NPMCN Primary flashcards

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

Brachial plexus roots

The brachial plexus is formed by anterior rami of C5 to T1; Erb's palsy affects C5–C6 and produces waiter's tip, while Klumpke's palsy affects C8–T1.

Femoral triangle boundaries

Superiorly the inguinal ligament, laterally sartorius, medially adductor longus; the floor is iliopsoas and pectineus, and the femoral vessels and nerve lie within.

Cardiac output formula

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

Glomerular filtration rate determinants

GFR equals filtration coefficient times net filtration pressure; net pressure is glomerular capillary pressure minus plasma oncotic pressure and Bowman's capsule pressure.

Oxygen dissociation curve shift

The curve shifts right, reducing haemoglobin affinity, with raised 2,3-DPG, acidosis, hypercapnia and fever; fetal haemoglobin and carboxyhaemoglobin shift it left.

Rate-limiting enzyme of glycolysis

Phosphofructokinase-1 catalyses the committed step of glycolysis and is inhibited by ATP and citrate and activated by AMP and fructose-2,6-bisphosphate.

Urea cycle overview

Carbamoyl phosphate combines with ornithine to form citrulline, then argininosuccinate and arginine, releasing urea; carbamoyl phosphate synthetase I is rate-limiting.

Competitive versus non-competitive inhibition

Competitive inhibitors raise apparent Km without altering Vmax; non-competitive inhibitors lower Vmax without altering Km, reflecting binding at a separate site.

Virchow's triad

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

Granuloma composition

A collection of activated epithelioid histiocytes, often with Langhans giant cells and lymphocytes; caseating granulomas are typical of tuberculosis.

Myocardial infarct timeline

Coagulative necrosis appears by 6–12 hours, neutrophil infiltration peaks at 1–3 days, granulation tissue by 1–2 weeks and a fibrous scar by 6–8 weeks.

Nephrotic syndrome features

Proteinuria above 3.5 g per day, hypoalbuminaemia, generalised oedema and hyperlipidaemia, resulting from increased glomerular permeability to protein.

Half-life and steady state

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

Bioavailability calculation

Oral bioavailability is the oral area under the concentration–time curve divided by the intravenous area under the curve, expressed as a percentage.

Paracetamol antidote

N-acetylcysteine replenishes hepatic glutathione and detoxifies the toxic metabolite NAPQI; it is most effective when given within 8–10 hours of overdose.

First-order versus zero-order kinetics

First-order elimination removes a constant fraction per unit time, whereas zero-order removes a constant amount, as seen with ethanol, phenytoin and high-dose aspirin.

Immunoglobulin classes

IgM is the first antibody in primary infection, IgG crosses the placenta, IgA is secretory, IgE mediates type I hypersensitivity and IgD is a B-cell receptor.

Type IV hypersensitivity

A delayed, T-cell mediated reaction without antibody, exemplified by the tuberculin test and contact dermatitis, peaking 48–72 hours after exposure.

Tuberculosis culture medium

Mycobacterium tuberculosis is acid-fast due to cell-wall mycolic acids and grows slowly on Löwenstein–Jensen medium, appearing as rough buff colonies.

Active versus passive immunity

Active immunity follows infection or vaccination and develops memory over weeks; passive immunity from maternal antibody or immunoglobulin acts immediately but is transient.

Incidence and prevalence

Incidence is new cases divided by population at risk per unit time; prevalence is all existing cases divided by total population at a given time.

Sensitivity and specificity

Sensitivity is true positives divided by true positives plus false negatives; specificity is true negatives divided by true negatives plus false positives.

Relative risk versus odds ratio

Relative risk compares incidence between exposed and unexposed groups in cohort studies; the odds ratio estimates this association in case–control studies.

Herd immunity threshold

The proportion needing immunity to interrupt transmission equals one minus one divided by the basic reproduction number, R0.

Informed consent elements

Valid consent requires patient capacity, sufficient and comprehensible information about the proposed intervention and alternatives, and freedom from coercion.

Four principles of bioethics

Autonomy respects patient choice, beneficence promotes welfare, non-maleficence avoids harm, and justice requires fair distribution of benefits and burdens.

Kübler-Ross stages

Denial, anger, bargaining, depression and acceptance describe common emotional responses to loss; progression is not strictly sequential and patients may revisit stages.

Cushing's triad

Signs of raised intracranial pressure: hypertension with widened pulse pressure, bradycardia and irregular respiration, indicating impending brainstem herniation.

Diabetic ketoacidosis criteria

Glucose above 11 mmol/L with ketonaemia, metabolic acidosis pH below 7.3 and bicarbonate below 15 mmol/L; management is fluids, insulin and potassium replacement.

Shock clinical features

Tachycardia, hypotension, cool clammy peripheries, prolonged capillary refill above two seconds, oliguria and altered consciousness from inadequate tissue perfusion.

Standard error of the mean

The standard deviation of the sample divided by the square root of the sample size; it measures precision of the estimated mean, not spread of individuals.

Type I and type II error

Type I error rejects a true null hypothesis at rate alpha; type II error fails to reject a false null at rate beta, and statistical power equals one minus beta.