Mixed connective tissue disease

Question 1

What antibody is ass with MCTD?

Answer 1

Anti - U1 RNP (75 - 90%)

(binds to U1 small nuclear ribonucleoprotein)

Question 2

Genetic risk factors fot MCTD?

Answer 2

HLA DRB1, DRB4
DQA103,
DQB10301,
HLA B*08

Question 3

When to suspect MCTD?

Answer 3

When a patient has features of an AICTD but does not fit a diagnostic criteria

Common presentations:
- Raynauds + nail fold abnormalities + postitive serology
- Rash + positive serology with other non-diagnostic features + biopsy with vacolar change

Question 4

Cutanoues features of MCTD

Answer 4

Not well defined

Raynauds is the most common
Photosensitivity
Urticaria
Oedema
Psoriaiss
Papulosquamous eruptions
Livedo
Vasculitic changes
Oral ulcers
Telagnectasia
Subcutaneous nodules

Question 5

Non-cutanoues features of MCTD?

Answer 5

Highly variable

Pulmonary (ILD, PAH)
Myositis
Cardiac
GI dysmotility
Renal disease

Question 6

Management of MCTD?

Answer 6

Smoking cessation
Hand and skin care advice

Topical CS
Topical Calcinurin inhibiotrs

Oral CS
Rs of Raynauds (CCB, PD5 inhibiotrs (sildenafil) prostacyclin analouges Ileoprost)

HCQ
MTx
MMF
etc