informed consent

**Core elements (must be present):** 1. **Capacity**: the patient can understand, appreciate, reason, and express a choice. Capacity is decision-specific and assessed by any physician. Competence is a legal determination made by a court. 2. **Disclosure/information**: the physician explains the diagnosis (if known), the nature of the proposed intervention, its risks and benefits, reasonable alternatives (including no treatment), and the risks and benefits of each. The standard is what a "reasonable patient" would want to know. 3. **Understanding**: the patient comprehends the information. Use a qualified medical interpreter if needed (not family members), plain language, and teach-back. 4. **Voluntariness**: the decision is free of coercion or undue influence. 5. **Decision/authorization**: the patient agrees (or refuses). Consent is a process, not just a signed form. It can be verbal or written (written is typically required for surgery, anesthesia, blood transfusion, and research). The patient can withdraw consent at any time.

**Exceptions (consent not required):** - **Emergency (implied consent)**: the patient is incapacitated, there is an immediate threat to life or health, and no surrogate is available. The physician assumes a reasonable person would consent. - **Patient waiver**: the patient voluntarily declines information and delegates the decision to someone else. - **Therapeutic privilege**: the physician withholds information that would cause severe harm. It is rarely justified and very narrowly applied. - **Lack of capacity**: use a surrogate (see below). - **Public health or legal mandates**: for example, involuntary treatment of some communicable diseases (such as active TB) or court-ordered treatment.

**Patients who lack capacity:** - Follow an advance directive, if present, such as a living will or durable power of attorney for healthcare (the health care proxy). - If there is no directive, use a surrogate in the usual order: spouse, adult children, parents, siblings, and so on. - Surrogates should use **substituted judgment** (what the patient would have wanted). If the patient's wishes are unknown, use the **best interest** standard.

**Minors:** - Parents or guardians generally consent for minors. - Minors can consent on their own in some situations: **emancipated minors** (married, in the military, self-supporting, or declared by a court) and treatment of **STIs, pregnancy/contraception/prenatal care, substance abuse, and (in many states) mental health**. Minors do not need parental consent for these, and confidentiality is maintained. - In an emergency, treat without parental consent. If parents refuse life-saving treatment for religious reasons, treat the child and seek a court order if time allows.

**Other high-yield points:** - **Refusal of care**: a patient with capacity may refuse any treatment, even if it is life-saving. Make sure the patient understands the consequences, then document the discussion. - **Pregnant patients**: a pregnant woman with capacity can refuse treatment even if it may harm the fetus. - **Research**: consent is overseen by an Institutional Review Board (IRB). It must be voluntary, and participants can withdraw at any time without penalty. Special protections apply to vulnerable groups such as prisoners, children, and pregnant women. - **Physician conflict of interest**: disclose it. - **Disclosure of medical errors**: the physician must disclose them to the patient. - **Legal consequences**: treating without valid consent can be **battery** (unwanted touching). Inadequate disclosure of risks can lead to a **negligence** claim. - **Historical context**: the Nuremberg Code (1947), the Declaration of Helsinki, the Belmont Report (respect for persons, beneficence, justice), and the Tuskegee syphilis study (a major ethical violation that led to modern research protections). - **Decision-making capacity vs. psychiatric illness**: a psychiatric diagnosis (for example, schizophrenia or depression) does not automatically mean a patient lacks capacity. - **Informed consent vs. assent**: assent is the agreement of a child or an adult who lacks capacity. It is sought in addition to the surrogate's consent but is not legally sufficient on its own.

**Common USMLE scenarios:** - A patient with capacity refuses a necessary treatment: respect the decision and document the discussion. - An unconscious patient arrives in the emergency department: treat under implied consent. - A family member asks you not to tell the patient the diagnosis: the patient has the right to know. Ask the patient how much they want to know, and respect a waiver if they decline. - A 16-year-old requests contraception or STI treatment: treat confidentially without parental consent. - A patient needs a medical interpreter: use a trained interpreter, not a family member.