ABDOMINAL PAIN

Abdominal pain is a very common complaint in childhood, though may not be recognized in infants. Sudden coiling-up of body with abdominal rigidity, excessive crying and anxious, restless appearance may be a sign of abdominal pain in young children.

Abdominal pain may arise from somatic tissues or internal viscera. Visceral pain indicates spasm, distension, inflammation or ischemia of these organs and may be referred from or to other sites, e.g. abdominal pain due to basal pneumonia or right shoulder pain from the gallbladder.

Etiology: Abdominal pain may be acute or recurrent and idiopathic or secondary to identifiable cause (Table 14.4).

Acute abdominal pain is usually organic in origin and needs exclusion of surgical/medical emergencies, specially if—(a) lasts for gt;3 hours, (b) well-localized or (c) associated with abdominal tenderness, distension, vomiting, fever or sick appearance. However, mild, short-duration, colicky pain is common in children and tends to be benign.

Recurrent abdominal pain (RAP), defined as at least one episode per month for minimum three consecutive months, is complained by 10-20% of children, of which ~70-80% are functional or psychological. It is often, but not always, possible to differentiate functional RAP from organic causes (Table 14.5) to avoid unnecessary investigations. Functional RAP is uncommon below 5 years of age and tends to be more common in females, first-born children and those with timid or anxious personality. These children often find it difficult to describe or localize the pain and are usually normal in between attacks. Any stress in family or school may precipitate these attacks. Many functional disorders associated with abdominal pain have been described, as follows:

• Irritable bowel syndrome (IBS), defined as abdominal pain for at least one day per week in last 3 months, with any one of the following features during the episode: (a) pain related to defecation, (b) change in frequency of stools, and (c) change in consistency of stools (Rome IV criteria).

• Abdominal migraine presents with paroxysmal episodes of intense abdominal pain, lasting for at least one hour with normal intervening periods of weeks/months and presence of any two of the following associated features - nausea, vomiting, anorexia, headache, photophobia and pallor.

• Functional dyspepsia denotes any one of the following for at least four times in a month for 2 months with- (a) post-prandial fullness, (b) early satiety, (c) epigastric pain.

• Functional abdominal pain-not otherwise specified (FAP- NOS), refers to episodic or continuous periumbilical

TABLE 14.5: D/D functional vs organic RAP

TABLE 14.4: Causes of abdominal pain

AGE: Acute gastroenteritis; AIO: Acute intestinal obstruction; GER: Gastroesophageal reflux; MAS: Malabsorption syndrome; PID: Pelvic inflammatory diseases; UTI: Urinary tract infection.

pain at least four times in a month for gt;2 months, which does not fulfil criteria for IBS, Abdominal migraine or functional dyspepsia. Treatment includes reassurance, high-fiber diet, avoidance of carbonate drinks/ refined food and psychotherapy.

Diagnostic evaluation of abdominal pain includes:

• Detailed history about its—(a) onset, duration and progression, (b) character (colicky, dull, burning, sharp shooting), (c) localization* (epigastric, supraumbilical or infra-umbilical), (d) any migration or change in its character and severity, (e) relationship with feeding, respiration and movements and (f) associated complaints, e.g. vomiting, diarrhea/constipation, worm infestation, pica, urinary complaints and abdominal trauma, etc. Menstrual history is important in pubertal girls.

*Pain arising from stomach, upper bowel, hepatobiliary system and pancreas is often localized in epigastrium. Periumbilical pain, common characteristic in appendicitis, also indicates distal bowel, cecal or proximal colon disease. Distal colonic, pelvic and bladder pain is usually suprapubic in location.

• Clinical examination for abdominal distension, tenderness, rigidity or guarding, ascites, organomegaly, lump, bowel sounds, etc., along with examination of hernial sites, genitals and spine. Examination of lungs (basal pneumonia), heart (CCF/pericardial effusion) and rectal examination for pelvic inflammatory disease (in adolescents) is necessary to exclude extra- intestinal causes.

• Baseline investigations are necessary even in appar­ently functional cases to exclude organic pathologies and include:

± Complete hemogram

± Stool exam, specially for parasites and occult blood

- Urine exam, specially for pus cells and crystals

- Chest skiagram for basal pneumonia, TB, etc.

- Tuberculin test

- X-ray abdomen for obstruction, stones, etc.

• Relevant investigations: Ultrasonography is highly informative and essential investigation in all cases of unexplained/recurrent abdominal pain. Other investigations, e.g. contrast studies, CT/MRI or endoscopies are necessary only in selected cases.

Differential diagnosis of some important causes of organic abdominal pain is as follows:

• Esophagitis or gastritis presents with retrosternal pain with burning character, frequently associated with history of drug intake or viral infection.

• Intestinal obstruction may be acute or subacute and associated with vomiting, constipation and distension.

• Acute appendicitis begins in periumbilical pain, which slowly migrates to right ileac fossa after 4-6 hours. Rebound tenderness at McBurney's point is characteristic.

• Biliary colic is rare in children and generally pre­sents with pain referred to right scapula or back. Intermittent colic with jaundice is a strong indicator of gallstones, specially in hemolytic anemia.

• Ureteric or renal colic typically begins in lumbar region and descends from loin to groin. Urinary retention for variable period during these episodes is common.

• Dietel's crisis presents with severe intermittent pain and oliguria, followed by polyuria after torsion of ectopic kidney is relieved.

• Pelvic inflammatory diseases are common in sexually active adolescents, best diagnosed on rectal examination.

14.4.4