Examkin

Question

Difficulty: Very hardRheumatology and Immunology

Correlate each complex clinical scenario with the specific autoantibody marker that best corresponds to the patient's underlying rheumatologic diagnosis.

  • A previously healthy individual develops rapidly progressive, profound proximal weakness and severe dysphagia over three weeks. Laboratory analysis reveals a creatine kinase level of 14,500 U/L. Muscle biopsy demonstrates extensive necrotizing myopathy lacking prominent inflammatory infiltrates.Anti-signal recognition particle (anti-SRP) antibodies
  • A patient evaluated for recent-onset extensive cutaneous induration across the trunk and proximal extremities presents to the emergency department with a severe headache, blurred vision, blood pressure of 215/115 mmHg, and a rapidly rising serum creatinine.Anti-RNA polymerase III antibodies
  • An individual presents with profound, generalized hand edema ('puffy fingers'), severe digital vasospasm upon cold exposure, and exertional breathlessness. Echocardiography estimates a right ventricular systolic pressure of 55 mm Hg with normal left ventricular function and no pulmonary parenchymal disease.Anti-U1-ribonucleoprotein (anti-U1-RNP) antibodies
  • A patient describes difficulty rising from low chairs, persistent dry cough, and thickened, cracked, hyperkeratotic skin on the radial aspects of the digits. High-resolution computed tomography of the chest shows bilateral basilar ground-glass opacities.Anti-aminoacyl-tRNA synthetase (anti-Jo-1) antibodies

Answer

The correct mappings associate immune-mediated necrotizing myopathy with anti-SRP, scleroderma renal crisis with anti-RNA polymerase III, Mixed Connective Tissue Disease with anti-U1-RNP, and antisynthetase syndrome with anti-Jo-1 antibodies.
Each autoantibody represents a distinct pathophysiologic entity within the rheumatologic spectrum. Anti-SRP mediates aggressive necrotizing myopathy. Anti-RNA polymerase III correlates with rapidly progressive diffuse systemic sclerosis and scleroderma renal crisis. Anti-U1-RNP defines Mixed Connective Tissue Disease with a high risk of pulmonary arterial hypertension. Anti-Jo-1 defines antisynthetase syndrome characterized by myositis, interstitial lung disease, and mechanic's hands.

Step-by-Step Solution

1
Analyze the first clinical presentation featuring massive CK elevation and necrotizing biopsy without inflammation.
Identified as immune-mediated necrotizing myopathy.
Differentiates this aggressive pathology from classic polymyositis, which typically features prominent CD8+ T-cell endomysial inflammation.
2
Evaluate the patient with diffuse skin thickening and malignant hypertension.
Identified as diffuse cutaneous systemic sclerosis complicated by scleroderma renal crisis.
Requires recognition of the specific autoantibody (anti-RNA polymerase III) conveying the highest risk for this life-threatening renal complication.
3
Assess the presentation of puffy fingers, Raynaud's, and isolated pulmonary arterial hypertension.
Identified as Mixed Connective Tissue Disease (MCTD).
The lack of parenchymal lung disease combined with these specific overlapping connective tissue features points to MCTD rather than pure systemic sclerosis.
4
Review the triad of proximal weakness, interstitial lung disease, and hyperkeratotic fingers.
Identified as antisynthetase syndrome.
The skin findings represent 'mechanic's hands', which alongside ILD and myopathy, are pathognomonic for this specific overlap syndrome driven by anti-Jo-1.

Key Concept

Advanced serologic profiling in systemic autoimmune diseases, specifically differentiating unique autoantibodies in inflammatory myopathies and scleroderma-spectrum disorders.
Estimated Time:2m 30s
Rate this question

Topics

Rheumatology and Immunology

More questions from this topic