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A 58 year old man of Arabic descent presented to the clinic with a cough.

As one may surmise, this is one of the most common reasons people come to the clinic. The tussive reflex is meant to keep the airways clear of debris but, as we have seen before, this can get way out of hand.

The patient’s cough was dry and fairly constant throughout day and night. It has been accompanied by feelings of being feverish, although he never took his own temperature (we call these “tactile fevers”). He also complains of night sweats and general malaise. All these have been going on for over a week. He denies head congestion, runny nose, sore throat, nausea, vomiting. His daughter is also sick with something similar. He does not smoke or use drugs. He has no history of chronic lung ailments such as asthma or COPD. Recent travel includes his family’s participation in the Hajj a month ago or so.

His exam was unremarkable; his lungs sounded fine. His vital signs were fine, including temperature and oxygen levels. A chest X-ray was unremarkable (remember that “unremarkable” is the medical way of saying “good”). Bloodwork was ordered.

WHAT IS YOUR GUESS AS TO THE DIAGNOSIS?

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Active pulmonary infection with Mycobacterium tuberculosis

la boheme

TB continues today as one of mankind’s most ancient and most persistent enemies, having bedeviled civilization for as long as humans have gathered together in settlements. Transmitted by air, the risk of catching the ailment is directly proportional to population density, which probably impacted life expectancy of our earliest cities. Evidence of TB is found from ancient China, Africa, Europe, and even the New World. Hippocrates considered it the most widespread disease of his time. And before the introduction of antibiotics, it was almost always fatal.

Tuberculosis is a difficult infection to diagnosis if the chest X-ray is clear, which can happen early on as with my patient. The standard pre-employment PPD skin test can only tell if you’ve ever been exposed to it in your life, or have had the BCG vaccine; it does not tell you if you currently have an active infection. The Quantiferon blood test is better, and this patient was positive for that, but even in this day and age TB is mostly a clinical diagnosis: you have to go by the history and physical. An AFB stain often yields false negatives. The real test for it — the culture — takes literally weeks to come back, and the patient must be started on medication while you wait.

Like the culture, the disease is one that takes its time. Staph aureus it ain’t: Mycobacterium tuberculosis does not rampage through a person’s bloodstream, killing within days, or instantly put grandmothers in the ICU like a typical pneumonia. It is a patient killer, slowly establishing itself in your lungs, gradually causing damage over months and years, eventually metastasizing like a particularly lazy form of cancer. It may wander to the abdomen, the brain, the skeleton, the genitals. And, just like cancer, the patient gradually wastes away as if being eaten from the inside by the disease. Hence, its old name, consumption.

Early on, even the chest X-ray may be clear as with my patient. Sure, they’ll have a cough, but then again, who at the urgent care clinic doesn’t have a cough? Fever and night sweats for longer than a day or two indicates something more severe than a routine URI. You also have to listen for the dogs who aren’t barking: no congestion, no preceding cold or flu, no sore throat. But most importantly, they will have exposure to TB. And crowding along with millions of others in the Hajj is one massive exposure risk.

Because the bacteria is so hard to kill, it takes months or even years of medication to fully eradicate the disease. And, as with most diseases, resistances are increasingly a problem. The traditional regimen of INH and rifampin is no longer enough; patients are now typically started on no fewer than four antibiotics. (And Lord help you if this is not enough.) Because the regimen is so difficult, and because the public health risks are so grave, patients undergo directly observed administration of their pills as if they were methadone patients. This is obviously beyond an urgent care’s scope, and the patient and his daughter were referred to the health department.

Incidentally, TB in the industrialized world is also associated with HIV. So perhaps it is fitting that the scourge of the opera La bohème, TB, gets supplanted by AIDS in its descendant musical, Rent.

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