Uncertainty in medical practice can throw House rules into disarray
IN medical TV dramas, patients frequently present with baffling symptoms. As the hour progresses, so the patient declines while lesser doctors strive in vain for a diagnosis. Then, when all seems lost and the case completely inexplicable, Dr Hero MD furrows his brow one last time and discovers the vital clue others have missed. Amid gasps of wonder and gratitude, the villain’s true identity is finally revealed. The miscreant is usually some magnificently rare but eminently treatable condition, allowing for a suitably upbeat closing scene.
Does this compare to my surgery? Would reality GP-TV provide similar excitement?
Unexplained or unusual symptoms are certainly common in general practice, but they rarely play out in a way that would make for great telly — despite most GPs being better-looking than Dr House.
While textbooks commonly set out algo- rithms that provide logical pathways from presentation to diagnosis, in reality doctors often rely on pattern recognition, a skill most humans are very good at. Quite often while taking a history or conducting an examination the bits just fall into place, and the diagnosis simply presents itself.
When this doesn’t happen, getting a really thorough history is usually helpful. Every illness has a narrative, and getting the story will tell at least what genre of illness you’re dealing with. A good examination and some tests will often then reveal the precise title.
Not infrequently, however, even after a thorough history, examination and initial tests we are unable to make a definitive diagnosis. Uncertainty is part and parcel of medicine, particularly general practice. Why is this? Is it just because most of us are Constable Plod, baffled by cases that medical super sleuths would crack in an instant? And what do we do in the face of diagnostic uncertainty?
Of course, some doctors are better diagnosticians than others, but GPs are in a difficult position. Most patients with complex and confusing symptoms, scant physical signs and inconclusive test results will not turn out to have a rare or life-threatening disease.
This is not to say nothing is wrong with them — many will have very real illnesses such as fibromyalgia, irritable bowel, regional pain syndrome or somatoform disorder, where psychological distress is being expressed as bodily symptoms. Nonetheless, rare diseases will occasionally turn up.
By definition they are not things we see regularly, so we are unlikely to recognise their particular pattern. On the one hand we don’t like to over-investigate. I’ve lost count of the times I’ve tested for porphyria without ever getting a positive result. On the other, failing to make a significant rare diagnosis leaves both doctor and patient feeling pretty awful.
So what guides us in the zone of uncertainty? Generally we try and keep in mind likely common causes and possible serious ones. We also remember that unusual presentations of common illness are more common in general practice than typical presentations of rare diseases. The patient with headache, for instance, commonly has tension headache or migraine. Typical presentations require no further investigation.
Most of those with atypical features will still have a benign cause, but once a slight possibility of temporal arteritis, cerebral infection, haemorrhage or tumour has been raised we feel obliged to exclude it. When exactly we reach the threshold for conducting further tests or referral is a matter of judgment and experience.
So even in this high-tech age, uncertainty remains very much a part of medicine and even the best diagnosticians need to know how to cope with it.
We all hope to provide our patients with a prompt, definitive diagnosis, or if not, at least exclude major pathology. It’s always interesting, and sometimes a truly fascinating process. But you’d need a lot of editing to make GP-TV competitive in the ratings. Simon Cowap is a GP in Newtown, Sydney