Thromboembolectomy procedures US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for Thromboembolectomy procedures. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Thromboembolectomy procedures US Medical PG Question 1: A 20-year-old woman is brought to the emergency department because of severe muscle soreness, nausea, and darkened urine for 2 days. The patient is on the college track team and has been training intensively for an upcoming event. One month ago, she had a urinary tract infection and was treated with nitrofurantoin. She appears healthy. Her temperature is 37°C (98.6°F), pulse is 64/min, and blood pressure is 110/70 mm Hg. Cardiopulmonary examination shows no abnormalities. The abdomen is soft and non-tender. There is diffuse muscle tenderness over the arms, legs, and back. Laboratory studies show:
Hemoglobin 12.8 g/dL
Leukocyte count 7,000/mm3
Platelet count 265,000/mm3
Serum
Creatine kinase 22,000 U/L
Lactate dehydrogenase 380 U/L
Urine
Blood 3+
Protein 1+
RBC negative
WBC 1–2/hpf
This patient is at increased risk for which of the following complications?
- A. Myocarditis
- B. Metabolic alkalosis
- C. Compartment syndrome
- D. Acute kidney injury (Correct Answer)
- E. Hemolytic anemia
Thromboembolectomy procedures Explanation: ***Acute kidney injury***
- The patient's elevated **creatine kinase (CK)** of 22,000 U/L, muscle soreness, and dark urine (positive for blood but negative for red blood cells) are all indicative of **rhabdomyolysis**.
- **Rhabdomyolysis** releases large amounts of myoglobin, which is nephrotoxic and can precipitate in the renal tubules, leading to **acute tubular necrosis** and subsequent acute kidney injury.
*Myocarditis*
- While CK elevations can be seen in myocarditis, this patient's presentation is dominated by **skeletal muscle symptoms** and a history of intense exercise.
- There are no specific cardiac symptoms or signs (e.g., chest pain, arrhythmias) to suggest myocardial involvement.
*Metabolic alkalosis*
- Rhabdomyolysis typically causes **metabolic acidosis** due to the release of cellular contents, including phosphate and sulfate.
- There is no clinical or lab evidence (e.g., vomiting, diuretic use) to suggest metabolic alkalosis.
*Compartment syndrome*
- **Compartment syndrome** involves increased pressure within a muscle compartment, leading to pain, pallor, paresthesia, pulselessness, and paralysis.
- While rhabdomyolysis can occasionally lead to severe swelling that causes compartment syndrome, the diffuse muscle tenderness and absence of focal limb findings make it less likely as the primary direct complication.
*Hemolytic anemia*
- Though the urine is positive for blood and negative for RBCs, this is characteristic of **myoglobinuria**, not hemoglobinuria, which would indicate hemolytic anemia.
- The patient's **hemoglobin** is normal (12.8 g/dL), and there are no other signs of hemolysis (e.g., jaundice, reticulocytosis).
Thromboembolectomy procedures US Medical PG Question 2: A 32-year-old man is brought to the emergency department after a car accident; he was extricated after 4 hours. He did not lose consciousness and does not have headache or nausea. He is in severe pain. He sustained severe injuries to both arms and the trauma team determines that surgical intervention is needed. Urinary catheterization shows dark colored urine. His temperature is 38°C (100.4°F), pulse is 110/min, and blood pressure is 90/60 mm Hg. The patient is alert and oriented. Examination shows multiple injuries to the upper extremities, contusions on the trunk, and abdominal tenderness. Laboratory studies show:
Hemoglobin 9.2 g/dL
Leukocyte count 10,900/mm3
Platelet count 310,000/mm3
Serum
Na+ 137 mEq/L
K+ 6.8 mEq/L
Cl- 97 mEq/L
Glucose 168 mg/dL
Creatinine 1.7 mg/dL
Calcium 7.7 mg/dL
Arterial blood gas analysis on room air shows a pH of 7.30 and a serum bicarbonate of 14 mEq/L. An ECG shows peaked T waves. A FAST scan of the abdomen is negative. Two large bore cannulas are inserted and intravenous fluids are administered. Which of the following is the most appropriate next step in management?
- A. Intravenous mannitol
- B. Intravenous sodium bicarbonate
- C. Packed red blood cell transfusion
- D. Intravenous calcium gluconate (Correct Answer)
- E. Intravenous insulin
Thromboembolectomy procedures Explanation: ***Intravenous calcium gluconate***
- The patient presents with severe **hyperkalemia** (K+ 6.8 mEq/L) and ECG changes (peaked T waves), indicating immediate cardiotoxicity risk. **Calcium gluconate** stabilizes the cardiac cell membranes, protecting the heart from the effects of high potassium.
- While other options address other issues, stabilizing the heart takes precedence in cases of extreme hyperkalemia with ECG changes.
*Intravenous mannitol*
- **Mannitol** is an osmotic diuretic used to reduce intracranial pressure or acute cerebral edema. The patient does not show signs or symptoms requiring this intervention (no consciousness loss, headache, or nausea).
- Its use here would not address the life-threatening hyperkalemia or cardiologic findings.
*Intravenous sodium bicarbonate*
- **Sodium bicarbonate** can help shift potassium intracellularly and correct metabolic acidosis, but its effect is slower and less reliable than calcium for immediate cardiac stabilization in severe hyperkalemia.
- The primary concern here is the acute cardiac risk, which calcium directly addresses.
*Packed red blood cell transfusion*
- The patient has a hemoglobin of 9.2 g/dL, indicating **anemia**, likely due to trauma. However, his blood pressure is 90/60 mm Hg despite intravenous fluids, suggesting ongoing hypovolemia or other shock.
- While addressing blood loss is important, the immediate life threat is the **cardiac instability due to hyperkalemia**, which must be managed first.
*Intravenous insulin*
- Insulin, often given with dextrose, helps shift potassium into cells. This is an effective treatment for hyperkalemia but does not provide immediate **cardiac membrane stabilization** like calcium gluconate.
- Given the peaked T waves, protecting the heart from arrhythmias is the most critical first step.
Thromboembolectomy procedures US Medical PG Question 3: Five days after undergoing a pancreaticoduodenectomy for pancreatic cancer, a 46-year-old woman has 2 episodes of non-bilious vomiting and mild epigastric pain. She has a patient-controlled analgesia pump. She has a history of hypertension. She has smoked one pack of cigarettes daily for 25 years. She drinks 3–4 beers daily. Prior to admission to the hospital, her only medications were amlodipine and hydrochlorothiazide. Her temperature is 37.8°C (100°F), pulse is 98/min, and blood pressure is 116/82 mm Hg. Pulse oximetry on room air shows an oxygen saturation of 96%. Examination shows a midline surgical incision over the abdomen with minimal serous discharge and no erythema. The abdomen is soft with mild tenderness to palpation in the epigastrium. The remainder of the examination shows no abnormalities. Laboratory studies show:
Hemoglobin 11.6 g/dL
Leukocyte count 16,000/mm3
Serum
Na+ 133 mEq/L
K+ 3.4 mEq/L
Cl- 115 mEq/L
Glucose 77 mg/dL
Creatinine 1.2 mg/dL
Arterial blood gas on room air shows:
pH 7.20
pCO2 23 mm Hg
pO2 91 mm Hg
HCO3- 10 mEq/L
Which of the following is the most likely cause of this patient's acid-base status?
- A. Excessive alcohol intake
- B. Adrenal insufficiency
- C. Rhabdomyolysis
- D. Adverse effect of medication
- E. Fistula (Correct Answer)
Thromboembolectomy procedures Explanation: ***Fistula***
- The patient's **metabolic acidosis** (pH 7.20, HCO3- 10 mEq/L) with normal anion gap (Na+ - (Cl- + HCO3-) = 133 - (115 + 10) = 8 mEq/L) suggests **bicarbonate loss**.
- A pancreaticoduodenectomy (Whipple procedure) involves multiple anastomoses, making **fistula formation** (e.g., pancreatic, biliary, or enteric) a significant complication that can lead to large volume losses of electrolyte-rich fluids, including bicarbonate.
*Excessive alcohol intake*
- While chronic alcohol intake can cause various metabolic derangements, an acute episode of acidosis due to alcohol typically presents as **alcoholic ketoacidosis** (high anion gap) or lactic acidosis.
- The patient's presentation of a normal anion gap metabolic acidosis does not align with the typical acid-base disturbances directly caused by acute alcohol intoxication or withdrawal.
*Adrenal insufficiency*
- Adrenal insufficiency can cause **hyponatremia**, hyperkalemia, and sometimes **non-anion gap metabolic acidosis** due to impaired aldosterone function leading to decreased H+ secretion and bicarbonate reabsorption.
- However, the patient's **potassium (3.4 mEq/L)** is within the normal range to slightly low, and the clinical picture following recent major surgery points more directly to surgical complications.
*Rhabdomyolysis*
- Rhabdomyolysis typically causes a **high anion gap metabolic acidosis** due to the release of phosphorous and other organic acids from damaged muscle cells, as well as potential acute kidney injury.
- This patient has a **normal anion gap acidosis**, and there are no clinical signs (e.g., muscle pain, elevated creatine kinase) pointing towards rhabdomyolysis.
*Adverse effect of medication*
- The patient's medications, amlodipine and hydrochlorothiazide, are not typically associated with a severe normal anion gap metabolic acidosis in this context.
- While **thiazide diuretics** can rarely cause mild metabolic alkalosis due to volume contraction, they would not cause this degree of acidosis, especially with a normal anion gap, and are not known to directly cause bicarbonate loss associated with a fistula.
Thromboembolectomy procedures US Medical PG Question 4: A 54-year-old man is brought to the emergency department 1 hour after the sudden onset of shortness of breath, severe chest pain, and sweating. He has hypertension and type 2 diabetes mellitus. He has smoked one pack and a half of cigarettes daily for 20 years. An ECG shows ST-segment elevations in leads II, III, and avF. The next hospital with a cardiac catheterization unit is more than 2 hours away. Reperfusion pharmacotherapy is initiated. Which of the following is the primary mechanism of action of this medication?
- A. Conversion of plasminogen to plasmin (Correct Answer)
- B. Inhibition of glutamic acid residue carboxylation
- C. Blocking of adenosine diphosphate receptors
- D. Direct inhibition of thrombin activity
- E. Prevention of thromboxane formation
Thromboembolectomy procedures Explanation: ***Conversion of plasminogen to plasmin***
- **Fibrinolytic** (thrombolytic) drugs, like **tissue plasminogen activator (tPA)**, work by converting plasminogen to plasmin, which then degrades the **fibrin mesh** of a **blood clot**.
- This action helps to **restore blood flow** in cases of ST-segment elevation myocardial infarction (STEMI) where primary **percutaneous coronary intervention (PCI)** is not immediately available.
*Inhibition of glutamic acid residue carboxylation*
- This is the mechanism of action of **warfarin**, an anticoagulant that inhibits the synthesis of **vitamin K-dependent clotting factors** (II, VII, IX, X, protein C, and protein S).
- While important for long-term anticoagulation, it does not provide immediate reperfusion in an acute STEMI.
*Blocking of adenosine diphosphate receptors*
- This describes the mechanism of action of **P2Y12 inhibitors** such as **clopidogrel**, **prasugrel**, and **ticagrelor**.
- These drugs are **antiplatelet agents** that prevent platelet aggregation, but they do not directly dissolve an existing thrombus to restore blood flow in STEMI.
*Direct inhibition of thrombin activity*
- This is the mechanism of action of **direct thrombin inhibitors** like **dabigatran** and **bivalirudin**.
- These drugs primarily prevent clot formation or extension and are not used as primary reperfusion agents for acute STEMI due to an existing occlusive thrombus.
*Prevention of thromboxane formation*
- This is the primary mechanism of action of **aspirin**, which irreversibly inhibits **cyclooxygenase-1 (COX-1)**, thereby reducing the production of thromboxane A2.
- Aspirin is an important antiplatelet drug in STEMI management but does not provide reperfusion by dissolving the clot.
Thromboembolectomy procedures US Medical PG Question 5: A patient in a phase 1 trial for a novel epoxide reductase inhibitor, being studied for stroke prophylaxis, develops pain and erythema on the right thigh two days after starting the trial. This rapidly progresses to a purpuric rash with necrotic bullae within 24 hours. Lab results show a PTT of 29 seconds, PT of 28 seconds, and INR of 2.15. What is the most likely pathogenesis of this condition?
- A. Decreased plasmin activity
- B. Decreased platelet count
- C. Decreased protein C levels (Correct Answer)
- D. Increased factor VIII activity
- E. Decreased antithrombin III activity
Thromboembolectomy procedures Explanation: ***Decreased protein C levels***
- The clinical presentation of **pain and erythema progressing to purpuric rash with necrotic bullae** within 2-3 days of starting therapy, along with elevated PT/INR, is **pathognomonic for warfarin-induced skin necrosis**.
- This novel **epoxide reductase inhibitor** works like warfarin by inhibiting **vitamin K epoxide reductase**, which depletes all vitamin K-dependent factors.
- **Protein C and protein S** (natural anticoagulants) have **short half-lives** (6-8 hours) and drop rapidly, while procoagulant factors II, VII, IX, and X have longer half-lives (24-60 hours).
- This creates a **transient hypercoagulable state** in the first 2-3 days of therapy with **low protein C/S** but relatively preserved procoagulant factors, leading to **microvascular thrombosis** and skin necrosis.
- Most common in patients with **hereditary protein C or S deficiency** or those receiving loading doses.
*Decreased antithrombin III activity*
- Antithrombin III is **not a vitamin K-dependent factor** and is not directly affected by epoxide reductase inhibitors.
- Decreased antithrombin III would cause thrombosis but does not explain the **specific temporal relationship** and mechanism of warfarin-induced skin necrosis.
- Antithrombin III deficiency causes **venous thromboembolism**, not the characteristic cutaneous necrosis pattern.
*Decreased plasmin activity*
- Plasmin is involved in **fibrinolysis** and is not affected by vitamin K epoxide reductase inhibitors.
- Decreased plasmin activity would impair clot breakdown but does not explain the **early hypercoagulable state** specific to warfarin initiation.
- This mechanism is not relevant to warfarin-induced skin necrosis.
*Decreased platelet count*
- The lab values provided show **elevated PT/INR**, consistent with coagulation factor depletion, not thrombocytopenia.
- Thrombocytopenia causes **petechiae and mucosal bleeding**, not the large **necrotic bullae** seen here.
- Platelet count is not affected by epoxide reductase inhibitors.
*Increased factor VIII activity*
- Factor VIII is **not a vitamin K-dependent factor** and is not depleted by epoxide reductase inhibitors.
- While elevated factor VIII can contribute to hypercoagulability, it does not explain the **specific mechanism and timeline** of warfarin-induced skin necrosis.
- This is not the primary pathogenesis of this condition.
Thromboembolectomy procedures US Medical PG Question 6: Four days after undergoing a craniotomy and evacuation of a subdural hematoma, a 56-year-old man has severe pain and swelling of his right leg. He has chills and nausea. He has type 2 diabetes mellitus and chronic kidney disease, and was started on hemodialysis 2 years ago. Prior to admission, his medications were insulin, enalapril, atorvastatin, and sevelamer. His temperature is 38.3°C (101°F), pulse is 110/min, and blood pressure is 130/80 mm Hg. Examination shows a swollen, warm, and erythematous right calf. Dorsiflexion of the right foot causes severe pain in the right calf. The peripheral pulses are palpated bilaterally. Cardiopulmonary examination shows no abnormalities. Laboratory studies show:
Hemoglobin 10.1 g/dL
Leukocyte count 11,800/mm3
Platelet count 230,000/mm3
Serum
Glucose 87 mg/dL
Creatinine 1.9 mg/dL
Which of the following is the most appropriate next step in treatment?
- A. Urokinase therapy
- B. Iliac stenting
- C. Warfarin therapy
- D. Unfractionated heparin therapy (Correct Answer)
- E. Inferior vena cava filter
Thromboembolectomy procedures Explanation: ***Unfractionated heparin therapy***
- The patient presents with classic symptoms of **deep vein thrombosis (DVT)**, including unilateral leg pain, swelling, warmth, erythema, and a positive Homan's sign (pain on dorsiflexion). The recent craniotomy places him at high risk for DVT.
- **Unfractionated heparin is the anticoagulant of choice** for this patient due to TWO critical factors:
1. **Recent craniotomy (4 days ago)**: Requires a rapidly reversible anticoagulant in case of intracranial bleeding; UFH can be reversed with protamine sulfate
2. **Chronic kidney disease on hemodialysis**: Low molecular weight heparin (LMWH) is contraindicated in severe renal failure (CrCl <30 mL/min) as it is renally eliminated and increases bleeding risk. UFH is not renally cleared and can be monitored with aPTT.
*Urokinase therapy*
- **Urokinase is a thrombolytic agent** used to dissolve existing clots, primarily in cases of massive pulmonary embolism or severe DVT with limb-threatening ischemia (phlegmasia cerulea dolens).
- Given the patient's **recent craniotomy and subdural hematoma evacuation**, thrombolytic therapy is **absolutely contraindicated** due to very high risk of intracranial hemorrhage. Recent neurosurgery is a contraindication for at least 2-4 weeks.
*Iliac stenting*
- **Iliac vein stenting** is a procedure typically used to treat chronic **iliac vein compression** (e.g., May-Thurner syndrome) or chronic post-thrombotic obstruction.
- This is an **acute DVT presentation** (4 days post-op) with no indication of chronic iliac vein compression or obstruction. Stenting has no role in acute DVT management.
*Warfarin therapy*
- **Warfarin is an oral anticoagulant** used for long-term DVT treatment but has a **delayed onset of action** (requires 5-7 days to reach therapeutic INR).
- It is **not suitable for acute initial treatment** of DVT, especially in a patient requiring rapid anticoagulation. Warfarin must be overlapped with parenteral anticoagulation (heparin) initially.
- Additionally, warfarin dosing is complex in dialysis patients due to altered vitamin K metabolism.
*Inferior vena cava filter*
- An **IVC filter** is indicated for patients with DVT who have an **absolute contraindication to anticoagulation** (e.g., active bleeding, recent hemorrhagic stroke) or who develop recurrent thromboembolism despite adequate anticoagulation.
- This patient **does not have a contraindication to anticoagulation**. While he had recent neurosurgery, unfractionated heparin is safe to use with careful monitoring and is rapidly reversible if needed.
- IVC filters have significant complications (thrombosis, filter migration, IVC perforation) and should be avoided when anticoagulation is feasible.
Thromboembolectomy procedures US Medical PG Question 7: A 62-year-old man presents to the emergency department with sudden onset of severe left leg pain accompanied by numbness and weakness. His medical history is remarkable for hypertension and hyperlipidemia. His vital signs include a blood pressure of 155/92 mm Hg, a temperature of 37.1°C (98.7°F), and an irregular pulse of 92/min. Physical examination reveals absent left popliteal and posterior tibial pulses. His left leg is noticeably cold and pale. There is no significant tissue compromise, nerve damage, or sensory loss. Which of the following will most likely be required for this patient's condition?
- A. Antibiotics
- B. Warfarin
- C. Fasciotomy
- D. Amputation
- E. Thromboembolectomy (Correct Answer)
Thromboembolectomy procedures Explanation: ***Thromboembolectomy***
- The sudden onset of severe leg pain, numbness, and weakness with absent pulses, a cold, pale limb, and an irregular pulse suggests **acute limb ischemia** likely due to an **arterial embolus**, which requires emergent surgical removal.
- Given the symptoms and history of an irregular pulse (suggesting possible atrial fibrillation), a thromboembolectomy is the most appropriate first-line treatment to restore blood flow and prevent permanent damage.
*Antibiotics*
- Antibiotics are used to treat **bacterial infections** and are not indicated for acute limb ischemia caused by a vascular occlusion.
- There are no signs of infection present, such as fever, redness, or purulent discharge, that would warrant antibiotic therapy.
*Warfarin*
- Warfarin is an **anticoagulant** used for long-term prevention of clot formation, particularly in conditions like atrial fibrillation or deep vein thrombosis.
- While anticoagulation may eventually be part of management to prevent future events, it is insufficient as immediate therapy for an acute, established arterial embolus causing critical limb ischemia.
*Fasciotomy*
- Fasciotomy is performed to relieve **compartment syndrome**, which occurs when increased pressure within a muscle compartment compromises circulation and nerve function.
- While compartment syndrome can be a complication of reperfusion after prolonged ischemia, it is not the primary treatment for the initial arterial occlusion; the first step is to restore blood flow to prevent the need for it.
*Amputation*
- Amputation is a last resort considered when the limb is **irreversibly ischemic** and non-viable, or when revascularization attempts have failed and there is extensive tissue necrosis or infection.
- In this case, there is no significant tissue compromise or nerve damage mentioned, indicating that the limb is still salvageable with timely intervention.
Thromboembolectomy procedures US Medical PG Question 8: A 31-year-old man presents to the Emergency Department with severe left leg pain and paresthesias 4 hours after his leg got trapped by the closing door of a bus. Initially, he had a mild pain which gradually increased to unbearable levels. Past medical history is noncontributory. In the Emergency Department, his blood pressure is 130/80 mm Hg, heart rate is 87/min, respiratory rate is 14/min, and temperature is 36.8℃ (98.2℉). On physical exam, his left calf is firm and severely tender on palpation. The patient cannot actively dorsiflex his left foot, and passive dorsiflexion is limited. Posterior tibial and dorsalis pedis pulses are 2+ in the right leg and 1+ in the left leg. Axial load does not increase the pain. Which of the following is the best next step in the management of this patient?
- A. Lower limb CT scan
- B. Lower limb ultrasound
- C. Splinting and limb rest
- D. Fasciotomy (Correct Answer)
- E. Lower limb X-ray in two projections
Thromboembolectomy procedures Explanation: ***Fasciotomy***
- The patient presents with classic signs and symptoms of **acute compartment syndrome**, including unrelieved pain by analgesics, paresthesias, pain with passive stretching, and a tense compartment due to the bus door trauma.
- **Fasciotomy** is the definitive and urgent treatment to relieve pressure within the muscle compartments, prevent muscle ischemia, and avoid permanent nerve damage or limb loss.
*Lower limb CT scan*
- A **CT scan** is primarily used to evaluate bony structures and soft tissue injuries but is not the most immediate or definitive diagnostic tool for acute compartment syndrome.
- Delaying **fasciotomy** for imaging in a clear case of compartment syndrome can lead to irreversible damage.
*Lower limb ultrasound*
- **Ultrasound** can assess vascular flow and some soft tissue aspects but is not accurate or rapid enough for diagnosing compartment syndrome.
- It would not provide the necessary information to guide urgent surgical intervention.
*Splinting and limb rest*
- This approach is appropriate for fractures or soft tissue injuries without compartment syndrome; however, in acute compartment syndrome, **splinting or limb rest** will worsen the condition.
- **Immobilization** and elevation are contraindicated as they can further decrease blood flow and increase compartment pressure.
*Lower limb X-ray in two projections*
- An **X-ray** is useful for ruling out fractures but will not provide information about compartment pressure or muscle viability.
- While a fracture can sometimes cause compartment syndrome, the immediate concern here is the compartment syndrome itself, for which **X-rays** are not diagnostic.
Thromboembolectomy procedures 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)
Thromboembolectomy procedures 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.
Thromboembolectomy procedures US Medical PG Question 10: A 36-year-old man comes to the emergency department 4 hours after a bike accident for severe pain and swelling in his right leg. He has not had a headache, nausea, vomiting, abdominal pain, or blood in his urine. He has a history of gastroesophageal reflux disease and allergic rhinitis. He has smoked one pack of cigarettes daily for 17 years and drinks an average of one alcoholic beverage daily. His medications include levocetirizine and pantoprazole. He is in moderate distress. His temperature is 37°C (98.6°F), pulse is 112/min, and blood pressure is 140/80 mm Hg. Examination shows multiple bruises over both lower extremities and the face. There is swelling surrounding a 2 cm laceration 13 cm below the right knee. The lower two-thirds of the tibia is tender to palpation and the skin is pale and cool to the touch. The anterior tibial, posterior tibial, and dorsalis pedis pulses are weak. Capillary refill time of the right big toe is 4 seconds. Dorsiflexion of his right foot causes severe pain in his calf. Cardiopulmonary examination is normal. An x-ray is ordered, which is shown below. Which of the following is the most appropriate next step in management?
- A. Above knee cast
- B. IVC filter placement
- C. Fasciotomy (Correct Answer)
- D. Low molecular weight heparin
- E. Open reduction and internal fixation
Thromboembolectomy procedures Explanation: ***Fasciotomy***
- The patient's symptoms (severe pain, swelling, pain with passive dorsiflexion, weak pulses, pale/cool skin, and prolonged capillary refill) after a traumatic injury are highly suggestive of **acute compartment syndrome**.
- **Fasciotomy** is the definitive treatment for acute compartment syndrome to relieve pressure and prevent irreversible tissue damage.
*Above knee cast*
- While a cast is used for immobilization of fractures, it would worsen **compartment syndrome** by externally compressing an already swollen limb.
- This patient has signs of compartment syndrome which requires urgent surgical decompression, not just immobilization.
*IVC filter placement*
- **IVC filter placement** is indicated for preventing pulmonary embolism in patients with deep vein thrombosis (DVT) who have contraindications to anticoagulation.
- There is no clinical evidence to suggest DVT in this patient, and the primary concern is acute compartment syndrome.
*Low molecular weight heparin*
- **Low molecular weight heparin (LMWH)** is an anticoagulant used for DVT prophylaxis or treatment.
- It is not indicated for the immediate management of acute compartment syndrome and could increase the risk of bleeding in a patient who likely needs urgent surgery.
*Open reduction and internal fixation*
- **Open reduction and internal fixation (ORIF)** is a surgical procedure to stabilize complex fractures, which may be needed later for a tibial fracture if present.
- However, the immediate priority is to address the limb-threatening acute compartment syndrome before performing definitive fracture repair.
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