MLT GlobeBasic Pathology: Hemodynamic disorders – page 6
153 Basic Pathology MCQs on Hemodynamic disorders with answers and explanations.
Shock after severe trauma or sepsis can cause diffuse alveolar damage in the lungs. This condition is commonly called:
Lungs resist hypoxic injury itself, but systemic inflammation in shock produces diffuse alveolar damage, known as shock lung or acute respiratory distress syndrome.
Nitric oxide that maintains resting vascular tone is produced mainly by which isoform?
eNOS in endothelial cells produces constant low levels of NO to keep vessels relaxed. nNOS generates NO as a neurotransmitter; iNOS is induced in macrophages.
A large thromboembolus lodging astride the bifurcation of the main pulmonary artery is called a:
A saddle embolus straddles the pulmonary artery bifurcation and can cause sudden death. A paradoxical embolus crosses a septal defect into the systemic circulation.
Pulmonary infarcts are typically hemorrhagic. Which feature of the lung explains this?
Red (hemorrhagic) infarcts occur in loose tissues with dual circulation, like lung, where bronchial arteries bleed into the necrotic area. Solid organs with end arteries form pale infarcts.
Which condition is least likely to cause generalised oedema (anasarca)?
Anasarca results from low albumin (nephrotic, cirrhosis) or sodium/water retention (heart failure, hyperaldosteronism). Hypertension alone does not cause it.
A patient has many 1 to 2 mm skin haemorrhages. Which laboratory finding best explains them?
Petechiae reflect platelet or vessel-wall defects. Coagulation factor deficiencies typically cause deep haematomas and haemarthroses instead.
Purpura differs from petechiae mainly in size. Purpuric haemorrhages typically measure:
Petechiae are 1 to 2 mm, purpura 3 mm or larger, and ecchymoses 1 to 2 cm.
Factor V Leiden predisposes to venous thrombosis through which component of Virchow's triad?
Factor V Leiden resists inactivation by activated protein C, creating a hypercoagulable state (thrombophilia).
Ascites in cirrhosis results mainly from:
Fibrosis raises sinusoidal and portal pressure while reduced albumin synthesis lowers oncotic pressure, and secondary hyperaldosteronism retains sodium.
A bruise turns greenish around the end of the first week. The green colour is due to:
Haemoglobin (red-blue) is degraded to biliverdin (green), then bilirubin (yellow), and finally haemosiderin (golden-brown).
In primary haemostasis, von Willebrand factor mainly acts by:
vWF anchors platelets to exposed collagen through GPIb and also carries factor VIII. Fibrinogen links platelets via GPIIb/IIIa.
In disseminated intravascular coagulation, which microthrombi are most readily seen in glomerular capillaries?
DIC produces widespread fibrin microthrombi, especially visible in renal glomeruli, with consumption of platelets and factors.
Which coagulation factor acts as a non-enzymatic cofactor rather than a protease?
Factors VIII and V are cofactors that accelerate the tenase and prothrombinase complexes. Factors X, VII and XII are serine proteases.
By Light's criteria, a pleural fluid-to-serum protein ratio below 0.5, a fluid/serum LDH ratio below 0.6 and a pleural LDH below two-thirds of the serum upper reference limit indicate:
A transudate meets none of Light's three criteria (protein ratio >0.5, LDH ratio >0.6, pleural LDH >2/3 of the serum upper limit); meeting any one indicates an exudate.
Which factor plays the dominant role in the formation of venous thrombi, as opposed to arterial thrombi?
Arterial and cardiac thrombi arise at sites of endothelial injury or turbulence, whereas venous thrombi develop mainly where blood flow is slow or stagnant.
Relative to its point of attachment, an arterial thrombus usually extends in which direction?
Arterial thrombi typically propagate backward (retrograde) from the attachment point, whereas venous thrombi extend in the direction of blood flow toward the heart.
Which type of thrombus is almost always occlusive, extends toward the heart as a long cast in the lumen, and readily embolises?
Venous thrombi form in slow-flowing veins, fill the lumen and propagate with the direction of flow toward the heart; fragments commonly become pulmonary emboli.
In chronic passive congestion of the liver, the centrilobular areas appear grossly:
Centrilobular congestion appears red-brown against tan periportal (sometimes fatty) parenchyma, producing the 'nutmeg liver' pattern.
Most systemic arterial emboli originate from:
About 80% of systemic emboli arise from mural thrombi in the heart, often after myocardial infarction or with atrial fibrillation. Deep vein thrombi normally embolise to the lungs.
In a woman who died suddenly during labour, which finding in the maternal pulmonary microvessels confirms amniotic fluid embolism?
Amniotic fluid embolism is confirmed by fetal squames, lanugo hair, vernix fat and mucin in the pulmonary microcirculation. Fat globules and marrow fragments indicate fat embolism.