Intussuscepção em crianças

Intussusception is much more common in children than in adults. See the separate Intussusception in Adults artigo.

Patogênese

Intussusception is a term derived from the Latin intus (within) and suscipere (to receive). One segment of the bowel (intussusceptum) invaginates into another (intussuscipiens) just distal to it, leading to obstruction. The bowel may simply 'telescope' on itself (non-pathological lead point - up to 75%), or some pathology may be the focus of the invagination (pathological lead point). The mesentery of the intussuscepted bowel becomes compressed. The bowel wall distends and obstructs the lumen. Peristalsis is disrupted leading to colicky dor abdominal and vomiting. Lymphatic and venous obstruction occurs, causing ischaemia. In most children the intussusception is ileocaecal, although ileo-ileocolic and ileo-ileal or colocolic cases can occur.

Epidemiologia

• The male-to-female ratio is approximately 3:1.¹

• Two thirds of patients are under 1 year old..

• Intussusception is the most common cause of intestinal obstruction in patients aged 5 months to 3 years and accounts for up to 25% of abdominal emergencies in children up to age 5.

• It is rare preterm.

• The mean incidence of intussusception is 74 per 100,000 in children under 1 year of age, with a peak between 5-7 months of age.²

• It has been associated with the rotavirus vaccine but the incidence is small and it is outweighed by the benefits of the vaccine.^{3 4}

Sintomas de intussuscepção¹

• Intussusception is usually of sudden onset and may be more insidious in the older child.

• There are paroxysms (about every 10-20 minutes) of colicky abdominal pain (>80%) ± crying.

• The child may appear well between paroxysms initially.

• There is early vomiting - rapidly becoming bile-stained.

• Neurological symptoms such as lethargy, hypotonia or sudden alterations of consciousness can occur.

• There may be a palpable 'sausage-shaped' mass (often in the right upper quadrant).

• There may be absence of bowel in the right lower quadrant (Dance's sign).

• Dehydration, pallor, shock.

• Irritability, sweating.

• Later, mucoid and bloody 'redcurrant' stools.

• Late pyrexia.

Differential diagnosis of intussusception¹

• Hérnias abdominais

• Apendicite

• Blunt trauma abdominal

• Cólica

• Síndrome de vômito cíclico

• Gastric volvulus

• Gastroenterite

• Intestinal hernia

• Torção testicular

• Volvulus

Causes and associated conditions of intussusception

Non-pathological lead point (>90%)

• Viral 50% - rotavirus, adenovirus and human herpesvirus 6 (HHV6).⁴

• Amoebomata, shigella, yersinia.

• Peyer's patch hypertrophy.

Pathological lead point (<10%)

NB: more common in older patients (who may have a longer history):

• Meckel's diverticulum (75%).

• Polyps and Peutz-Jeghers syndrome (16%).

• Henoch-Schönlein purpura (3%).

• Lymphoma and other tumours (3%).

• Reduplication - a process by which the bowel wall is duplicated (2%).

• Fibrose cística.

• An inflamed appendix.

• Ascariasis.

• Nephrotic syndrome.

• .

• Postoperative - rarely, postoperative intussusception following operative treatment of an intussusception has been reported.

• Hyperperistalsis.

• Exclusive breast-feeding.

• Weight above average.

• Vacina contra rotavírus.

• Abdominal tuberculosis.

Investigações^{1 5}

• FBC - may show neutrophilia.

• U&Es - may reflect dehydration.

• Abdominal X-ray - may show dilated gas-filled proximal bowel, paucity of gas distally, multiple fluid levels (but may be normal in the early stages).

• Ultrasound - may show doughnut or target sign, pseudokidney/sandwich appearance. It is a very effective modality and many consider it the investigation of choice.

• Bowel enema - barium has been gold standard (crescent sign, filling defect) but air and water-soluble double-contrast now available; each has pros and cons - the choice is left to the individual radiologist.

• CT/MRI scanning - more often used in adults than in children.

Intussusception treatment and management⁶

• Any child with possible intussusception or other serious cause of abdominal pain should be referred urgently to hospital for further assessment.

• Early diagnosis reduces the need for open surgery.

• Resuscitation - 'drip and suck' - nasogastric tube and IV fluids.

• Use of prophylactic antibiotics does not reduce post-reduction infection rates.

• Radiological methods are used to diagnose in 95% cases (outside Africa):²
  

  • Repeated enema reductions (eg, three tries for three minutes each) are acceptable if clinically appropriate - ie if there is no sign of peritonitis, perforation or shock.

  • Air enema <120 mm Hg of pressure or barium enema may be superior to liquid enema.⁷

  • The choice of enema is usually left to the radiologist (many now favour air enema).

  • Laparoscopic reduction is safe and often successful.⁸

• Laparotomy (reduction/resection) - indications:
  

  • Peritonitis.

  • Perforation.

  • Prolonged history (>24 hours).

  • High likelihood of pathological lead point.

  • Failed enema.

• Hospital admission is usually required but outpatient management (a period of observation after reduction of ileocolic intussusception) may on occasions be an acceptable alternative.

Intussusception complications

• Missed diagnosis.

• Ischaemia of the intussusceptum/intussuscipiens.

• Sepse e septicemia.

• Necrosis.

• Hemorragia.

• Perforation.

• Peritonitis.

• Failure of enema reduction.⁴

• Chronic intussusception - rare cause of falha no desenvolvimento.

Prognóstico

With treatment, prognosis is excellent. Spontaneous resolution of intussusception may also occur and depends on multiple factors - eg, location and length. For example, small bowel intussusception without a lead point can be asymptomatic and an incidental finding.

• Post-reduction recurrence: ranges from 5-15%.^{9 10}

• Mortality: 1% with treatment.