Rheumatology and Immunology Practice Questions

Q: A 27-year-old male presents with low backache that occurs early in the morning, associated with stiffness that persists for more than 30 minutes. On examination, his chest expansion is also restricted. What is the most probable diagnosis?

Ankylosing spondylitis. The clinical presentation of a young male with chronic inflammatory back pain (morning stiffness >30 minutes that improves with activity) and restricted chest expansion is classic for **Ankylosing Spondylitis (AS)**. **1. Why Ankylosing Spondylitis is correct:** AS is a chronic inflammatory disease primarily affecting the sacroiliac joints and the axial skeleton [1]. It typically affects young males (late teens to 20s). The hallmark is **enthesitis** (inflammation at the site where tendons/ligaments insert into bone) [1]. Restricted chest expansion occurs due to involvement of the costovertebral and costosternal joints, leading to ankylosis (fusion). According to the Modified New York Criteria, chest expansion <2.5 cm is a significant clinical marker. **2. Why the other options are incorrect:** * **Rheumatoid Arthritis:** Primarily affects small joints of the hands and feet symmetrically. While it can involve the cervical spine, it characteristically **spares** the thoracolumbar spine and sacroiliac joints. * **Osteoarthritis:** This is a degenerative "wear and tear" disease. Pain typically worsens with activity and improves with rest [1]. Morning stiffness is brief (usually 90% of cases) [1]. * **Radiology:** Look for "Bamboo Spine" (syndesmophytes) and "Dagger Sign" on X-ray [1]. * **Schober’s Test:** Used to assess restricted lumbar flexion. * **Extra-articular manifestation:** **Acute Anterior Uveitis** is the most common [1]. * **Treatment:** NSAIDs are the first-line therapy; TNF-alpha inhibitors (e.g., Etanercept, Infliximab) are used for refractory cases [1].

Q: What is the earliest muscle to be involved in dermatomyositis?

Quadriceps. **Explanation:** Dermatomyositis (DM) is an idiopathic inflammatory myopathy characterized by symmetric, **proximal muscle weakness** [1]. While the disease typically affects the limb-girdle muscles, the **Quadriceps** (thigh muscles) are clinically recognized as the earliest muscles to be involved and often the most severely affected. Patients typically present with difficulty rising from a seated position or climbing stairs before upper limb involvement becomes prominent [1]. **Analysis of Options:** * **Quadriceps (Correct):** These are the primary proximal muscles of the lower limb. In the progression of DM, lower extremity proximal weakness usually precedes or is more symptomatic than upper extremity weakness at the onset [1]. * **Deltoid (Incorrect):** While the deltoid is a proximal muscle and is frequently involved in DM, it typically follows the involvement of the pelvic girdle/thigh muscles. * **Gluteal (Incorrect):** These are proximal muscles involved in the disease process, but clinical studies and electromyography (EMG) findings point to the quadriceps as the earliest site of functional deficit. * **Lumbricals (Incorrect):** Dermatomyositis characteristically **spares distal muscles** (like the lumbricals of the hand) until very late stages of the disease. **Clinical Pearls for NEET-PG:** * **Pathognomonic Signs:** Gottron’s papules (over MCP/PIP joints) and Heliotrope rash (periorbital edema with violaceous hue) [2]. * **Muscle Biopsy:** Shows **perifascicular atrophy** (pathognomonic) and perivascular inflammation. * **Malignancy:** DM has a strong association with internal malignancies (e.g., ovarian, lung, gastric) [2]. Age-appropriate cancer screening is mandatory. * **Antibody:** **Anti-Mi-2** is highly specific for dermatomyositis and carries a good prognosis.

Q: Which HLA marker is associated with Behcet's syndrome?

HLA-B51. ### Explanation **Correct Option: C. HLA-B51** Behcet’s syndrome is a multi-systemic, chronic relapsing vasculitis characterized by the triad of oral ulcers, genital ulcers, and uveitis. The strongest genetic risk factor associated with Behcet’s syndrome is **HLA-B51**, a subtype of HLA-B5. It is particularly prevalent in populations along the "Silk Road" (Middle East and East Asia). Patients carrying this marker often have a more severe disease course, specifically regarding ocular and gastrointestinal involvement. **Incorrect Options:** * **A. HLA-B27:** This is the hallmark marker for **Seronegative Spondyloarthropathies**, including Ankylosing Spondylitis, Reactive Arthritis, Psoriatic Arthritis, and Enteropathic Arthritis [1]. * **B. HLA-DR5:** This marker is traditionally associated with **Juvenile Rheumatoid Arthritis (JRA)** and **Pernicious Anemia**, but it is not a primary marker for Behcet’s. * **C. HLA-CW6:** This is the strongest genetic association for **Psoriasis vulgaris**, particularly early-onset (Type 1) psoriasis. **Clinical Pearls for NEET-PG:** 1. **Pathergy Test:** A unique diagnostic feature where a sterile needle prick results in a papule or pustule within 24–48 hours. It is highly specific for Behcet’s. 2. **Vascular Involvement:** Behcet’s is unique among vasculitides as it involves both **arteries and veins** (venous thrombosis is common). 3. **Pulmonary Artery Aneurysms:** A high-yield cause of death in these patients; Behcet’s is one of the few conditions causing "hemoptysis with a normal chest X-ray" or massive pulmonary hemorrhage. 4. **Treatment:** Colchicine is first-line for mucocutaneous symptoms; Azathioprine or Anti-TNF agents (Infliximab) are used for ocular or systemic involvement.

Q: A patient complains of finger stiffness and dysphagia. What is the most probable diagnosis?

Scleroderma. **Explanation:** The combination of **finger stiffness** and **dysphagia** is a classic clinical presentation of **Systemic Sclerosis (Scleroderma)**. 1. **Why Scleroderma is correct:** * **Finger Stiffness:** This is often the earliest manifestation, caused by skin thickening (sclerodactyly) and Raynaud’s phenomenon. * **Dysphagia:** Scleroderma involves the gastrointestinal tract in about 90% of cases. It causes atrophy of the smooth muscle in the lower two-thirds of the esophagus and collagen deposition, leading to **impaired peristalsis** and decreased lower esophageal sphincter (LES) pressure. This results in dysphagia (initially for solids) and severe gastroesophageal reflux (GERD). 2. **Why other options are incorrect:** * **Achalasia:** While it presents with dysphagia, it is characterized by *increased* LES pressure and failure to relax. It does not involve systemic features like finger stiffness. * **Lower Esophageal Ring (Schatzki Ring):** This causes intermittent dysphagia (usually for large boluses of meat) but is a localized structural issue with no systemic skin involvement. * **Esophageal Carcinoma:** Presents with progressive dysphagia (solids then liquids) and significant weight loss, typically in older patients, without rheumatological symptoms. **NEET-PG High-Yield Pearls:** * **CREST Syndrome:** Calcinosis, Raynaud’s, Esophageal dysmotility, Sclerodactyly, Telangiectasia. * **Antibodies:** **Anti-Scl-70** (topoisomerase I) is specific for Diffuse Scleroderma; **Anti-centromere** is specific for Limited Scleroderma (CREST). * **Manometry Finding:** Characterized by "Low-amplitude" or absent peristalsis in the distal esophagus and a **hypotensive LES**. * **Most common cause of death:** Interstitial Lung Disease (ILD) is now the leading cause of mortality in Scleroderma.

Q: A 21-year-old woman has a history since childhood of recurrent episodes of swelling of the submucosal and subcutaneous tissue of the gastrointestinal and respiratory tracts. Her C1 inhibitor level is less than 5% of the reference value. These findings support a diagnosis of:

Hereditary angioedema. **Explanation:** The clinical presentation of recurrent, non-pitting edema of the subcutaneous and submucosal tissues (especially the GI tract and airway) without urticaria, combined with a deficiency in **C1 esterase inhibitor (C1-INH)**, is pathognomonic for **Hereditary Angioedema (HAE)**. **Why the correct answer is right:** C1-INH is a serine protease inhibitor that regulates the classical complement pathway and the kinin-generating system. A deficiency leads to the unregulated activation of the kallikrein-kinin cascade, resulting in excessive production of **bradykinin**. Bradykinin increases vascular permeability, leading to the characteristic episodes of swelling. It is inherited in an autosomal dominant fashion. **Why incorrect options are wrong:** * **DiGeorge Syndrome:** A T-cell deficiency caused by 22q11.2 deletion, characterized by thymic hypoplasia, hypocalcemia, and cardiac defects. It does not involve C1-INH. * **Nutritional based immune deficiency:** Usually presents with generalized lymphopenia or specific vitamin/mineral deficiencies (e.g., Zinc) leading to opportunistic infections, not localized angioedema. * **Paroxysmal Nocturnal Hemoglobinuria (PNH):** Caused by a deficiency of GPI-anchored proteins (CD55/CD59) on RBCs, leading to complement-mediated hemolysis and thrombosis, not C1-INH deficiency. **High-Yield Clinical Pearls for NEET-PG:** * **Diagnosis:** Screen with **C4 levels** (consistently low during and between attacks). Confirm with C1-INH levels/function. * **Management:** Acute attacks are treated with **C1-INH concentrate** or **Icatibant** (bradykinin B2 receptor antagonist). * **Contraindication:** ACE inhibitors are contraindicated as they prevent bradykinin breakdown, worsening the edema. * **Key Distinction:** Unlike allergic angioedema, HAE does **not** present with itching or hives (urticaria).

Q: Anti-topoisomerase I is a marker of which condition?

Systemic sclerosis. **Explanation:** **Anti-topoisomerase I (also known as Anti-Scl-70)** is a highly specific autoantibody for **Systemic Sclerosis (SSc)** [1], particularly the **diffuse cutaneous subtype**. Topoisomerase I is a nuclear enzyme involved in DNA replication and transcription; the presence of these antibodies is strongly associated with an increased risk of interstitial lung disease (ILD) and more extensive skin involvement [2]. **Analysis of Options:** * **A. Systemic Sclerosis (Correct):** Anti-Scl-70 is one of the "big three" antibodies in SSc [1], alongside **Anti-centromere** (associated with limited cutaneous SSc/CREST syndrome) and **Anti-RNA polymerase III** (associated with rapid skin progression and renal crisis). * **B. Classic Polyarteritis Nodosa:** This is a medium-vessel vasculitis. It is typically **ANCA-negative** and is strongly associated with Hepatitis B infection. * **C. Nephrotic Syndrome:** This is a clinical complex (proteinuria, hypoalbuminemia, edema) caused by various glomerular diseases (e.g., Minimal Change Disease, FSGS). It is not defined by specific rheumatological autoantibodies. * **D. Rheumatoid Arthritis:** The hallmark markers are **Rheumatoid Factor (RF)** (sensitive but less specific) and **Anti-Cyclic Citrullinated Peptide (Anti-CCP)** (highly specific). **High-Yield Clinical Pearls for NEET-PG:** * **Most sensitive screening test for SSc:** ANA (positive in >95% of cases) [1]. * **Anti-Scl-70:** Marker for Diffuse SSc and Pulmonary Fibrosis. * **Anti-centromere:** Marker for Limited SSc (CREST) and Pulmonary Hypertension. * **Anti-RNA Polymerase III:** Marker for Scleroderma Renal Crisis and increased malignancy risk.

Q: A 72-year-old man presents to the emergency room after sustaining a right knee injury in a car accident. The pain, which began shortly after the accident, progressed to severe swelling and excruciating pain, significantly impairing ambulation. Physical examination reveals a warm, swollen knee with an effusion that is extremely painful to flex. Radiographs of the knee exclude fracture. Arthrocentesis yields opaque fluid containing rhomboid crystals with weak-positive birefringence. What is the most appropriate next step in management?

Oral NSAIDs. **Explanation:** The clinical presentation describes an acute attack of **Pseudogout (Calcium Pyrophosphate Deposition Disease - CPPD)**. In elderly patients, physical trauma (like a car accident) is a common trigger for an acute flare. The diagnosis is confirmed by the arthrocentesis findings: **rhomboid-shaped crystals** with **weakly positive birefringence** under polarized light. 1. **Why Oral NSAIDs are correct:** Non-steroidal anti-inflammatory drugs (NSAIDs) are the **first-line treatment** for acute pseudogout flares to reduce inflammation and pain. In the absence of contraindications (like renal failure or active peptic ulcers), they are preferred over other modalities for rapid symptom control. 2. **Why other options are wrong:** * **Oral Prednisone:** While steroids are used for pseudogout, they are typically reserved for patients who cannot tolerate NSAIDs or colchicine, or those with polyarticular involvement. * **Intravenous Antibiotics:** These are indicated for septic arthritis. While the fluid was "opaque," the presence of specific crystals and the absence of fever/chills point toward crystal-induced arthropathy rather than infection. * **Acetaminophen:** This provides mild analgesia but lacks the potent anti-inflammatory properties required to resolve a CPPD flare. **High-Yield Clinical Pearls for NEET-PG:** * **Crystal Morphology:** Gout = Needle-shaped, Strongly Negative Birefringent (Yellow when parallel); Pseudogout = Rhomboid-shaped, Weakly Positive Birefringent (Blue when parallel). * **Radiology:** Look for **Chondrocalcinosis** (linear calcification of articular cartilage/meniscus) on X-rays. * **Common Triggers:** Trauma, surgery (especially hyperparathyroidism surgery), and dehydration. * **Associated Conditions:** Always screen for "The 3 H's": Hyperparathyroidism, Hemochromatosis, and Hypomagnesemia.

Q: Which of the following is not included in the triad of Reiter's syndrome?

Keratoderma blenorrhagica. Reiter’s syndrome, now more commonly referred to as **Reactive Arthritis (ReA)**, is a classic seronegative spondyloarthropathy that typically follows a gastrointestinal or urogenital infection. To identify the correct answer, one must distinguish between the **defining clinical triad** and the **associated clinical features**. [1] **1. Why Option D is correct:** The classic triad of Reiter’s syndrome is famously remembered by the mnemonic *"Can't see, can't pee, can't climb a tree."* While **Keratoderma blenorrhagica** (hyperkeratotic skin lesions on palms and soles) is a highly characteristic and pathognomonic finding in Reactive Arthritis, it is considered an **associated mucocutaneous manifestation** rather than a component of the primary diagnostic triad. [1] **2. Why the other options are incorrect:** * **Option A (Conjunctivitis):** This represents the "Can't see" component. It is usually bilateral, sterile, and occurs early in the disease course. [1] * **Option B (Urethritis):** This represents the "Can't pee" component. In post-enteric cases, it may be sterile; in post-venereal cases, it is often triggered by *Chlamydia trachomatis*. [1] * **Option C (Arthritis):** This represents the "Can't climb a tree" component. It is typically an asymmetric, oligoarthritis affecting the large joints of the lower extremities (knees and ankles). [1] **Clinical Pearls for NEET-PG:** * **HLA Association:** Strongly associated with **HLA-B27** (seen in 60-80% of cases). [2] * **Common Triggers:** *Chlamydia trachomatis* (most common), *Shigella*, *Salmonella*, *Campylobacter*, and *Yersinia*. [1] * **Circinate Balanitis:** Another high-yield mucocutaneous finding (painless ulcers on the glans penis). [1] * **Treatment:** NSAIDs are the first-line treatment; antibiotics are used only to treat the underlying active infection (e.g., Chlamydia).

Question 1

A 27-year-old male presents with low backache that occurs early in the morning, associated with stiffness that persists for more than 30 minutes. On examination, his chest expansion is also restricted. What is the most probable diagnosis?

Accepted Answer

Ankylosing spondylitis

Answer

Rheumatoid arthritis

Answer

Osteoarthritis

Answer

Gouty arthritis

Question 2

Which of the following is NOT true regarding joint involvement in hemochromatosis?

Accepted Answer

Chondrocalcinosis is a feature

Answer

Progressive after phlebotomy

Answer

Involvement of 2nd & 3rd MCP joints on X-ray

Answer

Non-inflammatory changes

Question 3

What is the earliest muscle to be involved in dermatomyositis?

Accepted Answer

Quadriceps

Answer

Deltoid

Answer

Gluteal

Answer

Lumbricals

Question 4

Which HLA marker is associated with Behcet's syndrome?

Accepted Answer

HLA-B51

Answer

HLA-B27

Answer

HLA-DR5

Answer

HLA-CW6

Question 5

A patient complains of finger stiffness and dysphagia. What is the most probable diagnosis?

Accepted Answer

Scleroderma

Answer

Achalasia

Answer

Lower esophageal ring

Answer

Esophageal carcinoma

Question 6

A 21-year-old woman has a history since childhood of recurrent episodes of swelling of the submucosal and subcutaneous tissue of the gastrointestinal and respiratory tracts. Her C1 inhibitor level is less than 5% of the reference value. These findings support a diagnosis of:

Accepted Answer

Hereditary angioedema

Answer

DiGeorge syndrome

Answer

Nutritional based immune deficiency

Answer

Paroxysmal nocturnal hemoglobinuria

Question 7

What is the most diagnostic test for Systemic Lupus Erythematosus (SLE)?

Accepted Answer

Antibodies against double-stranded DNA (anti-dsDNA)

Answer

Complement fixation test

Answer

Antibodies against Antinuclear Antibody (ANA) cells

Answer

Antibodies against the nucleus

Question 8

Anti-topoisomerase I is a marker of which condition?

Accepted Answer

Systemic sclerosis

Answer

Classic polyarteritis nodosa

Answer

Nephrotic syndrome

Answer

Rheumatoid arthritis

Question 9

A 72-year-old man presents to the emergency room after sustaining a right knee injury in a car accident. The pain, which began shortly after the accident, progressed to severe swelling and excruciating pain, significantly impairing ambulation. Physical examination reveals a warm, swollen knee with an effusion that is extremely painful to flex. Radiographs of the knee exclude fracture. Arthrocentesis yields opaque fluid containing rhomboid crystals with weak-positive birefringence. What is the most appropriate next step in management?

Accepted Answer

Oral NSAIDs

Answer

Oral prednisone

Answer

Intravenous antibiotics

Answer

Acetaminophen

Question 10

Which of the following is not included in the triad of Reiter's syndrome?

Accepted Answer

Keratoderma blenorrhagica

Answer

Conjunctivitis

Answer

Urethritis

Answer

Arthritis

Rheumatology and Immunology — MCQs

Rheumatology and Immunology — MCQs

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