Intra-abdominal sepsis with abdominal pain from peritoneal irritation may have many causes, of which appendicitis is one of the most frequent. Other entities are less common and occur within groups with specific risk factors. Acute appendicitis classically produces abdominal pain that is initially vague and periumbilical and within hours of onset localizes to the right lower quadrant. Vomiting, anorrhexia, and low-grade fever are usually present. Table 71–5 reviews helpful clinical signs of appendicitis and peritoneal irritation. If the diagnosis is not made in 24 to 48 hours, appendicitis can progress to perforation with intra-abdominal abscess formation and sepsis. The concern for complications is what drives the conservative approach diagnosis and early surgical consultation in the ED. Early recognition of appendicitis before perforation occurs can be a clinical challenge in infants and young children complicated by the frequency of abdominal pain and a child's inability to describe or localize pain. It is also common for the clinical condition of the patient to improve, and abdominal pain temporarily resolve when an appendix perforates. Data demonstrates a 90% perforation rate by the time diagnosis is made in children younger than 5 years. Because of its high incidence, many authors have approached the diagnosis of appendicitis to identify the most important diagnostic studies to support early recognition.5,6 The diagnosis may be made clinically on the basis of right lower quadrant pain on examination, but the white blood count and a urinalysis may assist in decision making. Imaging studies can include plain films, CT scans, and abdominal ultrasounds. Ultrasound is very “user-dependent” but is quite accurate in thin children and may be particularly useful for females with right-sided pain where ovarian torsion is in the differential. Figure 71–1 provides a diagnostic algorithm for appendicitis. Once the diagnosis is confirmed, the surgical approach to appendectomy can be either open or laparoscopic3 (see Chapter 9).
Spontaneous or primary peritonitis is a condition that is often associated with disease processes such as nephrotic syndrome, which may result from ascites in the face of a relative immunodeficiency. Antibiotic therapy should be directed at the typical causative organisms including Streptococcus species and gram-negative rods, but other organisms should be considered especially if the patient has an indwelling catheter for peritoneal dialysis.
Necrotizing enterocolitis (NEC) is often thought to be a condition that is restricted to premature infants. While it is primarily diagnosed in the neonatal intensive care unit (NICU), NEC can be seen in neonates after being discharged to home. Risk factors include prematurity and difficulty in transitioning at birth, identified by a complicated resuscitation. Infants may present with irritability due to abdominal pain, poor feeding, and bloody stools. Directed resuscitation in the ED is mandatory and conservative treatment involves admission for bowel rest, parenteral antibiotics, and early surgical consultation. Some infants will require surgical resection of the involved areas that typically include those in watershed areas of the small intestine. As with patients in the NICU, there is a risk of losing the involved portions of the bowel and the patients with extensive losses may develop short gut syndrome.
Even though there may be a significant warning sign in abnormal stooling from birth, the recognition of Hirschsprung's disease may be delayed and patients can present with significant disease, including toxic megacolon. The disease is characterized by the lack of parasympathetic ganglia to the affected portion of the colon making peristaltic efforts of the bowel ineffective at moving stool through the colon. When the distal rectum is involved, digital rectal examination may be diagnostic since the lack of rectal tone gives the sensation of inserting one's finger into a glove when there is loss of the dilated rectal vault. Antibiotics and decompression of the bowel may be indicated to stabilize the patient before a diagnostic workup. This may include a barium enema demonstrating a “transition zone,” rectal manometry, or a suction biopsy of the rectum and colon.
Nonsurgical Causes of Abdominal Pain
Vomiting and diarrhea frequently accompany the chief complaint of abdominal pain, and commonly present together. The temptation to automatically diagnose such a patient with acute gastroenteritis can be dangerous as the symptoms are very nonspecific. Be particularly concerned with the patient who presents with vomiting and abdominal pain without diarrhea. Surgically correctable disease must be ruled out.
A common source of abdominal discomfort in children is both upper and lower urinary tract infections (UTI). Patients may have fever, nausea, emesis, abdominal pain, and urinary symptoms such as frequency, urgency, and dysuria. Screening urinalysis, culture, and Gram stain can identify affected patients. An oral course of antibiotics will suffice for treatment of patients who appear nontoxic. Inpatient, parenteral antibiotics required for infants younger than 2 to 6 months and ill patients where the risk of pyelonephritis, bacteremia, and urosepsis is greater (see Chapter 84).
One of the most common causes of colicky, cramping abdominal pain in children is constipation. The pain may limit their everyday function and progress to cause nausea and vomiting. Some patients will present with recurrent UTIs secondary to obstruction. Often the patient will have encoparesis, loose, or liquid stools resulting from leakage around impacted stool in the distal colon and rectum. The etiology of the symptoms often has significant behavioral overlay.
Although not likely an abdominal condition, colic often presents when parents interpret prolonged periods of crying as abdominal pain. Some parents describe an infant who strains to pass a stool. First, it is important to rule out pathologic causes for the infant's irritable behavior. Efforts should be directed to supporting the parents and empowering them with knowledge about the benign nature of the symptoms and giving them ample resources for stress relief. The parents can be exasperated and this puts the infant at risk for abuse because it stresses the parent–child dyad. An emergency provider must help them partner with their primary care physician to ensure that the family has ample follow-up after discharge.
Abdominal pain associated with bleeding from the gastrointestinal tract has many causes and is discussed in detail in Chapter 72. The history should attempt to quantify the amount of blood lost as well as its quality: bright red blood, dark blood, clots, or coffee ground emesis. Patients with a recent history of facial trauma and developing nausea and abdominal pain may have epistaxis when blood from the nose has been swallowed. Others who have had protracted emesis may develop Mallory–Weiss tears with subsequent bloody emesis. A nasogastric lavage with isotonic saline may be necessary to quantify the amount of bleeding and whether the bleeding is controlled.
Infants and toddlers may present with stool that are hard and covered or streaked with blood. The act of passing hard stools is painful and may cause anal fissures. A close examination of the anal opening with ample retraction of the skin of the perineum may be needed to discover the fissure. A more serious disease process is hemolytic uremic syndrome (HUS) that presents with anemia, thrombocytopenia, and renal failure. Abdominal pain with bloody diarrhea can be part of the prodrome; the causative agent is often Escherichia coli O157:H7. Patients with HUS require aggressive fluid resuscitation and treatment of hemolutic anemia and coagulation disorders. The characteristic rash of Henoch–Schöenlein purpura can also present with pain in the abdomen, arthralgias, and blood in the stool. The blood may be only occult in nature, and the physician should remember to obtain a urinalysis looking for proteinuria and hematuria with RBC casts, which can identify whether the patient will develop renal complications.
Gallbladder disease, including gallstone complications, is not common in the pediatric population but there are groups who are at risk, including patients with ongoing hemolytic disease such as sickle cell anemia. Patients with enteric infections and Kawasaki disease may also manifest biliary tract problems with pain. Patients may present with recurrent postprandial colicky epigastric or right upper quadrant abdominal pain. Upon diagnosis, the patient should be made NPO, given pain control, and started on antibiotics. Symptoms of gallstone movement through the bile duct should prompt appropriate diagnostic imaging and surgical or gastroenterology consultation.
Pancreatitis is another uncommon disease in the pediatric population. Obesity appears to be increasing the incidence of pancreatitis in children and adolescents. Patients may present with abdominal pain radiating to the back after high-fat meals in conjunction with pale stools. Some children will develop the disease as a result of an infection or exposure, while others will develop pancreatitis as a manifestation of a systemic or genetic disorder such as cystic fibrosis of hereditary pancreatitis. Lipase and amylase will be elevated. Care is mainly supportive, emphasizing pain control and bowel rest. They will often require hospitalization, fluids, and continuous nasogastric drainage till pain is resolved.
Jaundice and abdominal pain may be the first manifestations of hepatitis. The etiology of hepatitis can be related to infection, drug exposure (especially acetaminophen), systemic disease, or diseases inherent to the liver and biliary tree. The diagnostic pathway should include laboratory studies to assess damage to the liver, hepatic function, investigations into possible etiologies, and imaging of the biliary tract. In complicated patients, early consultation with gastroenterology is essential to ensure that the patient is followed to identify possible progression to liver failure. See Chapter 75 for a detailed discussion of hepatitis.
Inflammatory Bowel Disease
Inflammatory bowel disease (IBD) is another uncommon cause of abdominal pain in children; however, the undiagnosed patient may present repeatedly to the ED for complaints of abdominal pain. This can be frustrating for the patient, family, and the provider. The pain may be vague in nature, but it may be associated with melena or frankly bloody stool. The subset of patients with Crohn's disease may have early manifestations of the disease in the perianal area, including fistulae and skin tags. Patients with significant bowel involvement may progress to obstruction, perforation, or sepsis. At a minimum, the patient should have a CBC, liver function tests, and assessment of inflammatory markers. Patients with IBD will require gastroenterology consultation for long-term management, but a strong relationship with the primary care provider will reduce unnecessary ED visits and improve care.
Gynecologic Causes of Abdominal Pain
The complexity of decision making about the causes of abdominal pain is increased when considering the adolescent female. Pubescent females may have abdominal pain that can cause significant morbidity if left untreated. Ovarian cysts and tumors may cause pain but may also lead to ovarian torsion, so it is imperative to consider this diagnosis even in young girls. Additional complexities are introduced when puberty begins and with the onset of sexual activity. Dysmenorrhea and endometriosis should be considered in young women with recurrent abdominal pain. Pelvic inflammatory disease is possible when an adolescent has lower abdominal pain, cervical motion tenderness, and fever. Pregnancy and ectopic pregnancy should also be a consideration in any adolescent with abdominal pain.
Genital Problems in Males with Abdominal Pain
A diagnostic examination for abdominal pain must include careful evaluation of both the genitalia and rectum. Acute scrotal or testicular pain often presents as abdominal pain. Testicular torsion, torsion of the appendix testes, orchitis, and epididymitis can be reviewed in Chapter 82.