BSMMU Residency Phase-A key terms

The difference between measured and calculated serum osmolality. A raised gap suggests unmeasured solutes such as methanol, ethylene glycol, or isopropanol, and helps identify toxic alcohol poisoning in an unconscious patient.

Serum sodium minus the sum of chloride and bicarbonate. It estimates unmeasured anions and classifies metabolic acidosis into high-gap causes such as ketoacidosis, lactate, renal failure, and toxins, versus normal-gap causes.

Production of acidic urine despite systemic metabolic alkalosis. It occurs with severe potassium depletion, where the kidney reabsorbs sodium in exchange for hydrogen instead of potassium, perpetuating the alkalosis.

The loop of Henle mechanism that creates a medullary osmotic gradient by active salt transport in the thick ascending limb while water remains in the descending limb, allowing concentrated or dilute urine as needed.

The rule that increasing ventricular filling stretches cardiac muscle and increases the force of contraction, up to a point. Beyond optimal stretch, further filling reduces effective contraction and cardiac output.

The degree of ventricular stretch at the end of diastole, reflecting venous return and blood volume. It is estimated clinically by jugular venous pressure and determines stroke volume through the Frank-Starling relationship.

The percentage of end-diastolic ventricular volume expelled with each beat, normally about 55 to 70 percent. It measures systolic pump function and guides prognosis and treatment in heart failure.

A graph of haemoglobin oxygen saturation against partial pressure of oxygen. Its sigmoid shape reflects cooperative binding; shifts right with acidosis, hypercapnia, and fever release oxygen to tissues more readily.

The reduction in haemoglobin's oxygen affinity when carbon dioxide and hydrogen ions rise, as in exercising tissue. It shifts the dissociation curve rightward so oxygen is unloaded where metabolism is greatest.

A formula estimating alveolar oxygen partial pressure from inspired oxygen, barometric pressure, water vapour pressure, and arterial carbon dioxide. It underlies calculation of the alveolar-arterial oxygen gradient in hypoxaemia.

Heart rate multiplied by systolic blood pressure, an indirect index of myocardial oxygen demand. Values above roughly 20,000 in an exercise test suggest significant ischaemic burden during stress testing.

Forced expiration against a closed glottis, raising intrathoracic pressure. It is used to terminate supraventricular tachycardia, to test autonomic function, and diagnostically in suspected hypertrophic cardiomyopathy.

A clinical sign in which the examiner's hand pressing below the right costal margin elicits a sudden arrest of inspiration. It suggests acute cholecystitis because the inflamed gallbladder meets the descending diaphragm.

Pain felt in the right iliac fossa when the left iliac fossa is pressed. It indicates peritoneal irritation from appendicitis, supporting the diagnosis when the classic right-sided tenderness is equivocal.

Pain that worsens when the examining hand is suddenly released from the abdomen, indicating parietal peritoneal inflammation. It is a cardinal sign of peritonitis and a warning against further deep palpation.

A 15-point scoring system grading eye opening, verbal response, and motor response. Scores of 8 or below indicate severe impairment and prompt consideration of airway protection and urgent neuroimaging.

The combination of hypertension with widened pulse pressure, bradycardia, and irregular respiration. It signals raised intracranial pressure and impending brainstem herniation, requiring emergency decompressive measures.

With the patient supine, passive flexion of the hip then extension of the knee produces resistance or pain. It indicates meningeal irritation from meningitis or subarachnoid haemorrhage.

A single-sheet graphic record of labour plotting cervical dilatation, fetal head descent, contractions, and maternal vital signs against time. It helps detect slow progress and obstructed labour early enough to act.

A score of cervical dilatation, effacement, consistency, position, and fetal station used to predict the success of induced labour. Higher scores indicate a cervix already favourable for induction.

A package of a prophylactic uterotonic drug, controlled cord traction, and uterine massage given around delivery of the placenta. It reduces the incidence of postpartum haemorrhage and retained placenta.

Bleeding from the genital tract after 28 weeks of gestation but before delivery. Placenta praevia and placental abruption are the leading causes; initial assessment avoids digital vaginal examination until praevia is excluded.

A rapid assessment at one and five minutes after birth scoring heart rate, respiratory effort, muscle tone, reflex irritability, and colour, each from zero to two. It guides immediate newborn resuscitation.

A clinical tool estimating gestational age from neuromuscular and physical maturity signs in a newborn. It is useful when the last menstrual period or early ultrasound dating is uncertain or unavailable.

Respiratory distress of the preterm newborn caused by surfactant deficiency, with grunting, retractions, and ground-glass chest radiographs. Antenatal corticosteroids and early nasal continuous positive airway pressure reduce severity.

The proportion of people who truly have a disease and are correctly identified by a test. It reflects a test's ability to detect disease and is central to screening programme design.

The proportion of people without a disease who are correctly identified as disease-free by a test. It reflects a test's ability to exclude disease and complements sensitivity in interpreting results.

The probability that a person with a positive test result actually has the disease. It rises with disease prevalence, so the same test performs differently in different populations.

The proportion of people diagnosed with a condition who die from it within a stated period. It measures severity rather than how commonly the disease occurs in the population.

The number of new cases of a disease arising in a population over a period, divided by person-time at risk. It measures how rapidly new disease develops and is used for aetiological research.

Stiffening of muscles after death as adenosine triphosphate is depleted and actin and myosin cross-link. It begins in small muscles and later resolves with putrefaction, helping estimate time since death.

The purplish discolouration of dependent skin after death as blood settles under gravity. Its extent and fixity help estimate the postmortem interval and can indicate whether a body was moved.

The gradual cooling of a body after death toward ambient temperature. The pattern of heat loss is used, with caution, to estimate the time since death in forensic investigations.

The voluntary agreement of a competent patient after receiving adequate information about the nature, risks, benefits, and alternatives of a proposed intervention. It respects autonomy and must be documented appropriately.

The ethical and legal duty to protect information disclosed in a professional relationship and to share it only with consent or where law permits. Breach may be justified to prevent serious harm.

A person's ability to understand relevant information, weigh it, retain it, and communicate a decision about their own care. It is decision-specific and assessed clinically rather than assumed from age or diagnosis.

The effects that a poison produces on the body, including its mechanism and the resulting clinical features. It complements toxicokinetics, which describes how the body handles the poison.