Generating a differential diagnosis — that is, developing a list of the possible conditions that might produce a patient's symptoms and signs — is an important part of clinical reasoning. It allows a provider to perform appropriate testing to rule out possibilities and confirm a final diagnosis. Courts view the formulation and documentation of a differential diagnosis as evidence of a physician's competence, prudence, and thoughtfulness.

In 1966, Abraham Maslow, a renowned psychologist, said, "I suppose it is tempting, if the only tool you have is a hammer, to treat everything as if it were a nail." Do your records make it look like you treat every patient like a nail? Do they all have the same diagnoses and the same care plans?

Payers sometimes accuse chiropractors of providing cookie cutter care where every patient receives the same treatment regardless of the cause of their problem. Documenting a differential diagnosis lets third party reviewers know that you have considered all the possibilities.

Though it might not be common, consider the following case study.

57-year-old obese male, smoker, complains of severe low back pain that radiates to his abdominal area. Occasionally the pain is so bad that he vomits. X-rays come back normal, so the chiropractor begins treatment. Two days later the patient is dead, from a ruptured abdominal aortic aneurysm. The family of the deceased threatens to sue.

In appropriate clinical circumstances, the medical record should indicate that the diagnosis with the worst prognosis, in this case AAA, was considered and was pursued if reasonable to do so. The rationale for not investigating should also be clearly documented.

This kind of thing, fortunately, does not occur often. Regardless, how can a good doctor document the differential diagnosis without appearing like he or she is unable to make a clinical decision?

In this example it might have been "differential diagnoses such as gastroenteritis and AAA were considered and the patient was advised of the proper actions to take." Some cases may be so straightforward that there really is no differential diagnosis. Even then, it may be wise to simply state that differential diagnoses were considered and none appeared to apply to this case.

Use your best clinical judgment, document what you are thinking when you see a patient, and avoid being accused of ignoring differentials that could impact your patient and your medico-legal liability.