Approach to Abdominal Pain in Children. In this next section, we will be discussing the approach to abdominal pain– first, looking through a list of differential diagnosis. And after that, we will discuss the approach to acute and chronic abdominal pain going through each step of history, physical examination, and investigations. These are the causes of abdominal pain. They can be divided into acute and chronic causes. Under acute courses, importantly, we must rule out surgical causes, because many of these are time critical. In adolescent females, ectopic pregnancy is important to consider. Other gynecological core problems like ovarian cysts with complications should be considered. These can present with nonspecific lower abdominal pain. In all age groups, one must also rule out appendicitis in any child with severe abdominal pain. If missed, the appendix may perforate, leading to greater morbidity and even mortality. Testicular torsion can also present with abdominal pain in the lower quadrants. Hence, the testes must always be palpated in boys, looking for tenderness, swelling, or abnormal lie of the testes. Hernial orifices should always be inspected for hernia. After ruling out surgical causes, one can then move on to the non-surgical group. Gastroenteritis to enter rightists is common and is usually associated with vomiting and diarrhea. However, do not miss a urinary tract infection. This may present as suprapubic tenderness and cystitis, or even as loin pain in pyelonephritis. Metabolic causes like diabetic ketoacidosis may also present as nonspecific abdominal pain, and a child usually has significant dehydration. Do not forget that pathologies in the lower part of the chest, like basal pneumonia or even myocarditis can present as upper abdominal pain. Looking at the chronic causes of abdominal pain, we divide these into organic versus functional. We first rule out organic causes like inflammatory bowel disease and malignancies. Constipation is a very common cause of chronic recurrent abdominal pain and should always be thought about. Following that, the functional causes of abdominal pain are possible diagnoses. These include irritable bowel syndrome, functional dyspepsia, abdominal migraine, and aerophagia. When taking a history of abdominal pain, ask about the location of the pain. Right iliac fossa pain is a red flag for appendicitis but can also occur in intussusception. Suprapubic pain localizes to the bladder and pelvis, while pain over the groin points towards an inguinal hernia or testicular torsion. Fever is present in infection and inflammation. Vomiting is an important associated symptom. Do not forget to ask about the nature of the vomitus, because bilious vomiting points towards an obstruction distal to the ampulla of Vater. Ask about diarrhea. If bloody diarrhea is present, the differentials include bacterial gastroenteritis, anal fissure, or as a late sign in intussusception. Abdominal distention points to a possible distal obstruction and is common if antimotility agents were used for acute gastroenteritis. Specific symptoms point to specific diagnoses. For example, in Henoch-Schonlein purpura, non-blanch of purpuric rash is commonly seen over the shins. While periorbital and peripheral edema is seen in nephrotic syndrome. But they may be acites or even the dangerous complication of spontaneous bacterial peritonitis, which may account for abdominal pain. DKA classically presents of polyuria and polydipsia. While pneumonia is associated with cough, shortness of breath, or even chest pain. Vital signs are vital and should always be treated with respect. Heart rate, respiratory rate, and blood pressure norms are age related. Tachycardia comes first in dehydration before blood pressure falls. On general inspection, look for signs of dehydration. Look at the mucosal surfaces presence or lack of tears, decreased perfusion to the peripheries, and even sunken eyes or poor skin turgor. On abdominal examination, inspect for distention. And palpate carefully to localize the area of most marked tenderness. Remember that visceral pain often refers to the periumbilical region initially before localizing to the specific origin where the pathology is. Palpate carefully for masses. Rebound tenderness and guarding are red flags that point to a surgical cause. Complete the examination by auscultating for bowel sounds. Look at the perineum. Examine the testes carefully for torsion where there will be extreme tenderness, abnormal transverse lie, as well as the loss of cremasteric reflex. Testicular tenderness can also be present in epididymitis. And elevation of the affected scrotum then relieves the pain. This is Prehn sign. Also look out for anal fissures. Other specific signs of appendicitis that should be looked out for– tenderness that’s localized to the McBurney point. So a sign is right iliac fossa pain when there is flexion of the right hip against resistance. While the hop test is pain in the right iliac fossa while hopping on one leg. Moving on to investigations– a raised total white blood count points towards appendicitis or bacterial cause of gastroenteritis. A urine microscopic analysis is useful to look for pyuria, which would be present in urinary tract infections. When indicated, a blood gas can be done to look for metabolic acidosis. If the child appears unwell or is clinically dehydrated, electrolytes should be screened for abnormalities. An abdominal radiograph is not always indicated in abdominal pain. Specifically when done, small bowel intestinal obstruction would give the appearance of a stack of coins due to the plicae circulares crossing the entire width of the dilated bowel. While in more distal obstruction, the dilated bowel loops and may appear more like sausages identified by the presence of prostrations. These radiographs display some classical signs. The first one on the left shows small bowel obstruction. The next abdominal x-ray shows the presence of intussusception with paucity of gas in the right lower and right upper quadrants. Ultrasound abdomen is useful for picking out appendicitis as well as intussusception. This is an ultrasound showing the classic target sign of intussusception. The next ultrasound picture shows that of appendicitis with an inflamed thickened appendix with surrounding free fluid. Chronic abdominal pain– this is defined as at least three pain episodes over at least three months interfering with function. Look out for the red flags on history. Ask about the severity of the abdominal pain, especially those of nocturnal awakening. Ask about changes in bowel habits, especially chronic diarrhea or persistent vomiting. Ask about associated symptoms that may be found in malignancy and autoimmune disease. These include recurrent oral ulcers, joint involvement rash, loss of weight and appetite, and recurrent fever. Examine for any localized tenderness in the right upper or right lower quadrants. Any fullness or mass effect. Always palpate for the presence of any organomegaly, and look at the perianal region for stigmata that would suggest inflammatory bowel disease. Investigations depend on the findings from history and physical examination. Full blood count is useful when looking for anemia, specifically where the anemia is normocytic, normochromic, as in chronic illness or microcytic, hypochromic in iron deficiency from blood loss. Also the total white and differential counts help in making a diagnosis on the presence of bacterial infection. CRP is a useful inflammatory marker for acute infection, while ESR for chronic inflammation. The liver function test would show the level of albumin, giving the nutritional state of the child, and also reveal the presence of any transaminitis. Stool tests should be tailored specifically to the clinical suspicions for each patient. These include stool occult blood, stool bacterial cultures, stool for ova cysts and parasites, as well as Clostridium difficile toxin assay. Autoimmune markers may be performed if inflammatory bowel disease is suspected. In conclusion, the key to diagnosis is a good history and physical examination. In acute abdominal pain, always remember to think outside the box. If there is significant dehydration out of proportion to the presenting symptoms, always ask about preceding symptoms of polyuria, polydipsia, loss of weight as this patients may be presenting with diabetic ketoacidosis. With respiratory symptoms and minimal tenderness on abdominal palpation, consider referred pain from the chest, as in the case of basal pneumonia. Do not forget about urinary tract infections which are commonly seen. And remember to rule out gynecology causes in all adolescent females. In chronic abdominal pain, this is a common complaint in pediatrics. Look out for the red flags as mentioned above. Remember to take a thorough family and social history, as this may reveal triggers for causes of functional abdominal pain.