SPOTTING THE CURABLE

"To cure sometimes, to relieve often, to comfort always", wrote 16th century physician Ambroise Paré. Medical malpractice litigation is concerned almost exclusively with cure, even though failure to relieve and comfort are major causes of litigation enquiry ¹.

In reality, many diseases remain largely incurable and the first decade of Evidence Based Medicine has slain a large herd of traditional medicine's sacred cows ².

The medical malpractice prosecutor without medical training often has difficulty not only taking off the lenses of 20/20 hindsight but also appreciating the art-science of diagnostic process ³.

Alongside the likely diagnoses, physicians must also consider diseases that are improbable but curable. Where the cause of action is delayed diagnosis, defendant physicians and medical expert witnesses often struggle to find a balance point between systematic refinement of the most probable diagnosis on the one hand, and exclusion of treatable causes however improbable on the other hand ⁴.

Unusual presentations of common diseases are common. A central problem is that a significant minority of patients with common diseases present with patterns of symptoms and signs that are so atypical ⁵ that much time and other resources are first spent excluding more probable causes. Apart from economic considerations, acute diseases that require urgent treatment may be diagnosed too late for optimal intervention.

In unexplained unconsciousness or coma, there may be no circumstantial evidence to suspect low blood sugar (hypoglycemia), but standard management includes taking a blood sample for later analysis and immediately injecting a diagnostic and therapeutic dose of sugar ⁶: there are no medical conditions - including diabetic coma - in which this intervention has any harmful effect.

Common causes of missed diagnosis litigation illustrate different facets of this dilemma.

As a result of the traditional method of clinical teaching, physicians considering coronary artery disease ⁷ as a cause of acute chest pain ⁸ frequently place inappropriate emphasis on risk factors, despite the availability of accurate diagnostic check-lists ⁹. These pseudodiagnostic considerations may be a major factor in the erroneous emergency room discharge of 4-8% presenting with myocardial infarction ¹⁰.

Bacterial Endocarditis, by contrast, is a rare disease but one with a high litigation rate ¹¹. The community standard is a delay of some weeks between onset of symptoms and diagnosis, often because the symptoms, individually and in combination, are common to self-limiting infections that are very common.

Bacterial Meningitis is misdiagnosed most often when early treatment is least likely to make a material difference to outcome, on balance of probability ¹². Diagnostic spinal tap is not only painful and unpleasant, but also accompanied by significant risk of adverse outcome ¹³.

Some errors are inevitable for the patient's safety. Acute appendicitis present a different dilemma ¹⁴. Some clients seek to litigate removal of a normal ("lilywhite") appendix even though the chronic postoperative symptoms may not be attributable to substandard surgical technique or poor postoperative care.

Because clinical symptoms and signs are often atypical and diagnosis of acute appendicitis is far from an exact science, removing a significant percentage of normal appendices is a price that must be paid if risk of life-threatening rupture of the appendix is to be minimised ¹⁵.

Missing a diagnosis may have no causal implications. Screening people who are free of symptoms and apparently well may be more effective than early detection of disease after symptoms first appear.

Common examples are Pap smears for carcinoma of the cervix ¹⁶, measurement of eye pressure before glaucoma damages eyesight irreversibly and newborn tests for the rare but treatable brain-damagers, PhenylKetonUria (PKU) and underactive thyroid activity (hypothyroidism).

Less commonly recognised is that the prognosis of some colon cancers has changed little in 25 years ¹⁷, and universal routine colonoscopy for those over 50 years old may be the only intervention with a material impact on outcome ¹⁸.

Copyright © 2009 Electronic Handbook of Legal Medicine