A Sequela is a pathological situation resulting from another disease, trauma, or other injury. For example, chronic kidney disease is often a sequel of diabetes, and pain in the neck can be a normal sequel of cervical whiplash, or additional injury to the vertebrae. PTSD or “Post-traumatic stress disorder” might be an emotional sequel of rape. Sequelae of brain injury that is traumatic can include dizziness and headaches, apathy, anxiety, depression, cognitive diminishing, aggression, mania, personality changes, and psychosis. Typically a sequel is a disorder that is chronic and that is a complication of an acute disorder and began during the acute disorder.

Some medical conditions can be diagnosed with hindsight from their sequelae.

Other instances of sequelae consist of those following injury of the nerve; including ataxia, aphasia, hemi- and quadriplegia and any amount of other deviations that may be caused by nerve trauma. Note that these pathologies may be related to both chemical and physical traumas, as both can cause lasting neuron damage.

The phrase “status post”, is written with the abbreviation s/p, and is used to confer sequelae with reference to their cause. Clinicians classically use this phrase to denote back to the acute traumatic conditions.