Pathology of Thrombosis
Name the three components of Virchow's Triad
Changes in the vessel wall (endothelial injury)
Changes in blood flow (stasis or turbulence)
Changes in blood composition (hypercoagulability)
Which cranial nerve supplies facial sensation and the muscles of mastication? Provide number and name of CN
CN V — Trigeminal nerve
What dual antiplatelet therapy is given to all STEMI patients?
Aspirin plus a P2Y12 inhibitor (clopidogrel, prasugrel, or ticagrelor)
Name the biomarker used to diagnose myocardial infarction in the ED (specifically)
High-sensitivity troponin I (hsTnI)
Name three reversible causes of cognitive impairment
Infection (HIV, syphilis, meningitis, encephalitis — acute and chronic)
Metabolic (hyponatraemia, B12 deficiency, hypothyroidism)
Hypoxia (e.g., COPD, OSA)
Toxins (alcohol, substances of abuse, some medications)
Malignancy, systemic inflammation (MS, sarcoidosis)
Intracranial haemorrhage
Compare haemostasis and thrombosis
Haemostasis: Physiological process preventing blood coagulation in intact vessels while stopping bleeding at rupture sites
Thrombosis: Pathological coagulation of circulating blood inside intact vascular spaces
Which three cranial nerves are tested together during assessment of eye movements and pupillary responses? Provide number and name of CNs
CN III (Oculomotor), CN IV (Trochlear), CN VI (Abducens)
Name the three stages of haemostasis
Vascular spasm, platelet aggregation and plug formation, and coagulation (thrombus/clot formation)
Give three non-cardiac causes of an elevated troponin
Any three: renal failure/CKD, sepsis, pulmonary embolism, stroke, rhabdomyolysis, severe anaemia, strenuous/endurance exercise, hypothyroidism
Name three first-line drug classes for the management of essential hypertension
Any three of: ACE inhibitors/ARBs, calcium channel blockers, thiazide/thiazide-like diuretics (and beta-blockers in select cases)
Distinguish the composition of an arterial thrombus from a venous thrombus. State which is "white" vs "red" thrombus
Arterial thrombi ("white") are platelet-rich with little fibrin/RBC (form under high shear, e.g. on ruptured plaque)
Venous thrombi ("red") are fibrin- and RBC-rich with fewer platelets (form in areas of stasis)
A patient is unable to shrug their shoulders or turn their head against resistance. Which cranial nerve is being tested, and which muscles does it supply?
CN XI — Accessory nerve; it supplies the trapezius (shoulder shrug) and sternocleidomastoid (head turning)
Why are beta-blockers used following myocardial infarction?
They reduce heart rate and contractility, lowering myocardial oxygen demand, and reduce the risk of arrhythmia and re-infarction, improving long-term survival
Describe what happens biochemically inside a cardiomyocyte during ischaemia
Oxygen deprivation halts oxidative phosphorylation, forcing anaerobic glycolysis → lactate accumulation and intracellular acidosis → ATP depletion impairs ion pumps (e.g. Na+/K+-ATPase, Ca2+-ATPase) → intracellular Ca2+ and Na+ accumulate, causing cell swelling and, if prolonged, irreversible injury/necrosis
Distinguish dementia from delirium
Delirium
Core deficit: Attention and awareness
Consciousness: Impaired
Onset: Rapid (hours–days)
Course: Reversible (typically)
Cause: Medical illness, medication effect, toxin
Dementia
Core deficit: Intellect, memory, personality
Consciousness: Preserved
Onset: Gradual, insidious (≥6 months)
Course: Irreversible
Cause: Multiple specific conditions
Function: Impaired
Outline three features that distinguish a thrombus from a blood clot
Consistency: Thrombus is firm and friable (fragmentable); clot is soft, gelatinous, and elastic
Structure: Thrombus is laminated with Lines of Zahn (alternating platelet/fibrin and RBC layers); clot has no such lamination
Attachment: Thrombus is attached to the vessel wall or heart chamber where it formed; clot lies loosely and is easily removed
Relationship to vessel: Thrombus can be mural (non-occlusive) or occlusive; clot moulds to the vessel shape without expanding it
Formed in living tissue within flowing blood; clot forms after death or in a stationary (non-circulating) sample
A patient has facial droop that spares the forehead. Which nerve is affected, and is this an upper or lower motor neuron lesion?
CN VII (Facial nerve) — an upper motor neuron lesion, because the forehead receives bilateral cortical innervation and is spared
What is the difference between a selective (cardioselective) and a nonselective beta blocker? Give an example of each
Nonselective beta blockers competitively antagonize adrenaline and noradrenaline at all beta-adrenergic receptors — β1, β2, and β3. Example: propranolol
Selective (cardioselective) beta blockers preferentially antagonize β1 receptors. Examples: atenolol, metoprolol
Outline the biochemical basis of atherosclerotic plaque formation
LDL cholesterol enters the subendothelial space and undergoes oxidative modification → oxidised LDL triggers endothelial activation and monocyte recruitment → monocytes differentiate into macrophages that engulf oxidised LDL via scavenger receptors, becoming foam cells → foam cell accumulation and smooth muscle proliferation form the fatty streak and, over time, a fibrous-capped atheromatous plaque
How do you differentiate STEMI from NSTEMI on ECG and biomarkers?
STEMI shows ST-segment elevation (with reciprocal changes) plus elevated troponin, reflecting transmural infarction from complete coronary occlusion
NSTEMI shows ST depression, T-wave inversion, or a normal/non-specific ECG, plus elevated troponin, reflecting subtotal occlusion/partial-thickness infarction
Endothelial cells play a dual role in maintaining haemostatic balance. Outline two mechanisms by which endothelium acts in an anticoagulant capacity, and two mechanisms by which it acts in a procoagulant capacity
Anticoagulant mechanisms:
1. Secretion of prostacyclin and nitric oxide, causing vasodilation and inhibiting platelet aggregation and adhesion
2. Secretion of thrombomodulin, which captures thrombin and activates protein C, leading to thrombin degradation
3. Fibrinolysis, via generation of plasmin from plasminogen to lyse fibrin and limit clot growth
Procoagulant mechanisms:
1. Release of von Willebrand factor (vWF), which mediates platelet binding to surfaces and serves as a carrier for Factor VIII
2. Release of tissue factor (FIII), which activates the extrinsic coagulation pathway
3. Release of plasminogen activator inhibitor (PAI), which suppresses fibrinolysis
A patient has bitemporal hemianopia. Where is the lesion, and what is the classic underlying cause?
Optic chiasm — specifically the crossing (nasal) retinal ganglion fibres. Classic cause is a pituitary tumour compressing the chiasm from below
Statins have two main pharmacological effects. Name both effects, and give two examples of statins
Effect 1: Inhibit HMG-CoA reductase, blocking the conversion of HMG-CoA to mevalonate (the rate-limiting step in cholesterol synthesis)
Effect 2: Increase the number of LDL receptors on the surface of hepatocytes, increasing hepatic uptake of LDL cholesterol from the blood
Examples: Atorvastatin, rosuvastatin, fluvastatin, pravastatin, simvastatin
List the five types of lipoprotein in order of increasing density, and state one function of each
Chylomicron — transports dietary triglycerides and cholesterol from intestine to liver/peripheral tissues
VLDL — transports triglycerides from liver to peripheral tissues
IDL — transports triglycerides from liver to peripheral tissues (derived from VLDL after triglyceride loss)
LDL — carries cholesterol from liver to peripheral tissues
HDL — collects excess cholesterol from tissues and returns it to the liver
Outline the immediate management priority for a confirmed STEMI
Urgent reperfusion therapy — primary percutaneous coronary intervention (PCI), targeting door-to-balloon time within 90 minutes; if timely PCI isn't available, thrombolysis (fibrinolytic therapy) is given instead, alongside dual antiplatelet therapy and anticoagulation