Rheumatology and Immunology Practice Questions

Q: Which of the following is the most appropriate initial treatment for a patient with newly diagnosed rheumatoid arthritis (RA)?

Methotrexate. Methotrexate - **Methotrexate** is considered the **first-line disease-modifying anti-rheumatic drug (DMARD)** for newly diagnosed RA due to its proven efficacy and favorable safety profile [1]. - It works by **inhibiting folate metabolism**, leading to anti-inflammatory and immunosuppressive effects that slow disease progression [1]. Infliximab - **Infliximab** is a **biologic DMARD** (TNF-alpha inhibitor) typically reserved for patients who have had an inadequate response to conventional DMARDs like methotrexate [1]. - Its use as initial therapy is generally not recommended due to higher cost and potential for serious side effects, unless specific severe presentations or contraindications to conventional DMARDs exist [1]. Hydroxychloroquine - **Hydroxychloroquine** is a milder DMARD, often used for **mild RA** or in combination with other DMARDs. - It is generally not considered the most appropriate initial monotherapy for newly diagnosed RA due to its **slower onset of action** and less potent effect compared to methotrexate. Prednisone - **Prednisone** is a **corticosteroid** used for short-term relief of acute RA symptoms due to its potent anti-inflammatory effects [1]. - While effective for symptom control, it does not alter the underlying disease progression and is associated with significant long-term side effects, making it unsuitable as a long-term initial monotherapy for RA.

Q: A 55-year-old man develops severe pain and swelling in his knee over the past 24 hours. His knee is erythematous and warm. Arthrocentesis reveals negatively birefringent needle-shaped crystals. What is the most likely diagnosis?

Gout. **Gout** - The presence of **negatively birefringent needle-shaped crystals** in joint fluid is pathognomonic for **gout** [1]. - **Acute onset** of severe pain, swelling, erythema, and warmth in a single joint, such as the knee, are classic symptoms of an acute gout attack [2]. *Pseudogout* - Characterized by the presence of **positively birefringent rhomboid-shaped crystals**, which are calcium pyrophosphate dihydrate (CPPD) crystals, not negatively birefringent needle-shaped crystals [1]. - While it can present with acute joint inflammation similar to gout, the crystal morphology in the joint fluid is distinct. *Rheumatoid arthritis* - Typically presents as a **chronic, symmetric polyarthritis** affecting smaller joints, and rarely causes acute monoarticular inflammation of this severity. - Joint fluid analysis in rheumatoid arthritis would show inflammatory changes but not specific crystals like those described. *Septic arthritis* - While septic arthritis can cause acute, severe joint pain and inflammation, joint fluid analysis would reveal a **high white blood cell count** with a predominance of neutrophils and **positive bacterial cultures**, but not crystals. - The crucial finding of negatively birefringent needle-shaped crystals rules out septic arthritis as the primary diagnosis.

Q: A 30-year-old woman presents with bilateral, symmetric joint pain and morning stiffness lasting more than an hour. Laboratory tests show positive rheumatoid factor and anti-CCP antibodies. What is the most likely diagnosis?

Rheumatoid arthritis. ***Rheumatoid arthritis*** - The combination of **bilateral**, **symmetric joint pain**, **prolonged morning stiffness** (over an hour) [1], and positive **rheumatoid factor (RF)** and **anti-CCP antibodies** is highly characteristic of rheumatoid arthritis [2]. - This condition involves chronic **inflammation of the synovium**, leading to potential joint destruction and systemic manifestations [2]. *Systemic lupus erythematosus* - While it can cause **arthralgia** and **arthritis**, it typically presents with a broader range of symptoms like **malar rash**, photosensitivity, and renal involvement, which are not described. - Although ANA can be positive, **RF** and **anti-CCP** are not as specific or consistently high in SLE as they are in RA. *Osteoarthritis* - Characterized by **degenerative joint disease**, with pain that worsens with activity and **short-lived morning stiffness** (usually less than 30 minutes). - It does not show positive **rheumatoid factor** or **anti-CCP antibodies**, as it is not primarily an autoimmune inflammatory condition. *Ankylosing spondylitis* - Primarily affects the **axial skeleton** (spine and sacroiliac joints), causing **inflammatory back pain** that improves with activity. - It is strongly associated with **HLA-B27**, and **RF** and **anti-CCP antibodies** are typically negative.

Q: A 30-year-old man presents with a history of migratory arthritis, carditis, and erythema marginatum. What is the most likely diagnosis?

Rheumatic fever. ***Rheumatic fever*** - This diagnosis aligns perfectly with the classic presentation of **migratory arthritis**, **carditis**, and **erythema marginatum**, which are major criteria for rheumatic fever (Jones criteria) [1]. - Its etiology is typically a delayed, non-suppurative complication of a Group A beta-hemolytic streptococcal infection [1]. *Rheumatoid arthritis* - Characterized by **symmetric polyarthritis** primarily affecting small joints, prolonged morning stiffness, and can have systemic manifestations [2]. - While it can involve multiple joints, it doesn't typically present with a **migratory pattern** or **erythema marginatum**. *Systemic lupus erythematosus* - A multisystem autoimmune disease that can cause arthritis, serositis, and skin manifestations like the **malar rash** [3]. - However, **erythema marginatum** is not a typical skin finding, and its arthritis is usually non-erosive and non-deforming. *Psoriatic arthritis* - Associated with **psoriasis** and can present with various forms of arthritis, including oligoarthritis, polyarthritis, and spondyloarthritis. - It does not present with **carditis** or **erythema marginatum**, which are key features in the question.

Q: A 40-year-old man presents with a history of hypertension and episodes of abdominal pain. Angiography reveals multiple aneurysms in the renal arteries. What is the most likely diagnosis?

Polyarteritis nodosa. Polyarteritis nodosa - This systemic vasculitis is characterized by necrotizing inflammation of medium-sized arteries, often leading to aneurysm formation and organ ischemia [1]. - Renal artery involvement, manifesting as multiple aneurysms and resulting in hypertension and abdominal pain, is highly characteristic of this condition. Takayasu arteritis - This condition primarily affects large arteries, particularly the aorta and its major branches, leading to stenosis and occlusion, not multiple aneurysms in the renal arteries. - It typically presents in younger females and is often associated with symptoms of reduced pulse and claudication in the limbs. Kawasaki disease - This is an acute vasculitis of childhood primarily affecting medium-sized arteries, notably the coronary arteries, leading to aneurysms [1]. - It is unlikely in a 40-year-old and presents with a distinct clinical picture including fever, rash, conjunctivitis, and mucositis [1]. Granulomatosis with polyangiitis - This is a small vessel vasculitis characterized by granulomatous inflammation of the respiratory tract and glomerulonephritis, often associated with c-ANCA antibodies. - While it can affect the kidneys, it typically causes vasculitic lesions and glomerulonephritis, not multiple macroscopic aneurysms in the renal arteries [2].

Q: A 55-year-old man with a history of gout presents with a sudden onset of severe pain in the big toe. What is the best initial treatment?

Colchicine. **Colchicine** - **Colchicine** is effective in treating acute gout flares when administered promptly, ideally within 24-36 hours of symptom onset. - It works by **inhibiting neutrophil migration** and activity, reducing inflammation in the affected joint. *Allopurinol* - **Allopurinol** is a xanthine oxidase inhibitor used for **long-term management** of gout by reducing uric acid production [1]. - It is generally **not recommended during an acute gout flare** as it can potentially worsen the attack by rapidly altering serum urate levels [1]. *Probenecid* - **Probenecid** is a uricosuric agent used for **long-term prevention** of gout attacks by increasing renal excretion of uric acid [1]. - Like allopurinol, it is **contraindicated during an acute gout attack** as it can exacerbate symptoms [1]. *Indomethacin* - While **Indomethacin**, a non-steroidal anti-inflammatory drug (NSAID), is an appropriate treatment for acute gout, it is not listed as the "best initial treatment" in this option set, as **colchicine** is also a first-line option [1]. - NSAIDs work by **reducing inflammation** and pain, but they may have contraindications such as renal insufficiency or gastrointestinal bleeding risk. *Overview of Pathophysiology* - Gout is characterized by recurrent attacks of arthritis and elevated uric acid levels, commonly affecting the metatarsophalangeal joint of the great toe [2].

Q: A 65-year-old woman presents with a femur fracture after minimal trauma. Laboratory studies reveal hypercalcemia and elevated serum alkaline phosphatase. What is the most likely diagnosis?

Paget disease of bone. ***Paget disease of bone*** - **Hypercalcemia** and a significantly **elevated serum alkaline phosphatase** in an elderly patient with a fracture after minimal trauma are classic findings in Paget disease. - Paget disease is characterized by disordered bone remodeling with excessive bone resorption and formation, leading to structurally unsound and fragile bones [1]. *Osteoporosis* - While osteoporosis causes fractures with minimal trauma, it typically does not cause **hypercalcemia** or a markedly **elevated serum alkaline phosphatase**. - Bone density is reduced, but bone turnover markers (including ALP) are usually normal or only mildly elevated. *Osteomalacia* - Osteomalacia is characterized by defective mineralization of bone, usually due to **vitamin D deficiency**, leading to bone pain and fractures. - It typically presents with **hypocalcemia** or normal calcium, and **hypophosphatemia**, along with an elevated alkaline phosphatase, but not typically hypercalcemia. *Primary hyperparathyroidism* - Primary hyperparathyroidism causes **hypercalcemia** due to increased PTH, which leads to bone resorption [1]. - While it can cause elevated alkaline phosphatase due to increased bone turnover, it does not typically cause the extreme elevations seen in Paget disease, and fractures are often more related to generalized bone loss rather than focal disorganized bone.

Q: In a patient with a history of chronic back pain and morning stiffness that improves with exercise, which radiographic finding is characteristic of ankylosing spondylitis?

Syndesmophytes. ***Syndesmophytes*** - **Syndesmophytes** are characteristic radiographic findings in ankylosing spondylitis, representing ossification within the **annulus fibrosus** and along the outer fibers of the intervertebral disc [1]. - Their presence indicates active disease processes leading to **bony fusion** of vertebrae, contributing to spinal stiffness [1]. *Osteophytes (associated with osteoarthritis)* - **Osteophytes** are bony spurs that form at the margins of joints, primarily associated with **osteoarthritis** due to degenerative changes. - Unlike **syndesmophytes**, they are not specific to inflammatory conditions like ankylosing spondylitis and are typically unilateral and not vertically oriented [1]. *Schmorl's nodes (indicate disc herniation)* - **Schmorl's nodes** are vertebral endplate indentations where the nucleus pulposus herniates into the vertebral body. - While sometimes associated with back pain, they are indicative of **disc degeneration** or trauma, not the inflammatory process of ankylosing spondylitis. *Bamboo spine* - **Bamboo spine** is a descriptive term for the advanced stage of ankylosing spondylitis, resulting from widespread **syndesmophyte formation** and fusion of the vertebrae [1]. - While ultimately a feature of ankylosing spondylitis, it describes the overall appearance due to multiple **syndesmophytes**, rather than being a specific individual finding itself [1].

Q: A 40-year-old woman with newly diagnosed lupus presents with proteinuria. Which antibody test is the most specific for lupus nephritis?

Anti-dsDNA. ***Anti-dsDNA*** - **Anti-dsDNA antibodies** are highly specific for **Systemic Lupus Erythematosus (SLE)** and their titers often correlate with disease activity, especially **lupus nephritis** [1]. - High levels of **anti-dsDNA antibodies** are found in up to 70% of lupus patients and are particularly implicated in the pathogenesis and severity of **renal involvement** [1]. *ANA* - **Antinuclear antibodies (ANA)** are a very sensitive screening test for lupus, being positive in over 95% of patients, but they are **not specific** to lupus and can be found in other autoimmune diseases or even healthy individuals [1]. - A positive ANA alone does not confirm a diagnosis of lupus or indicate **lupus nephritis** [1]. *Anti-Ro* - **Anti-Ro antibodies** (also known as SS-A) are associated with **subacute cutaneous lupus erythematosus**, **neonatal lupus**, and **Sjogren's syndrome**, as well as a subset of SLE patients [1]. - While present in some lupus patients, they are not specifically linked to **lupus nephritis** as strongly as anti-dsDNA [1]. *Anti-Smith* - **Anti-Smith (Sm) antibodies** are highly specific for SLE, but their prevalence is lower (around 20-30%) compared to other lupus-related antibodies [1]. - While diagnostic for SLE, anti-Sm antibodies do not correlate well with disease activity or specifically with **lupus nephritis** in the same way as anti-dsDNA [1].

Q: A 55-year-old man presents with muscle weakness and elevated creatine kinase levels. Muscle biopsy reveals endomysial inflammation. What is the most likely diagnosis?

Polymyositis. ***Polymyositis*** - Characterized by **proximal muscle weakness** and **elevated creatine kinase (CK)**, which are classic signs of inflammatory myopathy [1]. - The key diagnostic feature in polymyositis is **endomysial inflammation** with cytotoxic T-cells invading non-necrotic muscle fibers on muscle biopsy [3]. *Dermatomyositis* - While also an inflammatory myopathy with similar muscle weakness and elevated CK, it is distinguished by characteristic **skin rashes** (e.g., heliotrope rash, Gottron's papules) which are not mentioned here [2]. - Biopsy typically shows **perimysial and perivascular inflammation** with B-cells and macrophages, rather than endomysial. *Inclusion body myositis* - This condition is usually seen in older individuals, but the biopsy would reveal **rimmed vacuoles** and **intranuclear/intracytoplasmic inclusions** in addition to endomysial inflammation [3]. - Often presents with **asymmetric weakness**, particularly affecting forearm flexors and quadriceps, and progresses more slowly. *Rhabdomyolysis* - Involves rapid **muscle breakdown** leading to very high CK levels, muscle pain, and often **myoglobinuria**, which would manifest as dark urine. - While it causes muscle weakness, the primary pathological finding is **muscle fiber necrosis** without a prominent inflammatory infiltrate like that seen in polymyositis.

Question 1

Which of the following is the most appropriate initial treatment for a patient with newly diagnosed rheumatoid arthritis (RA)?

Accepted Answer

Methotrexate

Answer

Infliximab

Answer

Hydroxychloroquine

Answer

Prednisone

Question 2

A 55-year-old man develops severe pain and swelling in his knee over the past 24 hours. His knee is erythematous and warm. Arthrocentesis reveals negatively birefringent needle-shaped crystals. What is the most likely diagnosis?

Accepted Answer

Gout

Answer

Pseudogout

Answer

Rheumatoid arthritis

Answer

Septic arthritis

Question 3

A 30-year-old woman presents with bilateral, symmetric joint pain and morning stiffness lasting more than an hour. Laboratory tests show positive rheumatoid factor and anti-CCP antibodies. What is the most likely diagnosis?

Accepted Answer

Rheumatoid arthritis

Answer

Systemic lupus erythematosus

Answer

Osteoarthritis

Answer

Ankylosing spondylitis

Question 4

A 30-year-old man presents with a history of migratory arthritis, carditis, and erythema marginatum. What is the most likely diagnosis?

Accepted Answer

Rheumatic fever

Answer

Rheumatoid arthritis

Answer

Systemic lupus erythematosus

Answer

Psoriatic arthritis

Question 5

A 40-year-old man presents with a history of hypertension and episodes of abdominal pain. Angiography reveals multiple aneurysms in the renal arteries. What is the most likely diagnosis?

Accepted Answer

Polyarteritis nodosa

Answer

Kawasaki disease

Answer

Takayasu arteritis

Answer

Granulomatosis with polyangiitis

Question 6

A 55-year-old man with a history of gout presents with a sudden onset of severe pain in the big toe. What is the best initial treatment?

Accepted Answer

Colchicine

Answer

Allopurinol

Answer

Probenecid

Answer

Indomethacin

Question 7

A 65-year-old woman presents with a femur fracture after minimal trauma. Laboratory studies reveal hypercalcemia and elevated serum alkaline phosphatase. What is the most likely diagnosis?

Accepted Answer

Paget disease of bone

Answer

Osteoporosis

Answer

Osteomalacia

Answer

Primary hyperparathyroidism

Question 8

In a patient with a history of chronic back pain and morning stiffness that improves with exercise, which radiographic finding is characteristic of ankylosing spondylitis?

Accepted Answer

Syndesmophytes

Answer

Bamboo spine

Answer

Osteophytes (associated with osteoarthritis)

Answer

Schmorl's nodes (indicate disc herniation)

Question 9

A 40-year-old woman with newly diagnosed lupus presents with proteinuria. Which antibody test is the most specific for lupus nephritis?

Accepted Answer

Anti-dsDNA

Answer

ANA

Answer

Anti-Ro

Answer

Anti-Smith

Question 10

A 55-year-old man presents with muscle weakness and elevated creatine kinase levels. Muscle biopsy reveals endomysial inflammation. What is the most likely diagnosis?

Accepted Answer

Polymyositis

Answer

Dermatomyositis

Answer

Inclusion body myositis

Answer

Rhabdomyolysis

Rheumatology and Immunology — MCQs

Rheumatology and Immunology — MCQs

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