Chapter 10: Musculoskeletal Flashcards
What is rheumatoid arthritis?
- Autoimmune disease where the immune system mistakenly attacks the synovium (lining of the joints)
- systemic
RA symptoms?
- joint pain and swelling
- usually affects the hands, feet and wrists
- stiffness is worse after periods of inactivity, especially in the morning, when it can be severe and last for more than thirty minutes.
RA treatment ?
- DMARDS (Disease Modifying Anti-Rheumatic Drugs)
- new diagnosis of RA: methotrexate + other dmard + temporary corticosteroid
DMARD treatment drugs?
- Oral methotrexate, leflunomide or sulfasalazine should be given first line
- hydroxychloroquine (weak conventional DMARD) is an alterntive in patients with mild RA or palindromic rheumatism
- dose should be titrated up to maximum tolerated effective dose
- TNF alpha inhibitors can also be used (e.g. adalimumab, inflixumab) when inadequate response to combination therapy
- rituximab in combo with methotrexate alternative option for severe RA
What is gold?
- sodium aurothiomalate: no longer commonly used in RA in practice due to availability of newer, more effective drugs
- same goes for azathioprine, ciclosporin and penicillamine
Pain relief in rheumatoid arthritis?
- short term use of NSAID or COX 2 inhibitor should be considered for additional control of pain and stiffness
- offered PPI to minimise GI side effects
- in patients already taking low dose aspirin, other treatments should be considered before NSAID
What is methotrexate?
- high risk drug
- anti-folate; inhibits the conversion of dihydrofolate (folic acid) to tetrahydrofolate needed to make purines and pyrimidines and therefore DNA; prevents cellular replication
*anti-folate drugs are teratogenic and cause blood dyscrasias
Methotrexate uses?
- RA
- cancer
- psoriasis
- crohn’s disease
Methotrexate dose?
- Once weekly (on same day each week)
- prescription must state: dose and frequency (Xmg weekly) and prescribe only one strength
What should be used alongside methotrexate to help reduce side effects?
- folic acid
Possible regimens:
- 5mg once weekly on day after methotrexate day (BNF)
- 5mg daily except on methotrexate day
- 1mg daily except on methotrexate day
Methotrexate missed doses?
- if >3days, take next scheduled dose on normal day
Methotrexate patient counselling?
- weekly dose and avoid OTC NSAIDs (risk of toxicity)
- annual flu vaccination (methotrexate causes immunosuppression)
- methotrexate treatment booklet
Methotrexate side effects?
BLOOD DYSCRASIAS
- low WBCs; susceptible to infection, report mouth ulcers, fever, malaise, sore throat
- low RBCs; anaemia, report extreme tiredness, pallor, dizziness
- low platelets; thrombocytopeonia, report bruising and bleeding easily
HEPATOTOXICITY
- report nausea, vomiting, dark urine, jaundice, abdominal pain (upper right), pruritus, malaise, pale coloured spots
NEPHROTOXICITY
- also renally excreted
PULMONARY TOXICITY
- report SOB, cough and fever
GI TOXICITY
- report stomatitis, first sign of GI toxicity (inflamed and sore mouth)
MTX-INDUCED SIDE EFFECTS/TOXICITY: Folinic acid residue
Methotrexate and contraception?
- TERATOGENIC
- effective contraception during and 3 months after; both men and women
Handling methotrexate?
- CYTOTOXIC
- pregnant women should avoid handling at all
What interacts with methotrexate to increase risk of blood disorders?
- phenytoin
- trimethoprim/co-trimoxazole (anti-folates)
- clozapine (neutropoenia)
What is the interaction between methotrexate and NSAIDs?
- reduces renal excretion (vasoconstriction of afferent renal arteriole) = methotrexate toxicity
What interacts with methotrexate to increase risk of hepatotoxicity?
- isotretinoin
- phenothiazine antipsychotics
- rifampicin
- ketoconazole
(hepatotoxic drugs)
What is osteoarthritis ?
- most common form of arthritis
- caused by wear and tear of joints
- tends to only affect individaul joints (not systemic)
- symptoms often occurs towards the end of the day, after using the affected joint
- Osteoarthritis can affect the lower parts of the spine, and the finger joints closest to the nailbeds, both of which are areas of the body rarely affected in RA
What is gout?
- gout is a condition that causes sudden severe pain, swelling and redness in the joints, caused by the accumulation of uric acid crystals forming in the joints
Gout drug causes?
(HYPERURICAEMIA)
- diuretics (loop and thiazides)
- ciclosporin, tacrolimus
- cytotoxics
- cancer
Gout treatment for acute attack?
- relive pain
- first line: NSAIDs e.g. diclofenac, naproxen
- *aspirin not indicated in gout
- alternative: colchine
- do not repeat course in 3 days
- max dose: 500mcg every 2-4 times a day
- max 6mg per dose