Psoriatic Arthritis — MCQs
Which condition is associated with the pencil in cup deformity?
Which of the following is true about psoriatic arthritis
Which one of these should not be used in severe widespread psoriasis?
Which of the following represents important radiological differentiating features between psoriatic arthritis, rheumatoid arthritis, and ankylosing spondylitis?
Which of the following is true of psoriatic arthritis?
21-Hydroxylase deficiency - false is ?
A 54-year-old man presents with well-demarcated scaly plaques on the extensor surfaces of elbows and knees. The scales are silvery-white in appearance. What is the most likely diagnosis?
All are true about psoriasis except:
A 25-year-old patient presents with well-demarcated plaques with silvery scales on the elbows and knees. What is the most likely diagnosis?
A 54-year-old man presents with well-demarcated, erythematous plaques covered with silvery scales on the extensor surfaces of elbows and knees. What is the most likely diagnosis?
Psoriatic Arthritis Indian Medical PG Practice Questions and MCQs
Question 1: Which condition is associated with the pencil in cup deformity?
- A. Rheumatoid arthritis
- B. Ankylosing spondylitis
- C. Avascular necrosis
- D. Psoriatic arthritis (Correct Answer)
Explanation: ***Psoriatic arthritis*** - The **pencil-in-cup deformity** is a classic radiographic finding in advanced psoriatic arthritis, occurring due to **periarticular bone erosion** and phalangeal telescoping. - This specific deformity is characterized by the proximal phalanx eroding and fitting into the expanded distal phalanx, resembling a "pencil in a cup." *Rheumatoid arthritis* - While rheumatoid arthritis causes significant joint destruction, it typically presents with **periarticular erosions** and **joint space narrowing**, but not the characteristic pencil-in-cup morphology. - Common deformities include **swan-neck** and **boutonnière** deformities, and ulnar deviation. *Ankylosing spondylitis* - This condition primarily affects the **axial skeleton**, leading to spinal fusion and **sacroiliitis**. - Peripheral joint involvement is less common and typically does not result in the pencil-in-cup deformity; instead, it can cause **syndesmophytes**. *Avascular necrosis* - **Avascular necrosis** (AVN) involves the death of bone tissue due to lack of blood supply, primarily affecting the femoral head or other major joints. - Radiographic findings include **subchondral collapse**, crescent sign, and eventual joint destruction, but not the specific deformities seen in inflammatory arthritis like pencil-in-cup.
Question 2: Which of the following is true about psoriatic arthritis
- A. Sacroiliitis is a common feature
- B. Pencil in cup deformity is a radiological finding
- C. Involves distal joints of hand and foot and proximal interphalangeal joints
- D. All of the options (Correct Answer)
Explanation: ***All of the options*** - **Psoriatic arthritis** is a seronegative spondyloarthropathy [2] that can manifest with a wide range of joint involvement, including **sacroiliitis**, characteristic radiological changes like **pencil-in-cup deformity**, and involvement of both **distal** and **proximal interphalangeal joints** [1]. *Sacroiliitis is a common feature* - **Sacroiliitis** occurs in approximately 20-40% of patients with psoriatic arthritis, contributing to inflammatory back pain. - It is often **asymmetrical** and can be detected radiographically [1], distinguishing it from the typically symmetrical sacroiliitis of ankylosing spondylitis. *Pencil in cup deformity is a radiological finding* - This characteristic radiological finding, known as **arthritis mutilans**, is seen in a severe subtype of psoriatic arthritis where there is **osteolysis** of the phalanx and telescoping of the digit [2]. - It results from severe bone erosion at the joint margins, creating a "pencil-in-cup" appearance. *Involves distal joints of hand and foot and proximal interphalangeal joints* - **DIP joint involvement** (distal interphalangeal) is a classic feature of psoriatic arthritis, distinguishing it from rheumatoid arthritis [1], [2]. - Involvement of the **PIP joints** (proximal interphalangeal) and other peripheral joints is also common [1], along with **dactylitis** (sausage digits) and **enthesitis**.
Question 3: Which one of these should not be used in severe widespread psoriasis?
- A. Methotrexate
- B. Oral retinoids
- C. Cyclosporin
- D. Oral glucocorticoids (Correct Answer)
Explanation: ***Oral glucocorticoids*** - While they may provide temporary relief, **oral glucocorticoids** can exacerbate psoriasis upon withdrawal, leading to a severe flare-up or **pustular psoriasis**. - Their long-term use is associated with numerous side effects, making them unsuitable for widespread, chronic conditions like severe psoriasis. *Methotrexate* - **Methotrexate** is a systemic agent commonly used for severe psoriasis due to its immune-modulating and anti-proliferative effects. - It is effective in reducing inflammation and slowing down epidermal cell turnover. *Oral retinoids* - **Oral retinoids** like acitretin are effective systemic treatments for severe widespread psoriasis, especially **pustular** and **erythrodermic** forms. - They work by normalizing keratinocyte proliferation and differentiation. *Cyclosporin* - **Cyclosporin** is a potent immunosuppressant widely used for severe psoriasis, particularly when rapid disease control is needed. - It works by inhibiting T-cell activation and is highly effective in clearing psoriatic lesions.
Question 4: Which of the following represents important radiological differentiating features between psoriatic arthritis, rheumatoid arthritis, and ankylosing spondylitis?
- A. Radiological patterns and joint distribution (Correct Answer)
- B. Laboratory markers and genetic associations
- C. Clinical presentation and extra-articular features
- D. Spinal involvement patterns
Explanation: ***Radiological patterns and joint distribution*** - **Radiological patterns and joint distribution** are the most important radiological differentiating features among these three arthropathies. - **Psoriatic arthritis**: Asymmetric distribution, DIP joint involvement, pencil-in-cup deformity, periostitis, and sausage digit appearance; can involve spine with asymmetric sacroiliitis and bulky syndesmophytes. - **Rheumatoid arthritis**: Symmetric polyarticular involvement of MCP, PIP, and wrist joints (DIP spared), periarticular osteoporosis, marginal erosions, uniform joint space narrowing, and subluxations. - **Ankylosing spondylitis**: Predominantly axial involvement with bilateral symmetric sacroiliitis, bamboo spine appearance, thin marginal syndesmophytes, squaring of vertebral bodies, and enthesitis. - These distinct **radiological patterns** allow differentiation based on imaging alone. *Laboratory markers and genetic associations* - While **laboratory markers** (rheumatoid factor, anti-CCP, HLA-B27) and **genetic associations** are important for diagnosis, they are **not radiological features**. - The question specifically asks for **radiological** differentiating features, making this option incorrect despite its clinical importance. - Laboratory data complements imaging but cannot be visualized on radiographs, CT, or MRI. *Clinical presentation and extra-articular features* - **Clinical presentation** and **extra-articular features** (skin psoriasis, uveitis, inflammatory bowel disease) are crucial for diagnosis but are **not radiological features**. - These are clinical findings obtained through history and physical examination, not through imaging studies. - Though they guide which imaging to order, they don't represent radiological differentiating features themselves. *Spinal involvement patterns* - While **spinal involvement patterns** are radiologically visible and help differentiate ankylosing spondylitis from rheumatoid arthritis, this option is too narrow. - It doesn't account for peripheral joint patterns which are crucial for differentiating psoriatic arthritis and rheumatoid arthritis (both can have minimal spinal involvement). - **Radiological patterns and joint distribution** is more comprehensive, encompassing both axial and peripheral manifestations across all three conditions.
Question 5: Which of the following is true of psoriatic arthritis?
- A. Pencil in cup deformity
- B. All of the options (Correct Answer)
- C. Sacroilitis
- D. Involves distal joints of hand and foot
Explanation: ***All of the options*** - All listed options (Pencil in cup deformity, Sacroiliitis, and involvement of distal joints of hand and foot) are characteristic features of **psoriatic arthritis**. [1] - Psoriatic arthritis is a **seronegative spondyloarthropathy** with diverse clinical manifestations. [2] *Pencil in cup deformity* - This specific finding on **X-ray** refers to the bone resorption of the distal phalanx and proliferation of the proximal phalanx, creating a "pencil-in-cup" appearance. - It is a classic, though not exclusive, radiographic feature seen in **severe psoriatic arthritis**, particularly in the **interphalangeal joints**. *Sacroilitis* - **Sacroiliitis**, inflammation of the sacroiliac joints, is a common axial manifestation of psoriatic arthritis, occurring in about 20-40% of patients. [1], [3] - It can be **unilateral or bilateral** and may present with inflammatory back pain, similar to ankylosing spondylitis. [1] *Involves distal joints of hand and foot* - Psoriatic arthritis frequently affects the **distal interphalangeal (DIP) joints** of the hands and feet, which is less common in other forms of inflammatory arthritis like rheumatoid arthritis. [1] - This involvement can lead to **dactylitis** (sausage digits) and **nail changes** (pitting, onycholysis) that are highly characteristic of the disease. [1]
Question 6: 21-Hydroxylase deficiency - false is ?
- A. Female pseudohermaphroditism
- B. Autosomal recessive
- C. Most common cause of congenital adrenal hyperplasia
- D. Male pseudohermaphroditism (Correct Answer)
Explanation: ***Male pseudohermaphroditism*** - **21-hydroxylase deficiency** leads to an inability to synthesize **cortisol** and **aldosterone**, shunting precursors towards **androgen production** [1]. - In **genetic males (XY)**, the excess androgens are a normal part of development and do not cause **pseudohermaphroditism**. Males may present with precocious puberty but not ambiguous genitalia from this condition. *Female pseudohermaphroditism* - In **genetic females (XX)**, the excess androgens during fetal development lead to **virilization** of the external genitalia, resulting in **ambiguous genitalia** [2]. - This condition is often referred to as **female pseudohermaphroditism** because the internal reproductive organs are female, but the external genitalia appear male-like. *Autosomal recessive* - **Congenital adrenal hyperplasia (CAH)** due to **21-hydroxylase deficiency** is inherited in an **autosomal recessive pattern**. - This means that an individual must inherit two copies of the defective gene (one from each parent) to be affected by the condition. *Most common cause of congenital adrenal hyperplasia* - **21-hydroxylase deficiency** accounts for approximately **95% of all cases** of **congenital adrenal hyperplasia (CAH)** [1]. - This makes it by far the **most prevalent enzymatic defect** leading to impaired cortisol synthesis and androgen excess.
Question 7: A 54-year-old man presents with well-demarcated scaly plaques on the extensor surfaces of elbows and knees. The scales are silvery-white in appearance. What is the most likely diagnosis?
- A. Eczema
- B. Psoriasis (Correct Answer)
- C. Lichen planus
- D. Pityriasis rosea
Explanation: ***Psoriasis*** - **Psoriasis** classically presents with **scaly plaques** that often appear on the **extensor surfaces** like elbows and knees. - The scales are typically **silvery-white** and can be associated with itching or discomfort. *Eczema* - **Eczema** (atopic dermatitis) typically presents with **pruritic (itchy)**, **erythematous (red)**, and sometimes **weeping lesions**, often in flexural areas like the antecubital and popliteal fossae. - While it can be scaly, the scales are usually finer and less prominent than those seen in psoriasis, and it often presents on **flexor surfaces**. *Lichen planus* - **Lichen planus** is characterized by **pruritic, purple, polygonal, planar papules and plaques** (the "6 Ps"), often found on flexural surfaces, wrists, and ankles. - It does not typically present with the thick, silvery scales on extensor surfaces seen in this case. *Pityriasis rosea* - **Pityriasis rosea** typically begins with a **herald patch**, followed by an eruption of smaller, oval, scaly patches that follow the skin Langer's lines, often described as a "Christmas tree" pattern on the trunk. - It is usually self-limiting and rarely involves the thick, scaly plaques on extensor surfaces seen in psoriasis.
Question 8: All are true about psoriasis except:
- A. Parakeratosis & acanthosis
- B. Pitting of nails
- C. Very pruritic (Correct Answer)
- D. Joint involvement in 5–30%
Explanation: ***Very pruritic*** - While psoriasis can be itchy, it is generally not characterized as "very pruritic" compared to other dermatological conditions like **eczema** or **scabies**. - **Pruritus** in psoriasis tends to be mild to moderate, and it is not a defining characteristic that differentiates it from other skin disorders. *Parakeratosis & acanthosis* - **Parakeratosis** (retention of nuclei in the stratum corneum) and **acanthosis** (epidermal hyperplasia) are classic histopathological hallmarks of psoriasis. - These features reflect the rapid epidermal turnover characteristic of the condition. *Pitting of nails* - **Nail pitting**, onycholysis, and subungual hyperkeratosis are common and characteristic manifestations of psoriasis, affecting up to 50% of patients. - These nail changes are highly indicative of **psoriatic involvement**. *Joint involvement in 5–10%* - **Psoriatic arthritis**, involving inflammation of the joints, affects approximately 5-30% of individuals with psoriasis. - This statistic makes joint involvement a significant comorbidity of psoriasis.
Question 9: A 25-year-old patient presents with well-demarcated plaques with silvery scales on the elbows and knees. What is the most likely diagnosis?
- A. Lichen planus
- B. Pityriasis rosea
- C. Psoriasis (Correct Answer)
- D. Eczema
Explanation: ***Psoriasis*** - **Psoriasis** is characterized by well-demarcated erythematous plaques with characteristic silvery scales, commonly found on extensor surfaces like the **elbows and knees**. - This chronic inflammatory skin condition results from an accelerated epidermal turnover rate. *Lichen planus* - **Lichen planus** typically presents with pruritic, polygonal, purple, planar papules and plaques, often with **Wickham's striae**, which are absent here. - It commonly affects the wrists, ankles, and oral mucosa, not primarily the elbows and knees with silvery scales. *Pityriasis rosea* - **Pityriasis rosea** usually starts with a single **"herald patch"** followed by smaller, oval, salmon-colored patches in a "Christmas tree" distribution on the trunk. - It does not present with thick silvery scales on the elbows and knees. *Eczema* - **Eczema** (atopic dermatitis) typically presents with intensely itchy, erythematous, oozing, and crusted lesions in acute flares, or dry, thickened, and lichenified skin in chronic cases. - While it can affect the extremities, the presence of distinct **silvery scales** is more characteristic of psoriasis.
Question 10: A 54-year-old man presents with well-demarcated, erythematous plaques covered with silvery scales on the extensor surfaces of elbows and knees. What is the most likely diagnosis?
- A. Pityriasis rosea
- B. Lichen planus
- C. Psoriasis (Correct Answer)
- D. Eczema
Explanation: ***Psoriasis*** - **Psoriasis** is characterized by well-demarcated, erythematous plaques with thick, silvery scales, typically found on **extensor surfaces** like elbows and knees. - The age of the patient (54 years old) is consistent with the broad age range for psoriasis presentation, which can include middle age. *Pityriasis rosea* - Pityriasis rosea typically presents with an **oval shape** and a characteristic "herald patch" followed by smaller, fine-scaled lesions in a "Christmas tree" distribution on the trunk and proximal extremities. - It is often seen in younger individuals and usually resolves spontaneously within several weeks, unlike the chronic nature implied by "scaly plaques." *Lichen planus* - Lichen planus presents with characteristic **purplish, polygonal, pruritic papules and plaques**, often affecting flexor surfaces, wrists, and oral mucosa. - The description of "scaly plaques" on extensor surfaces does not fit the typical clinical picture of lichen planus. *Eczema* - Eczema (or **atopic dermatitis**) is characterized by intensely pruritic, erythematous, and often weeping or crusting lesions, commonly found in **flexural areas** (e.g., antecubital and popliteal fossae). - While scaly, eczema's scales are usually finer and less silvery than psoriasis, and its predilection for extensor surfaces is less common in chronic cases in adults.
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