Rheumat SAQ

Question 1

A woman with PIPJ arthritis was diagnosed with rheumatoid arthritis. She was started on an oral DMARD that is taken weekly.
1. Marker for RA?
2. DMARD given weekly injection. Coadministered with another supplement to alleviate its AE. What drug is taken?
3. 2 side effects of this DMARD
4. This DMARD no use. Wants to start on biologics. What 2 infections to exclude before starting.
5. Name another 2 classes of biologics or small molecules drugs for RA and describe their MOA

Answer 1

1. Anti CCP (cyclic citrullinated peptide)
2. Methotrexate (given with folate, vit b9)
3. Pulmonary fibrosis, hepatotoxic, teratogenic, nausea, vomiting
4. TB, Hep B (HBsAg, Anti HBc (occult hep B))
5. 1st line is anti TNFa (infliximab (binds to TNFa receptor), etarnecept (decoy TNFa receptor). Anti CD20 (rituximab): depletion of peripheral and synovial B cells. Costimlation blockade (abtacept): fused to extracellular domain of CTLA4 (blocks CD28-CD80/86 costimulatory activation of T cells).
   Anti IL6R: tocilizumab.

Question 2

Raynaud’s Phenomenon A woman with systemic sclerosis, admitted and IV drug was given for her Raynold Phenomenon
1. 2 drugs that are contraindicated for Raynaud
2. What is the parenteral drug
3. Mechanism of parenteral drug
4. 2 oral drugs that can be give nfor control
5. Referred to anesthesia department due to refractory disease, what intervention can be done to control?

Answer 2

1. B blocker, bleomycin, ergots, all vasoconstrictors (adrenaline and alpha agonist) which reduces blood flow to peripherals
2. Iloprost
3. Prostaglandin analogue
4. CCB, PDE5 inhibitor (sildenafil), endothelin receptor antagonsit (ambrisetan)
5. Stellate ganglion block (test the response of sympathectomy which is a surgical consideration to cut the nerves causing vasoconstriction)

Question 3

69/F, referred for suspected drug allergy, received diclofenac IM injection for OA at FM clinic, reaction after 15mins, presenting with rash, SOB and collapsed, BP65/40
1. What is the mechanism of action of Diclofenac?
2. What is this type of drug reaction?
3. What immediate medication to be given and route?
4. What blood test should be taken acutely after stabilisation?
Patient stabilised after treatment. Referred to immunology department, before provocative drug test done to confirm allergy to Diclofenac, in vivo and in vitro test is done.
5. What in vivo test should be done?
6. What in vitro test should be done?

Answer 3

1. Non selective cox1 and cox 2 inhibitor
2. Type 1 IgE mediated
3. IM adrenaline
4. Serum tryptase within 4 hours
5. Skin prick test or intradermal test
6. Radioallergosorbent IgE

Question 4

Answer 4

a)
Creatinine/urea –> renal biopsy –> due to sudden decline of renal function
Low C3 –> antidsDNA to detect if there is MCTD with SLE involvement
b) Interstitial lung disease
c) CXR, HRCT and lung function test
d) Scleroderma renal crisis

Management of scleroderma renal crisis
SBP >180 or DBP >110: target DBP 100-100mg Hg within 24 hours –> IV nitrates, continue low dose iloprost
If BP not above than oral antihypertensives with 1st line: long acting ACEI (ramipril), short acting ACEI (captopril) only required if haemodynamically unstable. 2nd line: ARB (losartan).

Admit HDU
Seizures: IV phenytoin, brain imaging
Pulmonary edema: fluid and salt restriction, IV furosemide
Severe AKI: may need RRT

Question 5

Answer 5

a) COX2 inhibitor which impedes production of prostaglandins which causes pain and swelling of inflammation
b) diarrhea, constipation, dyspepsia
c) Synovitis and tenosynovitis, synovial hypertrophy, bony erosion (better visualized with XR)
d) etanercept is a anti TNFa agent that acts as a decoy receptor where TNFa binds to it therefore less TNFa to induce inflammatory changes.
e) latent TB, demyelinating disease, heart failure

Question 6

Psoriatic arthropathy. On methotrexate

a. What is the mechanism of action of methotrexate?
b. How often should methotrexate be taken?
c. List 3 side effects of methotrexate
d. List 3 types of psoriatic arthropathy
Despite the methotrexate, the patient still complains of finger joint pain and back pain.
e. Name 2 other drugs you can give to the patient

Answer 6

a. Inhibits bodies use of folate/antifolate
b. Weekly
c. Interstitial pneumonititis, hepatotoxicity, nephrotoxicity, teratogenicity, BM suppression
d. 5 types: asymmetrical inflammatory oligoarthritis, symmetrial polyarthritis, DIPJ arthritis, psoriatic spondylitis, arthritis mutilans (deforming erosive arthritis targeting fingers and toes)
e.
Other DMARDs: leflonamide
TNFa inhibitors (infliximab, etanercept)
Biologics: ustekinumab (anti IL12, IL23)