voiceover: i'm charles prober. voiceover: and i'm morgan theis. voiceover: and in thisvideo, we're going to talk about pulmonary diseasecaused by tuberculosis. the reason we're dedicating afull-on video to pulmonary disease is that pulmonary disease is the mostcommon form of clinical tuberculosis. it represents somewhere between60 and 80% of all clinical disease attributable to tuberculosisworldwide, so it's way important. voiceover: okay.
voiceover: with pulmonary disease,as with any form of tuberculosis, disease may result eitherfrom a primary infection that is the first time thehost is seeing the infection, and that's called primary,or it may be secondary, which results from reactivationof dormant infection or sometimes from infectionfrom a second source in a person who had a prior infection. it's their second experiencewith tuberculosis. the distinction between these twois that with primary tuberculosis,
pneumonia following primary tuberculosis, or pulmonary diseasefollowing primary tuberculosis is more common amongstchildren than adults. children are more likely tomanifest pulmonary disease with their primary infection. then the other contrasting elementis that with primary tuberculosis, the part of the lung which is involved is usually the lowerlobes or the middle lobes. that's contrasted fromsecondary tuberculosis,
where the part of the lung that'sinvolved is usually the upper lobes. it is said that this differenceresults from the higher oxygen tension in the upper lobes, which ithink facilitates reactivation, but i'm not sure about themechanism, but nonethless, it is an association whichhas stood the test of time. from a clinical standpoint, thedisease caused by tuberculosis can be the same whether it'sresulting from a primary infection or from a secondary infection. the disease can be alongan entire spectrum.
at one end of the spectrum is mild disease with a minimal amount of symptomsattributable to the infection and at the other extremeit can be very severe with progressive lung damage, severedisability, even leading to death. not only is there differencesalong that clinical spectrum, but in parallel, there are radiographicdifferences along the spectrum. in some occasions, pulmonarydisease is associated with a small infiltrate, a smallabnormality on the chest x-ray, whereas at other times thedisease may be widespread
throughout both lungs and maytake on a cavitary appearance, which results from lungparenchymal destruction, so really across a broad spectrum. voiceover: okay, so with eitherprimary or secondary pulmonary tb, you can be anywhere on this spectrum? voiceover: exactly. voiceover: the otherthing that i would say about pulmonary tuberculosisis if it is not recognized and not treated or back in the day
where there was noanti-tuberculous therapy, the clinical course of disease,a so-called natural history, that is what happensif you don't treat it, was divided a third, a third, and a third. one-third of patients went on to dieof their untreated pulmonary disease, and that death could often bequite rapid and it was called, back in the day, galloping consumption,consuming the person's life. that's about a third. a second third, the patients wouldactually spontaneously remit,
they would get better. their signs and symptoms would goaway and they would then be well. then the final third would haveprogressive lung involvement, not galloping, but more slow,and this was often referred to as consumption without theword galloping in front of it. that would be the naturalhistory of tuberculosis. voiceover: it always seemslike they should just call it the natural course, instead of thenatural history, but there you go. voiceover: i think thatthat's a good point.
now, when you see somebody whomay be infected with tuberculosis, they often have, in addition totheir pulmonary signs and symptoms, they have other nonspecificsigns and symptoms. so, this person who's lyingin bed and you can see, first of all, the personappears to be quite thin. in fact, weight loss is verycommon as a nonspecific finding of any chronic illness, butin this context, tuberculosis. other common so-called systemicsymptoms associated with tuberculosis are fevers and the fevers maygo on for a long period of time,
days to weeks to months. the fevers may beassociated with sweating, and that sweating often is mostprominent at nighttime, i'm not sure why, but that's so called night sweats,and this combination, of course, makes somebody just feel generally unwell, they have so-called malaise,they don't want to eat, so they're anorexic and thatcontributes to the weight loss. these are the systemic symptomsthat may accompany any kind of tuberculous infection,including lung disease.
then there are some signs, inaddition to the signs you will get because you have pneumonia, so the clinical signsassociated with pneumonia, or the clinical signs associated with progressive pulmonary symptoms, things like cough, shortness ofbreath, inability to breathe well, especially when laying down at nighttime. in addition to those findings, thereare some other nonspecific things that you should keep in mindwhen you're contemplating tb
as a diagnosis and they'reshown in the pictures. one picture, the bottompicture is of the legs of a young individual who has tuberculosis and it shows these elevated, red nodules. red, erythema, and nodular, nodosum, and this is referredto as erythema nodosum. it is not specific to tuberculosis. it can occur in other diseases,including some fungal infections, like that caused by coccidioidomycosis,
and including streptococcal infections, but it also is associatedwith tuberculosis and the upper picture,of course, is an eye and this is showing a particularform of conjunctivitis, so redness of the eye,and that is referred to as phlyctenular conjunctivitisand that is something which is associated withtuberculosis as well and i wouldn't worry toomuch about spelling it because it's kind of difficult to spell.
voiceover: all right, well - voiceover: as morgan is demonstrating. l-y-c-t-e-n-u-l-a-r, phlyctenular. voiceover: phlyctenular. voiceover: conjunctivitis. these are some of the signs and symptoms that may be associated withtuberculosis in general in pulmonary tb, which is thepredominant form of clinical disease. voiceover: the finalthing we'd like to spend
a few moments talkingabout, because it's at least in the chest cavity ispleural tuberculosis. this is little bit distinctfrom pulmonary tuberculosis, of course the pleural membraneis that which surrounds the lung and pleural disease caused by tuberculosiscan result in one of two ways. one is that it may be associated withthe first infection, primary infection and it is said that it canbe due to hypersensitivity, so an immune reaction ofthe body to the infection. then the other way that it canresult, either from primary disease,
or i think with secondarydisease, as well, is as a result of contiguous spread. direct spread of the infection fromthe lungs into the pleural space. one of the distinguishingfeatures of pleural tuberculosis, compared to other formsof a pleural infection is that the effusions mayreally be quite large. the one that you've drawn showing itin the lower part of the left lung, is a modest-sized pleural effusion, but sometimes it can beeven larger than that
and extend along the wholeside of the pleural space. a large pleural effusion,when you see that, you should think of tuberculosisas sort of one cause. pleural effusions result in anextension of the pulmonary symptoms. you can imagine because they'resqueezing down the lungs that the person is short of breath. if you percuss their cheston physical examination, it sounds dull, because there'snot air that you're percussing, but rather the solid pleural fluidand when you listen to their chest,
they may have decreased breath sounds, because you're not hearingthe lung as clearly, because the pleural fluid is inbetween the stethoscope and the lung. the best way to figure out what'scausing a pleural effusion in general and for tuberculosis specifically,is to sample the pleural fluid, to do a pleurocentesis, a pleural tap. when you do that, the typical findings are that the fluid appears straw incolor, so yellowish in color, it typically has a veryhigh protein concentration,
a low to normal glucose concentration, and white cells that numberbetween 500 and a few thousand. voiceover: is that high or low? voiceover: that's high, there shouldbe no white cells in the pleural space. there should be no pleuralfluid, so 500 to a few thousand. with a bacterial effusion, it may be a much higher white count than that,but with tb it's in that range. you can try to visualizethe tb in the pleural fluid by doing a tb specific stain, such asa ziehl-neelson stain, or a zn stain.
voiceover: so it'sz-i-e-h-l-n-e-e-l-s-e-n stain and that's actually lookingfor the tuberculosis bacteria. voiceover: right. voiceover: the ziehl-neelsenstain is positive somewhere between 10 and 25% of the time when tb is actually there,so it's not very sensitive. culturing the fluid is more sensitive. it takes a longer time, it can takeup to four to six weeks to culture and it has a sensitivityin the range of 25 to 75%.
actually, the best sensitivityand the test, therefore, that you should do, if you thinkthat this effusion represents tuberculosis is tobiopsy the pleura itself and a pleural biopsy hasa yield of about 80%. if you think somebody's gotpleural tb with an effusion, pleural biopsy certainly should be done.
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