Pediatric Bone and Joint Infections — MCQs
A boy presented with multiple non suppurative osteomyelitis with sickle cell anaemia. What will be the causative organism?
A child presents with painful limp and restricted hip rotation. ESR and CRP are elevated. Initial plain radiograph is normal. What is the next best imaging study?
How is Brodie's abscess classified?
An 8-year-old boy complains of left leg pain for 3 days. On physical examination, his temperature is 38.9°C, and he exhibits irritability when his left leg is moved. A radiograph of the left leg shows changes suggesting acute osteomyelitis in the proximal portion of the left femur. Culture of the infected bone is most likely to grow which of the following organisms?
Which of the following is an orthopedic emergency?
A 25-year-old male presents with localized pain in the tibia and swelling. Imaging reveals a bone abscess. Identify the condition.
What will the aspirated synovial fluid in a case of septic arthritis typically show?
Pediatric patient with an upper humerus lytic lesion and cortical thinning, which among the following is not a treatment modality?
Fracture of the femur in young children (2-5 years) is typically treated by:
What is the most common complication of a felon?
Pediatric Bone and Joint Infections Indian Medical PG Practice Questions and MCQs
Question 1: A boy presented with multiple non suppurative osteomyelitis with sickle cell anaemia. What will be the causative organism?
- A. Salmonella (Correct Answer)
- B. H. influenzae
- C. Enterobacter species
- D. Staphylococcus aureus
Explanation: ***Salmonella*** - **Salmonella species** are a well-known cause of **osteomyelitis** in patients with **sickle cell anemia**, due to factors like gut mucosal damage and functional asplenia. [1] - The unique pathophysiology of sickle cell disease, including areas of bone infarction and compromised reticulendothelial system function, predisposes these patients to **Salmonella infections**. [1] *Staphylococcus aureus* - While **Staphylococcus aureus** is the most common cause of osteomyelitis in the general population, it is less likely to be the causative organism in patients with **sickle cell anemia** compared to Salmonella. - Its presence usually indicates other predisposing factors like trauma or prosthetic devices. *H. influenzae* - **Haemophilus influenzae** was a common cause of osteomyelitis in children before widespread vaccination but is now rare, especially with routine immunizations. - It is not specifically associated with a higher risk in patients with **sickle cell disease** for osteomyelitis compared to other pathogens. *Enterobacter species* - **Enterobacter species** can cause osteomyelitis, particularly in immunocompromised individuals or following surgery, but they are not uniquely associated with **sickle cell anemia** as a primary cause compared to Salmonella. - Their involvement in non-suppurative osteomyelitis in this specific patient population is less common.
Question 2: A child presents with painful limp and restricted hip rotation. ESR and CRP are elevated. Initial plain radiograph is normal. What is the next best imaging study?
- A. CT Scan
- B. MRI with contrast (Correct Answer)
- C. Bone Scan
- D. Plain Radiograph
Explanation: ***MRI with contrast*** - An **MRI with contrast** is the most sensitive and specific imaging modality for detecting early changes in **osteomyelitis** or **septic arthritis**, which are serious conditions given the child's symptoms and elevated inflammatory markers. - It can visualize soft tissue and bone marrow edema, joint effusions, and abscesses, guiding immediate treatment. *CT Scan* - While useful for bony detail, a CT scan is **less sensitive than MRI** for detecting early bone marrow changes or soft tissue inflammation in the hip joint. - It also involves **radiation exposure**, which should be limited in children when other effective modalities are available. *Bone Scan* - A bone scan using **technetium-99m** is sensitive for detecting increased bone turnover, but it is **not specific for infection** and cannot differentiate between inflammatory processes, tumors, or fractures. - It provides less anatomical detail compared to MRI, making precise localization of an infection more challenging. *Plain Radiograph* - Plain radiographs are typically the **initial imaging study** for orthopedic complaints but are often **normal in early stages** of septic arthritis or osteomyelitis. - Significant radiographic changes, such as bone erosion or joint space widening, usually appear much later in the disease process.
Question 3: How is Brodie's abscess classified?
- A. Acute osteomyelitis
- B. Subacute osteomyelitis
- C. Septic arthritis
- D. Chronic osteomyelitis (Brodie's abscess) (Correct Answer)
Explanation: ***Chronic osteomyelitis (Brodie's abscess)*** - Brodie's abscess is a **subacute or chronic localized osteomyelitis**, characterized by an intraosseous abscess often surrounded by a thick layer of sclerotic bone. - It represents a **contained infection** within the bone, lacking the widespread inflammatory response seen in acute forms. *Acute osteomyelitis* - Characterized by a **rapid onset** of severe pain, fever, and inflammation, usually within days to weeks of infection. - It involves a **widespread inflammatory process** and potential for bone destruction, differentiated from the contained and indolent nature of Brodie's abscess. *Subacute osteomyelitis* - This term describes an osteomyelitis with a more gradual onset and less severe symptoms than acute osteomyelitis, typically lasting several weeks to a few months. - While Brodie's abscess can present subacutely, it is specifically classified as a **form of chronic osteomyelitis** due to its localized, walled-off nature and prolonged course. *Septic arthritis* - Involves an infection within a **joint space**, leading to inflammation and destruction of articular cartilage. - It is distinct from Brodie's abscess, which is an infection of the **bone tissue itself**, not the joint.
Question 4: An 8-year-old boy complains of left leg pain for 3 days. On physical examination, his temperature is 38.9°C, and he exhibits irritability when his left leg is moved. A radiograph of the left leg shows changes suggesting acute osteomyelitis in the proximal portion of the left femur. Culture of the infected bone is most likely to grow which of the following organisms?
- A. Hemophilus influenzae
- B. Neisseria gonorrhoeae
- C. Salmonella enterica
- D. Staphylococcus aureus (Correct Answer)
Explanation: ***Staphylococcus aureus*** - **_Staphylococcus aureus_** is the most common cause of **acute osteomyelitis** in children. - The clinical presentation with a febrile child, localized leg pain, and radiographic changes strongly points to **bacterial osteomyelitis**, with **_S. aureus_** being the predominant pathogen. *Hemophilus influenzae* - **_Hemophilus influenzae_** was once a significant cause of osteomyelitis in children before widespread **HiB vaccination**. - Its incidence has drastically decreased, making it a less likely cause compared to **_S. aureus_** in an 8-year-old. *Neisseria gonorrhoeae* - **_Neisseria gonorrhoeae_** typically causes **septic arthritis** or osteomyelitis in sexually active adolescents and adults, often in disseminated infections. - It is an **uncommon cause** of osteomyelitis in an 8-year-old child and highly unlikely without a history of sexual abuse or neonatal exposure. *Salmonella enterica* - **_Salmonella enterica_** can cause osteomyelitis, particularly in patients with **sickle cell disease** or other **hemoglobinopathies**. - Without any mention of underlying predisposing conditions like sickle cell disease, **_Salmonella_** is a less probable cause than **_S. aureus_**.
Question 5: Which of the following is an orthopedic emergency?
- A. Intraarticular fracture
- B. Septic arthritis (Correct Answer)
- C. Fracture lateral condyle humerus
- D. Fracture neck femur
Explanation: ***Septic arthritis*** - This is an **orthopedic emergency** due to the rapid destruction of cartilage and bone if not treated promptly. - It requires urgent **surgical washout** and intravenous antibiotics to prevent irreversible joint damage and systemic infection. *Intraarticular fracture* - While requiring careful management to optimize joint function, an **intraarticular fracture** is typically not an immediate emergency unless there's associated neurovascular compromise or compartment syndrome. - Surgical intervention can often be planned within a certain timeframe (days) rather than hours. *Fracture lateral condyle humerus* - This fracture in children is significant due to potential for non-union or avascular necrosis, but it is not considered an immediate **life- or limb-threatening emergency**. - Management usually involves **reduction and fixation** but does not carry the same degree of urgency as active joint infection. *Fracture neck femur* - A fractured neck of femur requires surgical intervention to prevent complications like **avascular necrosis** and optimize mobility, particularly in elderly patients. - While serious, it primarily presents a risk of long-term disability and complications, not an immediate destructive process like septic arthritis.
Question 6: A 25-year-old male presents with localized pain in the tibia and swelling. Imaging reveals a bone abscess. Identify the condition.
- A. Brodie abscess (Correct Answer)
- B. Osteoid osteoma
- C. Intracortical hemangioma
- D. Chondromyxoid fibroma
Explanation: ***Brodie abscess*** - A Brodie abscess is a **subacute or chronic osteomyelitis** characterized by a well-circumscribed, **radiolucent lesion** (an abscess cavity) often surrounded by a zone of **sclerosis**, representing the body's attempt to wall off the infection. - The presentation of localized pain and swelling in the tibia, with imaging revealing a bone abscess, is consistent with this condition, which is a common form of localized osteomyelitis. *Osteoid osteoma* - This is a **benign bone tumor** characterized by a small, radiolucent nidus surrounded by a large area of **sclerotic bone**. The pain from an osteoid osteoma is typically **worse at night** and dramatically relieved by NSAIDs. - While it can cause localized pain and swelling, the imaging features of a distinct abscess cavity are not characteristic of an osteoid osteoma. *Intracortical hemangioma* - An intracortical hemangioma is a **rare benign vascular lesion** within the cortex of a bone. - Imaging typically shows a **lytic lesion** with a characteristic **"honeycomb" or "sunburst" appearance**, not a well-defined abscess. *Chondromyxoid fibroma* - This is a rare, **benign cartilaginous tumor** that usually presents as an **eccentric lytic lesion** in the metaphysis of long bones, often with a scalloped border and sclerotic rim. - While it can cause localized pain and swelling, the imaging appearance of an abscess with sclerotic margins is not typical of a chondromyxoid fibroma.
Question 7: What will the aspirated synovial fluid in a case of septic arthritis typically show?
- A. Clear and straw-colored fluid
- B. Low viscosity fluid
- C. Cloudy or purulent fluid
- D. Markedly increased polymorphonuclear leukocytes (Correct Answer)
Explanation: ***Markedly increased polymorphonuclear leukocytes*** - **Septic arthritis** is characterized by an acute infection within the joint, leading to a profound inflammatory response with a significant influx of **neutrophils** (polymorphonuclear leukocytes) into the synovial fluid. - A synovial leukocyte count greater than **50,000 cells/mm³** with over **75% neutrophils** is highly suggestive of septic arthritis. *Clear and straw-colored fluid* - This description typically corresponds to **normal synovial fluid** or fluid from a mild **non-inflammatory condition**, which is not consistent with bacterial infection. - Normal synovial fluid is usually **transparent**, indicating the absence of significant cellular debris or inflammatory cells. *Low viscosity fluid* - While septic synovial fluid can have reduced viscosity due to the breakdown of **hyaluronic acid** by bacterial enzymes and inflammatory mediators, this characteristic alone is not the most definitive diagnostic feature. - Reduced viscosity is also observed in other inflammatory conditions, making it less specific than direct cellular analysis for diagnosing infection. *Cloudy or purulent fluid* - The presence of **cloudy** or **purulent (pus-like)** fluid *is* often seen in septic arthritis, reflecting the high cell count and protein content. - However, this is a **gross visual observation**, and a more precise and diagnostic indicator is the microscopic finding of markedly increased **polymorphonuclear leukocytes**.
Question 8: Pediatric patient with an upper humerus lytic lesion and cortical thinning, which among the following is not a treatment modality?
- A. Curettage and bone grafting
- B. Steroids
- C. Sclerosant (Correct Answer)
- D. Radiotherapy
Explanation: ***Sclerosant*** - While sclerosants can be used in some vascular lesions or cysts, they are **not a standard or primary treatment modality for an upper humerus lytic lesion** with cortical thinning, which often represents a bone cyst or benign tumor. - Their mechanism of action involves **inducing fibrosis and closing off vascular structures**, which isn't the main goal for common lytic bone lesions in children. *Curettage and bone grafting* - This is a very common and effective treatment for **benign lytic bone lesions** like **unicameral bone cysts (UBCs)** or aneurysmal bone cysts (ABCs). - **Curettage** removes the diseased tissue, and **bone grafting** (autograft or allograft) fills the defect, promoting healing and stability. *Steroids* - **Intralesional steroid injection** is a recognized treatment for **unicameral bone cysts (UBCs)**, especially in actively growing lesions in children. - Steroids help **reduce inflammation and promote resolution** of the cyst lining, often leading to bone healing. *Radiotherapy* - While radiotherapy is used for malignant bone tumors, it is **generally avoided for benign lytic lesions in children** due to concerns about long-term risks like growth disturbance and secondary malignancy. - It might be considered in **recalcitrant or aggressive benign lesions** where other treatments have failed, but it is not a first-line treatment.
Question 9: Fracture of the femur in young children (2-5 years) is typically treated by:
- A. Gallow's splint
- B. Open reduction (surgical intervention)
- C. Closed reduction & splintage (Correct Answer)
- D. Intramedullary nailing (surgical fixation)
Explanation: ***Closed reduction & splintage*** - In young children (2-5 years), **femur fractures** are often treated non-operatively with **closed reduction** and immediate application of a **hip spica cast** or other splintage. - This approach takes advantage of the excellent **bone remodeling potential** in young children, allowing for good functional outcomes. *Open reduction (surgical intervention)* - **Open reduction** is generally reserved for open fractures, - It is also indicated for fractures with associated neurovascular injury, compartment syndrome, or in older children where non-operative management has failed. *Gallow's splint* - The **Gallow's splint** (also known as Bryant's traction) involves suspending both legs vertically, and is typically used for **femur fractures in infants younger than 1 year** due to the risk of vascular compromise or compartment syndrome in older or heavier children. - It is not the primary treatment for children aged 2-5 years. *Intramedullary nailing (surgical fixation)* - **Intramedullary nailing** is a surgical option, usually considered for **femur fractures in older children** (typically 6 years and above) or adolescents. - It provides stable fixation but is generally avoided in very young children due to potential damage to the **growth plates** or complications related to implant size.
Question 10: What is the most common complication of a felon?
- A. Osteomyelitis (Correct Answer)
- B. Subungual hematoma
- C. Infective arthritis
- D. No complications
Explanation: ***Osteomyelitis*** - A **felon** is a severe infection of the **distal pulp space** of the fingertip, which has numerous fibrous septa. - The tightly compartmentalized nature of this space can lead to increased pressure, compromising blood supply and facilitating the spread of infection to the underlying **phalanx bone**, causing **osteomyelitis**. *Subungual hematoma* - A **subungual hematoma** is a collection of blood under the nail, usually resulting from direct trauma. - It is not a complication of an infection like a felon, but rather a separate traumatic injury. *Infective arthritis* - **Infective arthritis** involves the joint space, typically resulting from direct inoculation, hematogenous spread, or spread from adjacent soft tissue infection. - While possible, it is less common for a felon to directly spread to the **distal interphalangeal joint** compared to the more immediate risk of bone involvement. *No complications* - A **felon** is a serious infection that, if left untreated, almost always leads to complications due to the unique anatomy of the fingertip pulp space. - The high pressure within the compartments of the distal pulp makes it prone to necrosis and spread of infection to adjacent structures.
Want unlimited practice?
Get full access to all questions, explanations, and performance tracking.
Start For Free