A burn scar is not a complication, and doctors care about the difference
In medicine a complication is an unwelcome turn: a disease or a treatment makes things worse or sparks new problems elsewhere in the body. It is distinct from a sequela, the lasting mark an illness leaves behind, and from a comorbidity, an unrelated illness that merely happens alongside.
Complications can deepen the severity of an illness or trigger fresh symptoms and tissue changes that spread to other organ systems, sometimes producing new diseases outright. Who suffers them depends on age, overall health, immune status and individual vulnerability. Knowing which complications a disease or procedure most often causes lets clinicians try to prevent them and prepare in case they occur.
The vocabulary is precise. A sequela is a residual effect following the acute phase of an illness or injury, such as scarring after a burn or swallowing difficulty after a stroke. A comorbidity is a disease present at the same time with no causal link. Adverse effect overlaps with complication but tends to be used for drugs, or for harms that are expected or common.
Many complications stem from care itself, and medical errors fall into several recognisable families. Prescribing mistakes arise because medication orders pass through many hands; electronic prescribing, pre-packaged unit doses and better patient understanding help. Surgical errors most often mean operating on the wrong site or wrong patient, which is why standard protocols demand identity checks and marking the site. Diagnostic errors, whether missed, wrong or excessive diagnoses, often reflect patient characteristics and physician bias. Other categories include clumsy interaction with equipment, slips during handovers between people or sites, and breakdowns in teamwork. The proposed remedy for the last is a culture of safety in which staff can raise concerns and admit mistakes without fearing punishment.
Infections picked up during treatment form a large group. They most often follow indwelling devices such as urinary catheters and central lines, or earlier surgery, and commonly involve bacteria such as Escherichia coli and Clostridioides difficile. Hand hygiene is the single most effective defence.
Source: Complication (medicine)
