Wound healing

Wound healing US Medical PG Question 1: A 30-year-old man comes to the physician for a follow-up examination 1 month after sustaining a chemical burn over the dorsum of his right hand and forearm. Physical examination shows hyperextension of the hand at the wrist. The skin over the dorsum of the wrist is tense and there is a thick, epithelialized scar. Range of motion of the right wrist is restricted. This patient's contracture is most likely due to activity of which of the following cells?

• A. Fibroblasts
• B. Myofibroblasts (Correct Answer)
• C. Neutrophils
• D. Macrophages
• E. Endothelial cells

Wound healing Explanation: ***Myofibroblasts*** - The patient presents with a **contracture** (restricted range of motion and hyperextension of the hand due to a thick scar) after a burn, which is characteristic of the action of **myofibroblasts**. - Myofibroblasts are specialized cells that possess features of both fibroblasts (synthesizing **collagen** and extracellular matrix) and smooth muscle cells (containing **actin microfilaments**), allowing them to exert contractile force which leads to scar contraction. *Fibroblasts* - While fibroblasts are crucial for **wound healing** by producing collagen and other extracellular matrix components, they primarily lay down the foundation for scar tissue. - They lack the strong contractile capabilities that lead to significant **tissue retraction** and contracture. *Neutrophils* - Neutrophils are **acute inflammatory cells** that primarily function in the early stages of wound healing to phagocytose debris and pathogens. - They do not play a direct role in the formation of **scar tissue** or **contractures**. *Macrophages* - Macrophages are important **immune cells** involved in clearing debris, presenting antigens, and releasing growth factors during the later stages of wound healing. - They also influence fibroblast activity, but they do not directly cause **tissue contraction** or scar formation. *Endothelial cells* - Endothelial cells line **blood vessels** and are essential for **angiogenesis** (formation of new blood vessels) during wound healing. - They are not involved in the **contractile process** that leads to scar contracture.

Wound healing US Medical PG Question 2: A 15-year-old female presents to her family physician for an annual school physical exam and check-up. She is accompanied by her mother to the visit and is present in the exam room. The patient has no complaints, and she does not have any past medical problems. She takes no medications. The patient reports that she remains active, exercising 5 times a week, and eats a healthy and varied diet. Which of the following would be the best way for the physician to obtain a more in-depth social history, including sexual history and use of alcohol, tobacco, or recreational drugs?

• A. Disallow the mother to be present in the examination room throughout the entirety of the visit
• B. Give the patient a social history questionnaire to fill out in the exam room
• C. Ask the mother to step outside into the hall for a portion of the visit (Correct Answer)
• D. Ask the patient the questions directly, with her mother still in the exam room
• E. Speak softly to the patient so that the mother does not hear and the patient is not embarrassed

Wound healing Explanation: ***Ask the mother to step outside into the hall for a portion of the visit*** - This approach allows the physician to speak with the adolescent **privately and confidentially**, which is crucial for obtaining sensitive information such as sexual history, drug use, and mental health concerns. - Adolescents are more likely to disclose personal information when their parents are not present, fostering trust and ensuring **comprehensive history-taking** vital for their well-being. *Disallow the mother to be present in the examination room throughout the entirety of the visit* - This is an **overly restrictive** approach that might create tension or distrust between the physician, patient, and parent, especially at the start of the visit. - While privacy is essential for sensitive topics, parental presence can be valuable for discussing general health, family history, and **treatment plans**, especially for younger adolescents. *Give the patient a social history questionnaire to fill out in the exam room* - While questionnaires can be useful for gathering basic information, they often **lack the nuance** of a direct conversation and may not prompt the patient to elaborate on sensitive issues. - Furthermore, having the mother present while the patient fills out a questionnaire on sensitive topics still **compromises confidentiality** and may lead to incomplete or dishonest answers. *Ask the patient the questions directly, with her mother still in the exam room* - Asking sensitive questions with a parent present is **unlikely to yield truthful and complete answers**, as adolescents may feel embarrassed, judged, or fear parental disapproval. - This approach compromises the **confidentiality** that is fundamental to building trust with adolescent patients. *Speak softly to the patient so that the mother does not hear and the patient is not embarrassed* - Speaking softly is **unprofessional** and still does not guarantee privacy, as the mother might still overhear parts of the conversation. - This method also **fails to establish true confidentiality**, which is central to building rapport and encouraging open communication with adolescent patients about sensitive topics.

Wound healing US Medical PG Question 3: A 56-year-old male died in a motor vehicle accident. Autopsy reveals extensive atherosclerosis of his left anterior descending artery marked by intimal smooth muscle and collagen proliferation. Which of the following is implicated in recruiting smooth muscle cells from the media to intima in atherosclerotic lesions?

• A. Vascular endothelial growth factor
• B. Platelet-derived growth factor (Correct Answer)
• C. Factor V Leiden
• D. IgE
• E. Prostacyclin

Wound healing Explanation: ***Platelet-derived growth factor*** - **Platelet-derived growth factor (PDGF)** is a crucial **chemotactic** and **mitogenic** factor for **smooth muscle cells (SMCs)**, promoting their migration from the tunica media to the tunica intima and subsequent proliferation in atherosclerotic lesions. - Released by activated platelets, macrophages, and endothelial cells, PDGF contributes significantly to the **fibroproliferative response** seen in **atherosclerosis**. *Vascular endothelial growth factor* - **Vascular endothelial growth factor (VEGF)** is primarily involved in **angiogenesis** and **vascular permeability**. - While angiogenesis can play a role in advanced atherosclerotic plaques, VEGF is not the primary mediator of **smooth muscle cell migration** and proliferation into the intima. *Factor V Leiden* - **Factor V Leiden** is a **genetic mutation** that increases the risk of **thrombosis** due to resistance to inactivation by activated protein C. - It is a risk factor for **venous thromboembolism** and does not directly recruit smooth muscle cells to the intima in atherosclerosis. *IgE* - **Immunoglobulin E (IgE)** is an antibody class primarily involved in **allergic reactions** and **parasitic infections**. - IgE has no direct role in the recruitment or proliferation of **smooth muscle cells** in the context of atherosclerosis. *Prostacyclin* - **Prostacyclin (PGI2)** is a **vasodilator** and a potent **inhibitor of platelet aggregation**. - It works to prevent thrombus formation and has a protective role against atherosclerosis, rather than promoting **smooth muscle cell migration**.

Wound healing US Medical PG Question 4: A 14-year-old girl is brought to the physician after she accidentally cut her right forearm earlier that morning while working with her mother's embroidery scissors. She has no history of serious illness. The mother says she went to elementary and middle school abroad and is not sure if she received all of her childhood vaccinations. She appears healthy. Her temperature is 37°C (98.6 °F), pulse 90/min, and blood pressure is 102/68 mm Hg. Examination shows a clean 2-cm laceration on her right forearm with surrounding edema. There is no erythema or discharge. The wound is irrigated with water and washed with soap. Which of the following is the most appropriate next step in management?

• A. Administer Tdap only (Correct Answer)
• B. Administer DTaP only
• C. No further steps are necessary
• D. Administer TIG only
• E. Intravenous metronidazole

Wound healing Explanation: ***Administer Tdap only*** - A 14-year-old with an unknown or incomplete vaccination history requires a **Tdap (tetanus, diphtheria, acellular pertussis) booster** for **tetanus prophylaxis** after a wound. - The wound is clean, and there are no signs of active infection or high-risk features that would necessitate tetanus immune globulin (TIG). *Administer DTaP only* - **DTaP (diphtheria, tetanus, acellular pertussis)** is typically administered to children younger than 7 years of age. - This patient is 14 years old, making Tdap the more appropriate vaccine formulation for her age group. *No further steps are necessary* - Given the patient's **unknown vaccination history** and a laceration, tetanus prophylaxis is crucial to prevent **tetanus**, a potentially life-threatening condition. - Simply cleaning the wound is insufficient protection without adequate vaccination status. *Administer TIG only* - **Tetanus immune globulin (TIG)** is typically reserved for patients with **dirty or severe wounds** and an unknown or incomplete vaccination history, or for those who are immunocompromised. - This patient has a **clean laceration** with no indication of high-risk features that would warrant TIG. *Intravenous metronidazole* - **Metronidazole** is an antibiotic used to treat **anaerobic bacterial infections** and certain parasitic infections. - The patient has no signs of infection (no erythema, discharge, or fever) that would necessitate antibiotic treatment at this time.

Wound healing US Medical PG Question 5: A 35-year-old male is brought into the emergency department for a trauma emergency. The emergency medical services states that the patient was wounded with a knife on his upper left thigh near the inguinal ligament. Upon examination in the trauma bay, the patient is awake and alert. His physical exam and FAST exam is normal other than the knife wound. Large bore intravenous lines are inserted into the patient for access and fluids are being administered. Pressure on the knife wound is being held by one of the physicians with adequate control of the bleeding, but the physician notices the blood was previously extravasating in a pulsatile manner. His vitals are BP 100/50, HR 110, T 97.8, RR 22. What is the next best step for this patient?

• A. CT lower extremities
• B. Radiograph lower extremities
• C. Coagulation studies and blood typing/crossmatch
• D. Tourniquet of proximal lower extremity
• E. Emergent surgery (Correct Answer)

Wound healing Explanation: ***Emergent surgery*** - The pulsatile bleeding from a thigh wound near the inguinal ligament is highly suggestive of a major arterial injury, such as to the **femoral artery**. - Given the potential for rapid blood loss and hemodynamic instability, **emergent surgical exploration and repair** are necessary to control the bleeding and prevent further compromise. *CT lower extremities* - While CT angiography could further delineate vascular injury, the presence of **active pulsatile bleeding** necessitates immediate surgical intervention rather than delaying for imaging. - Delaying surgery for imaging risks **exsanguination** and worsening patient outcomes, especially with a blood pressure of **100/50 mmHg** and a heart rate of **110 bpm**, indicating early shock. *Radiograph lower extremities* - A radiograph would primarily visualize bone structures and foreign bodies but would not provide adequate information regarding the **vascular injury** and active bleeding. - It would not change the urgent need for **surgical exploration** to address the pulsatile hemorrhage. *Coagulation studies and blood typing/crossmatch* - These are important preparatory steps for major surgery involving significant blood loss, but they should be carried out **concurrently with preparations for emergent surgery**, not instead of it. - Delaying surgery to await these results would be inappropriate when facing **active arterial bleeding**. *Tourniquet of proximal lower extremity* - While a tourniquet can be used for temporary hemorrhage control, especially in an uncontrolled external hemorrhage, the current bleeding is being controlled by **direct pressure**. - Applying a tourniquet could cause **ischemic damage** to the extremity if applied for too long, and for a deep stab wound, direct compression is often effective until surgical control can be achieved.

Wound healing US Medical PG Question 6: A 30-year-old woman dies shortly after admission to the emergency department. The family requests an autopsy to determine cause of death. During the autopsy, multiple linear, parallel marks are noted across her wrists. Which of the following patterns suggests these are hesitation marks rather than defensive wounds?

• A. Irregular, scattered marks
• B. Diagonal, deep lacerations
• C. Deep, single cuts
• D. Superficial, parallel cuts (Correct Answer)

Wound healing Explanation: ***Superficial, parallel cuts*** - **Hesitation marks** are typically numerous, **superficial**, and **parallel**, reflecting a tentative or indecisive attempt and often made in the same direction. - They tend to be concentrated in an area of the body chosen for self-harm, such as the wrists, and are usually consistent with a non-fatal intent. *Irregular, scattered marks* - This pattern is more indicative of **defensive wounds**, which are often scattered and irregular due to attempts to ward off an attack. - Defensive wounds are typically found on the palms, forearms, and other areas used for protection. *Diagonal, deep lacerations* - **Deep lacerations**, especially if diagonal and singular, are less characteristic of hesitation marks and more suggestive of a determined attempt to inflict fatal injury or could be defensive. - **Hesitation marks** are typically not aimed at quickly causing fatal harm. *Deep, single cuts* - A single, **deep cut** is often associated with a resolute intent to cause significant injury or death, rather than the hesitant, superficial nature of hesitation marks. - This pattern would warrant further investigation into the intent and circumstances surrounding the injury.

Wound healing US Medical PG Question 7: In a randomized controlled trial studying a new treatment, the primary endpoint (mortality) occurred in 14.4% of the treatment group and 16.7% of the control group. Which of the following represents the number of patients needed to treat to save one life, based on the primary endpoint?

• A. 1/(0.144 - 0.167)
• B. 1/(0.167 - 0.144) (Correct Answer)
• C. 1/(0.300 - 0.267)
• D. 1/(0.267 - 0.300)
• E. 1/(0.136 - 0.118)

Wound healing Explanation: ***1/(0.167 - 0.144)*** - The **Number Needed to Treat (NNT)** is calculated as **1 / Absolute Risk Reduction (ARR)**. - The **Absolute Risk Reduction (ARR)** is the difference between the event rate in the control group (16.7%) and the event rate in the treatment group (14.4%), which is **0.167 - 0.144**. *1/(0.144 - 0.167)* - This calculation represents 1 divided by the **Absolute Risk Increase**, which would be relevant if the treatment increased mortality. - The **NNT should always be a positive value**, indicating the number of patients to treat to prevent one adverse event. *1/(0.300 - 0.267)* - This option uses arbitrary numbers (0.300 and 0.267) that do not correspond to the given **mortality rates** in the problem. - It does not reflect the correct calculation for **absolute risk reduction** based on the provided data. *1/(0.267 - 0.300)* - This option also uses arbitrary numbers not derived from the problem's data, and it would result in a **negative value** for the denominator. - The difference between event rates of 0.267 and 0.300 is not present in the given information for this study. *1/(0.136 - 0.118)* - This calculation uses arbitrary numbers (0.136 and 0.118) that are not consistent with the reported **mortality rates** of 14.4% and 16.7%. - These values do not represent the **Absolute Risk Reduction** required for calculating NNT in this specific scenario.

Wound healing US Medical PG Question 8: A 28-year-old male presents to his primary care physician with complaints of intermittent abdominal pain and alternating bouts of constipation and diarrhea. His medical chart is not significant for any past medical problems or prior surgeries. He is not prescribed any current medications. Which of the following questions would be the most useful next question in eliciting further history from this patient?

• A. "Does the diarrhea typically precede the constipation, or vice-versa?"
• B. "Is the diarrhea foul-smelling?"
• C. "Please rate your abdominal pain on a scale of 1-10, with 10 being the worst pain of your life"
• D. "Are the symptoms worse in the morning or at night?"
• E. "Can you tell me more about the symptoms you have been experiencing?" (Correct Answer)

Wound healing Explanation: ***Can you tell me more about the symptoms you have been experiencing?*** - This **open-ended question** encourages the patient to provide a **comprehensive narrative** of their symptoms, including details about onset, frequency, duration, alleviating/aggravating factors, and associated symptoms, which is crucial for diagnosis. - In a patient presenting with vague, intermittent symptoms like alternating constipation and diarrhea, allowing them to elaborate freely can reveal important clues that might not be captured by more targeted questions. *Does the diarrhea typically precede the constipation, or vice-versa?* - While knowing the sequence of symptoms can be helpful in understanding the **pattern of bowel dysfunction**, it is a very specific question that might overlook other important aspects of the patient's experience. - It prematurely narrows the focus without first obtaining a broad understanding of the patient's overall symptomatic picture. *Is the diarrhea foul-smelling?* - Foul-smelling diarrhea can indicate **malabsorption** or **bacterial overgrowth**, which are important to consider in some gastrointestinal conditions. - However, this is a **specific symptom inquiry** that should follow a more general exploration of the patient's symptoms, as it may not be relevant if other crucial details are missed. *Please rate your abdominal pain on a scale of 1-10, with 10 being the worst pain of your life* - Quantifying pain intensity is useful for assessing the **severity of discomfort** and monitoring changes over time. - However, for a patient with intermittent rather than acute, severe pain, understanding the **character, location, and triggers** of the pain is often more diagnostically valuable than just a numerical rating initially. *Are the symptoms worse in the morning or at night?* - Diurnal variation can be relevant in certain conditions, such as inflammatory bowel diseases where nocturnal symptoms might be more concerning, or functional disorders whose symptoms might be stress-related. - This is another **specific question** that should come after gathering a more complete initial picture of the patient's symptoms to ensure no key information is overlooked.

Wound healing US Medical PG Question 9: A 37-year-old-woman presents to the emergency room with complaints of fever and abdominal pain. Her blood pressure is 130/74 mmHg, pulse is 98/min, temperature is 101.5°F (38.6°C), and respirations are 23/min. The patient reports that she had a laparoscopic cholecystectomy 4 days ago but has otherwise been healthy. She is visiting her family from Nebraska and just arrived this morning from a 12-hour drive. Physical examination revealed erythema and white discharge from abdominal incisions and tenderness upon palpations at the right upper quadrant. What is the most probable cause of the patient’s fever?

• A. Pulmonary atelectasis
• B. Residual gallstones
• C. Urinary tract infection
• D. Wound infection (Correct Answer)
• E. Pulmonary embolism

Wound healing Explanation: ***Wound infection*** - The presence of **erythema**, **white discharge from abdominal incisions**, and **fever** 4 days post-laparoscopic cholecystectomy strongly indicates a surgical site infection. - This is a common complication after surgery, especially with visible signs of local inflammation and purulent discharge. *Pulmonary atelectasis* - **Atelectasis** typically presents within **24-48 hours post-op** and usually resolves spontaneously. - While it can cause fever, the prominent local wound signs and the timing (4 days post-op) make it less likely to be the primary cause of fever. *Residual gallstones* - **Residual gallstones** would typically present with symptoms resembling acute cholecystitis or cholangitis, such as **right upper quadrant pain**, **jaundice**, or **elevated liver enzymes**, without direct signs of wound infection. - These do not account for the **erythema and discharge from the incision sites**. *Urinary tract infection* - A **urinary tract infection (UTI)** would present with **dysuria**, **frequency**, **urgency**, or **suprapubic pain**, and would not explain the local wound findings. - While surgery can increase the risk of nosocomial UTIs, the clinical presentation is primarily focused on the surgical site. *Pulmonary embolism* - A **pulmonary embolism (PE)** would likely cause **dyspnea**, **tachycardia**, **hypoxia**, and **pleuritic chest pain**, which are not reported in this case. - Though prolonged immobility (e.g., long drive) is a risk factor, the specific local signs of infection are not consistent with PE.

Wound healing US Medical PG Question 10: Three days after being admitted to the hospital because of a fall from the roof of a two-story building, a 27-year-old man is being monitored in the intensive care unit. On arrival, the patient was somnolent and not oriented to person, place, or time. A CT scan of the head showed an epidural hemorrhage that was 45 cm3 in size and a midline shift of 7 mm. Emergency surgery was performed with craniotomy and hematoma evacuation on the day of admission. Perioperatively, a bleeding vessel was identified and ligated. Postoperatively, the patient was transferred to the intensive care unit and placed on a ventilator. His temperature is 37°C (98.6°F), pulse is 67/min, and blood pressure is 117/78 mm Hg. The ventilator is set at a FiO2 of 55%, tidal volume of 520 mL, and positive end-expiratory pressure of 5.0 cm H2O. In addition to intravenous administration of fluids, which of the following is the most appropriate next step in managing this patient's nutrition?

• A. Enteral feeding via nasogastric tube (Correct Answer)
• B. Oral feeding
• C. Keep patient NPO
• D. Total parenteral nutrition
• E. Enteral feeding using a percutaneous endoscopic gastrostomy (PEG) tube

Wound healing Explanation: ***Enteral feeding via nasogastric tube*** - This patient has been **somnolent** and on a ventilator for 3 days after a significant head injury, indicating a prolonged period without oral intake and an inability to protect his airway for oral feeding. **Early enteral nutrition** via a nasogastric tube is preferred in critically ill patients, especially those with head injuries, as it helps maintain gut integrity and reduces complications compared to parenteral nutrition. - The patient's **hemodynamic stability** (blood pressure and pulse are within a reasonable range for a ventilated patient) suggests he can tolerate enteral feeding, and there are no signs of gut ischemia or ileus that would contraindicate it. *Enteral feeding using a percutaneous endoscopic gastrostomy (PEG) tube* - While a PEG tube provides enteral nutrition, it is typically reserved for patients requiring **long-term enteral support** (usually more than 4-6 weeks) or those who cannot tolerate a nasogastric tube. - Given that it has only been 3 days post-injury, a **less invasive method** like a nasogastric tube is initially preferred. *Oral feeding* - The patient is described as **somnolent** and on a ventilator, meaning he is not awake enough or able to protect his airway to safely receive oral feeding. - Attempting oral feeding in this state carries a high risk of **aspiration pneumonia**. *Keep patient NPO* - Keeping the patient NPO (nil per os) for an extended period in critical illness is associated with several negative outcomes, including **gut mucosal atrophy, increased infection risk**, and poorer clinical outcomes. - After 3 days, initiating nutritional support is crucial to prevent these complications. *Total parenteral nutrition* - **Total parenteral nutrition (TPN)** is generally considered a last resort when the gastrointestinal tract is non-functional or enteral feeding is contraindicated. - TPN is associated with a **higher risk of complications**, such as central line infections, liver dysfunction, and metabolic disturbances, compared to enteral feeding.

Wound healing Flashcard 1 of 4

Question: Cutaneous healing by _____ intention is when the wound edges are brought together (e.g. suturing a surgical incision)

Answer: primary

Wound healing Flashcard 2 of 4

Question: What type of graft is from self? _____

Answer: Autograft

Wound healing Flashcard 3 of 4

Question: An entire leg burn is _____% of the body surface area.

Answer: 18

Wound healing Flashcard 4 of 4

Question: Superficial partial thickness burns cause the skin to _____

Answer: blister