Medical history

The medical history or (medical) case history (also called – typically discharge summary to referring GP, or anamnesis, especially historically) (often abbreviated hx or Hx) of a patient is information gained by a physician by asking specific questions, either of the patient or of other people who know the person and can give suitable information (in this case, it is sometimes called heteroanamnesis), with the aim of obtaining information useful in formulating a diagnosis and providing medical care to the patient. The medically relevant complaints reported by the patient or others familiar with the patient are referred to as symptoms, in contrast with clinical signs, which are ascertained by direct examination on the part of medical personnel. Most health encounters will result in some form of history being taken. Medical histories vary in their depth and focus. For example, an ambulance paramedic would typically limit their history to important details, such as name, history of presenting complaint, allergies, etc. In contrast, a psychiatric history is frequently lengthy and in depth, as many details about the patient's life are relevant to formulating a management plan for a psychiatric illness.

The information obtained in this way, together with the physical examination, enables the physician and other health professionals to form a diagnosis and treatment plan. If a diagnosis cannot be made, a provisional diagnosis may be formulated, and other possibilities (the differential diagnoses) may be added, listed in order of likelihood by convention. The treatment plan may then include further investigations to clarify the diagnosis.

A practitioner typically asks questions to obtain the following information about the patient:

History-taking may be comprehensive history taking (a fixed and extensive set of questions are asked, as practiced only by health care students such as medical students, physician assistant students, or nurse practitioner students) or iterative hypothesis testing (questions are limited and adapted to rule in or out likely diagnoses based on information already obtained, as practiced by busy clinicians). Computerized history-taking could be an integral part of clinical decision support systems.

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