Patients-not just Images

Devoted to Education and Practice in Patient-centered Radiology

The Zebra Syndrome

Ravi Ramakantan

Very early in life, I learned from a great teacher of surgery that:

“If I told you that, on my way to the hospital, I saw a four-legged animal outside the KEM Hospital (my alma mater in Mumbai), it is likely to be dog or a cat or a bull or a cow.. sometimes a horse, rarely an elephant - but, never a zebra.”

He was very emphatically teaching us an important principle of clinical medicine - that common diseases occur commonly and that the uncommon occur uncommonly but they still can occur; rare things are rare.

It is almost 45 years since that time but the profound importance of this simple truth has not changed except and I have since named it..

The Zebra Syndrome

This principle obviously gets extrapolated to radiology.

When you look at an image and think of a differential diagnosis – always think of the common first and the rare last.

All this would appear to be common sense; but, alas…

Usually what is common is what you have seen frequently in your three-year residency and what you have not seen in three years is not common … and so on.

DO NOT ever try to remember the differential diagnosis by smart, easy to remember mnemonics. If that were so and only memory matters, computers would be far better physicians than…you or I. Fortunately that has not happened even as I write this..

In the examination, do not try to outshine others by enumerating the esoteric first.. you are then stepping on a landmine.. with possibility for a repeat performance.

I also teach – only half-jokingly that Indians are not 6 feet tall or have blond hair and blue eyes. Meaning thereby that to blindly apply data of disease patterns and prevalence from ‘foreign’ books to our context may often be fallacious.

Thus - infiltrates in the right upper zone in a patient in our country is vastly more likely to be tuberculosis than histoplasmosis – no matter what your mnemonics may say.

A four legged animal on the roads in Mumbai is likely to be a .......

zebra syndrome radiology
zebra syndrome radiology
zebra syndrome radiology
zebra syndrome radiology

Sometimes a ...

Surprisingly a ..

zebra syndrome radiology

And rarely, an...

But Never a Zebra!

By the way, have you heard of the animals that teach us about the