Understanding the Causes of Blood in Stool (Rectal Bleeding)

[Music] [Applause] [Music] hi this is tom from zero2finals.com in this video i'm going to be going through the causes of rectal bleeding or blood in the stools and you can find written notes on the topics covered in this video at zero2finals.com or in the zero to finals medicine and surgery books just a reminder before we get into it all the zero to finals videos including this one are for educational purposes only to help healthcare students prepare for exams and they should not be taken as medical advice so let's get straight into it let's start by talking about the gastrointestinal tract anytime there's blood coming from the back passage this indicates bleeding somewhere along the gastrointestinal tract the gastrointestinal tract starts at the mouth the esophagus takes food from the mouth to the stomach after the stomach comes the duodenum the jejunum and the ileum which together form the small intestine the small intestine connects with the large intestine at the cecum then there's the ascending colon the transverse colon the descending colon the sigmoid colon the rectum and finally the anus the first clue as to what is causing rectal bleeding comes down to the color of the blood in the stool as a general rule when the source of bleeding is lowered down or further along the gastrointestinal tract there will be a brighter redder colour to the blood compared with sources higher up the gastrointestinal tract where the blood will be darker in color one of the key consequences of bleeding from the gastrointestinal tract is anemia which refers to a low hemoglobin or a low blood count gastrointestinal bleeding specifically causes iron deficiency anemia patients with iron deficiency anemia have a low hemoglobin a low mean cell volume meaning the volume of the red blood cells is low referred to as a microcytic anemia referring to small red blood cells and a low ferritin level which is the iron level in someone with iron deficiency anemia without an obvious cause such as heavy menstrual periods or a restrictive diet low in iron the next step is to consider whether they may have chronic bleeding from their gastrointestinal tract and consider a referral for an upper and lower endoscopy to look at the stomach and the bowel looking for sources of bleeding next let's talk about suspected cancer referrals before we go into all the different possible causes of rectal bleeding first let's address the cause that's probably most important to identify urgently meaning colorectal cancer rectal bleeding is a red flag symptom and colorectal cancer needs to be excluded the nice guidelines on suspected cancer give the criteria for an urgent cancer referral called a two-week weight referral in someone presenting with rectal bleeding these criteria are anyone over the age of 50 with unexplained rectal bleeding or anyone under the age of 50 with rectal bleeding plus abdominal pain iron deficiency anemia weight loss or a change in the bowel habit it's worth noting the other referral criteria for colorectal cancer which is provided by the nice guidelines which are patients over the age of 40 with weight loss plus abdominal pain those over the age of 60 with iron deficiency anemia or a change in bowel habit a positive fecal immunochemical test or fit test a rectal mass or an abdominal mass we'll talk in more detail about colorectal cancer a bit later on in this video next let's talk about the causes of bright red blood on the toilet tissue fresh bright red blood seen on the toilet tissue when wiping indicates a problem right at the anus right at the end of the gastrointestinal tract the most likely causes of this are hemorrhoids or an anal fissure other potential causes to keep in mind are trauma from sexual activities infections and anal cancer let's talk in more detail about hemorrhoids hemorrhoids are enlarged anal vascular cushions it's not clear why they become enlarged and swollen but then often associated with constipation and straining they're also more common in pregnancy obesity increased age and increased intra-abdominal pressure for example from weight lifting or chronic coughing hemorrhoids can be internal or external when they're external you may see a small lump at the anus covered in mucosa as well as painless bright red bleeding typically on the toilet tissue and not mixed in with the stools hemorrhoids can cause symptoms of itching or a soft lump around or inside the anus hemorrhoids may be diagnosed on examination of the back passage which involves a digital rectal examination or by proctoscopy which involves inserting a hollow tube called a proctoscope into the anal cavity to visualize the mucosa there's more information on hemorrhoids in the zero to finals video on hemorrhoids and there's a link in the description to this video next let's talk in more detail about anal fissures anal fissures are small tears to the mucosa at the anus these typically cause two symptoms bright red blood which may be on the stool or seen on the toilet tissue and pain at the back passage when opening the bowels or wiping stretching of the tear as the stool goes past causes pain it's usually possible to see anal fissures on inspection a digital rectal examination is generally too painful to be performed anal fissures will generally heal with time and management may involve laxatives to soften the stools analgesia which may include topical anesthetics such as lidocaine ointment and glycerol trinitrate or gtn ointment to relax the sphincter muscles and aid healing it's worth noting a common side effect of the gtn ointment is headaches next let's talk about the causes of blood mixed in with the stools red blood mixed with the stools suggests bleeding from higher up in the large bowel the darker the blood the further up the bowel the bleeding is occurring there are a number of potential causes of bleeding inside the large bowel and we'll talk about these in more detail the causes to be aware of are gastroenteritis diverticular disease inflammatory bowel disease angiodisplasia polyps and colorectal cancer it's also worth noting that foods like beetroots can cause what looks like blood mixed in with the stools it's worth asking patients presenting in a panic with a sudden episode of blood in the stools whether they've recently eaten a lot of beetroot so let's talk in more detail about these causes of blood mixed in with the stools starting with gastroenteritis gastroenteritis refers to inflammation and infection of the gastrointestinal tract there are a large number of causes of gastroenteritis some of which can cause rectal bleeding which includes campylobacter e coli zero one five seven shigella salmonella and yesinia typical symptoms of gastroenteritis in addition to rectal bleeding include abdominal cramps diarrhea vomiting and fever the cause of gastroenteritis can be established by doing a stool sample sent to the lab for microscopy culture and antibiotic sensitivity testing management is mostly supportive with antibiotics only used when the specific cause is known next let's talk in more detail about diverticular disease a diverticulum is a pouch or a pocket in the bowel wool usually ranging in size from 0.5 to 1 centimeter diverticulosis refers to the presence of diverticula without inflammation or infection diverticulosis may be diagnosed on a colonoscopy or a ct scan diverticulitis refers to inflammation and infection of the diverticular acute diverticulitis presents with pain and tenderness typically in the left iliac fossa or the lower left abdomen fever diarrhea nausea and vomiting rectal bleeding a palpable abdominal mass if an abscess is formed and raised inflammatory markers on the blood tests for example ray crp and raised white blood cells management of acute diverticulitis is with antibiotics analgesia and limiting the oral intake to clear fluids only patients may need admission to hospital urgent surgery may rarely be required for complications such as a perforation of the bowel next let's talk about inflammatory bowel disease inflammatory bowel disease is an umbrella term for two main diseases causing inflammation of the gastrointestinal tract and these diseases are ulcerative colitis and crohn's disease both involve inflammation of the walls of the gastrointestinal tract and are associated with periods of remission and exacerbation of the symptoms ulcerative colitis typically affects only the large intestine and the rectum whereas crohn's disease can affect any part of the entire gastrointestinal tract rectal bleeding is more common in ulcerative colitis compared with crohn's typical presenting features are diarrhea abdominal pain passing blood in the stools and weight loss a key test to remember for inflammatory bowel disease is fecal calprotectin this is a marker of intestinal inflammation that's quite sensitive and specific for inflammatory bowel disease endoscopy and biopsy are required to make the diagnosis management is with steroids and immunosuppressant medications next let's talk about angiodysplasia angiodysplasia is a condition where there are patches of dilated and abnormal small blood vessels in the bowel wall the cause of angiodysplasia is unclear patients who have angiodisplasia may be asymptomatic they may present with rectal bleeding or iron deficiency anemia due to the blood loss it doesn't usually cause any other symptoms endoscopy is the investigation of choice for making a diagnosis of angiodysplasia the abnormal vessels can be treated during the endoscopy next let's talk about intestinal polyps intestinal polyps are growths of the lining of the bowel they usually do not cause any symptoms but they may cause rectal bleeding most polyps are benign but some develop into cancer they can be diagnosed and removed during a colonoscopy procedure next let's talk about colorectal cancer bowel cancer is the fourth most prevalent cancer in the uk behind breast prostate and lung cancer bowel cancer refers to cancer of the colon or the rectum we've already discussed the suspected cancer referral criteria the red flags that should make you think about bowel cancer are a change in bowel habit usually more loose and frequent stools unexplained weight loss rectal bleeding unexplained abdominal pain iron deficiency anemia which is a type of microcytic anemia with small red blood cells and a low ferritin and an abdominal or rectal mass on examination fecal immunochemical tests or fit tests look specifically for the amount of human hemoglobin in the stool fit tests are used as part of the bowel cancer screening program in england fit tests can be used as a test in general practice to assess for bowel cancer in specific patients who do not meet the criteria for a two week weight urgent cancer referral for example patients over the age of 50 with unexplained weight loss and no other symptoms or patients under 60 with a change in bowel habit a colonoscopy is the gold standard investigation for diagnosing bowel cancer it involves an endoscopy to visualize the entire large bowel any suspicious lesions can be biopsied taking a sample of the tissue to get a histological diagnosis the suspicious lesions can also be tattooed in preparation for surgery so the surgeon knows what to chop out other investigations include a staging ct scan of the thorax abdomen and pelvis or a ct tap to look for metastatic bowel cancer and carcinoembryonic antigen or cea is a tumor marker blood test for bowel cancer options for managing bowel cancer are surgical resection chemotherapy radiotherapy and palliative care when appropriate next let's talk about the causes of black stools when there's bleeding from the upper gastrointestinal tract the blood gets digested on the way down this results in stools that are black in color look a bit like tar and have an offensive smell this description of the stools is referred to as molina this may be associated with vomiting up blood which is called hematemesis there are a number of causes of bleeding from the upper gastrointestinal tract which would cause molina including stomach ulcers or duodenal ulcers cancers of the stomach or anywhere else in the upper gastrointestinal tract malory vice tears which refers to a tear of the lining of the esophagus usually associated with excessive vomiting and esophageal varices which are enlarged and abnormal veins in the esophagus usually associated with liver disease management of upper gastrointestinal bleeding can be remembered with the mnemonic abated a stands for an abcde approach to immediate resuscitation b stands for blood tests to get a full set of bloods a stands for access to get intravenous access in case the patient needs medications or a blood transfusion ideally with two large bore cannulas t stands for transfusion if the patient needs a blood transfusion e stands for endoscopy and they need an urgent endoscopy within 24 hours to identify the source of the bleeding and provide treatment as required and d stands for drugs to stop anticoagulants or blood thinners as well as nsaids finally i want to mention factors that increase the risk of bleeding the two key things to remember that will increase the risk of bleeding whether that's in the gastrointestinal tract or anywhere else in the body are medications and bleeding disorders some examples of medications that thin the blood and make bleeding more likely are aspirin clopidogrel ticagrelor heparin warfarin and doax such as a pixaban rivaroxaban and dabigatran disorders that increase the risk of bleeding include thrombocytopenia which is a low platelet count von willebrand disease and hemophilia if you like this video consider joining the zero to finals patreon account where you get early access to these videos before they appear on youtube you also get access to my comprehensive course on how to learn medicine and do well in medical exams digital flashcards for rapidly testing the key facts you need for medical exams early access to the zero to finals podcast episodes and question podcasts which you can use to test your knowledge on the go thanks for watching and i'll see you in the next video

Channel: Zero To Finals

Views: 579,583

Keywords: medical, education, medicine, doctor

Id: 7xG7EoG0-j0

Length: 21min 16sec (1276 seconds)

Published: Mon Aug 22 2022