Diabetic Foot Infections — MCQs
A 60-year-old person who completed treatment for leprosy many years ago now presents with a punched-out, painless ulcer on the sole of his foot. What is the most appropriate management?
Diabetic foot is associated with following type of gangrene -
A long-term diabetic patient with blisters walked barefoot for a few miles on hot sand. He presented with rapidly spreading deep tissue infection with extensive tissue necrosis. What is the most probable diagnosis?
Most sensitive imaging modality for detecting early osteomyelitis
A 60-year-old diabetic presents with painless swelling of foot joints. X-ray shows bone fragmentation. What is the most likely diagnosis?
A 50-year-old diabetic presents with a foot ulcer. Which pathogen is most likely?
A 28-year-old male with a history of trauma presents with a non-healing sinus on the tibia. An X-ray shows a sequestrum. What is the appropriate next step in management?
A 25-year-old male presents with localized pain in the tibia and swelling. Imaging reveals a bone abscess. Identify the condition.
Which one of the following is NOT a common cause of recurrent abortions?
Which of the following is NOT true regarding ‘Renal Carbuncle’?
Diabetic Foot Infections Indian Medical PG Practice Questions and MCQs
Question 1: A 60-year-old person who completed treatment for leprosy many years ago now presents with a punched-out, painless ulcer on the sole of his foot. What is the most appropriate management?
- A. Restart MDT
- B. Amputation
- C. Intense debridement and intravenous antibiotics (Correct Answer)
- D. Offloading and comprehensive wound care
Explanation: ***Intense debridement and intravenous antibiotics*** - The presence of a **punched-out, painless ulcer** in a patient with a history of leprosy suggests a **neuropathic ulcer** that has likely become infected due to compromised sensation and foot care [3]. - **Intense debridement** is crucial to remove necrotic tissue and reduce bacterial load, while **intravenous antibiotics** are necessary to treat the deep-seated infection often associated with such ulcers, especially given the poor vascularity and compromised healing in leprosy [2]. *Restart MDT* - The patient completed **leprosy treatment many years ago**, indicating that the current ulcer is not an active leprosy lesion requiring multidrug therapy (MDT). - Restarting MDT would be inappropriate as there is no evidence of **active Mycobacterium leprae infection**. *Amputation* - Amputation is a **last resort** for severe, uncontrolled infections or extensive tissue damage that cannot be salvaged. - While neuropathic ulcers can lead to amputation, it is not the initial or most appropriate management unless there are signs of **irreversible ischemia or overwhelming sepsis** that are not mentioned here. *Offloading and comprehensive wound care* - While **offloading** and comprehensive wound care are essential components of long-term management and prevention for neuropathic ulcers, they are insufficient as the primary treatment for an already **infected, deep ulcer** [2]. - **Debridement** and **antibiotics** are critical initial steps to control the infection before offloading and routine wound care can effectively promote healing [1].
Question 2: Diabetic foot is associated with following type of gangrene -
- A. Dry gangrene
- B. Wet gangrene (Correct Answer)
- C. Gas gangrene
- D. Fournier's gangrene
Explanation: ***Wet gangrene*** - Diabetic foot commonly leads to **ischemia** and **infection** [1], resulting in wet gangrene characterized by moist, necrotic tissue. - This type of gangrene is associated with **rapid progression** and can result in systemic toxicity, making prompt treatment essential. *Fournier's gangrene* - This type of gangrene specifically affects the **perineal** region and is not directly associated with diabetic foot. - It usually arises from infections related to **perineal trauma** or surgical procedures. *Gas gangrene* - Caused by **Clostridium** species and typically follows a traumatic injury or surgical procedure, not specifically related to diabetes. - Presents with **crepitus** and rapid systemic symptoms, different from the chronic nature of diabetic ulcers. *Dry gangrene* - Associated with **chronic ischemia** and necrosis, it occurs in conditions like peripheral arterial disease, not primarily with infections seen in diabetic foot [1]. - It usually develops gradually without the sudden onset of symptoms characteristic of wet gangrene.
Question 3: A long-term diabetic patient with blisters walked barefoot for a few miles on hot sand. He presented with rapidly spreading deep tissue infection with extensive tissue necrosis. What is the most probable diagnosis?
- A. Burn
- B. Cellulitis
- C. Diabetic foot
- D. Necrotizing fasciitis (Correct Answer)
Explanation: ***Necrotizing fasciitis*** - The rapid spread of deep tissue infection with extensive necrosis, especially in an immunocompromised patient like a diabetic, is highly characteristic of **necrotizing fasciitis**. [1] - **Diabetic peripheral neuropathy** can lead to unnoticed injury (walking barefoot on hot sand) and impaired wound healing, further predisposing to severe infections. [2] *Burn* - While walking on hot sand can cause burns, this patient's presentation of "rapidly spreading deep tissue infection" and "extensive tissue necrosis" goes beyond a typical burn injury, suggesting an overwhelming infection. - Burns primarily involve direct tissue damage from heat, whereas the described pathology is indicative of a **bacterial infection** escalating rapidly. *Cellulitis* - **Cellulitis** is a superficial skin infection that typically presents as localized redness, warmth, and swelling, but it usually does not involve deep tissue necrosis or such rapid, extensive spread. - It lacks the hallmark sign of rapid progression to **necrosis** and involvement of deep fascial planes that necessitate urgent surgical debridement. *Diabetic foot* - **Diabetic foot** is a broad term encompassing various foot complications in diabetes, including ulcers, infections, and Charcot arthropathy. While this patient has a diabetic foot, the specific presentation of **rapidly spreading infection** with **extensive necrosis** points to a particular, severe diagnosis within the diabetic foot spectrum, rather than the general term. [2] - The context describes a specific acute, life-threatening infectious process rather than the chronic complications typically associated with the general term "diabetic foot."
Question 4: Most sensitive imaging modality for detecting early osteomyelitis
- A. Nuclear bone scan
- B. CT scan
- C. MRI (Correct Answer)
- D. Plain radiograph
Explanation: **MRI** - **MRI** is the most sensitive imaging modality for detecting **early osteomyelitis** due to its superior ability to visualize **bone marrow edema** and soft tissue changes, which are the earliest signs of infection. - It can differentiate between **bone infection** and other processes like inflammation or tumor, even before cortical bone changes are evident. *Nuclear bone scan* - **Nuclear bone scans** (e.g., technetium-99m) are highly sensitive for detecting **increased bone turnover** but lack specificity for infection. - They can identify areas of **inflammation** or injury but cannot reliably distinguish between osteomyelitis and other conditions like **fractures** or **tumors**. *CT scan* - **CT scans** are excellent for visualizing **cortical bone destruction**, **sequestra**, and **involucrum** in later stages of osteomyelitis. - However, **CT scans** are not as sensitive as MRI for detecting early bone marrow changes and soft tissue involvement, making them less ideal for **early diagnosis**. *Plain radiograph* - **Plain radiographs** are often the first imaging study for suspected osteomyelitis but have **low sensitivity** in the early stages, with changes typically not visible until 10-14 days after infection onset. - Early findings may include **periosteal elevation** or soft tissue swelling, but **bone destruction** or new bone formation is usually required for a definitive diagnosis.
Question 5: A 60-year-old diabetic presents with painless swelling of foot joints. X-ray shows bone fragmentation. What is the most likely diagnosis?
- A. Osteoarthritis
- B. Charcot Arthropathy (Correct Answer)
- C. Gouty Arthritis
- D. Rheumatoid Arthritis
Explanation: ***Charcot Arthropathy*** - **Painless swelling** of foot joints with **bone fragmentation** in a diabetic patient is highly characteristic of Charcot arthropathy, a degenerative joint disease resulting from neuropathy [1]. - The neuropathy prevents the patient from feeling pain, leading to repetitive trauma and progressive joint destruction, often presenting as a **warm, swollen, and sometimes deformed foot** [1]. *Osteoarthritis* - Osteoarthritis typically involves **painful joints** and is characterized by cartilaginous degeneration, not significant bone fragmentation resulting from neuropathy [2]. - While X-rays show joint space narrowing and osteophytes, the absence of pain and presence of bone fragmentation in a diabetic points away from this diagnosis [2]. *Gouty Arthritis* - Gout presents with **acute, exquisitely painful** inflammation of joints, often the great toe, due to uric acid crystal deposition. - The key features here are **painless swelling** and **bone fragmentation**, which are inconsistent with gout. *Rheumatoid Arthritis* - Rheumatoid arthritis is a **symmetric polyarthritis** involving smaller joints, leading to pain, stiffness, and eventual joint destruction, often accompanied by systemic symptoms [2]. - The presentation of a **painless, unilateral foot swelling** with bone fragmentation in a diabetic is not typical for rheumatoid arthritis [2].
Question 6: A 50-year-old diabetic presents with a foot ulcer. Which pathogen is most likely?
- A. Pseudomonas aeruginosa
- B. Escherichia coli
- C. Staphylococcus aureus (Correct Answer)
- D. Candida albicans
Explanation: ***Staphylococcus aureus*** - **Staphylococcus aureus** is the most common bacterial pathogen isolated from **diabetic foot ulcers**, often due to compromised skin integrity and neuropathy. - It can cause a range of infections, from superficial cellulitis to deep tissue infections and osteomyelitis, common in diabetic foot. *Pseudomonas aeruginosa* - While *Pseudomonas aeruginosa* can infect foot ulcers, especially in patients with **previous antibiotic exposure** or **immersion injuries**, it is less common as a primary pathogen than *S. aureus*. - Infections by *Pseudomonas* often present with a **characteristic sweet, grape-like odor** and a green-blue exudate. *Escherichia coli* - *Escherichia coli* is generally associated with infections originating from the **gastrointestinal or genitourinary tracts** and is not a typical primary cause of foot ulcers. - Its presence in foot ulcers is rare and often suggests **polymicrobial infection** or fecal contamination. *Candida albicans* - *Candida albicans* is a **fungal pathogen** that can cause infections, particularly in immunocompromised individuals or those with chronic moist conditions between the toes. - While diabetics are prone to **fungal infections**, *Candida* is not a common primary cause of a deep foot ulcer; bacterial infections are far more prevalent.
Question 7: A 28-year-old male with a history of trauma presents with a non-healing sinus on the tibia. An X-ray shows a sequestrum. What is the appropriate next step in management?
- A. Systemic antibiotics
- B. Local wound care
- C. Sequestrectomy (Correct Answer)
- D. Bone grafting
Explanation: ***Sequestrectomy*** - A **sequestrum** is a piece of dead bone that has become separated from the surrounding healthy bone during necrosis. In the context of **chronic osteomyelitis**, this dead bone acts as a nidus for infection that cannot be eradicated by antibiotics alone. - The presence of a **non-healing sinus** and a sequestrum on X-ray clearly indicates **chronic osteomyelitis**, which requires surgical removal of the infected dead bone (sequestrectomy) for resolution. *Systemic antibiotics* - While systemic antibiotics are crucial in treating acute osteomyelitis and as an adjunct in chronic cases, they are unlikely to cure an infection with a sequestered dead bone. - The **avascular nature of the sequestrum** prevents adequate penetration of antibiotics, making them ineffective as a sole therapy. *Local wound care* - Local wound care might help manage the non-healing sinus superficially but does not address the underlying **bone infection and dead bone**, which is the primary pathology. - This approach would only provide symptomatic relief without resolving the infectious process. *Bone grafting* - Bone grafting is typically performed after the infection has been completely eradicated and involves filling a bone defect. - Performing bone grafting while a **sequestrum and ongoing infection** are present would likely lead to graft failure and continued infection.
Question 8: 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 9: Which one of the following is NOT a common cause of recurrent abortions?
- A. Antiphospholipid syndrome
- B. Chromosomal abnormality
- C. TORCH group of infections
- D. Maternal diabetes (Correct Answer)
Explanation: ***Maternal diabetes*** - While uncontrolled diabetes can increase the risk of **miscarriage** and **birth defects** in general, it is typically not considered a common or direct cause of *recurrent abortions* (defined as three or more consecutive pregnancy losses). - Its effects are often seen in isolated miscarriages or specific fetal anomalies rather than a pattern of repeated losses. *Antiphospholipid syndrome* - This is a well-established cause of recurrent abortions due to the formation of **thrombi** in the placental circulation, leading to impaired blood flow and fetal demise. - It involves the presence of **antiphospholipid antibodies** that interfere with normal pregnancy progression. *Chromosomal abnormality* - Both parental and embryonic chromosomal abnormalities are a very common cause of recurrent pregnancy loss, particularly in the **first trimester**. - These abnormalities often result in non-viable embryos, leading to spontaneous abortion. *TORCH group of infections* - Infections like **Toxoplasmosis, Other (syphilis, parvovirus), Rubella, Cytomegalovirus (CMV), and Herpes simplex virus (HSV)** can cause significant fetal damage and pregnancy loss. - While they can lead to miscarriage, they are generally associated with sporadic miscarriages or specific fetal syndromes rather than recurring abortions in consecutive pregnancies.
Question 10: Which of the following is NOT true regarding ‘Renal Carbuncle’?
- A. It occurs in diabetic patient
- B. It occurs in intravenous drug abusers
- C. It is a type of renal tuberculosis (Correct Answer)
- D. It is an abscess in renal parenchyma
Explanation: A **renal carbuncle** is essentially a **renal abscess** caused by bacterial infection, typically *Staphylococcus aureus* or *Escherichia coli*, not *Mycobacterium tuberculosis*. Renal tuberculosis manifests differently, often with **sterile pyuria** and granulomatous inflammation, and is not synonymous with a carbuncle. Patients with **diabetes mellitus** are at an increased risk of developing bacterial infections, including **renal carbuncles**, due to impaired immune function and glucose-rich urine. Poorly controlled diabetes is a significant **predisposing factor** for severe renal infections. **Intravenous drug users** are at higher risk of bloodstream infections, including **septic emboli** that can disseminate to the kidneys and form renal carbuncles. **Skin contaminants** and unsterile injection practices can introduce bacteria into the bloodstream that eventually localize in renal tissue. A **renal carbuncle** is defined as a focal collection of **pus** and necrotic tissue within the renal parenchyma, essentially a **renal abscess**. It results from the **hematogenous spread** of bacteria or, less commonly, from an ascending urinary tract infection [1].
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