Sygdom

Sygdom is the Danish word for disease or illness. In medical usage, a disease is a condition that impairs normal structure or function in a human, animal, or plant, and that can be recognized by signs (objective findings) and symptoms (subjective experiences).

Diseases are commonly categorized as infectious or non-infectious. Infectious diseases are caused by pathogens such as bacteria, viruses, fungi, or parasites, and can spread between individuals. Non-infectious diseases include genetic, metabolic, degenerative, nutritional, and environmental disorders. They can be acute (short-term) or chronic (long-lasting), localized to a body part, or systemic, affecting multiple organ systems. Some conditions are congenital, present at birth, while others develop later in life.

Causes and risk factors vary widely. A disease may result from pathogens, genetic mutations, environmental exposures, lifestyle factors, or a combination of these. In some cases the exact cause is unknown and the condition is described as idiopathic. Risk factors such as age, sex, smoking, or comorbidities influence likelihood and outcomes.

Diagnosis relies on medical history, physical examination, and targeted tests, including laboratory analyses, imaging, and sometimes biopsies. Signs are objective findings, while symptoms are subjective experiences reported by the patient. Many diseases require differential diagnosis to distinguish similar conditions.

Treatment and management aim to relieve symptoms, address underlying causes when possible, prevent complications, and maintain quality of life. Approaches include medications, surgery, lifestyle changes, physical therapy, vaccination, infection control measures, and palliative care for serious illness. Prognosis varies widely depending on the disease and available interventions.

From a public health perspective, disease burden is tracked to guide prevention and policy, with efforts such as vaccination, sanitation, screening, and education. The concept has evolved with advances in germ theory, diagnostics, and classifications like ICD codes used for reporting and research.