MRCPI GM Part I key terms

The volume of blood each ventricle pumps per minute, equal to heart rate multiplied by stroke volume. Resting value is about 5 litres per minute; it rises in sepsis and anaemia and falls in cardiogenic shock.

The proportion of ventricular end-diastolic volume ejected with each beat, usually measured for the left ventricle. Normal is roughly 55-70%; a reduced value supports a diagnosis of heart failure with reduced ejection fraction.

An exaggerated fall in systolic blood pressure of more than 10 mmHg during inspiration. It is classically found in cardiac tamponade, constrictive pericarditis and severe asthma because of increased ventricular interdependence.

An inactive fragment released when ventricular myocytes are stretched. A low level makes heart failure unlikely; raised levels also occur in renal impairment, atrial fibrillation, sepsis and older age.

The fraction of forced vital capacity exhaled in the first second. A post-bronchodilator value below 0.70 in adults confirms airflow obstruction and supports a diagnosis of chronic obstructive pulmonary disease.

Hypoxaemia (PaO2 below 8 kPa) with a normal or low arterial carbon dioxide. It results from ventilation-perfusion mismatch, shunt or diffusion problems, as in pneumonia, pulmonary embolism and pulmonary fibrosis.

A five-item score (confusion, urea, respiratory rate, blood pressure, age 65 or over) that estimates 30-day mortality in community-acquired pneumonia and helps decide whether hospital or intensive care is needed.

Serum albumin minus ascitic fluid albumin. A gradient of 11 g/L or more indicates portal hypertension as the cause of ascites, such as cirrhosis; lower values suggest malignancy, tuberculosis or pancreatic disease.

A score using bilirubin, albumin, prothrombin time, encephalopathy and ascites to grade the severity of cirrhosis and estimate prognosis. It also guides drug dosing and decisions about transplantation referral.

Model for End-stage Liver Disease: a score from bilirubin, INR and creatinine, sometimes with sodium, that predicts short-term mortality in cirrhosis and is used to prioritise patients for liver transplantation.

Glycated haemoglobin reflecting average blood glucose over the preceding two to three months. It is used to diagnose diabetes at 48 mmol/mol or above and to monitor control, but is unreliable in haemoglobinopathies and renal failure.

A metabolic emergency defined by hyperglycaemia, ketonaemia and metabolic acidosis, usually in type 1 diabetes. It presents with vomiting, abdominal pain, dehydration and Kussmaul breathing and is treated with fluids, insulin and potassium replacement.

A test in which dexamethasone is given at midnight and serum cortisol measured the next morning. Failure to suppress cortisol suggests Cushing's syndrome; false positives occur with obesity, depression, alcohol excess and some drugs.

An estimate of glomerular filtration rate calculated from serum creatinine, age and sex. It stages chronic kidney disease; values are unreliable in acute kidney injury, extremes of muscle mass and pregnancy.

The percentage of filtered sodium excreted in urine, calculated from paired serum and urine sodium and creatinine. A value below 1% suggests pre-renal hypoperfusion; higher values suggest intrinsic renal injury, although diuretics confound interpretation.

Serum sodium minus chloride and bicarbonate, with potassium added in some laboratories. A raised gap indicates accumulation of unmeasured acids such as ketones, lactate or toxins; a normal gap acidosis suggests bicarbonate loss.

Syndrome of inappropriate antidiuretic hormone secretion: euvolaemic hyponatraemia with concentrated urine and continued urinary sodium loss, without thyroid, adrenal or renal cause. Common triggers are drugs, small-cell lung cancer and central nervous system disease.

Findings suggesting damage above the anterior horn cell: spasticity, hyperreflexia, extensor plantar responses, clonus and loss of fine dexterity, with little muscle wasting and no fasciculation.

A score from 3 to 15 combining eye opening, verbal response and best motor response, used to grade and monitor impaired consciousness; a score of 8 or less indicates a need for airway protection.

An acute neurological emergency from thiamine deficiency, producing confusion, ophthalmoplegia and ataxia. It is common in alcohol misuse and malnutrition; untreated it progresses to Korsakoff syndrome, so thiamine is given before glucose.

Antibodies against cyclic citrullinated peptides, highly specific for rheumatoid arthritis and often present early. They predict more erosive disease, and a positive result supports the diagnosis when rheumatoid factor is negative.

Antibodies detected by immunofluorescence on cultured cells; a sensitive but non-specific screening test. Titre and pattern matter: high titres with specific antibodies support lupus, scleroderma or Sjogren's syndrome, while low titres occur in healthy people.

A condition of older adults with bilateral shoulder and hip girdle pain and stiffness, raised inflammatory markers and prompt response to low-dose prednisolone. Giant cell arteritis must be excluded, especially with headache or visual symptoms.

The average red cell size. It classifies anaemia as microcytic (iron deficiency, thalassaemia), normocytic (chronic disease, blood loss) or macrocytic (B12 or folate deficiency, alcohol, hypothyroidism).

The prothrombin time standardised against a reference thromboplastin. It monitors warfarin and reflects hepatic synthetic function; a prolonged ratio also occurs with vitamin K deficiency and disseminated intravascular coagulation.

A fragmented red cell seen on the blood film. Schistocytes indicate microangiopathic haemolysis, as in thrombotic thrombocytopenic purpura, haemolytic uraemic syndrome, disseminated intravascular coagulation and mechanical heart valves.

The lowest antibiotic concentration that prevents visible bacterial growth in vitro. It is compared with achievable blood levels to decide susceptibility and dosing, and is reported as sensitive, intermediate or resistant.

Fever or clinical deterioration in a patient with a neutrophil count below 0.5 x 10^9/L. It is a medical emergency: blood cultures are taken and empirical broad-spectrum antibiotics started immediately, before imaging or culture results.

The time taken for the plasma concentration of a drug to fall by half. It determines dosing interval and time to steady state, roughly four to five half-lives, and is prolonged in renal or hepatic impairment.

A theoretical volume relating the amount of drug in the body to its plasma concentration. Large values indicate extensive tissue binding or lipophilicity; it determines loading dose and whether haemodialysis can remove a drug.

Metabolism of an orally absorbed drug in gut wall and liver before it reaches the systemic circulation. It reduces oral bioavailability and explains why some drugs need much larger oral than intravenous doses.

A syndrome of reduced physiological reserve and increased vulnerability to stressors, identified by weight loss, exhaustion, weakness, slow gait and low activity. It predicts falls, hospitalisation and death and should prompt comprehensive assessment.

A structured multidisciplinary evaluation of an older person's medical, functional, psychological and social needs, producing a coordinated care plan. It improves survival and independence compared with usual care for frail hospitalised patients.

The proportion of people with a disease who test positive. A highly sensitive test is useful for ruling out disease when negative; sensitivity is a property of the test and does not depend on disease prevalence.

The proportion of people without a disease who test negative. A highly specific test is useful for confirming disease when positive, since false positives are uncommon; it is independent of prevalence and is often traded against sensitivity.

The probability that a person with a positive test truly has the disease. Unlike sensitivity, it depends strongly on prevalence, so a test performs better when applied to a high-risk population.

The number of patients who must receive an intervention for one additional person to benefit, calculated as the reciprocal of the absolute risk reduction. Smaller values indicate a larger treatment effect.

A third factor associated with both exposure and outcome that distorts their apparent relationship. It can be addressed at the design stage by randomisation, restriction or matching, or at analysis by stratification or multivariable regression.