X-rays à l'ancienne

As a medical student, you are often asked to "take a look at this X-ray". Sitting in front of the computer, mouse in hand, you quietly begin to scan the image in front of you for abnormalities. If the doctor has asked you to look at it, there must surely be something there to see. But you see nothing. Fortunately, you have a few tricks up your sleeve: a flick of the mouse-wheel and the image is magnified; a click-and-drag changes the contrast to further increase your chances of success. Still nothing. A few clicks and the patient's last two X-rays appear on-screen for you to compare. Expectant silence from the crowd behind you. Finally, there it is: a subtle fleck you had not so much ignored as simply not seen; suddenly the diagnosis becomes obvious.
Nowadays we're not often exposed to old-fashioned X-ray films, so it's easy to forget that this is a very privileged and modern way of looking at radiographs.

The scenario here is quite different. The X-ray comes out of a large brown envelope which is carried around by the junior doctors. Most of the rooms don't have a light-box, so you have to hold the film up to the light. This is harder than it sounds: too much light and you find yourself gazing through the image at the patients and doctors who are watching you. Not enough light and you simply can't make out anything. Try to ignore the fingerprints and the patient ID slip which has conveniently been stapled to the film. No zoom, no contrast setting, no integrated ruler; it's just you and the film, locked in a staring contest. The whirr of the ceiling fans is eventually interrupted when you accidentally loosen your grip on the film and it noisily flops down, lifeless.
When the decision to start TB treatment rests on your interpretation of the X-ray, you suddenly wish you had a dark room and a high-definition monitor to call upon.

TB or not TB?

I've always thought of tuberculosis as a disease of the lungs. I won't pretend that it's because of La Traviata and her persistent coughing which punctuates Puccini's work. Even after three and half years of medical school, I couldn't help associating TB with coughing, weight loss and a few other symptoms.
Of course, this isn't wrong: the lungs certainly are a site of predilection for Mycobacterium tuberculosis. It likes to set up camp there and hibernate for years, sometimes a whole lifetime. But despite this affinity for the draughty recesses of the chest, TB also enjoys going for a wander elsewhere. The spine, the kidneys, the eyes: no sites are really off limits for this bacterium if the conditions are right.
The conditions are definitely right in this patient. He contracted HIV many years ago and has not been receiving any antiretrovirals. Slowly, but surely, the virus has gained the upper hand over his immune system. Today, his body is essentially a very badly defended shelter for whichever micro-organism might choose to invade.
He came in to the hospital because he was having difficulty walking. On examination, he is weak all along his right-hand side. He has swollen lymph nodes throughout his body, along with headaches and fever. This picture is typical for toxoplasmosis, but the doctors here are convinced it will turn out to be TB in the brain. There's so much of the disease around, the investigations will probably prove them right.
A few weeks ago I would never have associated TB with hemiplegia, particularly if the patient didn't have any chest symptoms. Perhaps someone could have guided me there with some leading questions, but the two things just weren't linked in my mind. Having now seen nearly a dozen cases of TB meningitis, I'm starting to realise that most things could be due to this disease.