Arthrology and Infections Practice Questions

Q: Melon seed bodies are found in which of the following conditions?

Tuberculous tenosynovitis. **Explanation:** **Melon seed bodies** are characteristic macroscopic findings most commonly associated with **Tuberculous (TB) tenosynovitis**, particularly involving the flexor tendons of the wrist (Compound Palmar Bursa). 1. **Why Tuberculous Tenosynovitis is correct:** These bodies are formed due to chronic inflammation of the synovial lining. Fibrin deposits result from the exudative phase of tuberculosis; as the joint or tendon sheath moves, these fibrin masses are compressed and molded into small, smooth, white, oval structures resembling melon or rice seeds. They are typically found floating within the synovial fluid or attached to the synovium. 2. **Why other options are incorrect:** * **Chondrocalcinosis (Pseudogout):** Characterized by the deposition of **Calcium Pyrophosphate Dihydrate (CPPD)** crystals in cartilage, appearing as linear calcifications on X-ray, not fibrin bodies. * **Gout:** Involves the deposition of **Monosodium Urate** crystals. While it causes "tophi," these are chalky-white gritty deposits, not smooth melon seed bodies. * **Osteoarthritis:** A degenerative joint disease characterized by joint space narrowing, osteophytes, and subchondral sclerosis, rather than proliferative synovial fibrin bodies. **High-Yield Clinical Pearls for NEET-PG:** * **Compound Palmar Bursa:** TB tenosynovitis often presents as a "dumbbell-shaped" swelling across the flexor retinaculum (Cross-fluctuation sign). * **Rice Bodies:** While "Melon seed bodies" is the classic term for TB, similar "Rice bodies" can occasionally be seen in **Rheumatoid Arthritis (RA)** due to chronic synovial inflammation. * **Microscopy:** In TB, look for Caseating granulomas; in Gout, look for Needle-shaped negatively birefringent crystals.

Q: Examine the provided knee X-ray carefully. What is the most likely diagnosis?

Charcot's disease. ***Charcot's disease*** - Shows the classic **5 D's** on X-ray: **Destruction** of joint surfaces, **Disorganization** of normal anatomy, **Density** increase with sclerosis, **Debris** (loose bodies), and **Dislocation** or subluxation - Characterized by **neuropathic arthropathy** with loss of protective sensation leading to progressive joint destruction and **increased bone density** around the affected joint *Tuberculosis (TB)* - X-ray shows **periarticular osteoporosis** and **Phemister triad** (juxta-articular osteoporosis, peripheral erosions, gradual joint space narrowing) - Typically presents with **soft tissue swelling** and **erosive changes** without the sclerosis and debris seen in Charcot's disease *Gout* - X-ray demonstrates **punched-out erosions** with **overhanging edges** and **tophi** calcifications - **Joint space is preserved** in early stages, unlike the destructive changes with increased density seen in neuropathic arthropathy *Rheumatoid arthritis (RA)* - Shows **periarticular osteoporosis**, **joint space narrowing**, and **marginal erosions** without sclerosis - Characterized by **symmetrical involvement** and **absence of increased bone density** or debris formation typical of Charcot's disease

Q: What is the recommended total duration of antibiotic therapy for acute osteomyelitis?

6 weeks. **Explanation:** The management of **acute osteomyelitis** requires a prolonged course of antibiotics because bone is a relatively avascular tissue with poor penetration of antimicrobial agents. The goal is to achieve complete eradication of the pathogen to prevent the infection from transitioning into chronic osteomyelitis. **1. Why 6 weeks is correct:** The standard recommendation for acute osteomyelitis is a total duration of **4 to 6 weeks**. In the context of NEET-PG and standard orthopedic textbooks (like Campbell’s or Apley’s), **6 weeks** is the preferred answer. This duration ensures that the infection is cleared from the haversian systems and prevents recurrence. Usually, the treatment begins with 1–2 weeks of intravenous (IV) antibiotics, followed by oral therapy once clinical improvement and a decline in inflammatory markers (CRP/ESR) are observed. **2. Why other options are incorrect:** * **2 weeks (B):** This is insufficient for bone infections. While symptoms may subside, the bacteria often persist within the bone matrix, leading to a high risk of relapse. * **4 weeks (A):** While 4 weeks is the minimum threshold for some uncomplicated pediatric cases, 6 weeks remains the gold standard for ensuring complete resolution in a general clinical context. * **8 weeks (D):** This duration is typically reserved for chronic osteomyelitis or infections involving resistant organisms (like MRSA) and prosthetic joints, rather than uncomplicated acute osteomyelitis. **High-Yield Clinical Pearls for NEET-PG:** * **Most common organism:** *Staphylococcus aureus* (overall). * **Most common organism in Sickle Cell Anemia:** *Salmonella*. * **Earliest X-ray sign:** Soft tissue swelling (appears in 3–5 days); bone changes (periosteal reaction/rarefaction) take 10–14 days to appear. * **Investigation of choice:** **MRI** (most sensitive and specific for early diagnosis). * **Gold Standard for diagnosis:** Bone biopsy and culture.

Q: A pregnant woman presents with a 6-week history of right hip pain. On examination, she has guarding on passive hip movements. Plain X-ray showed osteoporosis of the proximal femur. What is the most likely diagnosis?

Transient osteoporosis. **Explanation:** **Transient Osteoporosis of the Hip (TOH)** is a self-limiting clinical syndrome characterized by sudden onset hip pain and radiographic evidence of localized bone loss. It most commonly affects **middle-aged men** and **women in the third trimester of pregnancy**. 1. **Why the correct answer is right:** The clinical presentation is classic: a pregnant woman in her third trimester (implied by the timeline) presenting with hip pain and functional limitation (guarding). The hallmark radiographic finding is **diffuse osteopenia/osteoporosis of the femoral head and neck**, while the joint space remains preserved. MRI (the gold standard) would typically show bone marrow edema. The condition is "transient" because it usually resolves spontaneously within 6–12 months with conservative management. 2. **Why the incorrect options are wrong:** * **Acute Chondrolysis:** This involves the rapid destruction of articular cartilage, leading to **joint space narrowing** on X-ray, which is absent here. * **Avascular Necrosis (AVN):** While pregnancy is a risk factor, early AVN usually shows normal X-rays or specific signs like the "crescent sign" and subchondral collapse. It does not typically present with diffuse osteoporosis of the entire proximal femur. * **Septic Arthritis:** This is an acute emergency presenting with high-grade fever, systemic toxicity, and elevated inflammatory markers (ESR/CRP), which are not mentioned. **High-Yield Clinical Pearls for NEET-PG:** * **Demographics:** "M" for Middle-aged Men; "M" for Mothers (3rd trimester). * **Imaging:** X-ray shows "Ghost-like" appearance of the femoral head. MRI shows decreased T1 and increased T2 signal (Bone Marrow Edema Syndrome). * **Management:** Conservative (protected weight-bearing and analgesics). * **Key Differentiator:** Unlike AVN, TOH usually resolves completely without surgical intervention.

Q: What is the radiographic appearance of dead bone on an X-ray?

More radio-opaque. **Explanation:** The correct answer is **A. More radio-opaque**. **Why it is correct:** In orthopaedics, dead bone (known as a **sequestrum**) appears more radio-opaque (whiter) than the surrounding living bone on an X-ray. This phenomenon occurs due to two primary reasons: 1. **Lack of Resorption:** Dead bone has no blood supply (avascular). Therefore, osteoclasts cannot reach the bone to resorb it. 2. **Relative Sclerosis:** In response to infection or injury, the surrounding living bone undergoes hyperemia (increased blood flow), leading to **disuse osteoporosis** (decalcification). Because the dead bone cannot lose calcium, it remains dense while the surrounding bone becomes more radiolucent, making the dead bone appear "whiter" by comparison. **Why the other options are incorrect:** * **B & C (Radiolucent/Less radio-opaque):** These terms describe bone that has lost mineral density (e.g., osteoporosis, osteolysis, or infection). Dead bone retains its original mineral content and often gains density through the precipitation of calcium salts from pus. * **D (Not seen at all):** Dead bone is clearly visible on X-rays and is a hallmark sign of chronic osteomyelitis. **High-Yield NEET-PG Pearls:** * **Sequestrum:** A piece of dead bone that has become separated during the process of necrosis (appears radio-opaque). * **Involucrum:** A layer of new living bone formed around the sequestrum (the "sheath"). * **Cloaca:** An opening in the involucrum through which pus and sequestra may emerge. * **Timmerman’s Sign:** The "ringing" sound produced when a sequestrum is tapped during surgery, indicating its dense, brittle nature.

Q: A 7-year-old boy presents with abrupt onset of hip pain, with the hip held in abduction. A hernogram is normal, and the ESR is elevated. What is the next line of management?

Ultrasound-guided aspiration of the hip. ### Explanation The clinical presentation of a 7-year-old boy with acute hip pain, an abducted position, and an elevated ESR strongly suggests **Septic Arthritis** of the hip. In the pediatric population, the primary differential diagnosis for an irritable hip is between **Transient Synovitis** (benign, self-limiting) and **Septic Arthritis** (a surgical emergency). **Why Option D is Correct:** According to the **Kocher Criteria**, an elevated ESR (>40 mm/hr) combined with acute joint pain is a significant predictor of septic arthritis. **Ultrasound-guided aspiration** is the gold standard for definitive diagnosis. It allows for the identification of a joint effusion and provides a synovial fluid sample for Gram stain, culture, and cell count. Early diagnosis is critical to prevent permanent damage to the femoral head due to increased intra-articular pressure and proteolytic enzymes. **Why Other Options are Incorrect:** * **A & B (Observation):** Observation is only appropriate for suspected Transient Synovitis (where the child is non-toxic and inflammatory markers are normal). Delaying diagnosis in septic arthritis leads to avascular necrosis. * **C (IV Antibiotics):** Antibiotics should never be started *before* obtaining a sample for culture, as this can lead to false-negative results and hinder targeted therapy. **NEET-PG High-Yield Pearls:** * **Kocher Criteria for Septic Arthritis:** 1) Non-weight bearing, 2) Fever >38.5°C, 3) ESR >40 mm/hr, 4) WBC >12,000/mm³. (4/4 criteria = 99% probability). * **Position of Ease:** In septic arthritis of the hip, the joint is held in **flexion, abduction, and external rotation** (position of maximum joint capacity). * **Gold Standard Investigation:** Joint aspiration (Arthrocentesis). * **Most Common Organism:** *Staphylococcus aureus*.

Q: Which of the following drugs is NOT known to produce osteonecrosis?

NSAIDs. **Explanation:** Osteonecrosis (Avascular Necrosis - AVN) is a condition resulting from the temporary or permanent loss of blood supply to the bone, leading to bone cell death and eventual collapse of the articular surface. **Why NSAIDs is the correct answer:** Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) are primarily used to manage the pain associated with osteonecrosis. They do not cause the condition; rather, they are part of the symptomatic treatment regimen. Unlike the other options, NSAIDs do not interfere with microcirculation or lipid metabolism in a way that leads to bone ischemia. **Analysis of Incorrect Options:** * **Glucocorticoids:** These are the most common pharmacological cause of non-traumatic osteonecrosis. They increase adipogenesis in the bone marrow, leading to increased intraosseous pressure and decreased blood flow. * **Alcohol:** Chronic alcohol consumption is a major risk factor. It causes hyperlipidemia and fat emboli, which obstruct the subchondral microcirculation. * **Cytotoxic agents:** Chemotherapeutic drugs (e.g., Methotrexate, Cisplatin) can cause direct toxicity to osteocytes or lead to a hypercoagulable state, resulting in vascular compromise. **Clinical Pearls for NEET-PG:** * **Most common site:** The **femoral head** is the most frequently affected site due to its retrograde blood supply. * **Imaging:** **MRI** is the gold standard and the most sensitive investigation for early diagnosis (detecting the "double line sign"). * **Other causes:** Sickle cell anemia (vaso-occlusive crises), Caisson disease (nitrogen bubbles), and Gaucher disease. * **Staging:** The **Ficat and Arlet classification** is commonly used to stage the progression of AVN.

Q: Which of the following is NOT a complication of acute osteomyelitis?

Osteoclastoma. **Explanation:** **1. Why Osteoclastoma is the Correct Answer:** Osteoclastoma (Giant Cell Tumor) is a **primary benign bone tumor**, not a sequela of infection. Its etiology is related to the neoplastic proliferation of mononuclear stromal cells, whereas acute osteomyelitis is an inflammatory process caused by pyogenic bacteria (most commonly *Staphylococcus aureus*). There is no pathophysiological link between acute infection and the development of this neoplasm. **2. Analysis of Other Options (Complications of Acute Osteomyelitis):** * **Chronic Osteomyelitis:** This is the most common complication, occurring if the acute infection is inadequately treated, leading to bone necrosis (sequestrum formation). * **Septicemia:** Since acute osteomyelitis is often hematogenous in origin, bacteria can re-enter the bloodstream from the bone, leading to systemic sepsis, multi-organ failure, or metastatic abscesses. * **Recurrence:** Even with treatment, bacteria can remain dormant in the canaliculi or within necrotic bone, leading to recurrent bouts of infection months or years later. **3. NEET-PG High-Yield Pearls:** * **Most common site:** Metaphysis of long bones (due to hair-pin arrangement of vessels and sluggish blood flow). * **Most common organism:** *Staphylococcus aureus* (overall); *Salmonella* (in Sickle Cell Anemia patients). * **Pathognomonic features:** **Sequestrum** (dead bone) and **Involucrum** (new bone formation around the dead bone). * **Cloaca:** An opening in the involucrum through which pus and sequestra are discharged. * **Malignant transformation:** While Osteoclastoma is not a complication, **Squamous Cell Carcinoma** (Marjolin’s ulcer) can occur in the skin of a chronic discharging sinus tract.

Question 1

What is true about frozen shoulder?

Accepted Answer

Improves after intraarticular steroid injection.

Answer

May occur after myocardial infarction.

Answer

Seen following Colles' fracture.

Answer

Less commonly seen in diabetes.

Question 2

A patient with nephrotic syndrome on long-term steroid therapy for 6 years presents with a limp gait and limitation of hip abduction and internal rotation. What is the most probable diagnosis?

Accepted Answer

Avascular necrosis of the hip

Answer

Renal osteodystrophy

Answer

Septic arthritis

Answer

Osteomyelitis of the hip joint

Question 3

Melon seed bodies are found in which of the following conditions?

Accepted Answer

Tuberculous tenosynovitis

Answer

Chondrocalcinosis

Answer

Gout

Answer

Osteoarthritis of the wrist

Question 4

Examine the provided knee X-ray carefully. What is the most likely diagnosis?

Accepted Answer

Charcot's disease

Answer

Tuberculosis (TB)

Answer

Gout

Answer

Rheumatoid arthritis (RA)

Question 5

What is the recommended total duration of antibiotic therapy for acute osteomyelitis?

Accepted Answer

6 weeks

Answer

4 weeks

Answer

2 weeks

Answer

8 weeks

Question 6

A pregnant woman presents with a 6-week history of right hip pain. On examination, she has guarding on passive hip movements. Plain X-ray showed osteoporosis of the proximal femur. What is the most likely diagnosis?

Accepted Answer

Transient osteoporosis

Answer

Acute chondrolysis of pregnancy

Answer

Avascular necrosis of the femoral head

Answer

Septic arthritis

Question 7

What is the radiographic appearance of dead bone on an X-ray?

Accepted Answer

More radio-opaque

Answer

Radiolucent

Answer

Less radio-opaque

Answer

Not seen at all

Question 8

A 7-year-old boy presents with abrupt onset of hip pain, with the hip held in abduction. A hernogram is normal, and the ESR is elevated. What is the next line of management?

Accepted Answer

Ultrasound-guided aspiration of the hip

Answer

Hospitalize and observe

Answer

Ambulatory observation

Answer

Intravenous antibiotics

Question 9

Which of the following drugs is NOT known to produce osteonecrosis?

Accepted Answer

NSAIDs

Answer

Glucocorticoids

Answer

Alcohol

Answer

Cytotoxic agents

Question 10

Which of the following is NOT a complication of acute osteomyelitis?

Accepted Answer

Osteoclastoma

Answer

Chronic osteomyelitis

Answer

Septicemia

Answer

Recurrence

Arthrology and Infections — MCQs

Arthrology and Infections — MCQs

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