Pathology

 the precise study and diagnosis of disease

Pathogenesis

is the mechanism by which the disease is caused

Etiology

the study of causation, or origination

Idiopathic

arising spontaneously or from an obscure or unknown cause

Iatrogenic

an inadvertent adverse effect or complication resulting from medical treatment or advice

Nosocomial

Diseases acquired as a consequence of being in a hospital environment

Remissions

Periods when clinical manifestations disappear or diminish significantly

Exacerbation

Periods when clinical manifestations become worse or more severe

Sequelae

is a pathological condition resulting from a disease, injury, or other trauma