ILA/GP Flashcards
Tunica intima
Innermost layer of blood vessel
Endothelial cells
Smooth layer for seamless blood flow
Tunica media
Middle layer of blood vessel
- Smooth muscle cells = contract and relax.
- Elastic fibers = withstand pressure changes.
Tunica adventitia
Outermost layer of artery.
- Collagen and elastic fibers = support and structure.
- Vasa vasorum - network of small blood vessels that supply the outer layers of larger blood vessels.
- Anchors the vessel to the surrounding tissue.
Primary prevention for atherosclerosis?
- Cut alcohol - 14 units/ week for men and women
- Improve diet - reduce cholesterol
- Increase exercise - reduce weight
- Stop smoking
- Take prescribed medications
Secondary prevention for atherosclerosis?
- Manage diabetes risk —> review again
- Statins (side effects: muscle cramping)
- Low dose aspirin - 75mg - enough to inhibit platelet clotting (thrombus formation)
- Manage hypertension and other conditions
Define anaphylaxis
Severe, life-threatening, generalised or systemic hypersensitivity reaction.
Caused by asevere type 1 hypersensitivityreaction (IgE-mediated)
Stages/pathophysiology of anaphylaxis?
- Sensitisation phase - first encounter with allergen = IgE Abs produced by B cells
- Re-exposure: allergen binds to IgE Abs on mast cells + basophils.
=> production of histamine, tryptase, chymase, leukotrienes, interleukins and cytokines. - Histamine causes vasodilation = SHOCK
Signs and symptoms of anaphylaxis?
- Skin reactions (hives)
- Breathing difficulties
- Swelling
- Cardiovascular symptoms due to vasodilation = rapid, weak pulse + shock + prlonged cap refill time
- GI symptoms
- Neurological (disorientation, LOC)
Treatment for anaphylaxis?
- IM adrenaline (300 microgram EPIPEN or 500 micrograms in hospital)
- Repeat after 5 mins if required
- ABCDE
- High flow oxygen
- IV fluids
- IV antihistamines (for skin symptoms)
- Beta-agonists
Mode of action of adrenaline in treatment of anaphylaxis?
Activates sympathetic response
= B2 adrenoreceptors (bronchodilation) = A1 receptors (vasoconstriction to increase BP)
= B1 receptors (increased cardiac contractility)
Confirmatory blood test for anaphylaxis?
Tryptase (due to mast cell degranulation)
What characteristics should drug have to put patient to sleep quickly?
- Pass through cell membranes - lipophilic (lipid-soluble)
- Low protein binding - bioavailable - high amount of free drug
Oral bioavailability of morphine?
50%
Hence need double dose if given orally
What is the metabolite of morphine?
Morphine-6-glucoronoide
More potent than morphine - can cause toxicity in renal impairment
Metabolised by CYP2D6
Signs of ARTERIAL vs venous thrombosis?
ARTERIAL:
Peripheral vascular disease
6Ps
VENOUS:
DVT/PE
Virchow’s triad
6PS of arterial thrombosis?
Pulselessness
Pallor
Pain
Perishingly cold
Paralysis
Paraesthesia
Virchow’s triad?
- Stasis of blood flow - immobilisation - long haul flights etc
- Endothelial injury - i.e. smoking, cellulitis, AF, LV dysfunction
- Hyper-coagulability - i.e. dehydration, meds (oestrogen), polycythaemia, thrombocytosis, inflammation, IBD, autoimmune diseases, pregnancy, immobilisation, malignancies (esp. blood cancers), sickle cell anaemia, sepsis
Signs of venous thrombosis? DTV/PE
Unilateral swelling]
Oedema
Tender
Erythematous
Distension of superficial veins
Pre-renal causes of AKI?
Insufficient blood supply reduces filtration of blood
= dehydration, shock (i.e. sepsis, anaphylaxis, or acute blood loss), heart failure, renal artery stenosis, AF/arrhythmias, MI, diarrhoea, diuretics, burns
Complications of AKI?
- Chronic kidney disease
- Heart failure
- Hyperkalaemia
- Metabolic acidosis – which can cause nausea, vomiting, drowsiness and breathlessness
- Fluid overload - peripheral or pulmonary oedema
Renal causes of AKI?
Glomerulonephritis
Acute interstitial nephritis
Acute tubular necrosis
Haemolytic uraemic syndrome
Rhabdomyolysis
Post-renal causes of AKI?
- Kidney stones
- Tumours (retroperitoneal, bladder or prostate)
- Strictures of the ureters or urethra
- Benign prostatic hyperplasia
- UTIs
- Neurogenic bladder
Cushing’s triad?
Body response to raised ICP due to intracranial bleed (haemorrhagic stroke):
- Bradycardia
- Irregular respirations
- Hypertension
Causes of ischaemic stroke?
Blood supply to brain may be disrupted by:
- Thrombusorembolus
- Atherosclerosis
- Shock
- Vasculitis
Signs of raised ICP?
- Papilloedema
- Headache (non-specific and diffuse)
- Nausea
- Pulsatile tinnitus
- Transient visual loss
- Visual disturbance (visual field defects, photophobia)
Describe the main stages involved in the formation of an atherosclerotic plaque
- Endothelial injury
- Entry of LDL and cholesterol into tunica intima
- Injured endothelial cells express adhesion molecules on surface = diapadesis of WBCs into tunica intima
- FOAM CELLS FORM (macrophages ingest oxidised LDL) - many foam cells appear as a fatty streak
- Foam cells BURST = releases LDL and cholesterol = triggers further inflammatory response
- Smooth muscle cells from artery wall migrate into the fatty streak = produce collagen
= FIBROUS CAP over the fatty streak
= known as fibrous plaque
** PLAQUE RUPTURE = thrombus formation, or can embolise.
Causes of endothelial injury (leading to atherosclerosis)
High blood pressure
Chemical irritants (smoking)
High levels of cholesterol and triglycerides
Define concordance
INFORMED patients having an active role in treatment decisions.
Respects the beliefs and wishes of a patient in determining whether, when and how medicines are to be taken.
Define compliance
PASSIVE behaviour, following a list of instructions from the doctor
Define adherence
The active choice of patients to follow through with the prescribed treatment, while taking responsibility for their own well-being
Types of adverse drug reactions?
A - AUGMENTED
B - BIZARRE
C - CHRONIC USE
D - DELAYED
E - END OF USE (WITHDRAWAL)
F - FAILURE OF TREATMENT
G - GENETIC
Explain - AUGMENTED adverse drug reaction?
Exaggerated effect at recommended dose - reversible upon withdrawing the drug
i.e bradycardia with beta blockers / bleeding with anti-coagulants
Explain - CHRONIC USE adverse drug reaction?
ADR continues even after the drug has stopped