MI5.1-5 | Musculoskeletal, Skin & Soft-Tissue Infections — Practice Quiz

A farmer sustains a deep soil-contaminated leg wound. Three days later, he develops severe pain, tense swelling, and gas can be felt in the tissue. Gram stain of wound exudate shows large Gram-positive rods with a conspicuous ABSENCE of polymorphonuclear leucocytes. Which organism is most responsible?

A 12-year-old boy presents with trismus, board-like rigidity, and opisthotonus following a penetrating nail injury one week ago. The wound was not cleaned at the time of injury. Which statement best describes the mechanism of the causative toxin?

A 10-year-old child from a rural village presents with honey-coloured crusted lesions on the face around the nose and mouth. No fever. The lesions began as vesicles 3 days ago. Which organism is most likely responsible?

During an emergency laparotomy for a suspected necrotising fasciitis, the surgeon finds thin, grey-brown watery fluid seeping from fascial planes with no frank pus, and the tissue separates easily with blunt dissection. Which organism combination is MOST classically associated with this Type I necrotising fasciitis?

A patient with sickle cell disease presents with fever, bone pain, and tenderness over the diaphysis of the femur. Blood cultures grow a Gram-negative rod. Which organism should be specifically considered in this clinical context?

A 35-year-old man from Tamil Nadu presents with a 2-year history of hypopigmented, well-defined, completely anaesthetic skin patches. Sensation to light touch and temperature is absent over the patches. Slit-skin smear from the ear lobe is negative for acid-fast bacilli. Which type of leprosy does this MOST likely represent?

The CORRECT site and technique for slit-skin smear collection in leprosy diagnosis is:

A diabetic patient develops a rapidly spreading erythema of the lower limb with blistering, severe pain out of proportion to appearance, and crepitus on palpation. Blood culture grows mixed organisms. MRI shows gas tracking along fascial planes. Which is the MOST appropriate immediate management?

A child presents with fever, refusal to walk, and a swollen, warm knee joint with restricted range of motion. Joint aspiration yields turbid fluid with 80,000 WBCs/mm³ (predominantly neutrophils) and Gram stain shows Gram-positive cocci in clusters. Which statement about the pathogenesis is MOST correct?

Which of the following features distinguishes lepromatous leprosy from tuberculoid leprosy in skin histopathology?