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Video transcript

this is Charles prober and I'm Morgan theis and we're back to talk about part two of two of extra pulmonary disease and the reason we created two videos on this again is because tuberculosis is such an important worldwide pathogen and in part two we're going to focus on TB infection involving the bones involving the gastrointestinal tract the central nervous system and infection of the heart or around the heart so called pericarditis the bones that are most prominently affected actually the most common is the vertebral column that's odd it is odd because when compared with other kinds of bone infection for example acute hematogenous osteomyelitis which is usually caused by a staph aureus the the spinal column is actually quite uncommon it occurs but it's quite uncommon bone infections tend to occur in weight-bearing areas because they take so much trauma just in daily life but with staff those weight-bearing joints are usually the hips and so the lower extremities and not so much the vertebral column but for TB the vertebral column is commonly affected and I'm not exactly sure why so I have a question about that because back pain is a really common complaint I think it's like 40% of primary care doctors achieve complaints from patients so how would you distinguish TB in the spinal column which is within the vertebral column which is very scary from you know your muscle strain or something like that so that's a very important point and the physical examination can be helpful because with an infection of the vertebral columns as you push along the back along the spinal column you may encounter an area of exquisite tenderness and pain and that would be more suggestive of a bone infection and the bone infection could include tuberculosis so that's all I'm going to say about TB involving the bones it can't involve other bones but remembering the vertebral column is particularly important there's a name that is associated with vertebral TB that I mentioned called pots disease and platz disease is simply tuberculosis of the spinal column radiographically which you see is two adjacent vertebrae that tend to be eroded with the infection so pots disease the next form of tuberculosis that I'll mention extra pulmonary tuberculosis involves the central nervous system and it's much less common than these other forms that we've already spoken about estimated to maybe be about 5% of infections but the problem is because it involves a central nervous system it can be very serious leading to substantial long-term consequences morbidity and also potentially leading to death so though less frequent it is very important and the thing about tuberculosis involving the central nervous system compared to other regular bacteria like pneumococcal meningitis or meningococcal is that tuberculosis tends to be subacute in presentation it doesn't the symptoms and signs don't come on over a couple of days they come over a couple of weeks or even longer so they sneak up on the patient in clot in terms of causing disease and at the very beginning the symptoms may be really quite nonspecific meaning they don't point to a particular kind of infection or even sight so the patient may have a couple of weeks of a headache or a little bit of confusion some slight mental changes associated with nonspecific things like fever and feeling rundown and not wanting to eat sort of those general symptoms that we've also talked about in the context of TB in the chest but if it's not recognized as a problem sneaking up the patient and it continues to progress the patient may have a progressive decreased level of consciousness and some patients present with very advanced disease coming in in coma oh dear and as you might anticipate it's better to recognize this earlier rather than later there are good data when you treat TB involving a central nervous system if the infection is treated very early on with the nonspecific symptoms the patients often do quite well whereas if it's not treated until the patient comes in coma the patient's often do very poorly okay and when you're talking about the CNS sites you're talking about meningitis and then is that the main thing that you see or do you see anything else in the central nervous system so meningitis is the main thing you see and you've drawn at the base of the brain in green the inflammation and that's a well-placed drawing because you are correct that TB often involves a so called basal ER area of the brain and the reason that that is important is it's an association that will make you think more of TB but also what often happens is this inflammatory response at the base of the brain entraps the cranial nerves that come off the base of the brain and patients often present with cranial theives abnormalities in their cranial nerves so that should be a tip-off to consider tuberculosis more likely the other important element of it involving the base of the brain is that the infection interferes with the flow of spinal fluid so it blocks the flow of spinal fluid and these patients may develop increased spinal fluid in the ventricles or hydrocephalus and that's another tip-off that this might involve that the infection might be involving tuberculosis when you are evaluating a patient with suspected TB meningitis or any meningitis for that for that matter a spinal tap is usually part of the workup after you've assured yourself that it's safe and with tuberculosis the typical results of the spinal tap is there are and Inc there are white cells present and the white cells are often lymphocytes in their nature and the number often in the range of several hundred to maybe a couple of thousand also the protein concentration in the spinal fluid tends to be quite increased and progressively so so it can go 100 200 or several hundred hundred and the glucose tends to be a little bit depressed but not as severely so as acute bacterial meningitis caused by pneumococcus so the glucose instead of being zero like it can be with pneumococcus maybe in the 20 to 30 range you may see when a stain is done for tuberculosis some of those little red characters under the specially stained CSF but often times and it but that's only occurs about a third of the time that you can actually see them even with the special stains microscopically so you culture them like for other forms of TB and the culture is positive about 80 percent of the time there's also a PCR test available for tuberculosis that especially in the developing world is used to augment our ability to diagnose it so that's tuberculous meningitis we're not talking much about treatment here but one thing that I will throw in is that the role of steroids in tuberculous meningitis more often than not clinicians do use steroids for this form of TB infection although it's not without without some controversy about whether they should be used okay a couple of final things about extra pulmonary sites and then we'll wrap up the gastrointestinal tract the gut can be involved with tuberculosis as well but it's really quite uncommon maybe three percent or so and quite nonspecific like both other forms of tuberculosis the infection for reasons that aren't clear to me often involves the terminal ileum and the cecum so down there around the appendiceal area with often a lot of lymph node involvement one can have obstruction and if the infection is not recognized and treated it can erode through the gastrointestinal tract so perforation and you can get peritonitis and air in the peritoneal cavity so the whole myriad of symptoms that occurs in other parts of the body can also involve the gastrointestinal tract and how do you actually get it into the gastrointestinal tract is that here eat stuff that has TB in it or are you getting it throughout your own body so actually both so there you can actually ingest certain kinds read certain kinds of TB bugs so mycobacterium bovis which is what it sounds like Michael vector and it comes from cows can contaminate cow milk and if you ingest unpasteurized cow milk then that can occur and that's one way you can get TB involving the gastrointestinal tract the other is that if you have pulmonary disease with tuberculosis and you cough up the TB bacilli you can then swallow them and that can cause the gut to be infected as well and then the another form of tuberculosis again in the uncommon variety but continue to emphasize the great imitator characteristics of this infection tuberculosis can cause infection around the heart so TB pericarditis and this can be either from direct extension of lymph nodes around the heart that often are involved when you have pulmonary disease or it also can spread directly through the blood it seems to be a more common type of infection in the elderly whose immune system is not as robust as as the youth or in patients who have compromised immunity for other reasons for example in fact patients infected with human immunodeficiency virus involvement of the heart is not good mortality is very high estimated to be almost 50% and the infection because it has a vigorous inflammatory response associated with it can cause so-called constrictive pericarditis so the pericardium actually squeezes the heart so the heart can't contract effectively and one dies of heart failure as a result of that so those are the key elements with regards to extra pulmonary tuberculosis there are other organs that can be involved that are very very uncommon the adrenals and so forth but the main sites of involvement lymph nodes very high on the list and then less likely the other ones that we've spoken about okay another great reason to treat this as soon as you can so you don't get all of these extensive complications exactly