Chronic wounds pathophysiology US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for Chronic wounds pathophysiology. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Chronic wounds pathophysiology US Medical PG Question 1: A researcher is studying the ability of breast cancer cells to metastasize. Neoplastic cells obtained from 30 patients with stage IV ductal carcinoma of the breast are tagged with a fluorescent antibody. The cells are then inserted into a medium resembling normal human tissue. After 2 weeks, all samples show in vitro hematogenous invasion and migration away from the original site of insertion. Which of the following properties is most likely responsible for the ability of these neoplastic cells to metastasize?
- A. Loss of cellular polarity
- B. Presence of fibrous tissue capsule
- C. Overexpression of HER2/neu
- D. Increase in N:C ratio
- E. Release of matrix metalloproteinase (Correct Answer)
Chronic wounds pathophysiology Explanation: ***Release of matrix metalloproteinase***
- **Matrix metalloproteinases (MMPs)** degrade components of the **extracellular matrix (ECM)** and **basement membrane**, allowing cancer cells to invade surrounding tissues and metastasize [1].
- The in vitro observation of **hematogenous invasion** and **migration** confirms the ability to break down barriers critical for metastasis [2].
*Loss of cellular polarity*
- While **loss of polarity** is a feature of malignant transformation, it primarily contributes to disorganized growth and invasion rather than the active breakdown of the physical barriers required for long-distance metastasis.
- It does not directly explain the enzymatic degradation of the **ECM** necessary for transmural passage into blood vessels [2].
*Presence of fibrous tissue capsule*
- A **fibrous tissue capsule** typically indicates a **benign tumor** or a well-demarcated malignant tumor with limited invasiveness, restricting spread.
- Its presence would hinder, rather than promote, the ability of cancer cells to metastasize.
*Overexpression of HER2/neu*
- **HER2/neu overexpression** is a marker of aggressive breast cancer and can promote cell proliferation and survival.
- However, it does not directly facilitate the enzymatic degradation of the **extracellular matrix** required for active invasion and migration [2].
**References:**
[1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 232-233.
[2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, pp. 314-316.
Chronic wounds pathophysiology US Medical PG Question 2: A 68-year-old woman comes to the physician because of a 3-month history of an oozing, red area above the left ankle. She does not recall any trauma to the lower extremity. She has type 2 diabetes mellitus, hypertension, atrial fibrillation, and ulcerative colitis. She had a myocardial infarction 2 years ago and a stroke 7 years ago. She has smoked 2 packs of cigarettes daily for 48 years and drinks 2 alcoholic beverages daily. Current medications include warfarin, metformin, aspirin, atorvastatin, carvedilol, and mesalamine. She is 165 cm (5 ft 4 in) tall and weighs 67 kg (148 lb); BMI is 24.6 kg/m2. Her temperature is 36.7°C (98°F), pulse is 90/min, respirations are 12/min, and blood pressure is 135/90 mm Hg. Examination shows yellow-brown spots and dilated tortuous veins over the lower extremities. The feet and the left calf are edematous. Femoral, popliteal, and pedal pulses are palpable bilaterally. There is a 3-cm (1.2-in) painless, shallow, exudative ulcer surrounded by granulation tissue above the medial left ankle. There is slight drooping of the right side of the face. Which of the following is the most likely cause of this patient's ulcer?
- A. Peripheral neuropathy
- B. Drug-induced microvascular occlusion
- C. Chronic pressure
- D. Decreased arterial blood flow
- E. Venous insufficiency (Correct Answer)
Chronic wounds pathophysiology Explanation: ***Venous insufficiency***
- The presence of **edema**, **dilated tortuous veins**, and **yellow-brown spots** (hemosiderin deposition) on the lower extremities, along with a **painless, shallow, exudative ulcer** above the medial ankle, are classic signs of chronic venous insufficiency.
- The ulcer's location (medial malleolus) and its characteristics (granulation tissue, oozing) further support a venous etiology, as good arterial pulses indicate adequate inflow.
*Peripheral neuropathy*
- Ulcers due to peripheral neuropathy (e.g., in diabetes) are typically **painless** but often occur on the **plantar surface of the foot** or pressure points and can be deep.
- While the patient has diabetes, the clinical presentation with prominent venous stasis signs and edema points away from a primary neuropathic ulcer in this location.
*Drug-induced microvascular occlusion*
- Drug-induced microvascular occlusion (e.g., from **warfarin necrosis**) typically presents as painful, irregular, purpuric lesions that can progress to necrosis and ulceration, often occurring within days of starting the medication or with high doses.
- The 3-month history, painless nature, and specific signs of venous stasis do not align with drug-induced microvascular occlusion.
*Chronic pressure*
- Pressure ulcers develop over **bony prominences** due to prolonged pressure, leading to tissue ischemia and breakdown.
- This patient's ulcer is above the medial ankle, which is not a common site for pressure ulcers, and the presentation includes clear signs of venous hypertension, not just external compression.
*Decreased arterial blood flow*
- Ulcers due to decreased arterial blood flow (arterial ulcers) are typically **painful**, often located on the **toes, heels, or dorsum of the foot**, and have a "punched-out" appearance with **pale bases** and minimal granulation tissue.
- The presence of palpable pedal pulses and the painless nature of the ulcer rule out significant arterial insufficiency as the primary cause.
Chronic wounds pathophysiology US Medical PG Question 3: A 62-year-old man comes to the physician because of an oozing skin ulceration on his foot for 1 week. He has a history of type 2 diabetes mellitus and does not adhere to his medication regimen. Physical exam shows purulent discharge from an ulcer on the dorsum of his left foot. Pinprick sensation is decreased bilaterally to the level of the mid-tibia. A culture of the wound grows beta-hemolytic, coagulase-positive cocci in clusters. The causal organism most likely produces which of the following virulence factors?
- A. Exotoxin A
- B. M protein
- C. P fimbriae
- D. IgA protease
- E. Protein A (Correct Answer)
Chronic wounds pathophysiology Explanation: ***Protein A***
- The culture finding of **beta-hemolytic, coagulase-positive cocci in clusters** is characteristic of ***Staphylococcus aureus***.
- ***Staphylococcus aureus*** produces **Protein A**, which binds to the Fc region of IgG, preventing opsonization and phagocytosis, thereby hindering the immune response.
*Exotoxin A*
- **Exotoxin A** is a virulence factor primarily produced by ***Pseudomonas aeruginosa***, particularly associated with deep tissue infections and sepsis.
- It functions as an **ADP-ribosylating toxin** that inhibits protein synthesis, but it is not characteristic of the organism isolated in this patient.
*M protein*
- **M protein** is a key virulence factor of ***Streptococcus pyogenes*** (Group A Streptococcus), responsible for preventing phagocytosis and promoting adhesion.
- ***S. pyogenes*** is beta-hemolytic but typically grows in **chains**, not clusters, and is **coagulase-negative**.
*P fimbriae*
- **P fimbriae** (pyelonephritis-associated pilus) are virulence factors predominantly found in uropathogenic strains of ***Escherichia coli***, mediating adhesion to uroepithelial cells.
- These fimbriae are associated with urinary tract infections, not typically with skin ulcers from **Gram-positive cocci in clusters**.
*IgA protease*
- **IgA protease** is a virulence factor produced by several pathogenic bacteria such as ***Neisseria gonorrhoeae***, ***Haemophilus influenzae***, and ***Streptococcus pneumoniae***.
- It cleaves IgA at hinge regions, allowing the bacteria to evade mucosal immunity, but it is not a primary virulence factor of ***Staphylococcus aureus*** or commonly associated with skin ulcers.
Chronic wounds pathophysiology US Medical PG Question 4: A 42-year-old man presents to the clinic for a second evaluation of worsening blackened ulcers on the tips of his toes. His past medical history includes diabetes mellitus for which he takes metformin and his most recent HbA1c was 6.0, done 3 months ago. He also has hypertension for which he's prescribed amlodipine and chronic obstructive pulmonary disease (COPD) for which he uses an albuterol-ipratropium combination inhaler. He is also a chronic tobacco user with a 27-pack-year smoking history. He first noticed symptoms of a deep aching pain in his toes. Several months ago, he occasionally felt pain in his fingertips both at rest and with activity. Now he reports blackened skin at the tips of his fingers and toes. Evaluation shows: pulse of 82/min, blood pressure of 138/85 mm Hg, oral temperature 37.0°C (98.6°F). He is thin. Physical examination of his feet demonstrates the presence of 3, 0.5–0.8 cm, eschars over the tips of his bilateral second toes and right third toe. There is no surrounding erythema or exudate. Proprioception, vibratory sense, and monofilament examination are normal on both ventral aspects of his feet, but he lacks sensation over the eschars. Dorsal pedal pulses are diminished in both feet; the skin is shiny and hairless. Initial lab results include a C-reactive protein (CRP) level of 3.5 mg/dL, leukocytes of 6,000/mm3, erythrocyte sedimentation rate (ESR) of 34 mm/hr, and negative antinuclear antibodies. Which part of the patient's history is most directly associated with his current problem?
- A. Diabetes mellitus
- B. Hypertension
- C. Autoimmune disorder
- D. Chronic obstructive pulmonary disease
- E. Tobacco smoking (Correct Answer)
Chronic wounds pathophysiology Explanation: ***Tobacco smoking***
- The patient exhibits symptoms consistent with **Buerger's disease (thromboangiitis obliterans)**, which is strongly associated with **heavy tobacco use**. The blackened ulcers on the fingertips and toes ("blackened skin" and "eschars") are indicative of **ischemia** due to **vasculitis** of small and medium-sized arteries.
- The "deep aching pain" in his toes and fingertips preceding the ulcers, along with diminished peripheral pulses and shiny, hairless skin, further supports a diagnosis of severe peripheral vascular disease primarily driven by smoking.
*Diabetes mellitus*
- While diabetes can cause **peripheral neuropathy** and **vascular disease**, this patient's **HbA1c of 6.0** indicates good glycemic control, making it less likely to be the primary cause of his extensive, severe ischemic ulcers.
- The normal proprioception, vibratory sense, and monofilament examination (except over the eschars) suggest that **diabetic neuropathy** is not the direct cause of the current ischemic problem.
*Hypertension*
- Hypertension is a risk factor for **atherosclerosis** and cardiovascular disease, but it typically affects larger arteries and does not directly explain the specific pattern of **vasculitis** and **digital ischemia** seen in this patient (blackened fingertips and toes).
- The patient's blood pressure is controlled with medication, and while it contributes to overall vascular risk, it's not as directly associated with the presented condition as tobacco use is.
*Autoimmune disorder*
- The negative antinuclear antibodies (ANA), near-normal ESR (34 mm/hr) and CRP (3.5 mg/dL) make a systemic **autoimmune disorder**, such as systemic lupus erythematosus or scleroderma, less likely to be the primary cause of his ulcers.
- While some autoimmune conditions can cause vasculitis, the clinical picture, particularly the strong association with tobacco use and the distribution of lesions, points away from a primary autoimmune etiology.
*Chronic obstructive pulmonary disease*
- COPD is a **pulmonary condition** primarily affecting the lungs and is strongly associated with smoking, but it does not directly cause **peripheral ischemic ulcers** on the fingers and toes.
- While COPD indicates the patient's long-standing smoking habit, it is the smoking itself, not the COPD directly, that causes the vascular pathology leading to the blackened ulcers.
Chronic wounds pathophysiology US Medical PG Question 5: A 31-year-old woman scrapes her finger on an exposed nail and sustains a minor laceration. Five minutes later, her finger is red, swollen, and painful. She has no past medical history and does not take any medications. She drinks socially with her friends and does not smoke. The inflammatory cell type most likely to be prominent in this patient's finger has which of the following characteristics?
- A. Segmented nuclei (Correct Answer)
- B. Dramatically expanded endoplasmic reticulum
- C. Large cell with amoeboid movement
- D. Multiple peripheral processes
- E. Dark histamine containing granules
Chronic wounds pathophysiology Explanation: ***Segmented nuclei***
- This scenario describes **acute inflammation** following a minor injury, with classic signs of **redness, swelling, and pain** within minutes.
- **Neutrophils** are the primary inflammatory cells in acute inflammation and are characterized by their **segmented (multi-lobed) nuclei.**
*Dramatically expanded endoplasmic reticulum*
- An expanded endoplasmic reticulum is characteristic of cells highly active in protein synthesis and secretion, such as **plasma cells** producing antibodies.
- Plasma cells are typically involved in **chronic inflammation** and adaptive immune responses, not rapid acute inflammation.
*Large cell with amoeboid movement*
- This describes **macrophages**, which are phagocytic cells important in both acute and chronic inflammation, and in cleaning up debris.
- While macrophages are present, **neutrophils** are the predominant early responders in acute bacterial infections and tissue injury.
*Multiple peripheral processes*
- This description is characteristic of **dendritic cells**, which are antigen-presenting cells that initiate adaptive immune responses.
- Dendritic cells play a role in linking innate and adaptive immunity but are not the primary inflammatory cell type in the immediate acute response.
*Dark histamine containing granules*
- This description applies to **mast cells** and **basophils**, which release histamine and other mediators in allergic reactions and acute inflammation.
- While mast cells are involved in the immediate response by releasing mediators, **neutrophils** are the main cellular players migrating to the site of injury.
Chronic wounds pathophysiology US Medical PG Question 6: A 45-year-old man comes to his primary care provider for a routine visit. The patient mentions that while he was cooking 5 days ago, he accidentally cut himself with a meat cleaver and lost the skin at the tip of his finger. After applying pressure and ice, the bleeding stopped and he did not seek treatment. The patient is otherwise healthy and does not take any daily medications. The patient’s temperature is 98.2°F (36.8°C), blood pressure is 114/72 mmHg, pulse is 60/min, and respirations are 12/min. On exam, the patient demonstrates a 0.5 x 0.3 cm wound on the tip of his left third finger. No bone is involved, and the wound is red, soft, and painless. There are no signs of infection. Which of the following can be expected on histopathological examination of the wounded area?
- A. Platelet aggregates
- B. Epithelial cell migration from the wound borders
- C. Neutrophil migration into the wound
- D. Deposition of type III collagen (Correct Answer)
- E. Deposition of type I collagen
Chronic wounds pathophysiology Explanation: ***Deposition of type III collagen***
- Five days post-injury, the **proliferative phase of wound healing** is active, characterized by the formation of an initial **granulation tissue** matrix primarily composed of **Type III collagen**.
- This type of collagen forms thinner, more flexible fibers that provide a temporary scaffold for tissue regeneration before being gradually replaced by stronger Type I collagen.
*Platelet aggregates*
- **Platelet aggregation** occurs immediately after injury as part of **hemostasis**, forming a plug to stop bleeding.
- By five days, this initial phase would have concluded, and the primary focus would be on tissue repair and regeneration.
*Epithelial cell migration from the wound borders*
- **Epithelial cell migration** for re-epithelialization typically occurs within the first 24-48 hours after injury, forming a new epidermal layer over the wound.
- While it continues, the dominant histological feature at day 5 in an open wound of this size would be **granulation tissue formation** in the dermis.
*Neutrophil migration into the wound*
- **Neutrophil migration** is a hallmark of the **inflammatory phase**, peaking within 24-48 hours post-injury to clear debris and microbes.
- By day 5, the inflammatory phase would be subsiding, and macrophages would be more prevalent, signaling the transition to the proliferative phase.
*Deposition of type I collagen*
- **Type I collagen** is the predominant collagen found in mature scar tissue and is deposited during the later **remodeling phase** of wound healing.
- While some Type I collagen may be present, **Type III collagen** is characteristic of the early granulation tissue prominent at day 5.
Chronic wounds pathophysiology US Medical PG Question 7: A 63-year-old man presents to the clinic complaining of burning bilateral leg pain which has been increasing gradually over the past several months. It worsens when he walks but improves with rest. His past medical and surgical history are significant for hypertension, hyperlipidemia, diabetes, and a 40-pack-year smoking history. His temperature is 99.0°F (37.2°C), blood pressure is 167/108 mm Hg, pulse is 88/min, respirations are 13/min, and oxygen saturation is 95% on room air. Physical exam of the lower extremities reveals palpable but weak posterior tibial and dorsalis pedis pulses bilaterally. Which of the following is the best initial treatment for this patient's symptoms?
- A. Exercise and smoking cessation (Correct Answer)
- B. Lovenox and atorvastatin
- C. Lisinopril and atorvastatin
- D. Balloon angioplasty with stenting
- E. Femoral-popliteal bypass
Chronic wounds pathophysiology Explanation: ***Exercise and smoking cessation***
- This patient presents with symptoms highly suggestive of **peripheral artery disease (PAD)**, characterized by **intermittent claudication** (leg pain worsening with activity and improving with rest), and risk factors like diabetes, hypertension, hyperlipidemia, and smoking.
- **Smoking cessation** is the single most important modifiable risk factor, and a supervised **exercise program** (walking to the point of claudication) is the most effective initial treatment to improve walking distance and quality of life for PAD patients.
*Lovenox and atorvastatin*
- **Atorvastatin** is appropriate for dyslipidemia and cardiovascular risk reduction in PAD patients, but **Lovenox (low molecular weight heparin)** is an anticoagulant typically used for acute thrombotic events or VTE prophylaxis, not initial management of chronic stable claudication.
- While statins are important for secondary prevention, Lovenox does not directly address the primary management of claudication symptoms or underlying atherosclerotic progression in this stable setting.
*Lisinopril and atorvastatin*
- **Lisinopril** is an ACE inhibitor suitable for hypertension, which is important for overall cardiovascular health but not the primary initial treatment for claudication symptoms.
- While both medications address risk factors, they do not directly target the improvement of walking function and symptom relief as effectively as exercise and smoking cessation in the initial phase.
*Balloon angioplasty with stenting*
- Invasive revascularization procedures like **balloon angioplasty with stenting** are typically reserved for patients with more severe symptoms (e.g., rest pain, non-healing ulcers, critical limb ischemia) or those who have failed conservative management like exercise therapy.
- This is not the **best initial treatment** for a patient with stable claudication.
*Femoral-popliteal bypass*
- **Femoral-popliteal bypass** is a surgical revascularization procedure indicated for more severe PAD, particularly in cases of critical limb ischemia or long-segment occlusions that are not amenable to endovascular repair.
- Like angioplasty, it is a more aggressive intervention and not the **initial treatment of choice** for intermittent claudication.
Chronic wounds pathophysiology US Medical PG Question 8: A 54-year-old man comes to the physician because of a painful mass in his left thigh for 3 days. He underwent a left lower limb angiography for femoral artery stenosis and had a stent placed 2 weeks ago. He has peripheral artery disease, coronary artery disease, hypercholesterolemia and type 2 diabetes mellitus. He has smoked one pack of cigarettes daily for 34 years. Current medications include enalapril, aspirin, simvastatin, metformin, and sitagliptin. His temperature is 36.7°C (98°F), pulse is 88/min, and blood pressure is 116/72 mm Hg. Examination shows a 3-cm (1.2-in) tender, pulsatile mass in the left groin. The skin over the area of the mass shows no erythema and is cool to the touch. A loud bruit is heard on auscultation over this area. The remainder of the examination shows no abnormalities. Results of a complete blood count and serum electrolyte concentrations show no abnormalities. Duplex ultrasonography shows an echolucent sac connected to the common femoral artery, with pulsatile and turbulent blood flow between the artery and the sac. Which of the following is the most appropriate next best step in management?
- A. Ultrasound-guided thrombin injection (Correct Answer)
- B. Covered stent implantation
- C. Ultrasound-guided compression
- D. Coil embolization
- E. Schedule surgical repair
Chronic wounds pathophysiology Explanation: ***Ultrasound-guided thrombin injection***
- The patient presents with a **post-catheterization pseudoaneurysm** as indicated by the pulsatile, tender mass with a bruit after recent femoral angiography, and confirmed by duplex ultrasonography showing an echolucent sac connected to the common femoral artery with pulsatile flow.
- **Ultrasound-guided thrombin injection** is the preferred treatment for pseudoaneurysms that are larger than 2-3 cm or have been present for more than 1 week, as it effectively closes the pseudoaneurysm sac with a high success rate and minimal invasiveness.
*Covered stent implantation*
- This is a treatment for arterial injury or aneurysm, but it is generally reserved for **larger or more complex pseudoaneurysms**, or those that have failed less invasive treatments, due to its greater invasiveness and potential complications.
- It involves placing a stent graft to exclude the pseudoaneurysm from the circulation.
*Ultrasound-guided compression*
- This technique involves applying sustained pressure to the pseudoaneurysm neck, which can lead to thrombosis. However, it has a **lower success rate** compared to thrombin injection, especially for larger pseudoaneurysms, and is often painful and time-consuming.
- It is often considered a first-line therapy for smaller pseudoaneurysms (<2-3 cm) before thrombin injection, but in this case, the pseudoaneurysm is 3 cm.
*Coil embolization*
- This procedure is typically used to treat **arteriovenous malformations** or high-flow bleeding rather than pseudoaneurysms.
- It involves placing coils into the vessel to induce thrombosis, but carries risks of distal embolization and might be overly aggressive for a femoral pseudoaneurysm.
*Schedule surgical repair*
- **Surgical repair** is indicated for pseudoaneurysms that are rapidly expanding, symptomatic with critical limb ischemia, infected, or those that have failed less invasive treatments.
- In this case, given the patient's stable condition and the availability of less invasive options, surgical repair is not the initial best step.
Chronic wounds pathophysiology US Medical PG Question 9: A 65-year-old man comes to the emergency department because of sudden, worsening pain in his right calf and foot that started 30 minutes ago. He also has a tingling sensation and weakness in his right leg. He has had no similar episodes, recent trauma, or claudication. He has type 2 diabetes mellitus and was diagnosed with hypertension 20 years ago. His sister has systemic sclerosis. He works as an office administrator and sits at his desk most of the day. He has smoked one and a half packs of cigarettes daily for 30 years. Current medications include metformin and lisinopril. His pulse is 110/min, respirations are 16/min, and blood pressure is 140/90 mm Hg. His right leg is pale and cool to touch. Muscle strength in his right leg is mildly reduced. Pedal pulses are absent on the right. Which of the following is the most likely underlying cause of this patient's symptoms?
- A. Popliteal artery aneurysm
- B. Atherosclerotic narrowing of the artery
- C. Arterial vasospasm
- D. Atheroembolism
- E. Arterial embolism (Correct Answer)
Chronic wounds pathophysiology Explanation: ***Arterial embolism***
- The sudden onset of severe unilateral limb pain, pallor, coolness, and absent pulses in a patient with risk factors for **atherosclerosis** and possible **arrhythmias** (given the history of hypertension and diabetes) strongly suggests acute limb ischemia due to an arterial embolism.
- The patient's presentation aligns with the "6 P's" of acute limb ischemia: **pain, pallor, pulselessness, paresthesias, poikilothermia (coolness), and paralysis** (weakness).
*Popliteal artery aneurysm*
- While a popliteal artery aneurysm can cause acute limb ischemia due to thrombosis or embolism within the aneurysm, it is more commonly associated with chronic limb ischemia or rupture, and a **palpable pulsatile mass** is typically present, which is not mentioned.
- The suddenness and severity of symptoms are more indicative of an embolic event rather than a thrombotic event within an aneurysm, which often presents less acutely.
*Atherosclerotic narrowing of the artery*
- **Atherosclerotic narrowing** typically causes chronic limb ischemia with symptoms like **claudication**, which is pain that worsens with exercise and improves with rest. The patient explicitly denies claudication.
- Acute worsening of atherosclerotic narrowing, often due to **plaque rupture and thrombosis**, would usually affect a limb with pre-existing claudication, and the onset might be less abrupt than described.
*Arterial vasospasm*
- **Arterial vasospasm** (e.g., Raynaud's phenomenon) primarily affects the small arteries and arterioles, typically in the digits, and is often triggered by cold or stress.
- It would not typically cause acute, severe, and widespread limb ischemia with absent pedal pulses in a large artery, and the patient's symptoms are not consistent with known vasospastic disorders affecting large vessels.
*Atheroembolism*
- **Atheroembolism** (e.g., "blue toe syndrome") typically involves multiple, small cholesterol emboli showering downstream, causing patchy ischemia, livedo reticularis, and renal or gastrointestinal involvement.
- While the patient has significant atherosclerotic risk factors, the sudden, complete obliteration of flow to the entire right leg, indicated by absent pedal pulses and diffuse symptoms, points more towards a **single, larger embolic occlusion** rather than diffuse microemboli.
Chronic wounds pathophysiology US Medical PG Question 10: A 45-year-old woman comes to the physician because of right foot pain for 3 months. She has a burning sensation in the plantar area between the third and fourth metatarsals that radiates to the third and fourth digits. She had a right distal radius fracture that was treated with a splint and physical therapy three months ago. She is an account executive and wears high heels to work every day. Vital signs are within normal limits. Examination of the right lower extremity shows intact skin. The posterior tibial and dorsalis pedis pulses are palpable. When pressure is applied to the sole of the foot between the metatarsal heads the patient feels pain and there is an audible click. Tapping on the affected area causes pain that shoots into the third and fourth digits. Which of the following is the most likely diagnosis?
- A. Ganglion cyst
- B. Metatarsal osteochondrosis
- C. Intermetatarsal neuroma (Correct Answer)
- D. Osteomyelitis
- E. Third metatarsal stress fracture
Chronic wounds pathophysiology Explanation: ***Intermetatarsal neuroma***
- The patient's presentation of a **burning sensation** between the third and fourth metatarsals, radiating to the digits, along with the reproduction of pain and an **audible click** (Mulder's sign) on palpation, are classic signs of an intermetatarsal neuroma, commonly known as **Morton's neuroma**.
- **Tinel's sign** (pain with tapping) in the affected area confirms nerve involvement, and wearing high heels is a common predisposing factor.
*Ganglion cyst*
- While ganglion cysts can cause pain, they typically present as a **palpable, mobile mass** and do not characteristically cause a burning sensation that radiates to the digits, or an audible click.
- The symptoms described are more consistent with **nerve compression** rather than a space-occupying lesion alone.
*Metatarsal osteochondrosis*
- This condition, such as **Freiberg's disease**, typically affects the **metatarsal head**, most commonly the second metatarsal, and presents with pain and swelling exacerbated by activity.
- It does not usually involve a radiating **burning sensation** or the characteristic click observed in this patient.
*Osteomyelitis*
- Osteomyelitis is a bone infection characterized by **severe, constant pain**, fever, redness, and swelling, often with elevated **inflammatory markers** (ESR, CRP).
- The patient's skin is intact, vital signs are normal, and there are no signs of infection, making this diagnosis unlikely.
*Third metatarsal stress fracture*
- A stress fracture typically causes ** localized pain** in the bone, which worsens with weight-bearing or activity and improves with rest.
- It would not typically involve a **burning sensation** radiating into the toes or an audible click, which are indicative of nerve pathology.
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