Summary: Vomiting and diarrhea are usually caused by food poisoning or a virus, but sometimes by a bacteria. Medications to treat vomiting and diarrhea are limited and commonly not recommended. Dehydration (when the body does not have enough fluid) can usually be prevented by drinking the right kinds of fluids. Intravenous fluids are often beneficial, but only sometimes necessary. Serious medical conditions causing vomiting require prompt medical evaluation.
Vomiting and diarrhea are usually caused by a germ (virus or bacteria) infecting the intestines (guts). The most common cause of this is a "stomach flu" virus. Other germs include parasites, salmonella, and other bacteria. Food poisoning is also possible. Diarrhea means that there is too much water in the stools. If there is too much water loss, dehydration (not enough fluid in the body) can occur. Vomiting occurs because the intestines are not moving forward (usually because of the intestinal infection). Fluid backs up into the stomach causing vomiting. Vomiting can also occur because the intestines are blocked or twisted.
Vomiting can also be caused by urine infections, appendicitis, problems in the brain, pneumonia, heart failure, other intestinal problems and many other things. These problems are much more serious than a stomach flu, but it may be hard to identify these conditions early on. Since stomach flu is so much more common, doctors frequently mistakenly attribute the vomiting and diarrhea to the stomach flu, when actually, a more serious condition exists.
It is difficult for doctors to always be correct. Thus, it would be difficult to write down a way for parents to identify these conditions, but here are some warning signs:
1. Abdominal pain: Although abdominal pain occurs with the stomach flu, the pain is usually mild. More severe abdominal pain may indicate conditions such as appendicitis, twisted intestines, blocked intestines, intussusception (a condition in which the intestine telescopes into itself), ulcers, or other serious conditions. Episodes of severe pain with retching or vomiting repeating itself every 3-20 minutes in a small child suggest the possibility of intussusception. The next chapter (chapter 57) is devoted entirely to the subject of abdominal pain.
2. Headache: Headache can occur with the stomach flu, but it is usually mild. More severe or persistent headache can be due to brain infection, brain tumor, brain injury, pressure in the brain, migraines or other brain related causes. Since small children cannot tell you that they have a headache, fussiness might be the only indication of headache or discomfort.
3. Lots of vomiting, lots of diarrhea, weakness, drowsiness, lethargy (not responding well), irritability (fussiness), blurred vision, pale color, puffiness in the face and high fever all suggest the possibility of something more serious than a stomach flu.
4. Vomiting which is bloody or contains material that looks like chocolate or ground coffee (this is blood). Vomiting which is greenish or dark yellow (suggests a blockage in the intestines). Abdominal distention (The belly is not flat. It appears to be full or bigger than it normally is).
5. Bloody stools (bowel movement) or stools which look like black tar. This suggests bleeding in the intestines, bloody invasive diarrhea (also called dysentery), intussusception, or hemolytic uremic syndrome (a condition in which the red blood cells pop and the kidneys fail).
6. Not urinating much. No tears when crying. Inside the mouth is dry or sticky. The eyes appear to be hollow or sunken in. The skin on the arms feels soft. These are signs of dehydration.
Treatment:
1. Anti-vomiting medicines often don't work well and they sometimes cause uncomfortable side effects. Anti-diarrhea medicines often help, but most experts recommend that these not be used in more severe causes of diarrhea. Note that minor cases of diarrhea usually don't need medication treatment, but in the case of more serious diarrhea where treatment relief is desired, these are the very instances when caution in using these anti-diarrhea medications is advised. Discuss these with your doctor.
2. Change to a gentle diet that is easy to digest to rest the intestines as much as possible. Don't eat or drink anything red because it will resemble blood when it is mixed with vomit or diarrhea.
a. Fluids: For infants, try Pedialyte and other "oral electrolyte solutions". For older kids who won't drink oral electrolyte solutions (because they don’t taste very good), try Gatorade and other sports drinks, Jello and non-creamy soup. While we were all taught to take a clear liquid diet (clear soda pop or apple juice) when we were kids, we now know this to be a bad idea. Fluid is absorbed from the intestine along with glucose (simple sugar) and salt. The intestines have difficulty absorbing liquid without a balanced amount of glucose and salt. Pedialyte and the other oral electrolyte hydration maintenance and rehydration solutions all have a more ideal ratio of glucose to salt. This balance makes it easiest for the intestines to absorb fluid. Unfortunately, this is too salty to be good tasting. Only babies will drink these electrolyte solutions. Older kids don't like the taste (even the flavored varieties) and usually won't drink these. Gatorade and the other sports drinks have some sugar and salt, but these drinks are not salty enough to be good rehydration solutions. While many criticize the use of sports drinks in the treatment of vomiting and diarrhea, at least these taste good enough to drink and although they are not salty enough, they are in second place. Clear soda pop (such as lemon-lime soda) and apple juice have too much sugar and almost no salt. Sports drinks are much better than soda pop and apple juice.
b. Formula (babies): Breast milk is best. Otherwise try Isomil or Prosobee. These are soy formulas which are easier to digest than cow's milk based formulas during vomiting and diarrhea illnesses. Isomil DF (diarrhea formula) is a constipating formula that may be useful for diarrhea.
c. Solids: Applesauce, toast, crackers, chicken noodle soup, rice cereal, rice, mashed or baked potatoes (but not French fries because of the fat), bananas, dry cereal, pretzels (but not potato chips), tortillas, pasta (without cheese), ramen, apples, pears.
d. Avoid: Fats, oils, meats, whole milk (but some skim milk is OK), and ice cream (but some yogurt is OK).
Recall that a diet limited to clear liquids such as sports drinks and oral electrolyte solutions is often recommended for diarrhea and vomiting. However, solids are an important part of normalizing intestinal function. A low fat diet (such as the items in paragraph "c" above) with the right kind of fluids will restore the intestines to normal functioning SOONER than a clear liquid diet alone. Give them some solids also.
For vomiting: The key is to give small amounts at a time. Since the stomach is upset, it will vomit if you fill it up. Prevent this by giving only 1 inch in a cup at a time. Wait 15-20 minutes then repeat 1 inch in the cup again. This will keep the stomach empty so it's less likely to vomit. If vomiting does occur, only a small amount will come up.
The stomach is like a bag. If you fill it up with water and squeeze it, a lot will come out. But if you put only a small cupful in the bag and you squeeze the bag, it will be hard to get anything to come up. If you can keep the stomach fairly empty, the small amount of fluid in the stomach will have a hard time coming up. But if you fill up the stomach, since it is upset, it will vomit up most of its contents.
The key is to prevent dehydration. Dehydration means that the body does not have enough fluid to circulate blood well throughout the body. Complications of severe dehydration include shock, stroke, kidney failure and death. Dehydration occurs when the amount of fluid taken in, is much less than the amount of fluid lost. This most commonly is due to severe vomiting and diarrhea when it is difficult to keep up with the fluid losses or the child vomits even small amounts of fluid given. Dehydration can be prevented or treated by getting enough fluid into the body. There are basically only two ways fluids can get into the body: 1) by mouth (oral), and 2) intravenously (IV) directly into the bloodstream.
In many poor countries where IV fluids are not easily available, children must depend on oral rehydration solutions to treat and prevent dehydration. Oral rehydration is highly effective using oral rehydration electrolyte solutions. It works well even if the child is vomiting. IV rehydration is easily available in this country, but it must be done in the hospital, an emergency room, or an urgent care center with IV capabilities, so it can be rather expensive. It also involves a needle poke which kids don't like. IV rehydration is rarely mandatory since it is only required in severe dehydration, but it is frequently preferred in this country even in mild dehydration despite the higher expense and pain.
Although oral rehydration works, it is "hard work" for parents. Parents must force down distasteful oral rehydration electrolyte solutions into their children one inch in a cup at a time. Although this treatment is designed to treat dehydration, it does not necessarily stop the vomiting and diarrhea. Despite all this "hard work", vomiting and diarrhea often continue. As long as parents persist with oral rehydration, dehydration should be kept in check in most instances. But their child continues to vomit and pass diarrhea. Vomit and diarrhea on the carpet and furniture can be more distressing than the dehydration itself. This can be the straw that breaks the camel's back. How much diarrhea and vomit on the carpet and furniture can parents take? Oral hydration may prevent dehydration in most cases, but it doesn't necessarily prevent vomit and diarrhea on the carpet and furniture. IV hydration bypasses the intestines so IV hydration does not add to the vomiting or diarrhea. Although it involves a needle poke and a trip to the hospital, emergency room or urgent care center, an IV gets fluid into the child without forcing down more electrolyte solution and parents don’t have to worry about vomit and diarrhea on the carpet and furniture. One of the major advantages of an IV is the convenience of it all. Over 2 to 4 hours, enough IV fluid can be given to rehydrate a mildly dehydrated child. Once the child is rehydrated, there is no need to force down more oral electrolyte solution. If the child's condition is satisfactory to be discharged home, the child can now rest (and so can the parents) overnight at home. After a good night's rest, hopefully, the child's intestines will have recovered enough to hold down some fluids to prevent further dehydration.
Not only is IV rehydration more convenient, it seems to be more comfortable. Imagine having vomited 10 times throughout the day with some diarrhea as well. I would feel quite miserable and the thought of sipping salty electrolyte solution does not sound too appealing. I would much rather get some IV fluid and relax over the next 2 to 4 hours.
Rapid IV rehydration seems to result in overall improvement for many patients. This is because although mild dehydration is not dangerous, it makes you feel sick. The flu germ causing the vomiting and diarrhea is making you feel sick plus the mild dehydration adds to the nausea. Rapid IV rehydration removes the nausea due to the dehydration so all that is left is the nausea due to the stomach flu germ. The bar graph below illustrates this point.
Following IV rehydration, there is less total nausea, because the additional nausea from the dehydration has been removed. This is very similar to what happens during a marathon run. During the long marathon, the runners are supposed to be periodically maintaining their hydration by drinking along the way. It is difficult to maintain this degree of drinking because it causes stomach cramps and it may slow the runners. Under the hot sun, the runners lose lots of fluid through perspiration and intense breathing. When they finally finish the marathon run, most of them are dehydrated and they feel nauseated and miserable. They try to drink some electrolyte solutions or sports drinks, but they will often vomit. They do not have a stomach flu, but they are dehydrated and this makes them nauseated. Most marathon runs have an IV tent so that dehydrated runners can get some IV fluids from medical volunteers. Once dehydrated marathon runners complete an IV fluid rehydration infusion, their dehydration is reversed and they can now drink without any nausea or vomiting.
If vomiting and diarrhea is mild, oral hydration with sports drinks or oral electrolyte solutions should be able to prevent dehydration. But when vomiting and diarrhea persist or worsen, oral hydration may be very difficult. Getting an IV in this country is easy. Why suffer? Why stay up all night forcing down sips of oral rehydration solution? IV rehydration is more expensive but it's more convenient and comfortable. As a physician, our job is to prevent death and complications when possible. Oral rehydration usually does this. But our job is also to provide relief and comfort during an illness. Oral rehydration is slow to provide relief and comfort if the vomiting and diarrhea are persistent or more severe. IV rehydration provides more reliable and quicker relief and comfort. Is it worth the extra expense? This is for you to decide.
When should IV rehydration be considered? My general rule is: V+D>10 = IV. This sounds very mathematical, but it's very simple. When the number of vomiting (V) and diarrhea (D) episodes add up to 10 or more, IV rehydration should be considered. At this point, 10 episodes (total) of vomiting and/or diarrhea is enough to cause mild dehydration and IV rehydration may provide some relief and comfort.
You may need to ask your doctor for an IV. Some doctors who favor oral rehydration don't believe in IV rehydration. You may need to convince them otherwise. Vomit and diarrhea on the carpet or furniture in their office will usually convince them.
A few words on the common causes of vomiting and diarrhea may be of interest to some readers. Viruses are by far the most common infectious cause of vomiting and diarrhea. This is often called "stomach flu". Bacteria sometimes cause vomiting and diarrhea (more so diarrhea), but when bacteria cause diarrhea it is usually more severe. Bacterial causes of diarrhea include salmonella, shigella, campylobacter, pathogenic E. coli and a few others. Salmonella is the bacteria that most people have heard of. E. coli is a normal bacteria in the intestine, but there are a few E. coli which are abnormal (pathogenic; which means it causes disease). E. coli 0157 is a type of E. coli that often causes bloody diarrhea. It can sometimes cause hemolytic uremic syndrome (HUS), which is a serious condition resulting in blood loss and kidney failure. Parasites and protozoans can also cause diarrhea, but these are less common and more difficult to diagnose.
Generally, compared to the more common stomach flu viruses, the bacterial causes of diarrhea tend to have: 1) high fever, 2) mucus (slimy, gooey, gelatinous, mucus) or blood in the diarrhea, 3) extra foul odor to the diarrhea (it smells worse than the normal stool odor), 4) lots of diarrhea, 5) diarrhea for more than a few days. A culture of the diarrhea should be done to determine if a bacteria is causing the diarrhea.
Viral causes of vomiting and diarrhea are usually less severe so the illness is often mild. Bacterial causes of diarrhea are more severe. Viruses cannot be treated with antibiotics. Some bacteria can be treated with antibiotics, but some bacterial causes of diarrhea become worse when antibiotics are given. In many instances, it is better to wait for the result of the stool culture to identify which bacteria is causing the problem. For example, salmonella is best NOT treated with antibiotics in most children since it usually resolves faster without antibiotics. Some bacteria are resistant to commonly used antibiotics. The main side effects of antibiotics are diarrhea and stomach discomfort. In a patient with vomiting and diarrhea, these side effects are unwelcomed, especially if the antibiotics provide no benefit. Antibiotics only appear to benefit some bacterial causes of diarrhea and only certain antibiotics provide benefit. Without knowing which bacteria is causing the diarrhea, treating with an antibiotic may be the wrong decision. Sometimes, treating with antibiotics can result in worsening the diarrhea or cause serious complications such as hemolytic uremic syndrome. It is usually better to wait for the stool culture result.
Food poisoning is commonly misunderstood. The most common food poisoning is from the bacteria Staph aureus. Called "staph" for short, the staph bacteria contaminate the food. While the bacteria sit on the food, the staph produce a toxin (a toxic chemical) which they leave on the food. When this food is eaten, the toxin immediately causes ill symptoms. Most commonly, stomach cramps, vomiting and diarrhea result within an hour or two. This is "food poisoning" because there is a poison on the food. The poison (a toxin) was made by the bacteria. The staph bacteria do not infect the person who ate the contaminated food so this is NOT an infection. Only the toxin causes illness which is why this is a food poisoning and not a food borne infection. Food poisoning usually starts very soon after eating the contaminated food, but it usually resolves quickly. A more serious food poisoning known as ciguatera occurs from eating fish contaminated with the ciguatera toxin. Patients with ciguatera are more severely ill and often require hospitalization.
Salmonella is commonly thought of as "food poisoning", but it is not. Salmonella is a food borne infection. In other words, the salmonella bacteria actually infect the intestines of a patient. Salmonella is often transmitted on food or from another infected person. If salmonella bacteria contaminate some food, the number of salmonella bacteria may be small, but when the food is eaten, the salmonella bacteria begin to multiply in the person. In about a few days, there may be enough salmonella bacteria to make the patient ill with vomiting and diarrhea. This is very different from food poisoning in which ill symptoms occur immediately after eating the contaminated food. In a food borne infection, the bacteria are still carried on the food, but several days must pass for the infection to "incubate" in the person (the bacteria must multiply to a number high enough to cause ill symptoms in the patient).
Food poisoning cases are usually easy to identify as food poisoning because many people who ate the same food all become sick on the same day. Food borne infection cases are difficult to identify because not everyone becomes sick. Only those persons who lack immunity to the bacteria and who ate enough contaminated food become sick. Also, they usually become sick many days after eating the contaminated food, so it may be difficult to figure out which food caused the problem.