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Chronic Pulmonary Infections

Chronic pulmonary infections: There are three that I am really going to discuss, in addition to tuberculosis. There is cocci, histoplasmosis, blastomycosis as well, and tuberculosis. These four infections - the three fungal, the three endemic mycoses and tuberculosis - are chronic pulmonary infections that have to come into your thinking in a child who has a chronic cough or chronic pulmonary infiltrate.

Clinical features of primary illness: most of the time asymptomatic illness is seen. Asymptomatic illness is what most people get and the majority of people who live in endemic areas may be skin-test or seropositive and never have any kind of compatible illness. A fair number of people, a minority but somewhere less than 50% of people, will get an illness that's very difficult to distinguish from a mild respiratory tract.

There are a few peculiarities about cocci and one is that although it doesn't disseminate often, when it disseminates it will kill you. This is a very very serious disease when it becomes disseminated, and for reasons that are not understood, the highest risk of dissemination is in Filipinos. Estimated to be 200-fold higher risk of dissemination than in Caucasians. With Latinos and African Americans falling somewhere in between. When it disseminates, the most common places where diseases establish is meningitis and osteomyelitis, in bones, where you typically get multiple lytic bone defects. The meningitis may be chronic and low grade so that patients may present with hydrocephalus, as we've seen here. In some cases progressive lung disease, liver disease, and cutaneous lesions may also be seen.

How do you diagnose this then? You would suspect this disease in somebody who is from an appropriate endemic area and has this chronic lung disease. Really if the person has never driven through or never even been in a car in an endemic area, or lived in that area, cocci really has to drop significantly down the list. If you want to evaluate it the best way to do so is really to use serological tests. And there are very good serological methods to look for IgM antibody. There is something peculiar about the serology in cocci. I know of no other infectious disease where, when you do a serology titer, it actually tells you something about disease activity. In general, when you get an antibody test and it's IgG positive, you'd look at that and say, "Okay, so he's been exposed at some time in the past." Cocci is different. If you get a comp-fix titer - and the method is important here - but if you send off serology and the comp-fix titer comes back 1-8 or more, you have an 80-90% chance that this patient will have disseminated disease. Meaning a bone focus, joint focus, meningitis, established disease. In fact the duration of treatment is predicated in bone disease on following that titer until it becomes non-reactive. In general, though, most people who have acute pulmonary disease will require no treatment whatsoever.

Now where we've come to is that the triazole agents, fluconazole and itraconazole, probably ... I'm probably waffling a little on the wording here, because they are increasingly being used with good success for disseminated disease. Another thing about cocci, and for that matter histo and blasto, is that they are not transmitted person-to-person, so isolation is not needed.

The next organism, the next fungal disease, Histoplasmosis. This is where you'll find it in the New World. It also can be found in India and other parts of Asia as well. But in general you find histo in North America, in the central river valley area, around the Mississippi and Ohio rivers. That's where you find it. The black areas on the map are where you have the highest rate of disease activity. Histo you will also find in construction, for example. Like the big outbreak that occurred in 1978 in Indianapolis. Outbreaks occur in conjunction with construction where you are really churning up the soil because it's a soil fungus. Recently there was also a report in MMWR about histo occurring in 60% of people who went into certain caves on a spelunker's convention. So histo has some peculiarities in terms of its endemicity as well, but you really have to really have to be in the right area. Histo is also a bad actor.

The diagnosis, however, is probably best made in histo - if you don't accidentally grow it - by virtue of looking for antigen in the urine as well as by serological methods. Like cocci, most cases require no treatment. If there is dissemination, amphotericin is the drug of choice and triazole agents, in particular itraconazole, have been found to be useful for disseminated disease. Like cocci, no person-to-person transmission. We don't need to worry about hospitalized patients.

The third disease of the endemic mycoses, Blastomycosis. This is the only one that I haven't seen. We see plenty of cocci in Southern California. I saw histo in training in New Orleans. Blasto I've never seen and it is the rarest of these. It's geographic distribution, as you'll see on the map, is extremely similar to histo so you won't see Blastomycosis typically in this part of the country. You'll tend to only see blasto when people are from that same Central U.S. to Eastern U.S.

What else to say about blasto? I guess maybe the way to try and encapsulate what I'm saying about these three endemic mycoses is that you can get an abnormal chest x-ray that may or may not be progressive, a cough that can stick with them for months, they are usually not hypoxic but it is obvious that there is some sort of lingering chronic pulmonary disease. Blasto can produce more cavitation, produces cavitation more frequently, though. Here the diagnosis is more difficult because with blasto the serology is no good whatsoever. Unfortunately you are only going to tumble to this diagnosis by culturing the organism from the appropriate specimens.