Rheumatology and Immunology Practice Questions

Q: What is true about antinuclear antibody (ANA) in relation to systemic lupus erythematosus (SLE)?

Double stranded Anti-DNA is specific for SLE. ***Double stranded Anti-DNA is specific for SLE*** - The presence of **double stranded Anti-DNA antibodies** is highly specific for **Systemic Lupus Erythematosus (SLE)** [1], helping differentiate it from other autoimmune diseases. - It correlates with **disease activity** and can be used to monitor the disease progress in SLE patients [1]. *None of the above* - This erroneously suggests that all provided statements are incorrect, whereas is indeed true. - It doesn't provide any useful information regarding ANA or its associations with diseases, making it an invalid choice. *ANA normally present in 80%* - While ANAs are commonly present in many autoimmune diseases [1], they are not normal findings and their positivity can vary widely among healthy individuals and those with various conditions [1], making this statement misleading. - Moreover, **80%** is a vague statistic, and the actual percentage can differ based on the population and the tested autoimmune condition. *Anti-RNA antibody is specific for SLE* - Anti-RNA antibodies are not specific for SLE; they can be found in other conditions as well, decreasing their clinical significance in diagnosing SLE. - The hallmark of SLE is better identified through the presence of specific antibodies like **double stranded Anti-DNA** [1] or **anti-Smith** antibodies.

Q: Laboratory evaluation of a patient with recurrent lip edema shows decreased C4 and C1 inhibitor (quantity and function) with normal C1q. Diagnosis is

Hereditary angioedema type I. ***Hereditary angioedema type I*** - This condition is characterized by **low levels of C4 and C1 inhibitor quantity and function**, with **normal C1q** [1]. - It is caused by a genetic deficiency in the **C1 inhibitor gene (SERPING1)**, leading to overactivation of the complement system and bradykinin production [1]. *Acquired angioedema type II* - This type involves the presence of an **autoantibody** that binds to and inactivates the C1 inhibitor. - While C4 and C1 inhibitor function are decreased, C1 inhibitor quantity is usually normal, which contradicts the patient's presentation. *Acquired angioedema type I* - This form is typically associated with **lymphoproliferative disorders** or **autoimmune diseases**, leading to consumption of C1 inhibitor. - It is characterized by **low C1q levels** in addition to low C4 and C1 inhibitor quantity and function, which is not seen in this patient. *Hereditary angioedema type II* - In this rare genetic variant, the **C1 inhibitor protein is dysfunctional** but present in normal or elevated quantities. - The patient exhibits a **decreased quantity** of C1 inhibitor, ruling out Type II hereditary angioedema.

Q: Which condition is most likely associated with specific angiographic findings such as the rosary sign?

Polyarteritis Nodosa. ***Polyarteritis Nodosa*** - The **rosary sign** on angiography, characterized by alternating areas of stenosis and dilation in medium-sized arteries, is a classic finding in **Polyarteritis Nodosa (PAN)**. - This sign represents **aneurysms and stenoses** resulting from inflammatory destructive lesions in the arterial wall. *Kawasaki disease* - Primarily affects young children and causes **coronary artery aneurysms**, which appear as focal dilations, rather than the "rosary sign" pattern of multiple stenoses and dilations seen in PAN. - While it can involve other medium-sized arteries, the widespread and characteristic "rosary sign" is not typical. *Takayasu arteritis* - This condition primarily affects the **aorta and its major branches**, leading to **stenosis or occlusion** of large arteries, often described as "pulseless disease." - It does not typically present with the **venous beads-like appearance** or rosary sign found in PAN. *Giant cell arteritis* - Characterized by inflammation of **large and medium-sized arteries**, predominantly affecting the temporal arteries. - Angiographic findings often include **long segments of smooth vessel wall thickening, stenosis, or occlusion**, but not the characteristic alternating aneurysms and stenoses of the "rosary sign."

Q: A 30-year-old female presents with a butterfly rash on her face, photosensitivity, and joint pain, and laboratory tests reveal positive antinuclear antibody (ANA) and anti-double-stranded DNA (anti-dsDNA) antibodies. What is the most likely diagnosis?

Systemic lupus erythematosus. ***Systemic lupus erythematosus*** - The combination of a **butterfly rash**, **photosensitivity**, **arthralgia**, and positive **ANA** and **anti-dsDNA antibodies** is highly characteristic of systemic lupus erythematosus (SLE) [1]. - **Anti-dsDNA antibodies** are very specific for SLE and correlate with disease activity, especially **renal involvement** [1]. *Rheumatoid arthritis* - While it causes **joint pain**, it typically presents with **symmetrical polyarthritis** affecting small joints and lacks the hallmark skin manifestations like a butterfly rash [1]. - Serologically, **rheumatoid arthritis** is associated with **rheumatoid factor (RF)** and **anti-CCP antibodies**, not anti-dsDNA. *Psoriatic arthritis* - This condition is associated with **psoriasis**, manifesting as **scaly skin patches**, and can cause **arthritis**. - It does not typically present with a **butterfly rash** or the specific autoantibodies (ANA, anti-dsDNA) seen in this patient. *Dermatomyositis* - Characterized by **proximal muscle weakness** and distinct skin rashes such as **heliotrope rash** (purplish discoloration around the eyes) and **Gottron's papules** (reddish-purple papules over knuckles). - While it can involve **photosensitivity**, it does not typically present with a **butterfly rash** [1] or **anti-dsDNA antibodies**.

Question 1

What is true about antinuclear antibody (ANA) in relation to systemic lupus erythematosus (SLE)?

Accepted Answer

Double stranded Anti-DNA is specific for SLE

Answer

Anti-RNA antibody is specific for SLE

Answer

ANA is rarely present in SLE cases

Answer

None of the options

Question 2

Soft tissue calcification around the knee is seen in:

Accepted Answer

Calcium pyrophosphate dihydrate crystal deposition (Pseudogout)

Answer

Vitamin C deficiency (Scurvy)

Answer

Primary hyperparathyroidism

Answer

Systemic sclerosis (Scleroderma)

Question 3

Laboratory evaluation of a patient with recurrent lip edema shows decreased C4 and C1 inhibitor (quantity and function) with normal C1q. Diagnosis is

Accepted Answer

Hereditary angioedema type I

Answer

Acquired angioedema type II

Answer

Acquired angioedema type I

Answer

Hereditary angioedema type II

Question 4

Which condition is most likely associated with specific angiographic findings such as the rosary sign?

Accepted Answer

Polyarteritis Nodosa

Answer

Giant cell arteritis

Answer

Kawasaki disease

Answer

Takayasu arteritis

Question 5

A 30-year-old female presents with a butterfly rash on her face, photosensitivity, and joint pain, and laboratory tests reveal positive antinuclear antibody (ANA) and anti-double-stranded DNA (anti-dsDNA) antibodies. What is the most likely diagnosis?

Accepted Answer

Systemic lupus erythematosus

Answer

Rheumatoid arthritis

Answer

Psoriatic arthritis

Answer

Dermatomyositis

Rheumatology and Immunology — MCQs

Rheumatology and Immunology — MCQs

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