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Nausea and Vomiting By MedRx Nausea and vomiting (N&V) is a very common medical presentation with a wide differential diagnosis encompassing numerous body systems. In this handout, we will go through the differential diagnosisofnauseaandvomitingandtheimportant aspects of a history. We will then cover three important conditions which cause nausea and vomiting: Bowel obstruction, nausea and vomiting of pregnancy and Meniere’s disease Using this Contents handout 1. Differential diagnosis of N&V a. Anatomical/physiological method b. History method The content in this handout is quite 2. Howa. HPCke a N&V history detailed. The most important aspects b. PMH are the differential diagnosis (section 1), c. DH the ‘essential advice’ and any writing in d. FH time, the content is not exhaustive andame e. SH should not be seen as covering every 3. N&V conditions detail but instead the most important a. Bowel obstruction ones. This handout is for purely b. Nausea and vomiting in pregnancy educational purposes and should not be c. Meniere’s disease used when treating patients. The essential differential diagnosis of N&V Physiological/anatomical method The first way to classify the differential diagnosis of N&V is using a more ‘physiological/anatomical approach’. The vomiting centre in the medulla oblongata controls vomiting, and there are four primary inputs into this centre: the CNS, the chemoreceptor trigger zone, the vestibular system and cranial nerves IX and X. By considering what could trigger each of these inputs, we can consider what the causes of N&V may be: History-based method Although the above means of splitting the differential is academically interesting, it may not be the most useful in determining the cause in clinical practice. A means of splitting the differential based on the history may be more useful: Acute Headache Abdominal pain None of these Dizziness Shortly after food • Meningitis Fever No fever • Drugs • Labyrinthitis • Gastric outlet • Encephalitis • Gastroenteritis • Bowel • Psychogenic • Ménière’s obstruction • Raised ICP • Cholecystitis obstruction (anxiety) disease • Migraine • Pancreatitis • Diabetic • Hyperthyroidism • Vestibular • Appendicitis ketoacidosis • Renal failure + neuronitis • Mesenteric • Drugs uraemia • Acoustic adenitis • Toxins • Cyclic vomiting neuroma • Mesenteric syndrome • BPPV ischaemia • Pregnancy • Motion • MI sickness • Kidney stones • Testicular torsion Chronic Weight loss No weight loss • Upper GI obstruction • Oesophagitis • Coeliac disease • Pharyngeal pouch Essential advice: Remember HANDS as a mnemonic for the way to split the differential for acute nausea and vomiting based on the history: headache, abdominal pain, none of the others, dizziness, and shortly after food. Taking a N&V history HPC A N&V HPC can be split into ‘questions about the vomit’ PMH and ‘associated symptoms: Diabetes Makes DKA and gastroparesis more likely 1. Questions about the vomit • Contents Cardiovascular disease o Undigested – high up (ie oesophagus) Makes mesenteric ischaemia/ MI more likely o partially digested (gastric outlet obstruction, gastroparesis) Psychiatric conditions o bilious – small bowel, after ampulla of vaterImportant to ask when considering functional o faeculent – Distal intestinal/ colonic cause obstruction o blood – haematemesis Gallstones • Volume Makes pancreatitis and cholecystitis more likely o large volume makes organic more likely • Timing History of abdominal surgery o Duration (acute vs chronic) Makes bowel obstruction more likely o early morning – pregnancy, raised ICP o after eating – gastroparesis 2. Associated symptoms FH 1. FH of any of the above conditions • HANDS o headache, o abdominal pain, o fever o dizziness SH • Weight loss • Bowel movements 1. Exposure to infectious bowel pathogens o Constipation – bowel obstruction a. Close contact with someone with similar o Diarrhoea – food poisoning/ gastroenteritis symptoms o Blood – from constipation or gastroenteritis b. Living in close quarters c. Recent foreign travel d. Recent unusual meals 2. Exposure to dangerous chemicals DH a. Organophosphate fertilizers 3. Lifestyle factors a. Ie alcohol Many drugs can cause nausea and vomiting. Some of the 4. Any chance of being pregnant? most important can be remembered with the ‘2Cs, 2 As, 2Os’ mnemonic: 2 Cs: chemotherapy, contraception 2 As: antibiotics, anticonvulsants 2 Os: opiates, overdose (ie paracetamol, aspirin) Drugs for N&V Many different drugs can be used to treat nausea Ondansetron and vomiting. Here, we will discuss some of the common ones, their mechanism of action, and how this mechanism of action relates to which causes of Ondansetron is a 5-HT3 receptor antagonist. These N&V they are used for: receptors are used in the connection between the CTZ and the vomiting centre and the gut and the vomiting centre. Hence, ondansetron is used in Haloperidol chemical causes of N&V (like haloperidol) and in N&V arising from radiotherapy involving the bowel. Haloperidol is a D2 antagonist. Remember, D2 receptors were used in activation of the CTZ. The CTZ responds to chemical causes of N&V. Therefore, haloperidol is used in chemical causes of N&V for example in uraemia secondary to renal failure, orin drug induced N&V. Cyclizine Cyclizine is a H1 and Ach receptor antagonist. Remember, these receptors are found in the vestibular system. Hence, cyclizine is useful in conditions which affect the vestibular system to cause N&V, such as BPPV, Meniere’s disease, labyrinthitis and vestibular neuronitis. Metoclopramide Metoclopramide is a D2 antagonist and 5-HT4 agonist. It is also a pro-motility medication. For this Essential advice: Remember that, by reason, it is often used in N&V due to delayed considering the mechanism of action of gastric emptying (ie gastroparesis) but is an anti-emetic, you can often figure out contraindicated in complete bowel obstruction. when it may be used for nausea and vomiting Levomepromazine Levomepromazine has a wide range of effects, acting as a 5-HT2, H1, Ach and D2 receptor antagonist. 5-HT2 receptors are found in the CNS so it’s antagonist properties at this receptor make it good in anxiety-caused N&V. Furthermore, the broad range of receptors it targets makes it good in N&V of unknown origin. Bowel obstruction roughly 1/3 of width) What is it? • Abdominal CT scan Bowel obstruction is when the passage of contents o More sensitive through the bowel becomes blocked. o Also can indicate cause of obstruction • Erect chest X ray What causes it? o Can show air under diaphgarm if The causes of bowel obstruction can be split into perforation the ‘big three’ (which account for around 90% of bowel obstruction) and ‘other’ causes: The big three: 1. Adhesions (small bowel) 2. Hernias (small bowel) 3. Malignancy (large bowel) Other causes: 1. Volvulus (sigmoid or caecal) 2. Diverticular disease 4. IntussusceptionChron’s) SBO LBO What are the symptoms/ signs? 1. Nausea and vomiting – bilious vomiting 2. Bloating What is the 3. Abdominal pain – diffuse 4. Absolute constipation management? 5. ‘Tinkling’ bowel sounds 1. ‘Drip and suck’ 6. Signs/ symptoms of underlying condition a. Nil by mouth b. IV fluids c. NG tube What is the diagnostic If drip and suck does not work after 48-72 hours, or there is signs of peritonism/ perforation then technique? surgery should be done: The diagnostic method for bowel obstruction can 2. Surgery (exact surgery depends on be split into bloods and imaging: cause): Bloods a. Exploratory (if cause unknown) • Blood gas – raised lactate and metabolic b. Adhesiolysis alkalosis c. Hernia repair • UsandEs - Electrolyte abnormality d. Resection of tumour Imaging • Abdominal X ray What are the o Small bowel obstruction – dilated loops of bowel >3cm with valvulae complications? coniventes (extend full width) 1. The main complication is perforation o Large Bowel obstruction – dilated 2. And subsequent peritonitis loops >6cm (9cm for caecum), with haustra (extend only Nausea and vomiting of pregnancy/ hyperemesis gravidarum What is the diagnostic What is it? technique? Nausea and vomiting in pregnancy (NVP) is very common in early stages. Hyperemesis gravidarum Severity (HG) describes the extreme end of the condition. The pregnancy-unique quantification of emesis (PUQE) gives a score out of 15 that can be used to What causes it/ what are determine severity of NVP. A score of less than 7 is mild, 7-12 is moderate and above 12 is severe. the risk factors? Hyperemesis gravidarum Cause According to RCOG, for HG to be diagnosed, one The placenta produces human chorionic must have protracted NVP with 5% pre- gonadotrophin (hCG) during pregnancy and NVP is pregnancy weight loss, Dehydration and thought to be caused by this hormone. Electrolyte imbalance Risk factors What is the There are numerous risk factors for N&V in pregnancy some of which work through producing management? higher hCG levels: 1. Conservative therapies: Ginger, 1. Multiple pregnancy (higher hCG) acupressure at PC6 point in inner wrist, avoid triggers, bland foods 2. Molar pregnancy (higher hCG) 2. Anti-emetics: 3. Nulliparity (first pregnancy) a. Prochlorperazine, cyclizine, 4. Obesity ondansetron, metoclopramide (PCOM) 5. Family history 3. Omeprazole/ ranitidine 6. Non-smoker 4. Admit if any of the following: Unable to What are the symptoms? tolerate oral fluids, Ketonuria (>2+ ketones) , Weight loss > 5%, Comorbidities being • NVP tends to be worse in the mornings affected but can occur throughout the day. 5. Iantiemetics, IV fluids, thiamineM • Symptoms tend to be worse in early supplementation, thromboprophylaxis pregnancy with a timeline as follows: o Start at 4-7 weeks What are the o Worst at 10-12 weeks complications? o Resolve by 16-20 weeks • Wernicke’s encephalopathy • VTE o However, symptoms can last • Dehydration and AKI throughout pregnancy. • Esophagitis and Mallory Weiss tear Ménière’s Disease What is it? What is the diagnostic Ménière’s disease is a long term disorder of the technique? inner ear which causes vertigo, tinnitus and hearing loss. • Ménière’s disease is primarily a clinical diagnosis made by an ENT specialist. What causes it? • Audiometry is needed to determine the degree of hearing loss. Ménière’s is caused by a buildup of endolymph in the labyrinth of the inner ear – this is What causes this build up of endolymph is What is the unknown. management? What are the The management of Meniere’s disease can be split into ‘driving rules’, ‘treating acute attacks’ symptoms? and ‘prophylaxis’. Driving rules The symptoms of Ménière’s disease can be split into the ‘classic triad’ and ‘other symptoms’: • Patients should inform the DVLA and not drive until they have control of symptoms The classic triad of Meniere’s disease is: Management during acute attack 1. Vertigo – comes in episodes which last minutes to hours. • Prochlorperazine 2. Tinnitus – unilateral, initially occurs alongside vertigo episodes but then • Antihistamines (cyclizine, cinnarizine, becomes permanent promethazine) 3. Sensorineural hearing loss – also Prophylaxis unilateral and initially comes with episodes then becomes permanent. Tends to affect • Betahistine lower frequencies first. • vestibular rehabilitation exercises Other symptoms of Ménière’s disease are: What are the 1. Feeling of fullness in the ear complications? 2. Unexplained falls without LOC The symptoms of Meniere’s disease should resolve 3. Nystagmus during attack within 5-10 years however there are two main complications: 4. Positive Romberg’s test 1. Degree of hearing loss 2. Psychological distress References 1. Farne, H., Norris-Cervetto, E. and Warbrick-Smith, J. (2015). Oxford cases in medicine and surgery. Oxford ; New York: Oxford University Press. 2. Anon, (n.d.). Zero To Finals – Tools for Medical School. [online] Available at: https://zerotofinals.com. 3. passmedicine.com. (n.d.). Passmedicine. [online] Available at: https://passmedicine.com. 4. https://geekymedics.com/bowel- obstruction/#:~:text=Abdominal%20X%2Dray%3A%20may%20demonstrate,severity%2C%20underlying%20 aetiology%20and%20complications 5. https://www.radiologymasterclass.co.uk/gallery/abdo/abdominal_xray/small_bowel_obstruction