Summary: Abdominal pain is a common condition for which medical care is sought. Most of these conditions are not serious, but most of the serious conditions (including appendicitis) are difficult to diagnose. These serious conditions are frequently missed by physicians. Parents must be on the look out for these conditions and insist on second opinions or rechecks if a serious condition such as appendicitis is suspected.
The summary paragraph above says it all. Finding the serious causes of abdominal pain is like finding a needle in a haystack. Although nearly all children with serious intestinal conditions have significant abdominal pain that parents notice, this is only a small fraction of all children with abdominal pain. Most children with abdominal pain have minor conditions causing the pain. Parents wouldn't want surgeons cutting open all these bellies unnecessarily just to check it out.
Constipation, stomach flu and indigestion are probably the most common causes of abdominal pain. What exactly do all these words mean? Some definitions are useful here.
First of all, the term "bowels" means the same thing as intestines. Thus, "bowel movement" means that the intestines are moving. Stomach growling is from the intestines contracting. The intestines can move without passing stools (feces, kaka, doo doo, poop, crap, and many of the other colorful words that are used to describe the malodorous solid waste that we prefer to pass in a toilet). Most people use the term "bowel movement" (BM) to mean the passage of stools so this is how we will use this term. BM means to pass stools.
Some believe that constipation means not having a bowel movement. Having a BM everyday is not a requirement. Skipping one or more days without a BM is quite common and this is not abnormal. Constipation could also mean that the stools are hard and/or are difficult to pass. There are several definitions of constipation so the use of this word leaves some uncertainty about what someone is referring to.
Another meaning of constipation is a common cause of severe abdominal pain. Normally, the intestines slowly contract like a snake to move things from the top end (goes in as food) to the back end (where it comes out as stool). This is called peristalsis, in which a gentle coordinated wave of intestinal contractions gently pushes the contents of the intestines forward toward the back end. Sometimes hard stools or a very large stool may get stuck somewhere in the lower intestines. To prevent an intestinal blockage, the intestines squeeze and contract very hard to get the stuck segment to move. If the stools don't move, gas pressure builds up behind the stuck stool and the intestines squeeze extra hard to get the stuck segment to move. These severe intestinal contractions are felt as painful abdominal cramps (similar to severe menstrual cramps or diarrhea cramps). A build up of gas pressure causes the intestines to enlarge and stretch, which results in additional pain. This pain can be very severe. Children often come to the emergency room or doctor's office crying, curled up in severe pain.
A rectal exam (doctor's finger in the anus to check inside the rectum) might detect a hard stool mass, but the stuck segment of stool might be higher up, in which case, the doctor's finger cannot reach it. An enema is a liquid solution, usually in a plastic bottle, which is squirt into the rectum. The liquid is frequently a soapy solution or an electrolyte (salts) solutions. The enema liquid runs up into the lower intestines loosening the stools and stimulating the lower intestines to contract. An enema will frequently result in a BM, movement of the stuck segment of stool, and total pain relief. A stool does not have to be passed for pain relief to occur. If the stuck stool segment is higher up, then it just has to move further down the intestine. Once movement occurs, the intestines no longer have to contract really hard. Normal gentle peristalsis returns and the painful abdominal cramps, which resulted from the severe intestinal contractions, now resolve.
At this point, the child has gone from severe pain to a normal pain-free condition. The child's parents are often stunned at this point and cannot believe that a stuck segment of stool could cause so much pain. Is this what we call "constipation"? This is one of the many meanings of constipation. I prefer to call this, severe abdominal cramps due to a temporary intestinal blockage by a stuck segment of stool. There is a more technical medical way to word this that sounds a lot better than just "constipation".
Indigestion is not really a medical diagnosis since this doesn't identify a well defined medical condition. It basically means that your stomach is upset (resulting in pain and discomfort) for various reasons. Medically, this might be called dyspepsia. Causes of this include stomach irritation, excess stomach acid, heartburn, early ulcers, gas pains, etc. Sometimes this is caused by food or a combination of foods which don't agree with each other. Imagine eating pickles, sardines, chocolate cake and a burrito. This combination alone might upset even a healthy stomach. Treatment with anti-acid medications may help treat some of these conditions if excess acid is the problem.
More severe causes of abdominal pain are much more serious because they often require surgery and can result in severe complications if the condition is not identified and treated early. The best known example of this is appendicitis. Appendicitis requires surgical removal of the appendix promptly. If the appendix is not removed, it will rot, perforate and leak stool into the belly cavity, which results in the spread of infection into the entire abdomen and possibly into the bloodstream. Appendicitis often presents with abdominal pain in the right lower quadrant (on the right side below the belly button). Other symptoms may include fever, vomiting, loss of appetite and inability to walk well. Unfortunately, the usual signs and symptoms of appendicitis are often not present. In about half the cases, a doctor is not able to diagnose appendicitis when the patient first comes in because the signs and symptoms do not indicate the presence of appendicitis. Often the pain is in the wrong spot. The pain can be in the middle of the abdomen, up high, or any place at all. Since most people have heard of appendicitis, most think that it is an easy condition to diagnose. This is absolutely not true. Appendicitis is one of the most difficult diagnoses for a doctor to make. Frequently, a patient will go to a doctor for abdominal pain, but it is too early for all the signs and symptoms to be present. The patient is often misdiagnosed with stomach flu, constipation or indigestion. The patient will then become worse and go back to the doctor or emergency room where the correct diagnosis is hopefully made. Most patients are very unhappy because the first doctor was unable to make the diagnosis of appendicitis during the initial visit, but this is a common occurrence. It is unrealistic to expect a doctor to be perfect especially with appendicitis. Most research studies show that about half the patients with appendicitis are initially misdiagnosed.
An early diagnosis of appendicitis by examination is only possible about half the time. An early diagnosis can be made by using advanced imaging studies. Tests commonly ordered in appendicitis include a white blood count, an analysis of the urine (urinalysis) and an abdominal x-ray series. Unfortunately, these basic tests cannot make the diagnosis of appendicitis most of the time. The white blood count is usually high in appendicitis, but it can also be high in flu illnesses, pneumonia, stress and other infections. In fact, a high white blood is more commonly due to a condition other than appendicitis. Additionally, a normal or low white blood count could occur in appendicitis.
Abdominal x-rays are usually normal in appendicitis. In only a few cases, an x-ray can detect a visible stone in the appendix. This is actually a very hard pearl of stool, called a fecalith (meaning a stone made of feces) or an appendicolith (meaning a stone in the appendix), which blocks the opening to the appendix. The appendix is a tiny finger of intestine which sticks out of the large intestine. When the opening to the tiny appendix is blocked, gas builds up inside and it begins to stretch which causes pain. Blood flow to the appendix stops because of this pressure and the appendix begins to rot causing more pain. The appendix needs to be removed. If it is not removed, the appendix will perforate forming a small leak. This deflates the gas pressure and the pain suddenly gets better for a while. This can be very misleading since both patient and doctor might believe that things are getting better, when in fact the appendix has perforated!! Stool contents and millions of bacteria leak out of this perforation spreading infection into the abdominal cavity. This spread of infection causes pain which may be spread out over a larger area of the abdomen. Pockets of pus may form and/or the infection may spread into the bloodstream. Antibiotics, removal of the appendix, and an extensive rinse-out of the abdominal cavity is required once the appendix perforates.
Abdominal x-rays can also see signs of perforation in some instances, and there are several x-ray patterns which suggest the possibility of appendicitis, but in most instances, abdominal x-rays are not able to convincingly demonstrate the presence of appendicitis.
Urinalysis is frequently ordered to look for the presence of a urinary tract infection (UTI). While a UTI does not usually cause pain in the area of the appendix, the location of the pain may be vague, especially in small children who have difficulty communicating. The presence of white blood cells in the urine suggest the presence of a UTI. However, this can mislead the doctor because appendicitis can also cause white blood cells in the urine. The doctor may decide that the patient has a UTI when in fact the patient has appendicitis.
There are many reasons why appendicitis is difficult to diagnose. Based on history and clinical examination, it is difficult to reliably identify appendicitis. Lab tests and x-rays are not very helpful. Realize that the treatment for appendicitis is an operation. This is fairly serious, so the diagnosis should be accurate before deciding to open up a child's belly.
It is estimated that in 10% of cases, the diagnosis is not made in time and the appendix perforates. This percentage is even higher in young children. In another 10% of cases, a surgeon will decide that a patient has appendicitis, an operation is performed, but the appendix is found to be normal. There are many conditions which mimic the signs and symptoms of appendicitis and few of them benefit from an operation.
One way to improve the accuracy of diagnosing appendicitis is to use advanced imaging such as CAT scan (more commonly called CT scan nowadays) or ultrasound. CT scan is able to visualize the appendix more accurately, but it is difficult to do. Abdominal CT scans require intestinal contrast. This is a liquid which the patient must drink to fill the intestines to help see the appendix on the CT scan. The appendix is far down so it takes 1-2 hours for the contrast liquid to travel down far enough to see the appendix. Appendicitis frequently causes nausea and vomiting so it is often difficult for patients to drink enough contrast. If the contrast is vomited, more must be given. This can be the most difficult aspect of completing an abdominal CT scan. Abdominal CT scans involves some x-ray exposure and it also requires intravenous contrast to visualize the kidneys and urine flow.
Abdominal ultrasound is also capable of visualizing the appendix. This is a lot easier to do because contrast is not required and there is no exposure to x-rays. The problem with ultrasound is that it often cannot see the appendix. Ultrasound cannot penetrate air pockets. The intestines frequently have small air pockets which reflect and scatter the ultrasound waves. In such instances, the appendix cannot be visualized at all. Ultrasound pictures are not as clear as CT scan pictures. Ultrasound pictures are fuzzy and have been commonly described as a snowstorm. Because of this, the interpretation of an abdominal ultrasound requires exceptional skill. If you are in a big city hospital with ultrasound specialists, then an ultrasound should be tried first. If you are in a general hospital without ultrasound specialists, it is probably better to skip the ultrasound since its interpretation may be misleading. The ordering decision relies on your child's doctor's knowledge of the skills of the hospital's radiology department.
When should an advanced imaging study, such as an ultrasound or CT scan, be ordered? There are two goals here. The first is to confirm the presence of appendicitis in those who are suspected as having it. The second is to rule out the presence of appendicitis in patients who are suspected to have only a slim chance of having appendicitis. The first situation occurs about twice a week, while the second situation occurs several times each day. It seems very reasonable to perform an imaging study to confirm the presence of appendicitis before committing to an operation. But is it reasonable to perform an expensive imaging study on many patients each day who only have a slim chance of having appendicitis? Consider that doctors must make these decisions all the time. What would you do if you were a doctor?
Many doctors believe that this is too many expensive studies to perform on too many patients. I've come to the opposite conclusion. Appendicitis is common. Appendicitis is difficult to diagnose. Failing to diagnose appendicitis early results in more severe complications for the patient. Under these circumstances, is it OK to miss a few cases of appendicitis? Most would say no. Recall that about half of the appendicitis cases are missed during the initial doctor evaluation and 10% of appendicitis cases rupture before the appendix can be removed. Most of the time, the doctor's diagnosis is correct. But when they are wrong and the diagnosis of appendicitis is missed, complications often occur.
Thus, it might be beneficial to take the strategy of not missing any case of appendicitis. To do this, a doctor would have to perform an advanced imaging study (CT or ultrasound) on every patient; a rather expensive strategy. The other alternative is to inform patients and parents of the signs and symptoms of appendicitis, instructing them to return if the child's condition worsens. This seems to be more reasonable, but if you ask parents which strategy they prefer for their child, most prefer to do the advanced imaging study.
Other serious abdominal pain conditions include intussusception, volvulus, tumors and pneumonia. Intussusception is a condition in which the intestines telescope into itself. Realize that the intestine is a long tube. Intussusception occurs like a long sleeve turning inside out, or a sock pulling the toe end through the top. The symptoms of intussusception include intermittent severe abdominal pain, vomiting, and lethargy. A doctor can sometimes feel a sausage shaped mass in the abdomen on examination. An intussusception can often be detected on plain abdominal x-rays, but this is difficult to read. An abdominal ultrasound can diagnose an intussusception in most instances. The standard test which is used to diagnose intussusception is a barium enema. Barium is a white liquid x-ray dye. Barium is run into the rectum from a pressure bag. Using an x-ray video camera (called a fluoroscope, just like the ones used to check airport passenger bags), the barium is watched as it enters the lower intestine. When the intussusception is encountered, the flow of barium outlines the abnormality. Intussusception is another important diagnosis to make early. If the diagnosis is not made early, the segment of intussusception will die and rot because it does not get enough blood supply (the telescoping stretches and blocks blood flow).
Volvulus occurs when the intestines twist upon themselves. This causes the intestines to be blocked and the blood supply to the intestines is lost. This is a true emergency because the intestines will die within a few hours or sooner. The only hope is for an operation to be performed in time to untwist the intestines to restore the blood flow. Not performing this operation in time is catastrophic because nearly ALL the intestines will die and then they must be removed in a surgical operation. There is a significant risk of death and even if the patient survives, this leaves the patient with only a few feet of intestine. This is not enough for adequate nutrition and such patients must be fed intravenously for the rest of their lives.
Tumors can cause abdominal pain. Tumors can be cancerous or benign. Plain abdominal x-rays can only sometimes identify an abdominal tumor. Usually an abdominal CT scan or ultrasound is required to identify a tumor.
Pneumonia (infection in the lungs) is a common cause of abdominal pain. If the pneumonia is high in the chest, it may cause chest pain, but pneumonia in the lower parts of the lung often causes abdominal pain. Abdominal x-rays will sometimes show the pneumonia, but doctors tend to focus their attention on the abdominal part of the x-ray and they frequently fail to notice a pneumonia on the upper edge of the x-ray in the lungs. More experienced physicians, who properly suspect a pneumonia as a possible cause of the abdominal pain, will order x-rays of the chest to more accurately look for a pneumonia.
There are many other causes of abdominal pain, but most of the serious ones have been discussed here. The main goal is to suspect the cause of abdominal pain to be serious or non-serious. Once a potentially serious cause of abdominal pain is suspected, then an advanced imaging study can be performed to accurately determine the cause.
The following set of instructions, which I wrote for our emergency room, can be used to suspect most serious causes of abdominal pain.
Realize that the actual cause of abdominal pain may be difficult to diagnose early on. It is important that you watch carefully for changes in the abdominal pain which may suggest an emergency condition (such as appendicitis which is hard to diagnose early on). See your physician or return to the emergency room immediately or call your physician if your condition gets worse. Watch for these symptoms which suggest serious causes of abdominal pain:
1. Unable to walk easily. Walking in a bent over position. Stepping or jumping which results in severe pain.
2. Pain in the right lower part of the abdomen.
3. An abdomen which is hard and painful when you attempt to press in on it.
4. Severe pain when coughing.
5. Persistent vomiting or retching. Vomiting which is bloody or contains material resembling chocolate or ground coffee. Vomiting which is greenish or dark yellow.
6. Abdominal distention (The belly is not flat. It appears to be full or bigger than it normally is).
7. Episodes of severe pain with or without retching or vomiting which repeat itself every 3-20 minutes.
8. Bloody stools (bowel movement) or stools which appear to resemble black tar.
9. Lethargy (drowsy and not responding well), irritability (fussiness), or pallor (pale color).
Numbers 1-4 above suggest appendicitis. Number 5 suggests ulcers or an intestinal blockage (bowel obstruction). Number 6 suggests an intestinal blockage (bowel obstruction). Number 7 suggests intussusception. Number 8 suggests intestinal bleeding. Number 9 suggests intussusception, dehydration or other serious conditions.
Parents should watch for these signs and symptoms. They should insist on a second opinion or recheck if their child's condition worsens and nothing is done to check it out further.