Arthrology and Infections — MCQs

Arthrology and Infections Indian Medical PG Practice Questions and MCQs

Question 91: Syndesmophytes are seen in which of the following conditions?

A. Ankylosing Spondylitis (Correct Answer)
B. Rheumatoid Arthritis
C. Osteoarthritis
D. All of the above

Explanation: **Explanation:** **Syndesmophytes** are the hallmark radiological feature of **Ankylosing Spondylitis (AS)**. They represent vertical bony outgrowths that develop due to inflammation and subsequent ossification of the outer fibers of the **annulus fibrosus** of the intervertebral discs. * **Why Option A is correct:** In AS, chronic enthesitis (inflammation at the site where ligaments/tendons attach to bone) leads to the formation of these thin, vertical, and symmetrical bony bridges between adjacent vertebrae. When these bridges connect multiple levels, it creates the classic **"Bamboo Spine"** appearance on X-ray. * **Why Option B is incorrect:** Rheumatoid Arthritis (RA) primarily affects the synovial joints (like the atlantoaxial joint in the spine) and causes bone **erosions** and joint space narrowing, not new bone formation like syndesmophytes. * **Why Option C is incorrect:** Osteoarthritis (OA) of the spine (Spondylosis) produces **Osteophytes**. Unlike syndesmophytes, osteophytes are horizontal, thick, and claw-like protrusions that arise from the vertebral body margins due to mechanical stress, rather than vertical ossification of the ligaments. **High-Yield Clinical Pearls for NEET-PG:** * **HLA-B27:** Strongly associated with Ankylosing Spondylitis (>90% of cases). * **Sacroiliitis:** The earliest radiological sign of AS (usually bilateral and symmetrical). * **Dagger Sign:** A single central radiodense line on X-ray due to ossification of the supraspinous and interspinous ligaments. * **Schober’s Test:** Used clinically to assess the restriction of lumbar spine flexion. * **Marginal vs. Non-marginal:** AS has *marginal* syndesmophytes, while Psoriatic Arthritis and Reiter’s syndrome have *non-marginal* (bulky/asymmetric) syndesmophytes.

Question 92: Which of the following is NOT a feature of Rheumatoid arthritis?

A. Osteosclerosis of the joint (Correct Answer)
B. Soft tissue swelling
C. Narrowing of the joint space
D. Periarticular osteoporosis

Explanation: **Explanation:** Rheumatoid Arthritis (RA) is a chronic, systemic inflammatory disease primarily affecting the **synovium**. The hallmark of RA is inflammatory pannus formation, which leads to bone destruction rather than bone formation. **Why Osteosclerosis is NOT a feature:** **Osteosclerosis** (increased bone density/hardening) is a characteristic feature of **Osteoarthritis (OA)**, a degenerative joint disease. In OA, the loss of cartilage leads to increased mechanical stress on the subchondral bone, resulting in sclerosis and osteophyte formation. In contrast, the inflammatory cytokines (like TNF-α and IL-1) in RA activate osteoclasts, leading to bone loss (osteopenia/erosion) rather than hardening. **Analysis of other options:** * **Soft tissue swelling:** This is the earliest radiographic sign of RA, caused by synovial hypertrophy and joint effusion. * **Narrowing of the joint space:** As the inflammatory pannus destroys the articular cartilage, the space between the bone ends decreases symmetrically. * **Periarticular osteoporosis:** This is a classic early sign of RA. Localized inflammation increases blood flow (hyperemia) to the joint, which promotes demineralization of the bone immediately surrounding the inflamed synovium. **NEET-PG High-Yield Pearls:** * **Radiological Hallmarks of RA:** Symmetric joint space narrowing, periarticular osteopenia, marginal erosions (at the "bare area"), and joint deformities (e.g., Swan-neck, Boutonniere). * **Radiological Hallmarks of OA:** Asymmetric joint space narrowing, **subchondral sclerosis**, subchondral cysts (Geodes), and osteophytes. * **Key Distinction:** RA is an **erosive** disease; OA is a **productive** (bone-forming) disease.

Question 93: What is the commonest cause of acute osteomyelitis?

A. Trauma
B. Surgery
C. Fungal infection
D. Hematogenous route (Correct Answer)

Explanation: **Explanation:** **Hematogenous route (Option D)** is the most common cause of acute osteomyelitis, particularly in the pediatric population. This occurs when bacteria (most commonly *Staphylococcus aureus*) enter the bloodstream from a distant site (like a skin boil or sore throat) and settle in the **metaphysis** of long bones. The metaphysis is the preferred site due to its high vascularity and the presence of "hairpin loops" in the capillary bed, which lead to sluggish blood flow, allowing bacteria to settle and proliferate. **Analysis of Incorrect Options:** * **Trauma (Option A):** While open fractures or deep soft tissue injuries can lead to "Direct Inoculation Osteomyelitis," it is statistically less common than the hematogenous spread in the general population. * **Surgery (Option B):** Post-operative infections (e.g., after ORIF or joint replacement) are significant causes of *chronic* or *iatrogenic* osteomyelitis but do not represent the primary etiology of acute cases globally. * **Fungal infection (Option C):** Fungal osteomyelitis is rare and typically seen only in immunocompromised patients or those on long-term parenteral nutrition. **High-Yield Clinical Pearls for NEET-PG:** * **Most common organism:** *Staphylococcus aureus* (overall). * **Most common organism in Sickle Cell Anemia:** *Salmonella* (though *S. aureus* remains a close second). * **Most common site:** Metaphysis of long bones (Distal Femur > Proximal Tibia). * **Earliest X-ray sign:** Soft tissue swelling (seen at 3–5 days). Bony changes (periosteal reaction/rarefaction) take **10–14 days** to appear. * **Investigation of choice:** **MRI** (most sensitive for early diagnosis).

Question 94: Which of the following is NOT a differentiating feature between psoriatic arthritis and rheumatoid arthritis?

A. Pencil-in-cup deformity
B. Telescoping of phalanges
C. Mael's sign (Correct Answer)
D. Tufting of phalanges

Explanation: **Explanation:** The question asks for the feature that does **not** differentiate Psoriatic Arthritis (PsA) from Rheumatoid Arthritis (RA). **Mael’s Sign** (also known as the "Mael sign" or "Mael's line") is actually a clinical sign associated with **scabies** (a linear burrow), not arthritic conditions. Therefore, it is the correct answer as it is irrelevant to the differentiation of these two types of arthritis. **Analysis of Incorrect Options (Differentiating Features):** * **Pencil-in-cup deformity:** This is a classic radiographic hallmark of **PsA**. It occurs due to periarticular erosions and resorption of the distal end of a phalanx (pencil) fitting into the expanded base of the adjacent phalanx (cup). It is not seen in RA. * **Telescoping of phalanges:** This occurs in **Arthritis Mutilans**, a severe form of PsA. Extensive osteolysis causes the bones to shorten, and the skin folds over the joint like a telescope (Opera-glass hand). While RA can cause joint destruction, this specific "telescoping" is characteristic of PsA. * **Tufting of phalanges:** Also known as acro-osteolysis, this refers to the resorption of the terminal phalangeal tufts. It is a feature of **PsA** (and scleroderma) but is absent in RA. **NEET-PG High-Yield Pearls:** 1. **Symmetry:** RA is typically symmetrical; PsA is often asymmetrical and involves the **DIP joints** (RA characteristically spares the DIP). 2. **Dactylitis:** "Sausage digits" are a hallmark of PsA, not RA. 3. **Serology:** RA is usually RF positive; PsA is a **Seronegative Spondyloarthropathy**. 4. **Radiology:** PsA shows a combination of bone destruction and **new bone formation** (periostitis), whereas RA is primarily a destructive process with periarticular osteopenia.

Question 95: Which of the following is false regarding Charcot's joint in diabetes mellitus?

A. Limitation of movements with bracing
B. Arthrodesis
C. Total ankle replacement (Correct Answer)
D. Arthrocentesis

Explanation: **Explanation:** **Charcot’s Joint (Neuropathic Osteoarthropathy)** is a progressive degenerative condition characterized by joint destruction, pathological fractures, and severe deformity due to loss of protective sensation (proprioception and pain), most commonly caused by **Diabetes Mellitus** in the foot and ankle. **Why Total Ankle Replacement (TAR) is the Correct Answer (False Statement):** Total Ankle Replacement is generally **contraindicated** in Charcot’s joint. The underlying pathology involves poor bone quality, ligamentous laxity, and ongoing microtrauma. A prosthetic implant requires stable bone stock and balanced soft tissues for fixation; in a Charcot joint, the implant is highly likely to fail, loosen, or cause periprosthetic fractures and infection. **Analysis of Other Options:** * **A. Limitation of movements with bracing:** This is a cornerstone of conservative management. Offloading using a **Total Contact Cast (TCC)** or a **Charcot Restraint Orthotic Walker (CROW)** is essential to prevent further joint collapse during the active Eichenholtz stages. * **B. Arthrodesis:** Surgical fusion (Arthrodesis) is the preferred surgical intervention for a stable, plantigrade foot when conservative measures fail. It provides a rigid, functional limb, though it carries a high risk of non-union. * **C. Arthrocentesis:** While not a primary treatment, it may be used diagnostically to rule out **Septic Arthritis**, which is the most critical differential diagnosis for an acute, red, swollen Charcot foot. **Clinical Pearls for NEET-PG:** * **Most common site in Diabetes:** Midfoot (Tarsometatarsal/Lisfranc joints). * **Eichenholtz Classification:** Stage 0 (At-risk), Stage 1 (Development/Fragmentation), Stage 2 (Coalescence), Stage 3 (Remodeling/Consolidation). * **Clinical Sign:** A "rocker-bottom foot" deformity. * **Differential Diagnosis:** Always rule out Osteomyelitis (MRI or Bone Scan/Indium-labeled WBC scan may be needed).

Question 96: Syndesmosis is a type of?

A. Fibrous (Correct Answer)
B. Plain
C. Pivot
D. Cartilaginous

Explanation: **Explanation:** Joints are classified based on the type of connective tissue that binds the bones together. **Syndesmosis** is a subtype of **Fibrous joints**, where two adjacent bones are linked by a strong interosseous membrane or ligament. Unlike sutures (which have minimal connective tissue), syndesmoses allow for slight, functional movement (amphiarthrosis). **Why the other options are incorrect:** * **Plain (Plane):** These are a subtype of **Synovial joints** characterized by flat articular surfaces that allow gliding movements (e.g., Intercarpal joints). * **Pivot:** This is a **Synovial joint** where a bony projection articulates within a ring formed by another bone and a ligament, allowing rotation (e.g., Atlanto-axial joint). * **Cartilaginous:** These joints are joined by hyaline or fibrocartilage. They are divided into Primary (Synchondrosis, e.g., Epiphyseal plate) and Secondary (Symphysis, e.g., Pubic symphysis). **High-Yield Clinical Pearls for NEET-PG:** 1. **Classic Examples:** The **Inferior Tibiofibular joint** and the **Middle Radio-ulnar joint** (interosseous membrane) are the most frequently tested examples of syndesmosis. 2. **Clinical Relevance:** A "High Ankle Sprain" refers to an injury of the inferior tibiofibular syndesmosis. 3. **Gomphosis:** Another specific type of fibrous joint is the Gomphosis (peg-and-socket), seen in the attachment of teeth to alveolar sockets. 4. **Sutures:** These are fibrous joints unique to the skull. In adults, when they ossify, they are termed **Synostoses**.

Question 97: Which of the following is true about acute osteomyelitis?

A. Cannot be detected by X-ray before 2 weeks.
B. Severe pain. (Correct Answer)
C. Limitation of movements.
D. Bone scan detects after 2 weeks.

Explanation: **Explanation:** Acute Hematogenous Osteomyelitis (AHO) is a surgical emergency primarily seen in children. The correct answer is **Severe pain** because it is the most consistent and earliest clinical feature. 1. **Why "Severe Pain" is correct:** The infection typically starts in the **metaphysis** of long bones. As pus accumulates within the rigid medullary cavity, the intraosseous pressure rises significantly. This pressure stretches the sensitive periosteum, leading to excruciating, throbbing pain and exquisite point tenderness. This is often the "earliest" sign before systemic symptoms or radiological changes appear. 2. **Why other options are incorrect:** * **Option A:** While it is a classic teaching that X-rays are negative for 10–14 days, modern digital radiography can sometimes detect subtle soft tissue swelling or periosteal reactions slightly earlier (around 7–10 days). However, "cannot be detected" is an absolute statement that is less clinically definitive than the presence of pain. * **Option C:** While there is "pseudoparalysis" (the patient refuses to move the limb due to pain), the **joint movements** themselves are usually preserved if the joint is moved passively and gently. This helps differentiate it from Septic Arthritis, where any movement is impossible. * **Option D:** Bone scans (Technetium-99m) are highly sensitive and can detect increased uptake within **24 to 48 hours** of infection. Waiting 2 weeks would lead to irreversible bone necrosis (sequestrum). **NEET-PG High-Yield Pearls:** * **Most common site:** Metaphysis (due to hairpin bends of vessels and sluggish blood flow). * **Most common organism:** *Staphylococcus aureus*. * **Investigation of choice:** **MRI** (most sensitive and specific for early diagnosis). * **Earliest X-ray sign:** Soft tissue swelling and blurring of fat planes. * **Earliest Bone sign on X-ray:** Periosteal reaction (takes 10–14 days).

Question 98: What is the most common site of tuberculosis of the spine?

A. Dorsal region
B. Dorsolumbar region (Correct Answer)
C. Lumbar region
D. Lumbosacral region

Explanation: **Explanation:** Tuberculosis of the spine (Pott’s disease) is the most common form of skeletal tuberculosis. The **Dorsolumbar region (T12–L1)** is the most frequently affected site. This is primarily because this region represents a transitional zone where the relatively rigid thoracic spine meets the highly mobile lumbar spine, making it subject to significant mechanical stress. Additionally, the rich vascular supply via the paravertebral venous plexus (Batson’s plexus) facilitates the hematogenous spread of *Mycobacterium tuberculosis* to this area. **Analysis of Options:** * **Dorsolumbar region (Correct):** Statistically the most common site (specifically T12 and L1). It is the junctional area most prone to weight-bearing stress and infection. * **Dorsal/Thoracic region:** The second most common site. While common in children, it is less frequent than the dorsolumbar junction in the general population. * **Lumbar region:** Frequently involved, but usually as an extension or secondary to dorsolumbar involvement. * **Lumbosacral region:** A relatively rare site for primary spinal TB compared to the segments above it. **Clinical Pearls for NEET-PG:** * **Initial Site of Infection:** Usually the **paradiscal** region (anterior part of the vertebral body near the disc). * **Earliest Sign on X-ray:** Reduction/narrowing of the **intervertebral disc space**. * **Cold Abscess:** A hallmark of spinal TB; in the lumbar region, it often tracks down the psoas muscle sheath (Psoas abscess). * **Deformity:** The destruction of the anterior vertebral body leads to wedge collapse, resulting in **Kyphosis** (Gibbus deformity). * **Neurological Deficit:** Pott’s paraplegia is most common when the **upper dorsal spine** is involved due to the narrow canal diameter in that region.

Question 99: Chondrocalcinosis is seen with which of the following conditions?

A. Gout
B. Osteoarthritis
C. Pseudogout (Correct Answer)
D. Septic arthritis

Explanation: **Explanation:** **Pseudogout (Calcium Pyrophosphate Deposition Disease - CPPD)** is the correct answer because chondrocalcinosis is its hallmark radiographic feature. This condition involves the deposition of **calcium pyrophosphate dihydrate crystals** within articular cartilage and fibrocartilage. On X-ray, this appears as linear or punctate radiopacities within the joint space (most commonly the knee, wrist, and symphysis pubis). **Analysis of Options:** * **Gout:** Characterized by the deposition of **monosodium urate crystals**. Radiographically, it presents with "punched-out" erosions and "overhanging edges" (Martel’s sign), but not typically chondrocalcinosis. * **Osteoarthritis (OA):** While OA and CPPD often coexist in elderly patients, OA itself is characterized by joint space narrowing, subchondral sclerosis, and osteophyte formation, rather than cartilage calcification. * **Septic Arthritis:** This is an acute bacterial infection of the joint. Radiographs usually show soft tissue swelling in early stages and joint destruction in late stages, but not chondrocalcinosis. **High-Yield Clinical Pearls for NEET-PG:** * **Crystal Morphology:** Pseudogout crystals are **rhomboid-shaped** and show **weak positive birefringence** under polarized microscopy (Gout crystals are needle-shaped and strongly negative birefringent). * **Associated Conditions:** Always screen a patient with chondrocalcinosis for "The 3 H's": **Hyperparathyroidism, Hemochromatosis, and Hypomagnesemia**, as well as Hypothyroidism and Wilson's disease. * **Common Site:** The **knee joint** is the most common site for both clinical pseudogout and radiographic chondrocalcinosis.

Question 100: In which of the following conditions dactylitis cannot be seen?

A. Sickle cell anaemia
B. Beta thalassemia (Correct Answer)
C. Congenital syphilis
D. Tuberculosis

Explanation: **Explanation:** **Dactylitis**, commonly known as "sausage digit," is the uniform swelling of a finger or toe resulting from inflammation of the small bones, tendons, and surrounding soft tissues. **Why Beta Thalassemia is the correct answer:** In **Beta Thalassemia**, the primary pathology is ineffective erythropoiesis and chronic hemolysis leading to expansion of the bone marrow. While this causes skeletal changes (like the "crew-cut" appearance on skull X-ray or "chipmunk facies"), it **does not** cause acute inflammation or infarction of the phalanges. Therefore, dactylitis is not a clinical feature of Beta Thalassemia. **Analysis of Incorrect Options:** * **Sickle Cell Anaemia:** This is the most common cause of dactylitis in infants (Hand-Foot Syndrome). It occurs due to **vaso-occlusive crises** leading to infarcts in the small bones of the hands and feet. * **Congenital Syphilis:** It causes **syphilitic dactylitis**, characterized by painless, symmetrical swelling of the proximal phalanges due to periostitis. * **Tuberculosis:** Known as **Spina Ventosa**, TB dactylitis involves a cold abscess and cystic expansion of the short tubular bones, usually seen in children. **NEET-PG High-Yield Pearls:** 1. **Spina Ventosa:** The classic radiological sign of TB dactylitis (subperiosteal new bone formation with internal bone destruction). 2. **Spondyloarthropathies:** Dactylitis is a hallmark feature of **Psoriatic Arthritis** (most common), Ankylosing Spondylitis, and Reactive Arthritis. 3. **Sarcoidosis:** Can also cause dactylitis, often presenting with a "lace-like" pattern on X-ray. 4. **Hand-Foot Syndrome:** In Sickle Cell, this is often the first clinical manifestation of the disease in early childhood.

Practice by Chapter

Septic Arthritis

Practice Questions

Osteomyelitis

Practice Questions

Tuberculosis of Bones and Joints

Practice Questions

Fungal and Parasitic Infections

Practice Questions

Diabetic Foot Infections

Practice Questions

Prosthetic Joint Infections

Practice Questions

Reactive Arthritis

Practice Questions

Management of Joint Infections

Practice Questions

Prevention of Orthopaedic Infections

Practice Questions

Biofilms in Orthopaedic Infections

Practice Questions

Antibiotic Prophylaxis

Practice Questions

Implant-Related Infections

Practice Questions

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