Most common organism causing infection after an open fracture?
What is a felon or whitlow?
In Congenital Diaphragmatic Hernia (CDH), the most commonly associated anomaly affects the
Volkmann's contracture: which artery is involved in this condition?
Hirschsprung disease is confirmed by ?
What is the most common complication of a felon?
Periorbital ecchymosis without direct orbital trauma (raccoon eyes) is most commonly associated with injury to:
NEET-PG 2012 - Surgery NEET-PG Practice Questions and MCQs
Question 41: Most common organism causing infection after an open fracture?
- A. Klebsiella
- B. Pseudomonas
- C. Gonococcus
- D. Staphylococcus aureus (Correct Answer)
Explanation: ***Staphylococcus aureus*** - *Staphylococcus aureus* is the **most common organism** causing infection in **open fractures**, accounting for 30-40% of cases. - It is present on **skin flora** and readily contaminates traumatic wounds, making it the predominant pathogen in the immediate post-injury period. - **Antibiotic prophylaxis** for open fractures (cephalosporins) primarily targets *S. aureus*, reflecting its clinical importance. - It causes both **early and late infections** in open fractures and is the leading cause of **post-traumatic osteomyelitis**. *Pseudomonas* - *Pseudomonas aeruginosa* can cause infections in open fractures but is **not the most common** organism. - More frequently seen in **Type III open fractures** with extensive soft tissue damage, **nosocomial infections**, or **delayed infections** after hospitalization. - Associated with **contaminated water exposure** and **chronic wounds** rather than being the primary pathogen in acute open fractures. *Klebsiella* - *Klebsiella* species are typically associated with **nosocomial infections**, particularly **urinary tract infections** and **pneumonia**. - Rarely the primary pathogen in acute open fracture infections. - May be seen in **hospital-acquired** infections in patients with prolonged hospitalization. *Gonococcus* - **Gonococcus** (*Neisseria gonorrhoeae*) is primarily associated with **sexually transmitted infections** and can cause **septic arthritis** through hematogenous spread. - It does **not** cause infections in open fractures as it is not found in the environment or on skin. - The mode of transmission is completely unrelated to trauma or wound contamination.
Question 42: What is a felon or whitlow?
- A. Terminal pulp space infection (Correct Answer)
- B. Infection of the ulnar bursa
- C. Infection of the radial bursa
- D. Midpalmar space infection
Explanation: ***Terminal pulp space infection*** - A **felon**, also known as a **whitlow**, is a **closed-space infection** of the **digital pulp** of the fingertip, distal to the distal interphalangeal joint. - This area contains numerous fibrous septa that create multiple small compartments, which, when infected, can lead to increased pressure, severe pain, and potential **ischemic necrosis** of the bone. *Infection of the ulnar bursa* - An infection of the **ulnar bursa** involves the synovial sheath surrounding the flexor tendons of the medial three and a half digits, extending into the palm. - This condition is often referred to as **ulnar bursitis** or **tenosynovitis** and presents with distinct clinical signs, such as swelling in the palm and along the little finger, known as Kanavel's signs. *Infection of the radial bursa* - An infection of the **radial bursa** affects the synovial sheath around the flexor pollicis longus tendon of the thumb. - This condition is known as **radial bursitis** or **thenar space infection** and typically presents with swelling and tenderness confined to the thumb and thenar eminence. *Midpalmar space infection* - A **midpalmar space infection** occurs in the deep fascial space of the palm, located between the flexor tendons and the interosseous muscles. - This infection presents as diffuse swelling and tenderness in the central palm, often with pain on passive extension of the fingers, but does not involve the fingertip pulp directly.
Question 43: In Congenital Diaphragmatic Hernia (CDH), the most commonly associated anomaly affects the
- A. Congenital heart defects (Correct Answer)
- B. Anomalies of the urinary tract
- C. Anomalies of the skull
- D. Craniofacial anomalies
Explanation: ***Congenital heart defects*** - **Congenital diaphragmatic hernia (CDH)** is frequently associated with other congenital anomalies. - **Cardiac malformations** are the most common co-occurring defects, affecting a significant proportion of CDH patients. *Anomalies of the urinary tract* - While **urogenital anomalies** can occur with CDH, they are less prevalent than congenital heart defects. - These typically include conditions like **renal agenesis** or **hydronephrosis**. *Anomalies of the skull* - **Skull anomalies** are not a primary or common association with congenital diaphragmatic hernia. - Genetic syndromes associated with both CDH and skull anomalies are relatively rare. *Craniofacial anomalies* - **Craniofacial anomalies**, such as **cleft lip/palate**, can occur with CDH but are less common than cardiac anomalies. - These are often seen within the context of specific genetic syndromes.
Question 44: Volkmann's contracture: which artery is involved in this condition?
- A. Radial
- B. Ulnar
- C. Brachial artery (Correct Answer)
- D. Anterior interosseous artery
Explanation: ***Brachial artery*** - **Volkmann's contracture** is an ischemic contracture of the forearm muscles, classically caused by injury or compression of the **brachial artery** - The most common cause is **supracondylar fracture of the humerus** in children, which can damage or compress the brachial artery - Brachial artery injury → **forearm ischemia** → **compartment syndrome** in the anterior (flexor) compartment → muscle necrosis → **ischemic contracture** - The **brachial artery** is the main arterial supply to the forearm, and its compromise leads to the widespread ischemia necessary for Volkmann's contracture - **Clinical features**: Flexion deformity of the wrist and fingers, claw hand, sensory loss in the distribution of median and ulnar nerves *Anterior interosseous artery* - The **anterior interosseous artery** is a branch of the common interosseous artery (from the ulnar artery) that supplies deep forearm muscles - While it contributes to forearm circulation, **isolated injury** to this smaller branch vessel does not typically cause the extensive ischemia required for Volkmann's contracture - The primary vascular pathology in Volkmann's contracture involves the **main arterial trunk** (brachial artery), not its distal branches *Radial* - The **radial artery** is one of the two terminal branches of the brachial artery in the forearm - It primarily supplies the **lateral compartment** and contributes to hand circulation - Isolated radial artery injury does not cause Volkmann's contracture, as the ulnar artery provides collateral circulation - The pathology requires compromise of the **main arterial supply** proximal to the forearm *Ulnar* - The **ulnar artery** is the other terminal branch of the brachial artery - It supplies the **medial forearm** and hand - Similar to radial artery, isolated ulnar artery injury has collateral compensation from the radial artery - Volkmann's contracture requires **proximal arterial compromise** (brachial artery level) affecting the entire forearm blood supply
Question 45: Hirschsprung disease is confirmed by ?
- A. Rectal biopsy (Correct Answer)
- B. Per/Rectal examination
- C. Rectal manometry
- D. X-ray abdomen
Explanation: ***Rectal biopsy*** - A **rectal biopsy** is the most definitive diagnostic test for Hirschsprung disease, revealing the absence of **ganglion cells** in the submucosal and myenteric plexuses. - This procedure involves taking a small tissue sample from the rectum, which is then examined under a microscope for characteristic histological changes. *Per/Rectal examination* - A **per/rectal examination** may reveal an empty rectum followed by a gush of stool and gas upon withdrawal of the finger, which is suggestive but not diagnostic. - It is a **clinical finding** that prompts further investigation but does not provide histological confirmation of aganglionosis. *Rectal manometry* - **Rectal manometry** measures pressures within the rectum and can detect the absence of the **rectoanal inhibitory reflex** (RAIR), a hallmark of Hirschsprung disease. - While highly sensitive, it is a **physiological test** indicating functional abnormalities, but it does not provide the definitive histological diagnosis of aganglionosis. *X-ray abdomen* - An **X-ray of the abdomen** may show dilated loops of bowel proximal to a narrowed, aganglionic segment, indicating intestinal obstruction. - This imaging study is useful for **initial assessment** and identifying signs of obstruction, but it is not specific for Hirschsprung disease and cannot confirm the absence of ganglion cells.
Question 46: 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.
Question 47: Periorbital ecchymosis without direct orbital trauma (raccoon eyes) is most commonly associated with injury to:
- A. Base of skull (Correct Answer)
- B. Pinna
- C. Scalp
- D. Eye
Explanation: ***Base of skull*** - **Periorbital ecchymosis** (raccoon eyes) is a classic sign of a **basilar skull fracture**, particularly one involving the **anterior cranial fossa**. - The fracture allows blood to leak from the cranial cavity and track along fascial planes into the periorbital soft tissues. - The key feature is that ecchymosis occurs **without direct trauma to the orbit or eye**, indicating the primary injury is to the **skull base**. - Often associated with CSF rhinorrhea and requires CT imaging for diagnosis. *Eye* - The question specifically states the ecchymosis occurs "**without direct orbital trauma**," meaning the eye/orbit is NOT the site of injury. - The eye region is where the sign **manifests** (blood tracks to this area), but it is not the site of the underlying injury. - Direct eye trauma would cause immediate localized periorbital swelling, not the delayed bilateral "raccoon eyes" pattern. *Pinna* - Pinna (ear) injury can be associated with head trauma, and Battle's sign (retroauricular ecchymosis) indicates temporal bone fracture. - However, pinna injury does not cause periorbital ecchymosis; these are separate findings. *Scalp* - Scalp injuries cause localized bleeding and swelling at the impact site. - While scalp trauma may accompany basilar skull fracture, the scalp itself is not the source of periorbital ecchymosis. - Blood from scalp wounds tracks superficially, not into deep fascial planes leading to the orbits.