OMSB Residency Selection (OMRSE) key terms

The proportion of people who truly have a disease and are correctly identified as positive by a test. A highly sensitive test rarely misses disease, so it is useful for ruling out a diagnosis when negative.

The proportion of people without the disease who are correctly identified as negative by a test. A highly specific test rarely produces false positives, so a positive result usually confirms the diagnosis.

The probability that a person with a positive test result actually has the disease. It rises as disease prevalence rises, so the same test performs differently in high-risk and low-risk populations.

The number of patients who must receive a treatment for one additional patient to gain the desired outcome. It is the reciprocal of the absolute risk reduction and reflects clinical benefit size.

The arithmetic difference in event rates between a control group and a treated group, expressed as a percentage or proportion. Unlike relative risk reduction, it reflects the true magnitude of benefit for an individual patient.

A structured framework for appraising randomised trials across domains such as randomisation, allocation concealment, blinding, incomplete outcome data, and selective reporting. Reviewers judge each domain as low, high, or unclear risk.

A range of values, calculated from sample data, that is likely to contain the true population estimate. A 95% interval means that if the study were repeated many times, 95% of such intervals would contain the true value.

The balance of hydrostatic and oncotic pressures across a capillary membrane that governs fluid movement between plasma and interstitial space. Net filtration out of the capillary occurs when hydrostatic pressure exceeds opposing oncotic pressure.

The physiological principle that increasing ventricular filling (preload) stretches cardiac muscle and increases the force of contraction, raising stroke volume within physiological limits. Beyond a point, overstretch reduces efficiency and worsens failure.

A calculated difference between measured cations and anions, usually sodium minus chloride and bicarbonate. An elevated gap suggests accumulation of unmeasured acids such as ketones, lactate, or toxins.

A hyperglycaemic emergency marked by insulin deficiency, ketone accumulation, metabolic acidosis, and total body potassium depletion. Management centres on fluids, insulin infusion, and careful potassium replacement before insulin if levels are low.

Serum potassium above the normal range, risking fatal arrhythmias and muscle weakness. Emergency treatment combines membrane stabilisation with calcium, intracellular shift using insulin and glucose, and removal via diuretics or dialysis.

A glomerular disorder characterised by heavy proteinuria, hypoalbuminaemia, oedema, and hyperlipidaemia. Loss of albumin lowers plasma oncotic pressure, promoting fluid shift into the interstitium and generalised swelling.

Circulatory failure caused by inadequate cardiac output despite adequate intravascular volume, often after myocardial infarction. Signs include hypotension, cool peripheries, raised jugular venous pressure, and reduced urine output.

Sepsis is life-threatening organ dysfunction caused by a dysregulated host response to infection, identified clinically by a rise in the Sequential Organ Failure Assessment score. Septic shock adds vasopressor need and raised lactate.

A bedside screening score for sepsis using three items: respiratory rate of 22 or more, altered mentation, and systolic blood pressure of 100 mmHg or less. Two or more positive items prompt urgent assessment for organ dysfunction.

A 3-to-15 score assessing eye opening, verbal response, and motor response to standardised stimuli. It is used to grade level of consciousness after head injury and to guide airway and escalation decisions.

The triad of hypertension with widened pulse pressure, bradycardia, and irregular respiration that signals raised intracranial pressure and impending brain herniation. It is a late and ominous sign requiring immediate decompression measures.

A prognostic measure combining the Glasgow Coma Scale score with the number of non-reactive pupils subtracted from it. Lower scores indicate greater severity and predict worse outcome after traumatic brain injury.

Acute inflammation of the vermiform appendix, typically causing periumbilical pain migrating to the right iliac fossa with localised tenderness. Untreated cases risk perforation and peritonitis, so timely surgical assessment is essential.

A clinical scoring system for suspected appendicitis using migratory pain, anorexia, nausea, tenderness, rebound, fever, and a raised white cell count. Higher totals support operative referral, while low scores allow observation.

Pain felt in the right iliac fossa when the left iliac fossa is palpated, caused by gas being displaced toward an inflamed appendix. It is a supportive clinical sign of appendicitis, not a definitive test.

A pregnancy-specific disorder of new hypertension after 20 weeks with proteinuria or maternal organ dysfunction. It can progress to eclampsia with seizures, so close monitoring and timely delivery are central to management.

A severe variant of preeclampsia defined by haemolysis, elevated liver enzymes, and low platelets. It may present with right upper quadrant pain and malaise, and delivery is often the definitive treatment.

The first-line anticonvulsant for eclampsia and seizure prophylaxis in severe preeclampsia. Toxicity can cause loss of deep tendon reflexes and respiratory depression, so monitoring of reflexes, respiration, and urine output is required.

Blood loss of 500 mL or more after vaginal birth, or 1000 mL or more after caesarean, often from uterine atony. Management follows a stepwise sequence of uterine massage, uterotonics, tranexamic acid, and surgical measures.

Continuous skin-to-skin contact between a newborn and caregiver, with exclusive breastfeeding, used especially for low-birth-weight infants. It improves thermoregulation, feeding, and survival compared with incubator care alone.

Yellow discolouration from bilirubin accumulation, common in the first week of life. Pathological features include onset within 24 hours, rapid rise, or persistence, and severe cases risk kernicterus if untreated.

A rapid assessment at one and five minutes after birth scoring heart rate, respiration, muscle tone, reflexes, and colour. It guides immediate neonatal resuscitation but does not predict long-term neurological outcome.

A class of antidepressant that blocks serotonin reuptake, raising synaptic serotonin. It is first-line for many anxiety and depressive disorders, with a delayed onset of two to four weeks and early adverse effects such as nausea and agitation.

A potentially fatal toxidrome from serotonergic excess, causing agitation, hyperthermia, clonus, and autonomic instability. It is distinguished from neuroleptic malignant syndrome by rapid onset and prominent clonus and hyperreflexia.

A rare reaction to dopamine-blocking antipsychotics marked by rigidity, fever, autonomic instability, and altered consciousness with raised creatine kinase. Management includes stopping the drug, supportive care, and sometimes dantrolene or bromocriptine.

A patient's voluntary agreement to an intervention after receiving adequate information about its nature, risks, benefits, and alternatives, and having capacity to decide. It is a process of shared decision-making, not merely a signature.

The principle that a minor may consent to treatment without a parent if they have sufficient understanding and intelligence to grasp the decision. It recognises evolving capacity rather than relying solely on chronological age.

The professional obligation to be open and honest with patients when something goes wrong in their care, including apologising and explaining what happened. It supports transparency and learning rather than blame.

A structured, non-punitive review of a patient safety incident that traces contributing system factors rather than individual blame. Findings inform changes to processes, equipment, or communication to prevent recurrence.

A safety framework in which harm occurs only when weaknesses in multiple defensive layers align and allow an error to pass through. It shifts attention from individual fault to strengthening system barriers.

The values underpinning involuntary psychiatric care, including least restrictive option, patient participation, respect, and protection of the patient's rights. Detention should be time-limited and reviewed independently.

The conditions in which people are born, grow, work, live, and age, including income, education, housing, and environment. They explain much of the avoidable variation in health outcomes between populations.

First-contact, person-centred, continuous and comprehensive care delivered close to where people live. It emphasises prevention, coordination, and equitable access, and forms the foundation of an efficient health system.

The absence of avoidable and unfair differences in health between groups, achieved by allocating resources according to need. It differs from equality, which gives identical treatment regardless of disadvantage.