Clinical features of cancer: how cancers cause clinical symptoms



hi and welcome back to oncology for medical students this section of videos is on cancer diagnosis beginning with the clinical features of cancers what-a-lights cover in this video is essentially the mechanisms by which cancers make people unwell in other words what effects they have on the body and what signs and symptoms they produce she was essentially parasites and they don't serve the purpose to their host all tumors benign or malignant can cause problems broadly speaking cancers cause problems via these mechanisms local effects systemic effects to the wider body rupture hormone production ulceration bleeding and inflection I'll go through each one of these with some examples the first example is local effects as tumors grow they can press on local structures and cause organs around them to stop working properly one example of this is the billary system so in this diagram we can see the liver at the top the gallbladder just underneath the liver the bile ducts and then the pancreas at the bottom so the normal function of the billary system is to drain bile which is produced by the liver the normal function of bile is in emulsifying fats which is basically changing their structure so that they're able to be digested and then absorbed well also serves another function and that's in the excretion of something called bilirubin bilirubin is a product of the breakdown of blood cells and basically the liver puts this into the bile and excretes it into the the gut as we can see here the biles draining from the liver through the bile ducts and then into the gut however if the Chiba grows in the head of the pancreas and the part of the pancreas where the bile ducts run through the drainage system gets blocked bile doesn't make its way into the intestine and eventually the bile leaks back this means that the the bilirubin which would normally be excreted in the bile builds up in the blood when you have high levels of bilirubin in the blood it then deposits in the skin and the eyes and causes jaundice cancers aren't the only cause of jaundice any condition that affects drainage of bile through the bile ducts and many diseases that affect the liver have the potential to cause jaundice as well but most of these also cause some element of inflammation and have associated pain in the case of tumors however there often isn't that much inflammation and pain often isn't a big feature this means that having a painless jaundice is often quite an ominous sign and is usually related to a cancer the head of the pancreas or the bile duct which is known as cholangiocarcinoma next mechanism on to talk about is hormone production all cancers especially those that rise from glandular tissue have the potential to produce hormones these hormones can travel around the body and have various effects a good example of this is the production of parathyroid hormone related protein or PTH RP which is commonly associated with certain types of lung cancer if you know anything about calcium metabolism you'd have heard of something called parathyroid hormone this is a hormone that's normally released in relation to low levels of calcium parathyroid hormone works on the bones of the gut and the kidneys in order to raise the level of calcium in the blood to a normal level when it's released by cancers however the level of power calcium in the blood is often normal to start with and it isn't releasing the hormone in response to any kind of detected levels of calcium what this means is that it leads to high levels of calcium in the blood a good way of remembering the symptoms of high calcium in the blood is this brine stones bones groans Thrones and psychiatric overtones stones relates to the development of kidney and gall stones bones bone pain groans is abdominal pain nausea vomiting Thrones relates to something called poly urea which is passing lots of water and psychiatrics overtones relates to depression cognitive problems and insomnia which are all symptoms of high calcium so PT HRP isn't the only hormone now is released by cancers there are lots of other examples which we'll cover in later videos the next example is ulceration bleeding and infection as tumors grow they invade tissues a local to them and this might mean invading blood vessels and causing bleeding or causing openings that allow bacteria to travel to parts of the body where they wouldn't normally be able to get and cause infection there's some examples of this might include something called him Optus which is coughing up blood as a result of lung tumors another example might be passing blood in the the stool or on bowel motions if you have a tumor that's causing bleeding in the lower parts the gut you might get fresh blood passing but if you get a tumor in higher parts of the gut the blood might get digested as it moves down and this forms something called Melina which is digested blood which has a very thick black appearance one thing that's worth mentioning at this point is something called microcytic anemia so basically if you have chronic blood loss over a long period of time as you might with this kind of bleeding the body tries to compensate by making more and more blood cells but it often ends up pushing these blood sets up blood cells out before they're mature so if you look at the blood Furret for a start you have higher low levels of hemoglobin which is anemia but also blood cells tend to be quite small in young women who are pre menopausal microcytic anemia is quite common because they have bleeding around the periods but postmenopausal women and in men microcytic anemia can be quite a worrying sign because it might mean there's a bleed somewhere in the body that just hasn't been detected yet the next example is rupture as tumors grow bigger and bigger they can become more and more unstable and they can burst and rupture through two part other parts of the body an example of this it might be a bough a tumor rupturing through to the peritoneal cavity this can cause a severe type of infection called peritonitis other problems might include rupturing large blood vessels leading to a lot of blood loss the last thing I wanted to mention are systemic effects which are affects around the wider body the first thing in this kateri to mention is cachexia which is a loss of body fat and muscle tissue it's not necessarily caused by the increased nutritional demands the tumors a lot of people might think but it's actually more likely to be related to the release of hormones and cytokines produced by the tumor and by their host and response to the tumor anorexia is also very common in patients with cancer even if their cancer isn't affecting directly affecting their gut but reduced intake doesn't completely explain this weight loss what we do know some people with cancer is that they have an increased basal metabolic rate which means their whole body consumes energy at a faster rate cachexia isn't the same starvation in starvation fat tends to disappear before muscle and the basal metabolic rate decreases in cachexia fat and muscle tissue disappear at the same rate experience suggests that this might be related to a cytokine called tumor necrosis factor lastly in terms of systemic effects is worth mentioning these things called paraneoplastic syndrome's paraneoplastic syndromes are basically collections of symptoms that are a result of a cancer but not related to the local effects of a tumor so some of the things we mentioned before in terms of hormone release actually apply to this as well some examples of this are Cushing's syndrome which is a release of a hormone called a TCH si si ADH which is caused by a release of a antidiuretic hormone hypercalcemia as we mentioned before and neuropathy so nerve problems related to cancers I won't go into an awful lot of detail about these now I'll do a video later on and we'll talk much more about neoplastic syndromes in the future so just to finish I thought I'd mention the two-week rule criteria so the two-week rule criteria are a list of signs and symptoms that should really alert GPS into suspecting that there might be an underlying cancer in a patient if they see any of these signs and symptoms they should refer the patient to the relevant specialty and there should be seen within two weeks so if we look closely at the two-week rule criteria we can see some examples of the symptoms that we've been talking about in this video result the lung cancer section we can see that hemoptysis is obviously very high up on the list which is coughing up blood you can also see that fatigue shortness of breath and weight loss er mentioned for safa geomancers dysphasia or a difficulty swallowing could be a sign of a tumor blocking the food pipe and for pancreatic cancers we can see that jaundice is high at the list as we explained earlier so to summarize cancers can cause illness by loke invasion or impingement on local structures hormone secretion ulceration bleeding infection cachexia and paraneoplastic processes thanks for listening if you found the video useful please click the subscribe button and check out the other videos on the channel thank you

2 comments

  1. omg you are wonderful!!!!!!!! the way you explain things is… incredible!! so easy to understand…….and you voice is ..simply unique ..thank you!!! greetings from Romania <3

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