Arthrology and Infections Practice Questions

Q: Tuberculous arthritis of a joint, in sites other than the spine, in advanced cases leads to which of the following?

Fibrous ankylosis. **Explanation:** The hallmark of healing in **Tuberculous (TB) arthritis** of peripheral joints is **Fibrous Ankylosis**. **Why Fibrous Ankylosis is correct:** In tuberculosis, the infection is characterized by chronic granulomatous inflammation. Unlike pyogenic (septic) arthritis, TB bacilli do not produce proteolytic enzymes (like elastase or hyaluronidase) that completely destroy the articular cartilage. Instead, the cartilage is slowly replaced by **pannus** (granulation tissue). When the infection heals, this granulation tissue matures into dense fibrous tissue, leading to a "fibrous ankylosis"—where the joint becomes stiff but not completely fused by bone. **Analysis of Incorrect Options:** * **A. Bony Ankylosis:** This is the characteristic outcome of **Pyogenic/Septic Arthritis**. Proteolytic enzymes in pus destroy the cartilage entirely, allowing raw bone ends to meet and fuse. *Exception:* In TB, bony ankylosis occurs only in the **Spine (Pott’s disease)** and occasionally the sacroiliac joint. * **C. Loose Joints:** TB arthritis typically leads to stiffness and contractures, not laxity. Joint destruction and fibrosis limit movement. * **D. Charcot’s Joints:** This refers to neuropathic arthropathy (painless destruction) caused by loss of proprioception and pain sensation, commonly seen in Diabetes Mellitus, Syphilis (Tabes dorsalis), or Syringomyelia. **High-Yield NEET-PG Pearls:** * **Triple Deformity:** Classic in TB Knee (Flexion, Posterior subluxation, and External rotation). * **Phemister’s Triad (Radiology):** Juxta-articular osteopenia, peripheral osseous erosions, and gradual narrowing of joint space. * **Cold Abscess:** A collection of pus/debris without signs of inflammation (heat/redness), typical of TB. * **Gold Standard Diagnosis:** Synovial biopsy showing caseating granulomas.

Q: What are the principles of treatment for a pyogenic infection of the skeletal system?

Antibiotics. **Explanation:** Pyogenic infections of the skeletal system, such as **Acute Osteomyelitis** or **Septic Arthritis**, are primarily bacterial in origin (most commonly *Staphylococcus aureus*). The cornerstone of management is the prompt administration of **intravenous antibiotics** to eradicate the pathogen, prevent bone necrosis (sequestrum formation), and avoid systemic sepsis. **Why Antibiotics is the Correct Answer:** The pathophysiology involves bacterial proliferation within the metaphysis of long bones or the joint space. Early empirical antibiotic therapy (later tailored by culture and sensitivity) is mandatory to halt the inflammatory process and prevent the transition from acute to chronic osteomyelitis. **Analysis of Incorrect Options:** * **Analgesics (A):** While important for symptomatic pain relief, they do not treat the underlying infectious etiology and are considered supportive, not definitive, therapy. * **Steroids (C):** These are generally contraindicated as they suppress the immune response, potentially worsening the infection and delaying healing. * **Non-operative management (D):** While some early cases respond to antibiotics alone, "non-operative management" is a broad term. In many cases, surgical drainage (sequestrectomy or arthrotomy) is required if there is no response to antibiotics within 48 hours or if an abscess is present. **Clinical Pearls for NEET-PG:** * **Most common organism:** *Staphylococcus aureus* (overall); *Salmonella* (in Sickle Cell Anemia patients). * **Initial Investigation of Choice:** MRI (most sensitive for early changes). * **Gold Standard Diagnosis:** Bone aspiration/biopsy for culture. * **Rule of Thumb:** If clinical improvement is not seen within 24–48 hours of starting antibiotics, surgical decompression/drainage is indicated.

Q: An 18-month-old girl presents with a fever of 104 extdegree F and refusal to walk since waking up. A hip x-ray reveals subtle widening of the left hip joint space. What is the most appropriate initial management?

Surgical drainage of the hip joint. **Explanation:** The clinical presentation of high-grade fever (104°F), refusal to walk (pseudoparalysis), and subtle widening of the hip joint space on X-ray in an 18-month-old is a classic description of **Septic Arthritis of the hip**. **Why Surgical Drainage is Correct:** Septic arthritis of the hip is a **surgical emergency**. The hip joint is a "constrained" joint with an intra-articular femoral neck. Increased intra-articular pressure from pus accumulation can tamponade the retinacular vessels, leading to **Avascular Necrosis (AVN)** of the femoral head within hours. Immediate surgical drainage (arthrotomy or ultrasound-guided aspiration) is mandatory to decompress the joint, evacuate the purulent material, and prevent permanent joint destruction. **Why Other Options are Incorrect:** * **A. Close observation:** This is contraindicated. Delaying treatment in septic arthritis leads to irreversible cartilage damage and hip dislocation. * **B & D. IV Antibiotics (Ceftriaxone/Oxacillin):** While antibiotics are a crucial part of management, they cannot effectively penetrate an undrained, pressurized abscess (the joint). **Drainage must precede or occur concurrently with the initiation of antibiotics.** **NEET-PG High-Yield Pearls:** * **Most common site:** Knee (overall), but the **Hip** is most critical in infants due to the risk of AVN. * **Most common organism:** *Staphylococcus aureus* (overall); *Streptococcus agalactiae* (neonates). * **Kocher’s Criteria:** Used to differentiate septic arthritis from transient synovitis (Non-weight bearing, ESR >40, Fever >38.5°C, WBC >12,000). * **Diagnosis:** Joint aspiration (Arthrocentesis) is the gold standard for diagnosis (WBC count typically >50,000/mm³).

Q: What are the potential complications of acute osteomyelitis?

Sepsis. **Explanation:** Acute osteomyelitis is a pyogenic infection of the bone, most commonly caused by *Staphylococcus aureus*. In the acute phase, the primary concern is the systemic spread of the infection. **Why Sepsis is the Correct Answer:** The hallmark of acute osteomyelitis, especially in children, is hematogenous spread. Bacteria from the bone marrow can easily enter the systemic circulation, leading to **sepsis**, septic shock, and multi-organ dysfunction. In the context of an "acute" presentation, sepsis is the most immediate and life-threatening systemic complication. **Analysis of Incorrect Options:** * **Malignancy (A):** While chronic osteomyelitis (specifically long-standing discharging sinuses) can lead to **Marjolin’s ulcer** (Squamous Cell Carcinoma), this is a late complication occurring decades later, not a feature of the acute phase. * **Fracture (B):** Pathological fractures are more characteristic of **chronic osteomyelitis** or bone tumors where the structural integrity is severely compromised by a large sequestrum or involucrum. * **Chronicity (D):** While acute osteomyelitis can progress to chronic osteomyelitis if undertreated, "chronicity" is considered a **sequela** or a stage of the disease progression rather than an acute clinical complication like sepsis. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site:** Metaphysis of long bones (due to hair-pin bends in vessels leading to sluggish blood flow). * **Most common organism:** *Staphylococcus aureus* (Overall); *Salmonella* (in Sickle Cell Anemia). * **Earliest X-ray sign:** Soft tissue swelling (10–14 days). Bone changes appear late. * **Investigation of choice:** **MRI** (most sensitive for early detection). * **Sequestrum:** Dead bone (radiodense); **Involucrum:** New bone formation (radiopaque).

Q: Which of the following is NOT a cause of neuropathic joint?

Psoriasis. **Explanation:** A **Neuropathic Joint (Charcot Joint)** is a progressive, degenerative arthropathy caused by a loss of pain and proprioceptive sensation. Without these protective mechanisms, repetitive microtrauma leads to joint destruction, instability, and deformity. **Why Psoriasis is the Correct Answer:** Psoriasis is associated with **Psoriatic Arthritis**, which is an **inflammatory** seronegative spondyloarthropathy. It is characterized by synovial inflammation and bone remodeling (pitting of nails, dactylitis) but does *not* involve sensory loss or denervation. Therefore, it does not cause a neuropathic joint. **Analysis of Incorrect Options:** * **Meningomyelocele:** A common cause of neuropathic joints in **children**, typically affecting the ankles and feet due to spinal cord malformation and associated sensory deficits. * **Tabes Dorsalis (Neurosyphilis):** Historically the most common cause. It classically affects the **knee** joint due to damage to the dorsal columns of the spinal cord. * **Leprosy:** A major cause in developing countries. Peripheral nerve damage (especially the ulnar and peroneal nerves) leads to sensory loss, frequently resulting in Charcot joints of the **hands and feet**. **NEET-PG High-Yield Pearls:** 1. **Most Common Cause Today:** Diabetes Mellitus (typically affects the **Tarsal/Metatarsal** joints). 2. **Syringomyelia:** Classically affects the **Shoulder** (Upper limb). 3. **Clinical Feature:** The "6 D’s" of Charcot Joint: Distension, Density (sclerosis), Debris, Disorganization, Dislocation, and Destruction. 4. **Key Sign:** A hallmark of a neuropathic joint is a **painless** joint that appears clinically "destroyed" or severely deformed on X-ray.

Question 1

A 30-year-old male who is positive for HIV and on antiretroviral therapy presents with pain in the right hip region. He has had a flexion, abduction, and external rotation deformity of the right hip for 2 months. What is the most likely diagnosis?

Accepted Answer

Tuberculous arthritis of the hip

Answer

Avascular necrosis

Answer

Transient synovitis

Answer

Septic arthritis

Question 2

Tuberculous arthritis of a joint, in sites other than the spine, in advanced cases leads to which of the following?

Accepted Answer

Fibrous ankylosis

Answer

Bony ankylosis

Answer

Loose joints

Answer

Charcot's joints

Question 3

All of the following findings are in favor of an inflammatory joint pathology except?

Accepted Answer

Non-uniform joint space loss

Answer

Juxta-articular osteoporosis

Answer

Bone erosions

Answer

Bilateral symmetric involvement

Question 4

What is the most common cause of fracture in a patient with hemophilia?

Accepted Answer

Osteoporosis and restricted joint movement

Answer

Osteonecrosis

Answer

Iron deposition

Answer

Pseudo-tumors

Question 5

What are the principles of treatment for a pyogenic infection of the skeletal system?

Accepted Answer

Antibiotics

Answer

Analgesics

Answer

Steroids

Answer

Non-operative management

Question 6

An 18-month-old girl presents with a fever of 104	extdegree F and refusal to walk since waking up. A hip x-ray reveals subtle widening of the left hip joint space. What is the most appropriate initial management?

Accepted Answer

Surgical drainage of the hip joint

Answer

Close observation in the hospital

Answer

Administration of intravenous ceftriaxone

Answer

Administration of intravenous oxacillin

Question 7

A non-healing sinus is a common clinical feature in chronic osteomyelitis. What is the most frequent cause for this presentation?

Accepted Answer

Presence of sequestrum

Answer

Resistant organisms

Answer

Retained foreign body

Answer

Intraosseous cavities

Question 8

What are the potential complications of acute osteomyelitis?

Accepted Answer

Sepsis

Answer

Malignancy

Answer

Fracture of the affected bone

Answer

Chronicity

Question 9

Which of the following is NOT a cause of neuropathic joint?

Accepted Answer

Psoriasis

Answer

Meningomyelocele

Answer

Tabes dorsalis

Answer

Leprosy

Question 10

Which of the following statements is true regarding skeletal tuberculosis in children?

Accepted Answer

Progression to kyphosis deformity is least likely with lumbar lesions.

Answer

The most common sites are the hip (40%), spine (20%), and knee (10%).

Answer

The most common site affected is the upper limb.

Answer

The dorsolumbar spine is the most commonly affected site.

Arthrology and Infections — MCQs

Arthrology and Infections — MCQs

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