A 26-year-old man is brought to casualty after a fall from a coconut tree. He cannot move his arms or legs. BP is 78/40 mmHg, pulse 52/min, and his skin is warm and dry. FAST shows no free fluid, the chest X-ray is clear and the pelvis is stable. After 1 litre of crystalloid, his BP is 84/46 mmHg. What is the most appropriate next step?

Start a vasopressor infusion such as noradrenaline

Transfuse four units of packed red cells at once

Perform emergency laparotomy for occult bleeding

A 66-year-old man was resuscitated after a prolonged cardiac arrest with long hypotension. After recovery, he has weakness of both shoulders and upper arms with sparing of the face and hands. MRI shows bands of infarction at the border between the anterior and middle cerebral artery territories. What type of infarct is this?

Watershed (border-zone) infarct

A 58-year-old man collapses and dies on the fifth day after a total knee replacement. At autopsy a large coiled embolus sits astride the bifurcation of the pulmonary trunk. What was the immediate mechanism of his death?

Acute right ventricular failure

Haemorrhagic infarction of both lungs

Left ventricular rupture from ischaemia

Bronchospasm from platelet mediators

Haemodynamics: thrombosis, embolism, infarction and shock

20 NEET-PG practice questions on Haemodynamics: thrombosis, embolism, infarction and shock, part of Pathology. The first 20 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

Question 1 · Easy
At autopsy of a 70-year-old man who died of a ruptured abdominal aortic aneurysm, the aneurysm sac contains a firm, grey-red thrombus attached to the wall. Its cut surface shows alternating pale and dark layers. What are these layers called?
1. ALines of Zahn
2. BChicken fat clot
3. CHeart failure cells
4. DMallory-Denk bodies
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Answer: A · Lines of Zahn
Lines of Zahn are alternating pale layers of platelets and fibrin and darker layers of red cells. They form only in thrombi that develop in flowing blood, so they show that the thrombus formed before death. Post-mortem clots, in contrast, are not attached to the wall and have a gelatinous, dark red dependent part with a yellow chicken fat upper part. Mural thrombi in aneurysms and in the heart can embolise.
- B: Chicken fat clot describes a post-mortem clot, which lacks lamination.
- C: Heart failure cells are haemosiderin-laden macrophages in congested lungs.
- D: Mallory-Denk bodies are keratin inclusions in injured hepatocytes.
Question 2 · Hard
A 42-year-old man with a mechanical mitral valve is admitted with a new DVT and started on warfarin 10 mg daily without heparin cover, because the ward ran out of LMWH. On day 4 painful purple patches appear on his thighs and abdomen and turn into black necrotic areas. His sister had a similar reaction after starting warfarin. Which inherited defect is most likely?
1. AProtein C deficiency
2. BFactor V Leiden mutation
3. CFactor XII deficiency
4. DAntithrombin deficiency
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Answer: A · Protein C deficiency
Warfarin-induced skin necrosis occurs in the first days of treatment, mostly in fatty areas such as the thighs, breasts and abdomen. Warfarin lowers all vitamin K-dependent proteins, but protein C has a much shorter half-life than factors IX, X and II, so its level falls first and creates a temporary prothrombotic state, which is much worse in people with inherited protein C deficiency. Microvascular thrombi in the skin then cause necrosis. Warfarin should be started under heparin cover, and the defect can be confirmed by testing protein C when the patient is off warfarin.
- B: Factor V Leiden is a thrombophilia but is not the classic cause of warfarin necrosis.
- C: Factor XII deficiency prolongs aPTT but does not cause thrombosis or skin necrosis.
- D: Antithrombin deficiency causes heparin resistance, not warfarin skin necrosis.
Question 3 · Hard
A 26-year-old man is brought to casualty after a fall from a coconut tree. He cannot move his arms or legs. BP is 78/40 mmHg, pulse 52/min, and his skin is warm and dry. FAST shows no free fluid, the chest X-ray is clear and the pelvis is stable. After 1 litre of crystalloid, his BP is 84/46 mmHg. What is the most appropriate next step?
1. ATransfuse four units of packed red cells at once
2. BInsert bilateral chest drains
3. CPerform emergency laparotomy for occult bleeding
4. DStart a vasopressor infusion such as noradrenaline
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Answer: D · Start a vasopressor infusion such as noradrenaline
Hypotension with bradycardia and warm, dry skin after a high spinal cord injury, with no source of bleeding, is neurogenic shock. Loss of sympathetic outflow below the injury causes vasodilation and unopposed vagal slowing of the heart, unlike haemorrhagic shock, which causes tachycardia and cold skin. After cautious fluid resuscitation, a vasopressor is used to restore pressure, with atropine for symptomatic bradycardia, and spinal immobilisation is maintained. Haemorrhage must still be excluded, as it was here, before attributing hypotension to the spinal injury.
- A: Blood is for haemorrhage, which has been excluded here.
- B: Chest drains treat pneumothorax or haemothorax; the chest X-ray is clear.
- C: Laparotomy is not indicated with a negative FAST and no signs of bleeding.
Question 4 · Medium
A 66-year-old man was resuscitated after a prolonged cardiac arrest with long hypotension. After recovery, he has weakness of both shoulders and upper arms with sparing of the face and hands. MRI shows bands of infarction at the border between the anterior and middle cerebral artery territories. What type of infarct is this?
1. AEmbolic cortical infarct
2. BHaemorrhagic venous infarct
3. CLacunar infarct
4. DWatershed (border-zone) infarct
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Answer: D · Watershed (border-zone) infarct
Global hypoperfusion damages the areas at the distal ends of two arterial territories first, because they receive the lowest perfusion pressure: the watershed or border-zone regions. The ACA-MCA border zone over the convexity produces proximal arm weakness (the man in a barrel pattern). The same principle explains ischaemia at the splenic flexure of the colon, between the superior and inferior mesenteric territories. Maintaining blood pressure after resuscitation helps prevent such injury.
- A: Embolic infarcts are in one arterial territory, not along border zones.
- B: Venous infarcts follow venous sinus thrombosis and are haemorrhagic.
- C: Lacunar infarcts are small deep infarcts from small-vessel disease in hypertension.
Question 5 · Medium
A 58-year-old man collapses and dies on the fifth day after a total knee replacement. At autopsy a large coiled embolus sits astride the bifurcation of the pulmonary trunk. What was the immediate mechanism of his death?
1. AHaemorrhagic infarction of both lungs
2. BAcute right ventricular failure
3. CLeft ventricular rupture from ischaemia
4. DBronchospasm from platelet mediators
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Answer: B · Acute right ventricular failure
A saddle embolus obstructs most of the pulmonary circulation suddenly. The right ventricle cannot pump against the sudden rise in resistance, so it dilates and fails (acute cor pulmonale), left ventricular filling and cardiac output collapse, and the patient dies of cardiovascular collapse or arrhythmia. There is no time for infarction to develop. Most pulmonary emboli come from deep veins of the leg at or above the knee, so thromboprophylaxis after joint replacement is standard.
- A: Infarction takes hours to develop and does not cause sudden death within minutes.
- C: Ventricular rupture follows myocardial infarction, usually 3-7 days after it.
- D: Bronchospasm can occur but is not the mechanism of sudden death.
Question 6 · Medium
A 36-year-old woman on a long bus journey develops left calf swelling. Two days later she has sudden right-sided weakness and aphasia; MRI shows an acute left middle cerebral artery infarct. Carotid Doppler and ECG are normal. Which investigation is most likely to show how the embolus reached her brain?
1. ABubble contrast echocardiography
2. BSerum lipid profile
3. C24-hour Holter monitoring
4. DCoronary angiography
Answer and explanation in LearnFree account
Question 7 · Medium
A 60-year-old man is in the ICU after a massive myocardial infarction with prolonged shock. A pathology postgraduate notes four statements about the stages of shock: 1. In the non-progressive stage, reflex sympathetic responses maintain perfusion of vital organs. 2. In the progressive stage, anaerobic glycolysis causes lactic acidosis. 3. Acidosis blunts the vasomotor response, so arterioles dilate and blood pools. 4. In the irreversible stage, ischaemic gut mucosa lets bacteria enter the circulation. Which statements are correct?
1. A2 and 4 only
2. B1, 2, 3 and 4
3. C1, 2 and 4 only
4. D1 and 3 only
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Question 8 · Medium
A 34-year-old diver working on a coral survey off Lakshadweep surfaces rapidly from a deep dive. Within an hour he has severe pain in the knees and shoulders, an itchy mottled rash and difficulty breathing. What is the definitive treatment?
1. AEmergency needle thoracocentesis
2. BIntravenous heparin infusion
3. CRecompression in a hyperbaric chamber
4. DThrombolysis with alteplase
Answer and explanation in LearnFree account
Question 9 · Hard
A 68-year-old diabetic man has coronary angiography through the femoral artery. Three weeks later he has mottled, lace-like purple skin on both legs, painful blue toes with good pedal pulses, and creatinine rising from 1.2 to 3.4 mg/dL. Eosinophils are 12% and serum C3 is low. Which finding on renal biopsy would confirm the diagnosis?
1. ASubepithelial immune complex deposits
2. BInterstitial eosinophils with tubulitis
3. CFibrin thrombi in glomerular capillaries
4. DEmpty needle-shaped clefts in arcuate arteries
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Question 10 · Easy
A 72-year-old woman is in bed for ten days after surgery for a fracture of the neck of the femur, without thromboprophylaxis. She develops a swollen, tender left calf, and Doppler shows thrombosis of the popliteal vein. Which component of Virchow's triad did the immobility mainly contribute?
1. ATurbulent arterial flow
2. BStasis of blood flow
3. CEndothelial injury
4. DHypercoagulability
Answer and explanation in LearnFree account
Question 11 · Medium
A 70 kg man is brought to casualty after a road traffic accident with an open fracture of the femur and a pelvic fracture. The surgeon estimates a blood loss of about 1,800 mL. He is anxious and confused, with a weak, rapid pulse, falling blood pressure and reduced urine output. Taking his blood volume as about 70 mL/kg, which ATLS class of haemorrhage is this?
1. AATLS class IV haemorrhage
2. BATLS class II haemorrhage
3. CATLS class III haemorrhage
4. DATLS class I haemorrhage
Answer and explanation in LearnFree account
Question 12 · Hard
A 9-year-old boy with nephrotic syndrome (urine protein 4+, serum albumin 1.6 g/dL) develops flank pain, haematuria and a rising creatinine; Doppler shows renal vein thrombosis. He is started on unfractionated heparin, but repeated aPTT values barely rise despite increasing doses. What explains both the thrombosis and the poor response to heparin?
1. APlatelet activation by heparin antibodies
2. BUrinary loss of protein C inhibitor
3. CIncreased hepatic synthesis of factor VIII
4. DUrinary loss of antithrombin
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Question 13 · Medium
A 29-year-old woman with three first-trimester miscarriages has a DVT of the left leg. aPTT is 52 s (control 30 s) and does not correct on a 1:1 mixing study with normal plasma; platelets are 110,000/µL. Consider four statements about her condition: 1. The prolonged aPTT reflects an in vitro effect, not a bleeding risk. 2. In a future pregnancy, aspirin alone is the recommended treatment. 3. Testing for anticardiolipin and anti-beta-2 glycoprotein I antibodies is indicated. 4. Positive tests should be repeated after at least 12 weeks to confirm persistence. Which statements are correct?
1. A1, 2, 3 and 4
2. B1 and 4 only
3. C1, 3 and 4 only
4. D3 and 4 only
Answer and explanation in LearnFree account
Question 14 · Medium
A 64-year-old man on unfractionated heparin after coronary bypass surgery has a fall in platelets from 2,40,000/µL to 85,000/µL on day 7, and a new right femoral artery thrombosis. What is the most appropriate next step?
1. ASwitch to low-molecular-weight heparin
2. BStop heparin and start warfarin
3. CStop heparin and start argatroban
4. DTransfuse platelets and continue heparin
Answer and explanation in LearnFree account
Question 15 · Easy
A 23-year-old motorcyclist with closed fractures of both femoral shafts becomes breathless and confused 36 hours after admission. He has petechiae over the chest, axillae and conjunctivae, and SpO2 is 86% on room air. What is the most likely diagnosis?
1. ATraumatic haemothorax
2. BPulmonary thromboembolism
3. CAir embolism
4. DFat embolism syndrome
Answer and explanation in LearnFree account
Question 16 · Easy
A 30-year-old man with infective endocarditis of the mitral valve develops sudden left upper quadrant pain. Contrast CT shows a wedge-shaped, non-enhancing area in the spleen with its base on the capsule. What is the expected gross appearance of this lesion after a few days?
1. APale (white) infarct
2. BCaseous granuloma
3. CRed (haemorrhagic) infarct
4. DAbscess with liquefaction
Answer and explanation in LearnFree account
Question 17 · Medium
A 52-year-old man has a confirmed small pulmonary embolus to a segmental artery. He has no heart or lung disease, and the CT does not show infarction of the lung. Why does pulmonary infarction usually not follow such an embolus?
1. AThe bronchial arteries keep supplying the lung tissue
2. BThe embolus is always lysed within minutes
3. CPulmonary veins perfuse the area backwards
4. DLung tissue is resistant to ischaemic injury
Answer and explanation in LearnFree account
Question 18 · Medium
A 24-year-old woman develops a proximal DVT three months after starting a combined oral contraceptive pill. Her mother had a pulmonary embolism at 40. A clotting assay shows that adding activated protein C fails to prolong her aPTT as expected. What is the most likely underlying defect?
1. AProthrombin G20210A variant
2. BHyperhomocysteinaemia
3. CFactor V Leiden mutation
4. DAntithrombin deficiency
Answer and explanation in LearnFree account
Question 19 · Medium
A 32-year-old multigravida in the labour room has just had her membranes ruptured when she suddenly becomes breathless, cyanosed and hypotensive, followed by seizures. Minutes later there is profuse bleeding from puncture sites. She cannot be revived. What would the autopsy most likely show in the pulmonary microcirculation?
1. AFetal squamous cells and lanugo hair
2. BNitrogen gas bubbles in vessels
3. CLarge saddle thromboembolus
4. DFat globules stained with oil red O
Answer and explanation in LearnFree account
Question 20 · Medium
A 42-year-old man with pyelonephritis is in the ICU with BP 80/40 mmHg despite 30 mL/kg of IV fluid. His extremities are warm and flushed, cardiac output is high, systemic vascular resistance is low and serum lactate is 5.2 mmol/L. Which mechanism mainly explains his low blood pressure?
1. ALoss of intravascular volume from haemorrhage
2. BFailure of the myocardium to pump effectively
3. CWidespread vasodilation from nitric oxide and mediators
4. DObstruction of venous return to the heart
Answer and explanation in LearnFree account

Haemodynamics: thrombosis, embolism, infarction and shock

At autopsy of a 70-year-old man who died of a ruptured abdominal aortic aneurysm, the aneurysm sac contains a firm, grey-red thrombus attached to the wall. Its cut surface shows alternating pale and dark layers. What are these layers called?

A 58-year-old man collapses and dies on the fifth day after a total knee replacement. At autopsy a large coiled embolus sits astride the bifurcation of the pulmonary trunk. What was the immediate mechanism of his death?

A 34-year-old diver working on a coral survey off Lakshadweep surfaces rapidly from a deep dive. Within an hour he has severe pain in the knees and shoulders, an itchy mottled rash and difficulty breathing. What is the definitive treatment?

A 72-year-old woman is in bed for ten days after surgery for a fracture of the neck of the femur, without thromboprophylaxis. She develops a swollen, tender left calf, and Doppler shows thrombosis of the popliteal vein. Which component of Virchow's triad did the immobility mainly contribute?

A 64-year-old man on unfractionated heparin after coronary bypass surgery has a fall in platelets from 2,40,000/µL to 85,000/µL on day 7, and a new right femoral artery thrombosis. What is the most appropriate next step?

A 23-year-old motorcyclist with closed fractures of both femoral shafts becomes breathless and confused 36 hours after admission. He has petechiae over the chest, axillae and conjunctivae, and SpO2 is 86% on room air. What is the most likely diagnosis?

A 30-year-old man with infective endocarditis of the mitral valve develops sudden left upper quadrant pain. Contrast CT shows a wedge-shaped, non-enhancing area in the spleen with its base on the capsule. What is the expected gross appearance of this lesion after a few days?

A 52-year-old man has a confirmed small pulmonary embolus to a segmental artery. He has no heart or lung disease, and the CT does not show infarction of the lung. Why does pulmonary infarction usually not follow such an embolus?

A 24-year-old woman develops a proximal DVT three months after starting a combined oral contraceptive pill. Her mother had a pulmonary embolism at 40. A clotting assay shows that adding activated protein C fails to prolong her aPTT as expected. What is the most likely underlying defect?

A 42-year-old man with pyelonephritis is in the ICU with BP 80/40 mmHg despite 30 mL/kg of IV fluid. His extremities are warm and flushed, cardiac output is high, systemic vascular resistance is low and serum lactate is 5.2 mmol/L. Which mechanism mainly explains his low blood pressure?