Preparatory Mindset
Internal Medicine is the foundation of clinical medicine — the branch dealing with the diagnosis and non-surgical treatment of diseases in adults, covering almost every organ system (neurology, infectious diseases, psychiatry included) and focusing on the whole disease process rather than a single organ. This opening lecture sets the stage: know where the specialty comes from, what its subspecialties are, how internists think, and the ethical framework that governs patient care. For LMCHK candidates, the single most practical takeaway is that internal medicine is examined as clinical reasoning: pattern recognition → differential diagnosis → evidence-based management — exactly the "10 steps of clinical thinking" taught in this chapter.
Core Concepts
Definition of Internal Medicine
- Internal medicine = branch of clinical medicine dealing with the diagnosis and non-surgical (medical) treatment of diseases in adults.
- Covers almost every organ (neurology, infectious diseases, psychiatry are all within its remit).
- Focuses on the whole disease process (prevention → detection → treatment → compassionate care), not just one organ.
- Practice environments span urgent care → hospitals → clinics.
- Historical roots: the German term "Innere Medizin" (late 19th century) described physicians who combined laboratory science with patient care; early-20th-century American physicians who studied in Germany brought the term to the U.S.
- Modern definitions of the internist: "Physicians for adults" (2009); specialists applying scientific knowledge + clinical expertise to diagnosis, treatment, and compassionate care of adults from health to complex illness (2013).
Founders of the discipline
- William Osler (1849–1919), Canadian physician, "Father of Modern Medicine": brought students from classroom to bedside teaching (Montreal General Hospital, 1879); founding professor at Johns Hopkins (1889, "the big four"); created the residency training program; attended the opening ceremony of Peking Union Medical College (1917).
- Rudolf Virchow (1821–1902), German physician-pathologist, "father of modern pathology": first to correctly link cancer origin to normal cells; described and named leukemia (leukämie, 1847). Eponyms: Virchow's node, Virchow–Robin spaces, Virchow's triad.
Subspecialties of Internal Medicine
| Subspecialty | Scope |
|---|---|
| Cardiology | Coronary artery disease, cardiomyopathy, arrhythmias, hypertension |
| Pulmonary medicine | Lung cancer, asthma, pneumonia, acute bronchitis, COPD |
| Gastroenterology | Stomach, intestines, liver, pancreas (e.g., H. pylori — Nobel Prize 2005, Marshall & Warren) |
| Rheumatology | RA, osteoarthritis, SLE, gout, scleroderma — immunology-related diseases |
| Endocrinology | Thyroid disorders, diabetes, gigantism — metabolism disorders |
| Others | Nephrology, haematology, medical oncology, infectious disease, geriatrics, critical care, interventional cardiology, sports medicine, hospice & palliative medicine |
The disease continuum (Cardiovascular example)
A recurring theme in internal medicine is that diseases exist on a continuum, not as isolated events: endothelial dysfunction → atherosclerosis → myocardial infarction → ventricular remodelling → end-stage cardiopathy (with microalbuminuria → end-stage renal disease as the parallel renal track). Treating risk factors early (hypertension, diabetes, dyslipidaemia) interrupts this cascade — a concept tested repeatedly in exams.
Clinical thinking — "10 steps"
- Anatomy: structural change?
- Physiology: functional change?
- Pathophysiology: pathologic change, developmental mechanism?
- Several aetiological factors?
- Mild or serious?
- Form 1–2 specific hypotheses
- Verify hypothesis with evidence (support or not)
- Special symptoms/signs for differential diagnosis
- Possibility of diagnosis
- Further examination and treatment
Key warnings (from real cases): a disease may not present as the textbook ("56-year-old man with neck ache → actually AMI"); be sensitive to unusual enzyme patterns (CK > LDH > AST > ALT → rhabdomyolysis vs ALT > AST > LDH > CK → liver damage); think reversely and completely — misdiagnosis rate historically 30–40% (1912–1996) due to mechanical, reversed, or overly simplistic thinking. Understand before memorising; correlate with basic knowledge; comprehensive understanding, not simple remembering.
Medical models & ethics
- Evolution of medical models: Spiritualistic → Nature-Philosophical → Mechanistic → Biomedical → Bio-psycho-social model (1977–now).
- Science medicine asks: "What is the correct and effective treatment?" — Humanity medicine asks: "What is the good and appropriate treatment?"
- Four rules of the Oath of Hippocrates: gratitude to the instructor; seek the patient's benefit; do no wrong; keep secrets and respect privacy.
- Three principles: Patient-centered care; patient autonomy; fairness and justice.
- Autonomy in practice: informed consent (competent refusal), truth telling, respecting confidentiality.
- "Good doctor" from the Chinese patients' view: care and communication, explanation in simple words.
HKHA Handbook (LMCHK) — Key Points
- The Handbook of Internal Medicine (Hospital Authority, COC(Medicine), 9th ed., 2024) is the key LMCHK internal-medicine reference — organised by acute clinical problems (Cardiology C, Endocrinology E, Gastroenterology G, Geriatrics Gr, Haematology H, Immunology IA, Infections In, Nephrology K, Neurology N, Palliative PM, plus General Medicine GM and Procedures Pr), each giving the HK-standard investigations + management.
- The handbook is paperless (electronic PDF; eKG internal medicine page: https://www.ekg.org.hk). For exams, be familiar with its structure so you can recall the HK management standard per presentation (e.g., CPR, arrhythmias, ACS, acute pulmonary oedema, hypertensive crisis, CAP, renal failure, electrolyte disorders).
- LMCHK-style internal medicine rewards exactly this chapter's skills: systematic clinical reasoning (10 steps), differential diagnosis, and evidence-based management — not isolated facts.
High-Yield Points
- IM = diagnosis & non-surgical treatment of adult diseases; covers whole disease process.
- Osler = bedside teaching + residency program; Virchow = modern pathology + named leukemia.
- Cardiovascular continuum: endothelial dysfunction → atherosclerosis → MI → remodelling → end-stage heart disease.
- Clinical thinking order: anatomy → physiology → pathophysiology → aetiology → severity → hypothesis → verification → differential → diagnosis → management.
- Enzyme pattern helps localise: CK>LDH>AST>ALT = muscle (rhabdomyolysis); ALT>AST>LDH>CK = liver.
- Misdiagnosis is driven by mechanical/simple thinking — always consider atypical presentations.
- Ethics: patient-centred, autonomy (informed consent, truth telling, confidentiality), fairness.
- Model of care today: bio-psycho-social.
Topic Summary
Internal medicine is the adult medical specialty built on bedside clinical reasoning. This chapter anchored its definition, history (Osler, Virchow), subspecialty landscape, the disease-continuum concept, the 10-step clinical thinking framework, and the ethics of patient care — the intellectual foundation for every clinical chapter that follows. For LMCHK, it establishes the mindset (reason systematically, treat the whole patient) and the source of truth (the HA Handbook's problem-oriented structure) used throughout this course.