What is true about antinuclear antibody (ANA) in relation to systemic lupus erythematosus (SLE)?
Q972
Soft tissue calcification around the knee is seen in:
Q973
Laboratory evaluation of a patient with recurrent lip edema shows decreased C4 and C1 inhibitor (quantity and function) with normal C1q. Diagnosis is
Q974
Which condition is most likely associated with specific angiographic findings such as the rosary sign?
Q975
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?
Rheumatology and Immunology Indian Medical PG Practice Questions and MCQs
Question 971: What is true about antinuclear antibody (ANA) in relation to systemic lupus erythematosus (SLE)?
A. Double stranded Anti-DNA is specific for SLE (Correct Answer)
B. Anti-RNA antibody is specific for SLE
C. ANA is rarely present in SLE cases
D. None of the options
Explanation: ***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.
Question 972: Soft tissue calcification around the knee is seen in:
A. Vitamin C deficiency (Scurvy)
B. Primary hyperparathyroidism
C. Calcium pyrophosphate dihydrate crystal deposition (Pseudogout) (Correct Answer)
D. Systemic sclerosis (Scleroderma)
Explanation: ***Calcium pyrophosphate dihydrate crystal deposition (Pseudogout)***
- **Pseudogout**, caused by calcium pyrophosphate dihydrate (CPPD) crystal deposition, commonly affects large joints like the knee and can lead to **chondrocalcinosis** (calcification of articular cartilage) [1].
- Radiographically, this presents as linear calcifications within the **menisci** or articular cartilage of the knee, which are considered soft tissue [1].
*Vitamin C deficiency (Scurvy)*
- Scurvy primarily causes impaired **collagen synthesis**, leading to fragile blood vessels, bleeding gums, and musculoskeletal pain.
- It does not typically result in **soft tissue calcification** around the knee.
*Primary hyperparathyroidism*
- This condition results in **hypercalcemia** and **hyperphosphatemia**, which can lead to calcification in various tissues, but it is not characteristically seen as localized soft tissue calcification around the knee.
- While it can be associated with **chondrocalcinosis**, it's a less direct and specific cause compared to CPPD deposition.
*Systemic sclerosis (Scleroderma)*
- Scleroderma is characterized by **fibrosis** and vascular changes, and can cause **calcinosis cutis** (calcification in the skin and subcutaneous tissues), especially in limited cutaneous scleroderma (CREST syndrome).
- However, this calcinosis is typically more widespread in the skin and not specifically described as prominent soft tissue calcification isolated to the periknee area in the same manner as CPPD.
Question 973: Laboratory evaluation of a patient with recurrent lip edema shows decreased C4 and C1 inhibitor (quantity and function) with normal C1q. Diagnosis is
A. Hereditary angioedema type I (Correct Answer)
B. Acquired angioedema type II
C. Acquired angioedema type I
D. Hereditary angioedema type II
Explanation: ***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.
Question 974: Which condition is most likely associated with specific angiographic findings such as the rosary sign?
A. Giant cell arteritis
B. Polyarteritis Nodosa (Correct Answer)
C. Kawasaki disease
D. Takayasu arteritis
Explanation: ***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."
Question 975: 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?
A. Rheumatoid arthritis
B. Systemic lupus erythematosus (Correct Answer)
C. Psoriatic arthritis
D. Dermatomyositis
Explanation: ***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**.
