Rheumatology: Important Points

UK MRCP
#1

Rheumatology: Important Points (… To be continued)

  • The combination of pulmonary and renal involvement combined with a history of chronic sinusitis points towards a diagnosis of Granulomatosis with polyangiitis.

  • Septic arthritis - most common organism: Staphylococcus aureus

  • Low levels of C4a and C4b have been shown to be associated with an increased risk of developing systemic lupus erythematosus.

  • Heerfordt syndrome is a subset of sarcoidosis: a combination of parotid enlargement, fever, and anterior uveitis.

  • The prevalence of rheumatoid arthritis in the UK population is approximately 1%.

  • Azathioprine - check thiopurine methyltransferase deficiency (TPMT) before treatment.

  • Thiopurine methyltransferase (TPMT) deficiency is present in about 1 in 200 people and predisposes to azathioprine-related pancytopaenia.

  • Adult-onset Still’s disease is typically rheumatoid factor-negative.

  • Hepatitis C infection is associated with type II (mixed) cryoglobulinaemia, suggested by the purpuric rash, positive rheumatoid factor and reduced complement levels.

  • Rheumatoid arthritis - TNF is key in pathophysiology.

  • Joint aspiration is mandatory in all patients with a hot, swollen joint to rule out septic arthritis. If this is excluded then intra-articular or systemic steroid therapy may be considered.
    :diamonds:Proximal myopathy in combination with mechanic hands is associated with anti-synthetase syndrome. It is important to ask about lung symptoms because there is an association with interstitial lung disease - particularly non-specific interstitial pneumonia or NSIP.

  • Anti-topoisomerase I antibodies (anti-Scl-70) are associated with systemic sclerosis.

  • Anti-centromere antibodies are associated with CREST syndrome.

  • Anti-Jo 1 antibodies are more commonly seen in polymyositis than dermatomyositis.

  • Glomerulonephritis is unusual in drug-induced lupus.

  • Colchicine is useful in gout patients with renal impairment as NSAIDs are relatively contraindicated.

  • The BNF advises to reduce the dose by up to 50% if creatinine clearance is less than 50 ml/min and to avoid if creatinine clearance is less than 10 ml/min.

  • Urethritis + arthritis + conjunctivitis = reactive arthritis

  • Denosumab: Inhibits RANK ligand, which in turn inhibits the maturation of osteoclasts.

  • The presence of hypertension, kidney injury, proteinuria and haematuria point towards a nephritic picture of kidney insult.

  • The multisystem presentation of fever, arthralgia, pericarditis and nephritis associated with the epidemiological clues (a young black female) suggest a diagnosis of systemic lupus erythematosus (SLE).

  • The most common histological pattern seen in lupus nephritis is diffuse proliferative glomerulonephritis.

  • In sarcoidosis, factors associated with a good prognosis include: HLA B8 and Lofgren’s syndrome (bilateral hilar lymphadenopathy, erythema nodosum, polyarthritis and fever).

  • Jaw claudication is a very specific sign for temporal arteritis. A negative temporal artery biopsy can occur in upto 50 percent of patients, often because the sampled region was not involved in the pathologic process. Therefore, it is not sensitive enough to rule out temporal arteritis.

  • Osteoarthritis - paracetamol + topical NSAIDs (if knee/hand) first-line.

  • The most common immunoglobulin class of RA is IgM but they can also be of the IgA and IgG class.

  • SLE - antibodies associated with congenital heart block = anti-Ro