Kegawatdaruratan dan Traumatologi
Core concepts
Use a structured approach: primary survey (airway, breathing, circulation, disability, exposure) with immediate resuscitation, then secondary survey. Know the lethal threats - tension pneumothorax, massive haemothorax, cardiac tamponade, airway obstruction, and massive external bleeding - and their immediate interventions. Understand shock classification (hypovolaemic, cardiogenic, distributive, obstructive) and damage-control resuscitation. Cover burns (rule of nines, fluid resuscitation), head injury and spinal precautions, and the recognition of crush injury and rhabdomyolysis.
Traps
Examiners test whether you fix the immediate threat before imaging. A patient with distended neck veins, hypotension, and muffled heart sounds has tamponade, not hypovolaemia. Do not remove an impaled object. In burns, estimate surface area accurately and remember that inhalation injury may present with hoarseness, soot, or stridor. Spinal immobilisation is guided by mechanism and findings, not applied reflexively to every patient.
Worked example
A motorcyclist after a crash has hypotension, distended neck veins, tracheal deviation away from the injured side, and absent breath sounds on one side. Diagnosis: tension pneumothorax. Rule of thumb: needle decompression immediately, followed by chest drain - do not wait for a chest X-ray.
Kedokteran Komunitas, Preventif, dan Etikolegal
Core concepts
Community medicine: incidence versus prevalence, sensitivity and specificity, positive and negative predictive value, and how prevalence changes predictive values. Understand study designs (cohort, case-control, randomised trial), measures of association (relative risk, odds ratio), and the sources of bias and confounding. Screening principles: an important condition, an acceptable test, effective treatment, and a defined population. Prevention levels: primordial, primary, secondary, tertiary. Public health: outbreak investigation, notifiable disease, and immunisation programmes. Ethics and law: informed consent, capacity, confidentiality, and its exceptions, negligence, and the four principles of biomedical ethics.
Traps
Sensitivity and specificity are properties of the test; predictive values depend on prevalence. A highly sensitive test is good for ruling out disease when negative; a highly specific test is good for ruling in disease when positive. Do not confuse incidence (new cases) with prevalence (existing cases). In ethics, a competent adult may refuse treatment even if the refusal seems unwise; capacity is decision-specific.
Worked example
A screening test has 90% sensitivity and 95% specificity, and disease prevalence is 1%. Rule of thumb: with low prevalence, most positive results are false positives, so the positive predictive value is low even for a good test. This is why screening programmes need confirmatory testing and why prevalence matters in interpreting results.