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SU5.1-4,SU6.1-2 | Wound Healing and Surgical Infection — Practice Quiz
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Which sequence correctly describes the four overlapping phases of normal wound healing?
Correct. Healing begins with haemostasis (vasoconstriction and platelet plug within seconds), followed by inflammation (neutrophils then macrophages), proliferation (fibroblasts, collagen, angiogenesis, granulation, epithelialisation) and finally remodelling/maturation, during which collagen is reorganised and tensile strength increases over months.
The four phases overlap in time but always begin with haemostasis and culminate in remodelling. Knowing the order lets you predict where a given factor (e.g. infection prolonging inflammation, or poor nutrition impairing proliferation) interrupts healing.
Healing always starts with haemostasis and ends with remodelling. The correct order is haemostasis → inflammation → proliferation → remodelling; the phases overlap but follow this sequence.
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A clean surgical incision whose edges are apposed neatly with sutures and heals with minimal scarring is healing by which mode?
Correct. Primary intention occurs when a clean wound has its edges directly apposed (e.g. a sutured surgical incision); minimal granulation tissue forms and the scar is small.
Primary intention = clean wound, edges apposed, minimal scar. Secondary intention = open wound granulating from the base (larger scar, contraction). Tertiary (delayed primary) = wound left open initially then closed once contamination is controlled.
When wound edges are cleanly apposed and the wound is clean, healing is by primary intention. Secondary intention is for open wounds left to granulate, and tertiary intention is delayed closure after a period of observation.
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A diabetic, malnourished man who smokes heavily develops breakdown of his abdominal surgical incision. Which combination of factors best explains his impaired wound healing?
Correct. Diabetes impairs neutrophil function and microcirculation, malnutrition deprives healing of protein and vitamin C needed for collagen synthesis, and smoking causes vasoconstriction and tissue hypoxia — together starving the healing phases.
Impairing factors are local (infection, foreign body, ischaemia, tension) and systemic (diabetes, malnutrition, smoking, steroids, age). Vitamin C is essential for collagen cross-linking; correcting modifiable factors is central to wound management.
Healing fails when its phases are starved of substrate or oxygen. Hyperglycaemia, protein/vitamin C deficiency and smoking-induced hypoxia are classic systemic impairing factors; the other options describe favourable conditions.
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An elective inguinal hernia repair with no breach of the gastrointestinal, respiratory or genitourinary tract and no inflammation encountered falls into which surgical wound contamination class?
Correct. A clean wound is an elective, non-traumatic, uninfected operative wound in which no viscus (GI, respiratory, GU tract) is entered and no inflammation is encountered, carrying the lowest risk of surgical-site infection.
The four contamination classes — clean, clean-contaminated, contaminated, dirty — predict SSI risk and guide prophylaxis. Clean = no viscus entered, no inflammation; this classification is distinct from the morphological description of a wound.
Class is defined by contamination. Clean wounds do not enter a hollow viscus and have no inflammation. Clean-contaminated wounds enter a viscus under controlled conditions; contaminated and dirty wounds involve gross spillage, fresh trauma or established infection.
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On examining a casualty patient you find a skin wound with sharp, clean, regular edges, its length clearly greater than its depth, caused by a kitchen knife. Which morphological type of wound is this?
Correct. An incised wound is produced by a sharp edge, has clean regular margins and is longer than it is deep. This is distinct from a stab/puncture wound, where depth exceeds the surface length and deep structures may be injured.
Morphological type reveals mechanism and danger: incised (sharp, length>depth), lacerated (blunt, ragged, tissue bridges), abrasion (graze), contusion (bruise), puncture/stab (depth>length — small surface wound may hide deep injury).
Sharp clean edges with length greater than depth define an incised wound. Lacerations have ragged edges with tissue bridges (blunt force), abrasions are superficial grazes, contusions are bruises with intact skin, and a stab is deeper than it is long.
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Whether a surgical wound becomes infected is classically described as a balance (Cruse–Foord). Which formulation best captures this balance?
Correct. Infection results from the interplay of the bacterial challenge (dose and virulence) on one side and host resistance plus the local environment (perfusion, dead space, foreign material, devitalised tissue) on the other.
The pathogen–host–environment triad governs surgical infection: reduce the bacterial dose (asepsis, debridement), support the host (perfusion, nutrition, glycaemic control) and optimise the local environment (no dead space, no foreign body, viable tissue).
Pathogenesis is a balance between the bacterial challenge (number and virulence of organisms) and the host plus local environment. The other options are not the determinants of whether infection establishes.
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A diabetic patient develops rapidly spreading limb swelling with pain that is far out of proportion to the visible skin changes, systemic toxicity, and crepitus. Which diagnosis must be excluded urgently?
Correct. Pain out of proportion to the visible signs, systemic toxicity and crepitus in a diabetic patient is the red flag of necrotizing fasciitis — a surgical emergency needing urgent broad-spectrum antibiotics and immediate radical debridement.
Necrotizing fasciitis is diagnosed clinically and treated by emergency source control (radical debridement) plus broad-spectrum antibiotics and resuscitation. Pain out of proportion to examination is the cardinal early warning sign.
Pain out of proportion, systemic toxicity and crepitus signal a necrotizing soft-tissue infection, not simple cellulitis or a minor wound infection. It demands urgent surgical debridement, not antibiotics alone.
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For a patient undergoing a clean-contaminated abdominal operation requiring antibiotic prophylaxis, when should the prophylactic intravenous antibiotic ideally be administered?
Correct. Surgical antibiotic prophylaxis should be given so that adequate tissue concentrations are present at incision — typically within 60 minutes before the skin incision. Giving it too early or after closure fails to protect during the period of contamination.
Distinguish prophylactic (single dose within 60 minutes of incision to prevent SSI) from therapeutic antibiotics (a full course to treat established infection). Correct timing of prophylaxis is one of the most effective measures against surgical-site infection.
Prophylaxis works only if therapeutic tissue levels are present when the wound is made. The correct timing is within 60 minutes before incision; doses given after closure or the next day do not prevent SSI.
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