Rheumatology and Immunology Practice Questions

Q: What is the most common cardiac involvement in rheumatoid arthritis?

Pericarditis. **Explanation:** **1. Why Pericarditis is the Correct Answer:** Pericarditis is the most common clinical and pathological cardiac manifestation of Rheumatoid Arthritis (RA). While it is often asymptomatic in up to 50% of patients (detected primarily via autopsy or echocardiography), symptomatic pericarditis occurs in about 10% of cases. It typically presents in patients with long-standing, seropositive (RF+) disease and extra-articular manifestations. The pericardial fluid in RA is characteristically "exudative," showing low glucose levels, low complement levels, and high LDH. **2. Analysis of Incorrect Options:** * **Pancarditis (A):** This involves inflammation of all three layers of the heart (pericardium, myocardium, and endocardium). While RA can affect multiple layers, it rarely presents as a simultaneous pancarditis; this is more characteristic of Acute Rheumatic Fever. * **Myocarditis (C):** Myocardial involvement in RA is rare and usually manifests as granulomatous nodules or interstitial myocarditis. It is significantly less common than pericardial disease. * **Endocarditis (D):** While RA can cause valvular nodules (Libman-Sacks endocarditis is specific to SLE, not RA), clinical endocarditis or valvular dysfunction is much rarer than pericarditis. **3. NEET-PG High-Yield Pearls:** * **Most Common Cardiac Manifestation:** Pericarditis. * **Most Common Cause of Death in RA:** Ischemic Heart Disease (due to accelerated atherosclerosis caused by chronic inflammation). * **Specific Finding:** Rheumatoid nodules can occasionally form on the conduction system, leading to heart blocks [1]. * **Pericardial Fluid Profile:** Low Glucose (<30 mg/dL) is a classic board-exam pointer for Rheumatoid pericarditis/pleuritis.

Q: Which antibody is associated with a reduced risk of lupus nephritis in Systemic Lupus Erythematosus (SLE)?

Anti-La antibody. **Explanation:** The correct answer is **Anti-La antibody (SS-B)**. In Systemic Lupus Erythematosus (SLE), certain autoantibodies serve as markers for specific organ involvement or protection. Clinical studies have consistently shown that the presence of **Anti-Ro (SS-A) and Anti-La (SS-B)** antibodies is associated with a **decreased risk of developing lupus nephritis** [1]. While these antibodies are classically linked to Sjögren’s syndrome and neonatal lupus (congenital heart block), in the context of SLE, they appear to be "protective" against severe renal disease compared to patients who are positive for anti-dsDNA [1]. **Analysis of Incorrect Options:** * **Anti-ribosomal P antibody:** This is highly specific for SLE and is strongly associated with **neuropsychiatric lupus** (lupus psychosis) and sometimes hepatitis, rather than renal protection. * **Anti-histone antibody:** This is the hallmark of **Drug-Induced Lupus (DIL)**. While DIL typically spares the kidneys and CNS, the antibody itself is not considered a "protective factor" for nephritis in idiopathic SLE. * **Antinuclear antibody (ANA):** This is the best initial screening test (high sensitivity) but has no prognostic value regarding specific organ involvement like nephritis due to its lack of specificity [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Most Specific for SLE:** Anti-dsDNA and Anti-Smith (Anti-Sm) [1]. * **Best Marker for Disease Activity/Nephritis:** Anti-dsDNA (levels correlate with renal flares and low C3/C4) [1]. * **Neonatal Lupus:** Associated with Anti-Ro and Anti-La; most common permanent complication is **congenital complete heart block** [1]. * **Subacute Cutaneous Lupus (SCLE):** Strongly associated with Anti-Ro antibodies [1].

Q: What is the treatment of choice in seronegative spondyloarthritis?

Indomethacin. **Explanation:** **1. Why Indomethacin is the Correct Answer:** Seronegative spondyloarthritides (SpA), such as Ankylosing Spondylitis (AS), Reactive Arthritis, and Psoriatic Arthritis, are characterized by axial involvement and enthesitis [2]. **Non-Steroidal Anti-Inflammatory Drugs (NSAIDs)** are the first-line treatment of choice for managing pain and stiffness. Among NSAIDs, **Indomethacin** is traditionally considered the gold standard and the most effective agent for symptomatic relief in SpA. It works by inhibiting prostaglandin synthesis, effectively reducing the spinal inflammation and peripheral arthritis associated with these conditions [1]. **2. Analysis of Incorrect Options:** * **A. Phenylbutazone:** While highly effective for AS, it is no longer the treatment of choice due to severe potential side effects, including **aplastic anemia** and agranulocytosis. It is reserved only for refractory cases. * **B. Aspirin:** Aspirin is generally ineffective at standard doses for the intense axial inflammation seen in SpA and requires very high, often toxic, doses to achieve an anti-inflammatory effect. * **D. Corticosteroids:** Systemic steroids have **minimal to no role** in treating the axial disease of seronegative SpA. While local injections may help peripheral enthesitis, long-term systemic use is avoided due to lack of efficacy and significant side effects. **3. NEET-PG High-Yield Pearls:** * **First-line:** NSAIDs (Indomethacin/Naproxen) [1]. * **Disease-Modifying (Peripheral):** Sulfasalazine is used for peripheral joint involvement but is **ineffective for axial (spinal) disease**. * **Biologicals:** TNF-alpha inhibitors (e.g., Etanercept, Infliximab) are the treatment of choice if NSAIDs fail [3]. * **Key Association:** HLA-B27 is strongly associated with these conditions (highest in Ankylosing Spondylitis, ~90%) [2].

Q: Which of the following is NOT true about psoriatic arthritis?

More common in males. ### Explanation Psoriatic arthritis (PsA) is a chronic inflammatory spondyloarthropathy occurring in approximately 30% of patients with psoriasis. **Why Option C is the correct answer:** The statement that PsA is "more common in males" is **incorrect**. Unlike many other spondyloarthropathies (like Ankylosing Spondylitis), psoriatic arthritis affects **males and females equally (1:1 ratio)**. While certain subtypes may show slight predilection (e.g., the spondylitis form is slightly more common in males), the overall prevalence is gender-neutral. **Analysis of other options:** * **A. Association with HLA-Cw6:** This is the strongest genetic risk factor for Psoriasis (Type 1). While HLA-B27 is linked to the axial/spondylitis subtype of PsA, HLA-Cw6 remains the primary genetic marker for the underlying cutaneous disease. * **B. Involvement of the DIP joint:** This is a **hallmark feature** of PsA. Involvement of the Distal Interphalangeal (DIP) joints helps clinically distinguish PsA from Rheumatoid Arthritis (which typically spares the DIP joints). * **D. Drug of choice is Methotrexate:** Methotrexate is the first-line Disease-Modifying Anti-Rheumatic Drug (DMARD) for PsA, as it effectively treats both the skin lesions and the peripheral joint inflammation. **High-Yield Clinical Pearls for NEET-PG:** 1. **Moll and Wright Criteria:** The most common clinical pattern is **Asymmetric Oligoarthritis**. 2. **Arthritis Mutilans:** The most severe form, characterized by "telescoping fingers" and "pencil-in-cup" appearance on X-ray. 3. **Dactylitis:** "Sausage digits" (diffuse swelling of a finger/toe) is a highly characteristic finding. 4. **Nail Changes:** Pitting and onycholysis are strong predictors of future joint involvement.

Q: Macrophage activation syndrome is most commonly seen in association with which of the following conditions?

Juvenile Rheumatoid Arthritis. **Explanation:** **Macrophage Activation Syndrome (MAS)** is a life-threatening complication characterized by an overwhelming inflammatory response due to the uncontrolled proliferation of T-lymphocytes and well-differentiated macrophages. These macrophages exhibit **hemophagocytosis** (engulfing erythrocytes, leukocytes, and platelets) in the bone marrow and reticuloendothelial organs. 1. **Why Juvenile Rheumatoid Arthritis (JRA) is correct:** MAS is most classically and frequently associated with **Systemic Juvenile Idiopathic Arthritis (sJIA)**, formerly known as Still’s disease or JRA [1]. It occurs in approximately 10% of sJIA patients and is considered a form of secondary Hemophagocytic Lymphohistiocytosis (HLH). The underlying trigger is often an infection or a change in medication, leading to a "cytokine storm" (specifically IL-1, IL-6, and TNF-alpha). 2. **Why other options are incorrect:** * **SLE (Systemic Lupus Erythematosus):** While MAS can occur in SLE, it is significantly less common than in sJIA. * **Systemic Sclerosis & Sweet’s Syndrome:** These conditions are not typically associated with the systemic hyperinflammation or the specific cytokine profile required to trigger MAS. **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Triad:** High-grade non-remitting fever, hepatosplenomegaly, and lymphadenopathy. * **Laboratory Hallmarks:** The "Paradox of MAS"—while the patient is highly inflamed, the **ESR characteristically drops** (due to fibrinogen consumption). * **Key Markers:** High Ferritin (often >10,000 ng/mL), high Triglycerides, low Fibrinogen, and cytopenias (anemia, thrombocytopenia). * **Treatment:** High-dose corticosteroids are first-line; Cyclosporine or IL-1 inhibitors (Anakinra) are used in refractory cases.

Q: What is the loading dose of leflunomide in rheumatoid arthritis?

100 mg. **Explanation:** Leflunomide is a Disease-Modifying Antirheumatic Drug (DMARD) that acts by inhibiting the mitochondrial enzyme **dihydroorotate dehydrogenase (DHODH)**, thereby blocking *de novo* pyrimidine synthesis. This inhibits the proliferation of activated T-cells. **Why 100 mg is correct:** Leflunomide has a very long half-life (approximately 14–15 days) due to extensive enterohepatic circulation. To achieve therapeutic steady-state plasma concentrations rapidly, a **loading dose of 100 mg once daily for 3 consecutive days** is recommended. Following this, a maintenance dose is initiated. **Analysis of Incorrect Options:** * **A (20 mg):** This is the standard **daily maintenance dose** for most patients with active rheumatoid arthritis. * **B (10 mg):** This is the lower-end maintenance dose, often used for patients who cannot tolerate 20 mg due to side effects like diarrhea or hepatotoxicity. * **D (400 mg):** This is an inappropriately high dose and is not used in clinical practice; it would significantly increase the risk of severe toxicity. **High-Yield Clinical Pearls for NEET-PG:** * **Active Metabolite:** Leflunomide is a prodrug; its active metabolite is **Teriflunomide (A77 1726)**. * **Washout Procedure:** Due to its long half-life, if a patient needs to stop the drug (e.g., for pregnancy or toxicity), **Cholestyramine** is used to enhance fecal excretion. * **Teratogenicity:** It is strictly contraindicated in pregnancy (Category X). * **Monitoring:** Baseline and periodic monitoring of **Liver Function Tests (LFTs)** and CBC is mandatory due to risks of hepatotoxicity and myelosuppression. * **Trend Note:** In modern practice, the loading dose is often omitted to reduce the incidence of gastrointestinal side effects (diarrhea), but for examination purposes, 100 mg remains the standard answer.

Q: The CASPAR criteria is used in the diagnosis of which condition?

Psoriatic arthritis. **Explanation:** The **CASPAR (Clasification Criteria for Psoriatic Arthritis)** criteria were developed to provide a standardized, highly sensitive, and specific method for diagnosing Psoriatic Arthritis (PsA). Unlike other inflammatory arthritides, PsA often lacks a specific biomarker (like RF), making clinical criteria essential. To meet the CASPAR criteria, a patient must have **inflammatory arthritis** (joint, spinal, or entheseal) plus at least **3 points** from the following categories: 1. **Evidence of Psoriasis:** Current (2 pts), history of, or family history of psoriasis (1 pt). 2. **Psoriatic Nail Dystrophy:** Pitting, onycholysis, or hyperkeratosis (1 pt). 3. **Negative Rheumatoid Factor (RF):** (1 pt). 4. **Dactylitis:** Current "sausage digit" or a history of it (1 pt). 5. **Radiographic Evidence:** Juxta-articular new bone formation on X-rays of the hand or foot (1 pt). **Analysis of Incorrect Options:** * **Rheumatoid Arthritis (B):** Diagnosed using the **ACR/EULAR 2010 criteria**, which focus on joint involvement, serology (RF/Anti-CCP), and acute phase reactants. * **Ankylosing Spondylitis (C):** Diagnosed using the **Modified New York Criteria** (requiring radiographic sacroiliitis) or the **ASAS criteria** (for axial spondyloarthritis). * **Reactive Synovitis (D):** Usually diagnosed based on a clinical history of a preceding infection (GI or GU) and the presence of asymmetric oligoarthritis (part of the ESSG criteria). **High-Yield Clinical Pearls for NEET-PG:** * **Pencil-in-cup deformity:** The classic radiographic hallmark of PsA (distal phalanx base widens while the proximal phalanx head narrows). * **DIP involvement:** PsA characteristically involves the Distal Interphalangeal joints, which are typically spared in Rheumatoid Arthritis. * **HLA Association:** Strongly associated with **HLA-B27** (especially in axial/spondylitic presentations).

Question 1

Which of the following is NOT true regarding reactive arthritis?

Accepted Answer

Keratoderma blennorrhagicum typically occurs on the glans penis.

Answer

HLA-B27 and HIV can affect the severity of reactive arthritis.

Answer

Dactylitis and enthesitis are common manifestations.

Answer

Asymmetrical sacroiliitis is a characteristic finding.

Question 2

What is the most common cardiac involvement in rheumatoid arthritis?

Accepted Answer

Pericarditis

Answer

Pancarditis

Answer

Myocarditis

Answer

Endocarditis

Question 3

Which antibody is associated with a reduced risk of lupus nephritis in Systemic Lupus Erythematosus (SLE)?

Accepted Answer

Anti-La antibody

Answer

Anti-ribosomal P antibody

Answer

Anti-histone antibody

Answer

Antinuclear antibody (ANA)

Question 4

A 17-year-old woman presents with agitation and a history of malaise, joint pain, weight loss, and sporadic fever over the past 3 months. Physical examination reveals a temperature of 38°C (101°F), malar rash, erythematous-pink plaques with telangiectatic vessels, oral ulcers, and non-blanching purpuric papules on her legs. Laboratory studies show elevated BUN and creatinine levels, and a positive anti-double-stranded DNA antibody test. Biopsy of sun-damaged lesional skin would most likely show which of the following histopathologic findings?

Accepted Answer

Granular distribution of immune complexes in the basement membrane zone

Answer

Acanthosis, parakeratosis, and neutrophils within the stratum corneum

Answer

Early dermal-epidermal separation mediated by eosinophils

Answer

Linear IgA deposits within dermal papillae

Question 5

What is the treatment of choice in seronegative spondyloarthritis?

Accepted Answer

Indomethacin

Answer

Phenylbutazone

Answer

Aspirin

Answer

Corticosteroid

Question 6

A 52-year-old male presented with purpura, arthralgia, neuropathy, and glomerulonephritis. Blood routine examination revealed low hemoglobin and high ESR, with mild alteration in LFT and mild transaminase elevation. He has a history of blood transfusion in 1987 following an accident. What is the underlying pathology in this clinical setting?

Accepted Answer

Essential mixed cryoglobulinemia

Answer

Henoch-Schonlein purpura

Answer

Amyloidosis

Answer

Chronic infection with malaria

Question 7

Which of the following is NOT true about psoriatic arthritis?

Accepted Answer

More common in males

Answer

Association with HLA-Cw6

Answer

Involvement of the DIP joint

Answer

Drug of choice is methotrexate

Question 8

Macrophage activation syndrome is most commonly seen in association with which of the following conditions?

Accepted Answer

Juvenile Rheumatoid Arthritis

Answer

Systemic sclerosis

Answer

Sweet's syndrome

Answer

SLE

Question 9

What is the loading dose of leflunomide in rheumatoid arthritis?

Accepted Answer

100 mg

Answer

20 mg

Answer

10 mg

Answer

400 mg

Question 10

The CASPAR criteria is used in the diagnosis of which condition?

Accepted Answer

Psoriatic arthritis

Answer

Rheumatoid arthritis

Answer

Ankylosing spondylitis

Answer

Reactive synovitis

Rheumatology and Immunology — MCQs

Rheumatology and Immunology — MCQs

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