The cascade effect involves:
(1) an initial finding or action that is relatively minor and unimportant
(2) someone (the patient, the physician, etc) responds to the finding
(3) because of the response something happens that requires another response
(4) each response becomes more complex or costly or risky
(5) eventually something negative happens, which in hindsight was unnecessary
Examples:
(1) an imaging study that finds an incidental tumor in an asymptomatic patient, resulting in major surgery
(2) a drug that has an adverse effect which is treated with another drug, which triggers the need for another, and so on
(3) a workup of a single abnormal laboratory test that results in an investigation that snowballs
Risk factors for the cascade effect (Mold and Stein):
(1) inaccurate or incomplete information, including unfamiliary with a patient or condition
(2) an error (data analysis, test result, interpretation)
(3) underestimation of an intervention's risk
(4) feeling a need to act (because of anxiety, compulsion to act or other factor)
(5) ordering unnecessary tests or prescribing unnecessary drugs
(6) not being able to stop before the situation becomes out of control
It can be very difficult to know when to pursue a finding and when not to. Experience with a disease and a discussion with the patient often can prevent an intervention from getting out of control.
