ACEM Primary flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Glasgow Coma Scale range

GCS sums eye (1-4), verbal (1-5) and motor (1-6) scores for a range of 3-15; a score of 8 or less generally indicates need for airway protection.

Anaphylaxis first-line drug

Intramuscular adrenaline 0.5 mg of 1:1000 into the anterolateral thigh in adults, repeated every five minutes as required; airway and fluid support are adjuncts, not substitutes.

Shock index

Heart rate divided by systolic blood pressure; a value above 0.9 suggests occult haemorrhage or haemodynamic compromise even when blood pressure appears normal.

Tension pneumothorax management

A clinical diagnosis requiring immediate needle decompression followed by tube thoracostomy; waiting for imaging risks cardiac arrest from obstructed venous return.

Parkland burn formula

Four millilitres of crystalloid per kilogram body weight per percent total body surface area burned in the first 24 hours, with half given in the first eight hours from injury.

Femoral triangle contents

From lateral to medial: femoral nerve, artery, vein, empty space and lymphatics (NAVEL), bounded by inguinal ligament, sartorius and adductor longus.

Erb palsy roots

Injury to the upper brachial plexus roots C5-C6 causes waiter's tip posture with the arm adducted, internally rotated and the forearm extended.

Median nerve thenar supply

The median nerve supplies the lateral two lumbricals, opponens pollicis, abductor pollicis brevis and flexor pollicis brevis, and is compressed in carpal tunnel syndrome.

Common fibular nerve injury

Injury at the fibular neck causes foot drop with loss of ankle dorsiflexion and eversion, plus sensory loss over the lateral leg and dorsum of the foot.

Recurrent laryngeal nerve course

The left nerve loops under the aortic arch and the right under the right subclavian artery; both ascend in the tracheo-oesophageal groove and are at risk in thyroid surgery.

Coagulative necrosis

Necrosis in which tissue architecture is preserved temporarily, typical of ischaemic injury in most organs except the brain, where liquefactive necrosis occurs.

Virchow's triad

Three factors predisposing to thrombosis: endothelial injury, abnormal blood flow such as stasis or turbulence, and hypercoagulability of the blood.

Granuloma definition

A collection of activated macrophages (epithelioid cells), often with multinucleated giant cells, seen in tuberculosis, sarcoidosis and foreign body reactions.

Knudson two-hit hypothesis

Tumour suppressor genes require loss of both alleles for malignant transformation, as in retinoblastoma where one germline and one somatic mutation are needed.

Metaplasia versus dysplasia

Metaplasia is a reversible change from one mature cell type to another; dysplasia is disordered growth with cytological atypia and may progress to malignancy.

Cardiac output equation

Cardiac output equals heart rate multiplied by stroke volume; the Fick principle calculates it as oxygen consumption divided by the arteriovenous oxygen content difference.

Mean arterial pressure

Approximately diastolic pressure plus one third of the pulse pressure; cerebral autoregulation maintains flow between roughly 60 and 160 mmHg.

Oxygen delivery formula

Oxygen delivery equals cardiac output multiplied by arterial oxygen content, where content is 1.34 times haemoglobin times saturation plus 0.003 times partial pressure.

Alveolar gas equation

PAO2 equals inspired oxygen fraction times (atmospheric pressure minus 47) minus arterial carbon dioxide divided by the respiratory quotient of 0.8.

Starling filtration forces

Net filtration equals capillary hydrostatic pressure plus interstitial oncotic pressure minus plasma oncotic pressure and interstitial hydrostatic pressure.

Clearance and half-life relation

Half-life equals 0.693 times volume of distribution divided by clearance; steady-state concentration is reached after approximately four to five half-lives.

Zero-order kinetics

Drug elimination at a constant amount per unit time because enzymes are saturated, as with ethanol and high-dose phenytoin, so half-life increases with dose.

Competitive antagonism effect

A competitive antagonist shifts the agonist dose-response curve to the right without reducing maximal response; non-competitive antagonism lowers the maximum response.

Heparin mechanism

Heparin potentiates antithrombin III, accelerating inactivation of thrombin and factor Xa; effect is monitored by activated partial thromboplastin time and reversed by protamine.

Warfarin mechanism

Warfarin inhibits vitamin K epoxide reductase, reducing synthesis of clotting factors II, VII, IX and X; monitored by INR and reversed by vitamin K.

Organophosphate antidotes

Atropine reverses muscarinic effects such as bradycardia and secretions, while pralidoxime reactivates acetylcholinesterase if given before enzyme ageing occurs.

Paracetamol antidote

N-acetylcysteine replenishes glutathione, detoxifying the reactive metabolite NAPQI that accumulates once sulfation and glucuronidation pathways are saturated.

Sepsis qSOFA criteria

Respiratory rate 22 or more, systolic blood pressure 100 or less, and altered mentation; two or more criteria indicate high risk in suspected infection.

Dermatome landmarks

C5 lateral arm, C6 thumb, C7 middle finger, C8 little finger, T4 nipple, T10 umbilicus, L4 medial malleolus, L5 dorsum of foot, S1 lateral foot.

Lung lobe anatomy

The right lung has three lobes separated by oblique and horizontal fissures; the left has two lobes and one oblique fissure, with the lingula as middle lobe equivalent.

Nephrotic syndrome features

Proteinuria above 3.5 grams per day, hypoalbuminaemia, generalised oedema and hyperlipidaemia; nephritic syndrome instead features haematuria and hypertension.

Hypersensitivity types

Type I is IgE-mediated (anaphylaxis), type II antibody-mediated, type III immune-complex mediated, and type IV delayed T-cell mediated as in tuberculosis.