Rheumatology and Immunology Practice Questions

Q: Ankylosing spondylitis may be associated with which of the following conditions?

Aortic incompetence. Ankylosing spondylitis (AS) is a chronic inflammatory spondyloarthropathy that primarily affects the axial skeleton but is frequently associated with extra-articular manifestations. **Why Aortic Incompetence is Correct:** The underlying pathology in AS involves inflammation of the aortic root and the adventitia of the aorta (aortitis). This chronic inflammation leads to: 1. **Dilation of the aortic root** and the aortic valve ring. 2. **Thickening and shortening of the aortic valve cusps**, often extending to the subvalvular region (forming "subaortic bumps"). These structural changes prevent the valve from closing properly, resulting in **Aortic Incompetence (Regurgitation)**. This is seen in approximately 3–10% of patients, with the prevalence increasing with the duration of the disease. **Why Other Options are Incorrect:** * **Atrial Fibrillation:** While chronic inflammation can theoretically predispose to arrhythmias, the classic conduction abnormality in AS is **Atrioventricular (AV) block**, caused by the extension of inflammation from the aortic root into the interventricular septum. * **Pulmonary Stenosis & Mitral Stenosis:** These are typically sequelae of Rheumatic Heart Disease or congenital malformations. AS specifically targets the elastic tissue of the aorta and does not typically involve the stenotic narrowing of the pulmonary or mitral valves. **High-Yield Clinical Pearls for NEET-PG:** * **Cardiac Triad in AS:** Aortic Regurgitation, AV Conduction Blocks, and Cardiomyopathy. * **Pulmonary Involvement:** Look for **Apical Lung Fibrosis** (often bilateral and can mimic TB). * **HLA Association:** Strongly associated with **HLA-B27** (>90% of cases) [1]. * **Radiology:** "Bamboo spine" (syndesmophytes) and "Dagger sign" (ossification of supraspinous ligaments) [1]. * **Schober’s Test:** Used to clinically assess restricted lumbar flexion.

Q: What is the commonest valvular lesion in SLE-related cardiac disease?

Mitral regurgitation. **Explanation:** The involvement of the heart in Systemic Lupus Erythematosus (SLE) is common, with the pericardium being the most frequent site of involvement. However, when considering **valvular disease**, the most common manifestation is valvular thickening and dysfunction [1]. **1. Why Mitral Regurgitation is correct:** Valvular heart disease in SLE typically presents as **Libman-Sacks endocarditis** (non-bacterial verrucous vegetations). These vegetations and subsequent chronic inflammation lead to leaflet thickening and scarring. The **mitral valve** is the most frequently affected valve, followed by the aortic valve. Among the functional abnormalities, **Mitral Regurgitation (MR)** is the most common clinical finding, resulting from the distortion of the valve apparatus [2]. **2. Why the other options are incorrect:** * **Tricuspid Regurgitation:** While right-sided valves can be involved, they are significantly less common than left-sided valves in SLE. * **Mitral Stenosis:** Although chronic inflammation can lead to valve thickening, SLE typically causes regurgitant lesions rather than stenotic ones. Mitral stenosis is classically associated with Rheumatic Heart Disease [1]. * **Aortic Regurgitation:** This is the second most common valvular lesion in SLE, but it occurs less frequently than mitral regurgitation. **High-Yield Facts for NEET-PG:** * **Libman-Sacks Endocarditis:** Characterized by small, sterile vegetations on *both* sides of the valve leaflets (pathognomonic feature). * **Most common cardiac manifestation of SLE:** Pericarditis. * **Most common cause of death in late SLE:** Accelerated Atherosclerosis/Ischemic Heart Disease. * **Association:** Valvular lesions in SLE are more frequently seen in patients with **Antiphospholipid Antibody Syndrome (APS)**.

Q: A 23-year-old man presents with fever, weight loss, malaise, abdominal pain, and myalgias. Workup reveals that the patient has polyarteritis nodosa. Which of the following is associated with this form of vasculitis?

Hepatitis B virus. **Explanation:** **Polyarteritis Nodosa (PAN)** is a systemic necrotizing vasculitis that primarily affects medium-sized muscular arteries. It is characterized by segmental, transmural inflammation that leads to "beading" (aneurysms) on angiography. **Why Hepatitis B is correct:** Approximately 10–30% of PAN cases are associated with **Hepatitis B Virus (HBV)** infection. The pathogenesis involves the deposition of immune complexes containing Hepatitis B surface antigen (HBsAg) within the vessel walls, triggering an inflammatory cascade [1]. This typically occurs within the first six months of HBV infection. **Analysis of Incorrect Options:** * **A. Arsenic:** Exposure to arsenic is classically associated with **Angiosarcoma of the liver** and squamous cell carcinoma of the skin, not systemic vasculitis. * **B. Chlamydia pneumoniae:** This pathogen has been linked to the pathogenesis of **Atherosclerosis** and some cases of reactive arthritis, but it has no established link with PAN. * **C. Human Immunodeficiency Virus (HIV):** While HIV can be associated with various vasculitides (like Polyarteritis-like syndrome or small vessel vasculitis), the classic, high-yield association for PAN remains HBV [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Spares the Lungs:** PAN characteristically involves the renal and visceral arteries but **spares the pulmonary circulation**. * **Microaneurysms:** "Rosary sign" or "string of pearls" appearance on renal or mesenteric angiography is diagnostic. * **P-ANCA:** PAN is typically **ANCA-negative**. If a patient has PAN-like symptoms but is P-ANCA positive, consider Microscopic Polyangiitis (MPA). * **Biopsy:** Gold standard diagnosis is via biopsy showing transmural inflammation with **fibrinoid necrosis**.

Q: A 23-year-old female presents with arthritis, malar rash, oral ulcers, and serositis (pleuritis or pericarditis). Which investigation is most likely to be positive?

Anti-nuclear antibody. The clinical presentation of a young female with a malar rash, arthritis, oral ulcers, and serositis is a classic description of **Systemic Lupus Erythematosus (SLE)** [1]. According to the ACR and EULAR classification criteria, **Anti-nuclear antibody (ANA)** is the most sensitive screening test for SLE [2]. 1. **Why ANA is correct:** ANA is positive in approximately **95–100%** of patients with SLE [2]. Due to its extremely high sensitivity, it is considered the "entry criterion" for the diagnosis. If ANA is negative, the diagnosis of SLE is highly unlikely. 2. **Why other options are incorrect:** * **Anti-collagen antibody:** These are not standard diagnostic markers for SLE or common autoimmune connective tissue diseases. * **Anti-epithelial antibody:** These are typically associated with pemphigus (anti-desmoglein) or other bullous skin diseases, not systemic multi-organ autoimmune disorders like SLE. * **Antigen-antibody complexes:** While SLE is a Type III hypersensitivity reaction involving immune complex deposition, measuring circulating complexes is non-specific and not a primary diagnostic investigation. **High-Yield Clinical Pearls for NEET-PG:** * **Most Sensitive Test for SLE:** ANA (Best screening test) [2]. * **Most Specific Tests for SLE:** Anti-dsDNA and Anti-Smith (Anti-Sm) antibodies [2]. * **Drug-Induced Lupus:** Anti-histone antibodies are the hallmark. * **Neonatal Lupus/Sjögren’s:** Associated with Anti-Ro (SSA) and Anti-La (SSB) antibodies [2]. * **Complement levels:** C3 and C4 levels are typically **decreased** during active SLE flares.

Q: Which autoantibody is associated with Sjögren's syndrome?

Anti Ro and Anti La antibodies. **Explanation:** Sjögren's syndrome is a chronic autoimmune disorder characterized by lymphocytic infiltration of exocrine glands, primarily leading to keratoconjunctivitis sicca (dry eyes) and xerostomia (dry mouth) [1]. **Why Option B is Correct:** The hallmark autoantibodies for Sjögren's syndrome are **Anti-Ro (SS-A)** and **Anti-La (SS-B)** [1]. These are directed against ribonucleoprotein antigens. Anti-Ro is found in about 60-90% of patients, while Anti-La is found in approximately 30-60%. Their presence is a key diagnostic criterion and is often associated with earlier disease onset, longer duration, and extraglandular manifestations (like vasculitis). **Analysis of Incorrect Options:** * **A. Anti-centromere antibody:** Highly specific for **Limited Cutaneous Systemic Sclerosis** (formerly CREST syndrome). * **C. Anti-dsDNA antibody:** Highly specific for **Systemic Lupus Erythematosus (SLE)** and correlates with disease activity and lupus nephritis. * **D. Anti-RNP antibody:** The defining serological marker for **Mixed Connective Tissue Disease (MCTD)**. **High-Yield Clinical Pearls for NEET-PG:** * **Schirmer’s Test:** Used to quantify decreased tear production. * **Lip Biopsy:** The gold standard for diagnosis, showing focal lymphocytic sialadenitis in minor salivary glands [1]. * **Malignancy Risk:** Patients with Sjögren's syndrome have a 40-fold increased risk of developing **B-cell Non-Hodgkin Lymphoma** (specifically MALT lymphoma) [1]. * **Neonatal Lupus:** Pregnant women with Anti-Ro/SSA antibodies are at risk of having infants with neonatal lupus and **congenital heart block**. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 234-236.

Q: The diagnosis of gout is best established by the presence of which of the following?

Intracellular uric acid crystals. The gold standard for diagnosing gout is the identification of **monosodium urate (MSU) crystals** in synovial fluid or tophus aspirate using polarized light microscopy [1]. ### Why Option B is Correct The presence of **intracellular** uric acid crystals (MSU crystals engulfed by neutrophils) is the definitive diagnostic finding. While extracellular crystals are also seen, finding them inside polymorphonuclear leukocytes (PMNs) confirms an **active inflammatory process** and is pathognomonic for an acute gouty attack. Under compensated polarized light, these crystals appear **needle-shaped** and exhibit **strong negative birefringence** (yellow when parallel to the axis of the compensator). ### Why Other Options are Incorrect * **Option A:** While synovial fluid contains crystals, the term "intracellular" is more specific for confirming the acute inflammatory nature of the gouty flare. * **Option C:** Serum uric acid levels can be **normal or even low** during an acute attack (due to cytokines increasing renal urate excretion). Conversely, asymptomatic hyperuricemia [4] is common and does not equate to a diagnosis of gout. * **Option D:** Podagra (inflammation of the 1st MTP joint) is the most common clinical presentation [4], but it is not definitive. Other conditions like pseudogout, sarcoidosis, or septic arthritis can mimic this presentation. ### High-Yield Clinical Pearls for NEET-PG * **Polarized Microscopy:** MSU crystals = Needle-shaped, **Yellow** when parallel (Negative birefringence) [2]. * **Pseudogout (CPPD):** Rhomboid-shaped, **Blue** when parallel (Positive birefringence) [2]. * **Radiology:** Look for "punched-out" erosions with overhanging edges (**Martel’s sign**) in chronic gout. * **Treatment:** NSAIDs, Colchicine, or Steroids for acute attacks; Allopurinol (Xanthine oxidase inhibitor) for chronic management (never start during an acute flare) [3].

Q: Raynaud's phenomenon is associated with which of the following conditions, except?

Osteoarthritis. Explanation: Raynaud’s phenomenon (RP) is a reversible vasospastic disorder of the digital arteries, typically triggered by cold or emotional stress. It is classified as Primary (idiopathic) or Secondary (associated with an underlying disease). Why Osteoarthritis (OA) is the correct answer: Osteoarthritis is a degenerative joint disease characterized by the breakdown of articular cartilage. It is not an autoimmune or systemic inflammatory condition and does not involve the vascular endothelium or autonomic dysregulation. Therefore, it is not associated with Raynaud’s phenomenon. Analysis of Incorrect Options: * Systemic Lupus Erythematosus (SLE): RP is a common secondary feature of SLE (occurring in ~30% of cases) due to underlying vasculopathy and circulating immune complexes [1]. * Rheumatoid Arthritis (RA): While less common than in Scleroderma or SLE, RA is a systemic inflammatory disease that can be associated with secondary RP, often linked to rheumatoid vasculitis [1]. * Cryoglobulinemia: This condition involves proteins that precipitate at low temperatures, leading to increased blood viscosity and vascular occlusion, which directly triggers Raynaud-like symptoms and digital ischemia. High-Yield Clinical Pearls for NEET-PG: 1. Scleroderma (Systemic Sclerosis): The most common cause of secondary RP (>90% of patients). It is often the initial presenting symptom. 2. CREST Syndrome: Raynaud’s is the 'R' in this variant of limited scleroderma. 3. Capillaroscopy: Used to differentiate Primary from Secondary RP. Abnormal (dilated/tortuous) nailfold capillaries suggest a secondary connective tissue disease [1]. 4. Drug-induced RP: Beta-blockers, ergotamine, and certain chemotherapy agents (cisplatin/bleomycin) are known triggers. 5. Treatment: Calcium channel blockers (e.g., Nifedipine) are the first-line pharmacological treatment.

Q: A 30-year-old woman presents with a heart murmur. She has a history of recurrent episodes of arthritis, skin rash, and glomerulonephritis. Blood cultures are negative. Laboratory tests for antinuclear antibodies (ANA) and anti-double-stranded DNA are positive. Which of the following is the most likely cause of the heart murmur in this patient?

Libman-Sacks endocarditis. The patient presents with a classic triad of Systemic Lupus Erythematosus (SLE): **arthritis, skin rash (malar/discoid), and glomerulonephritis**, supported by positive **ANA** [3] and **anti-dsDNA** antibodies. In a patient with SLE and a heart murmur, the most characteristic cardiac valvular lesion is **Libman-Sacks Endocarditis**. [2] **1. Why Libman-Sacks Endocarditis is correct:** Also known as verrucous endocarditis, this condition involves small, sterile (non-infective), fibro-fibrinous vegetations. Unlike infective endocarditis, these vegetations can occur on **both sides** (superior and inferior surfaces) of the valve leaflets and the chordae tendineae. The mitral valve is most commonly affected. The "negative blood cultures" in the prompt are a classic clue pointing toward a non-bacterial/sterile etiology. **2. Why the other options are incorrect:** * **Mitral Valve Prolapse (MVP):** While MVP can occur in the general population, it is not specifically associated with the systemic inflammatory markers (ANA/dsDNA) or the multi-organ involvement seen here. * **Myocardial Infarct:** While SLE patients have an accelerated risk of atherosclerosis and coronary vasculitis, a myocardial infarct presents with chest pain and EKG changes rather than a primary new-onset murmur related to valvular vegetations. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cardiac manifestation of SLE:** Pericarditis. * **Most specific valvular lesion of SLE:** Libman-Sacks Endocarditis. * **Pathology:** Vegetations consist of immune complexes, fibrin, and necrotic debris (Hematoxylin bodies). * **Association:** Strongly associated with **Antiphospholipid Antibody Syndrome (APS)**. [1] * **Distinction:** Unlike Rheumatic Heart Disease (which affects the edges of valves), Libman-Sacks vegetations can be found anywhere on the endocardial surface. [2]

Q: What is the screening test for scleroderma?

Anti-nuclear antibody. **Explanation:** The correct answer is **Anti-nuclear antibody (ANA)**. In the context of Systemic Sclerosis (Scleroderma), ANA is the most sensitive screening test, being positive in approximately **90-95%** of patients [1]. In medical diagnostics, a screening test must have high sensitivity to ensure that cases are not missed; while ANA is not specific to scleroderma (as it appears in SLE and other CTDs), its absence makes a diagnosis of systemic sclerosis highly unlikely. **Analysis of Incorrect Options:** * **B. U1-Ribonucleoprotein (U1-RNP) antibody:** This is the hallmark marker for **Mixed Connective Tissue Disease (MCTD)** [1]. While it can be present in some scleroderma patients, it is not the primary screening tool. * **C. Anti-L.K.M. antibody:** Anti-Liver Kidney Microsomal antibodies are markers for **Autoimmune Hepatitis (Type 2)** and are unrelated to systemic sclerosis. * **D. Anti-topoisomerase antibody (Anti-Scl-70):** While highly **specific** for Diffuse Cutaneous Systemic Sclerosis (dcSSc) and indicative of a higher risk for interstitial lung disease, it is only positive in about 30-40% of patients. Therefore, it is a confirmatory/prognostic marker rather than a screening test. **High-Yield Clinical Pearls for NEET-PG:** * **Anti-Centromere Antibody:** Highly specific for **Limited** Cutaneous Systemic Sclerosis (formerly CREST syndrome) and associated with pulmonary artery hypertension. * **Anti-RNA Polymerase III:** Associated with **diffuse** skin involvement and an increased risk of **Scleroderma Renal Crisis**. * **Most common cause of death:** Currently, Interstitial Lung Disease (ILD) is the leading cause of mortality in scleroderma patients [2].

Question 1

Ankylosing spondylitis may be associated with which of the following conditions?

Accepted Answer

Aortic incompetence

Answer

Atrial fibrillation

Answer

Pulmonary stenosis

Answer

Mitral stenosis

Question 2

What is the commonest valvular lesion in SLE-related cardiac disease?

Accepted Answer

Mitral regurgitation

Answer

Tricuspid regurgitation

Answer

Mitral stenosis

Answer

Aortic regurgitation

Question 3

A 23-year-old man presents with fever, weight loss, malaise, abdominal pain, and myalgias. Workup reveals that the patient has polyarteritis nodosa. Which of the following is associated with this form of vasculitis?

Accepted Answer

Hepatitis B virus

Answer

Arsenic

Answer

Chlamydia pneumoniae

Answer

Human immunodeficiency virus

Question 4

A 23-year-old female presents with arthritis, malar rash, oral ulcers, and serositis (pleuritis or pericarditis). Which investigation is most likely to be positive?

Accepted Answer

Anti-nuclear antibody

Answer

Anti-collagen antibody

Answer

Anti-epithelial antibody

Answer

Antigen-antibody complexes

Question 5

Which autoantibody is associated with Sjögren's syndrome?

Accepted Answer

Anti Ro and Anti La antibodies

Answer

Anti centromere antibody

Answer

Anti ds DNA antibody

Answer

Anti RNP antibody

Question 6

The diagnosis of gout is best established by the presence of which of the following?

Accepted Answer

Intracellular uric acid crystals

Answer

Synovial fluid uric acid crystals

Answer

Elevated serum uric acid

Answer

Involvement of the first metatarsophalangeal joint

Question 7

Raynaud's phenomenon is associated with which of the following conditions, except?

Accepted Answer

Osteoarthritis

Answer

Systemic Lupus Erythematosus (SLE)

Answer

Rheumatoid arthritis

Answer

Cryoglobulinemia

Question 8

A 30-year-old woman presents with a heart murmur. She has a history of recurrent episodes of arthritis, skin rash, and glomerulonephritis. Blood cultures are negative. Laboratory tests for antinuclear antibodies (ANA) and anti-double-stranded DNA are positive. Which of the following is the most likely cause of the heart murmur in this patient?

Accepted Answer

Libman-Sacks endocarditis

Answer

Mitral valve prolapse

Answer

Myocardial infarct

Answer

Mitral valve prolapse

Question 9

What is the screening test for scleroderma?

Accepted Answer

Anti-nuclear antibody

Answer

U1-Ribonucleoprotein antibody

Answer

Anti-L.K.M. antibody

Answer

Anti-topoisomerase antibody

Question 10

A 27-year-old female with a family history of autoimmune disease presents with a skin rash and recurrent joint pains 3 months postpartum. What is the most likely diagnosis?

Accepted Answer

Acquired Factor VIII inhibitors

Answer

Megakaryocytic thrombocytopenia

Answer

Amegakaryocytic thrombocytopenia

Answer

Functional platelet defect

Rheumatology and Immunology — MCQs

Rheumatology and Immunology — MCQs

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