[Undifferentiated connective tissue disease]

Mixed Connective Tissue Disease: The Two Cases Representing the Range of this Illness

INTRODUCTION

Mixed connective tissue disease (MCTD) is defined as a systemic rheumatic disease characterized by the presence of high titer anti-U1 ribonucleoprotein (U1 RNP) antibodies in combination with clinical features commonly seen in systemic lupus erythematosus (SLE), systemic sclerosis (SSc), rheumatoid arthritis (RA) and polymyositis (PM).

CASE PRESENTATION

The annual incidence of MCTD is 1.9 per 100,000 adults. Any organ system can be involved in MCTD however four clinical features that suggest the presence of MCTD rather than another systemic rheumatic disease are Raynaud phenomenon with swollen hands or puffy fingers, absence of severe kidney disease and central nervous system (CNS) disease at first presentation generally, insidious onset of pulmonary hypertension and presence of autoantibodies anti-U1 ribonucleoprotein (U1 RNP), especially antibodies to the 68 kD protein. MCTD, although initially thought to be a disease with a benign course is not considered a valid argument at present. This connective tissue disorder can present with life-threating organ involvement with rapid progression of disease.

CONCLUSION

We report two cases of MCTD, one with mild disease and another with life-threatening illness, describing the range of severity at presentation of this disorder.

Contrasting Autoimmune Comorbidities in Microscopic Colitis and Inflammatory Bowel Diseases

Background: Inflammatory bowel diseases (Crohn’s disease and ulcerative colitis) and microscopic colitis (lymphocytic and collagenous colitis) are immune-mediated diseases of the gastrointestinal tract, with distinct pathophysiology. Objective: We sought to compare the prevalence of autoimmune diseases between microscopic colitis (MC) and inflammatory bowel diseases (IBDs) in our patient cohorts in their medical history. Methods: We collected data from 611 patients (508 with IBD, 103 with MC). We recorded cases of other autoimmune diseases. The screened documentation was written in the period between 2008 and 2022. We sought to determine whether colonic involvement had an impact on the prevalence of autoimmune diseases. Results: Ulcerative colitis patients and patients with colonic-predominant Crohn’s disease had a greater propensity for autoimmune conditions across the disease course than patients with ileal-predominant Crohn’s disease. Gluten-related disorders were more common in Crohn’s disease than in ulcerative colitis, and slightly more common than in microscopic colitis. In ulcerative colitis, 10 patients had non-differentiated collagenosis registered, which can later develop into a definite autoimmune disease. Conclusions: Predominantly colonic involvement can be a predisposing factor for developing additional autoimmune disorders in IBD. Ulcerative colitis patients may have laboratory markers of autoimmunity, without fulfilling the diagnostic criteria for definitive autoimmune disorders (non-differentiated collagenosis).

Scleroderma Renal Crisis in a Case of Mixed Connective Tissue Disease Treated Successfully with Angiotensin-Converting Enzyme Inhibitors

Mixed connective tissue disease (MCTD) is a rheumatic disease syndrome with overlapping features of scleroderma, systemic lupus erythematosus, and polymyositis. An extremely rare but serious complication that can occur in MCTD is scleroderma renal crisis (SRC). There have been different approaches to the treatment of SRC associated with MCTD. We present a case of MCTD with chronic features of Raynaud's phenomenon, dermatomyositis, and thrombocytopenia complicated with acute SRC which showed a great response to ACE inhibitors. Here, we advise the early and aggressive use of ACE inhibitors as soon as SRC is suspected.

Undifferentiated vasculitis or an evolving systemic autoimmune rheumatic disease?

Undifferentiated connective tissue diseases usually present with arthralgias, sicca symptoms, Raynaud's phenomenon and leucopenia. This case presents the atypical presentation of an undifferentiated connective tissue disease with extensive cutaneous involvement of fingers and toes leading to gangrene with absence of typical rheumatological symptoms. The autoimmune profile showed positive ANA and anti-Ro/SS-A. Thromboembolism was ruled out on the basis of transthoracic and transesophageal echo. She was treated with I/V corticosteroids and cyclophosphamide that halted the disease progression.