epicondylitis, commonly known as tennis elbow, is a condition that usually occurs after engaging in activities that the body is not accustomed to, such as painting or playing tennis. It is most prevalent in individuals aged between 45 and 55 years and typically affects the dominant arm. The condition is characterized by pain and tenderness localized to the lateral epicondyle, which is worsened by wrist extension against resistance with the elbow extended or supination of the forearm with the elbow extended.

Episodes of lateral epicondylitis usually last between six months and two years, with patients experiencing acute pain for six to twelve weeks. To manage the condition, patients are advised to avoid muscle overload, take simple analgesia, undergo steroid injection, or receive physiotherapy. With proper management, patients can recover from lateral epicondylitis and return to their normal activities.