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Intussusception




Introduction of Intestinal Obstruction

Acquired Bowel Obstruction

Lecture № 2. Acquired Bowel Obstruction / Digestive system Hemorrhage

Lesson 3.

Intestinal obstruction can occur at any age from newborn infants to adults. The etiology of the obstruction varies greatly, depending on the age that it occurs and the past sur­gical history.

The lesions that cause intestinal obstruction can be separated into high anatomic obstructions, low anatomic obstructions, and functional obstructions.

High anatomic obstructions are caused by lesions that interrupt bowel continuity proximal to the midportion of the jejunum. Low anatomic obstructions are distal to the midportion of the jejunum. Functional obstructions may be caused by sepsis, electrolyte imbalance, necrotizing enterocolitis and hypothyroidism.

Small bowel obstruction in infants and children is more common than large bowel obstruction. There are many causes, both congenital and acquired, including adhesive small bowel obstruction; hernias, which may be congenital or acquired; and intramural and extramural intestinal lesions. By far the most common of these is adhesive small bowel obstruction, which accounts for up to 60% of small bowel obstructions. Adhesions are followed by tumors (20%), hernias (10%), inflammatory bowel disease (5%), volvulus (3%), and various miscellaneous causes of intestinal obstruction.

 

Classificationof Intestinal Obstruction

v Acquired v Congenital   § Partial (incomplete) intestinal obstruction § Complete intestinal obstruction
o Non-mechanical (dynamical) intestinal obstruction - paralytic (adynamic) ileus - spastic ileus o Mechanical intestinal obstruction (mechanical ileus) - strangulated intestinal obstruction - obturation intestinal obstruction - mixed intestinal obstruction

 

Intussusception, the telescoping or invagination of a proximal portion of intestine (intussusceptum) into a more distal portion (intussuscipiens), is one of the most common causes of bowel obstruction in infants and toddlers.

Vascular compromise and subsequent bowel necrosis are the primary concerns with intussusception. In addition to bowel obstruction, edema with venous obstruction and eventual obstruction of arterial flow leads to ischemia and eventual full-thickness necrosis of the intussuscepted bowel and mesentery.

Although uncommon, in patients who undergo operative reduction of intussusception, as many as 10% may require bowel resection.

 

Fig. 3.1. Illustration of an intussusception is showing the invaginated intussusceptum (blue) and the invaginating intussuscipiens (red). (A) demonstrates a direct or normograde intussusception occurring in the direction of normal peristalsis. (B) demonstrates an indirect or retrograde intussusception occurring against the normal direction of peristalsis.

 

Diagram shows a longitudinal view and three axial views of an intussusception; three bowel loops and the mesentery can be seen. The intussuscipiens (A) contains the two limbs of the intussusceptum: the everted returning limb (B), which is edematous, and the central entering limb (C), which is located at the center of the intussusception with the accompanying mesentery (M). The mesentery contains some lymph nodes (L). MS = contacting mucosal surfaces of the intussuscipiens and everted limb, S = contacting serosal surfaces of the everted limb and central limb.

History

Intussusception was first described by Barbette in 1674, and Wilson was the first to successfully treat it surgically in 1831. In 1876, Hirschsprung first reported the technique of hydrostatic reduction, and after monitoring a series of 107 cases, reported a 35% mortality rate in 1905.

 

Frequency

Intussusception primarily affects infants and toddlers, although it can also occur prenatally or during the neonatal period. Intussusception rarely occurs in adults.

The estimated incidence is about 1.5-4 cases per every 1,000 live births. Males are affected more than females at a ratio of 3:2.

Intussusception is primarily a disorder of infancy and occurs most commonly between 5–10 months of age. Two thirds of children with intussusception are less than 1 year of age at presentation.

Incidence peaks during two seasons of the year: spring/summer and middle of winter. This seasonal variation correlates with times of increased number of cases of viral gastroenteritis and upper respiratory infection.

 

Pathogenesis

The pathogenesis of intussusception has been ascribed to an inhomogeneity of longitudinal forces along the intestinal wall. In the resting state, normal propulsive forces meet a certain resistance at any point. This stable equilibrium can be disrupted when a portion of the intestine does not appropriately promulgate peristaltic waves. Small perturbations provided by contraction of the circular muscle perpendicular to the axis of longitudinal tension result in a kink in the abnormal portion of the intestine, creating a rotary force (torque). Distortion may continue, in-folding the area of inhomogeneity and eventually capturing the circumference of the small intestine. This invaginated intestine then acts as the apex of the intussusceptum.

Intramural, intraluminal, or extramural processes may produce points of disequilibrium. Along with anatomic abnormalities, flaccid areas that follow a paralytic ileus can also create unstable segments because adjoining areas create discordant contractions with the return of bowel activity. Such a model offers an explanation as to the cause of postoperative intussusceptions, which are rarely found to have a surgical lead point, but can complicate any procedures that produce an ileus, including thoracotomies and cardiac procedures.

 

Pathophysiology

Intussusception results in bowel obstruction, followed by congestion and edema with venous and lymphatic obstruction. This progresses to arterial obstruction and subsequent necrosis of the bowel. Ischemia and then necrosis results in fluid sequestration and bleeding from the GI tract. If untreated, the bowel may perforate and the patient becomes septic.

 

Etiology

Intussusception is most commonly idiopathic and no anatomic lead point can be identified. The vast majority of cases are idiopathic (95%).

Several viral gastrointestinal pathogens (adenovirus, rotavirus, reovirus, echovirus) may cause hypertrophy of the Peyer’s patches (mural lymphoid tissues) of the terminal ileum which may potentiate bowel intussusception.

A specific lead point that draws the proximal intestine and its mesentery inward and propagates it distally through peristalsis is identified in only 5% of cases and is most commonly found in cases of ileoileal intussusception.

Specific lead points are more commonly found in children older than 3 years and almost always in adults with intussusception.

The most commonly encountered anatomic lead point is a Meckel’s diverticulum.

Other lead points described include lymphomas, submucosal hemorrhage with Henoch-Schönlein purpura, hemangiomas, lymphosarcomas, inverted appendiceal stumps, and anastomotic suture lines. Children with cystic fibrosis (CF) may present with intussusception due to inspissated meconium in the terminal ileum. While generally observed as a complication in older children with CF, neonatal intussusception with meconium plug syndrome associated with CF has been reported.

Postoperative jejunoileal or ileoileal intussusception, which usually does not have a specific lead point, accounts for approximately 1% of intussusceptions in children of all ages.

In many cases, there is no known cause for intussusception. However, intussusception may sometimes occur as a complication of some medical conditions, including:

· Viral infections (especially adenovirus)

· Meckel's diverticulum

· Intestinal polyps

· Tumors, such as lymphosarcoma and neurofibroma

· Lymphoma

· Cystic fibrosis

· Recent abdominal surgery

· Henoch-Schonlein purpura

· Inflammatory bowel disease

· Hemophilia

· Hemangioma

 

Classification

by H. Feldman, 1977 § ileo-ileal (or jejuno-jejunal) (15%) § ileo-colic (80-90%) ü simple (without caecum) ü compound (with caecum) § colo-colic § rare forms (intussusception of Meckel’s diverticulum, appendix, and double or three-fold manner)     Acute (98,8%) Сhronic (0,7%) Recurrent (0,5%)  

 

The most common form is ileo-colic in 80-90% of cases, less often ileo-ileal occurs in up to 15% and rarely caeco-colic, jejuno-jejunal or even ileo-ileo-colic occur in a double or three-fold manner.

 

Clinical presentation

The initial symptoms may include:

§ Abdominal pain (83%) - usually severe and comes on suddenly, colicky or cramping; in children, this may be indicated by drawing knees to chest and crying.

§ Vomiting (sometimes yellow or green tinged) (85%)

§ Stools mixed with mucus and blood (often described as currant jelly) (53%)

§ Palpable abdominal mass

§ Lethargy

 

Additional symptoms include:

§ Poor feeding

§ Diarrhea (10-20%)

§ Shock

§ Dehydration

§ Fever

The classic triad of pain, abdominal mass, and bloody mucous stools (“red current jelly”) is present in only one third of infants with intussusception.

 

The infant with intussusception has a history of severe cramping or colicky abdominal pain occurring intermittently every 5-30 minutes. During these attacks, the infant screams and flexes at the waist, draws the legs up to the abdomen, and become pale and diaphoretic. These episodes may last for only a few seconds and are separated by periods of calm normal appearance and activity. However, some infants become quite lethargic and somnolent between attacks. Early on, vomiting of undigested food may occur. As attacks continue, emesis may turn bilious. Stools that appear normal in character early in the course of the illness eventually become dark red and mucoid (resembling currant jelly), a sign of intestinal ischemia and mucosal sloughing.

Between attacks, the infant may appear somnolent or quite normal, and findings on examination of the abdomen may be quite unremarkable. During an attack or spasm, the infant suddenly appears startled or anxious and begins to scream. Upon initial inspection, the abdomen may appear scaphoid; during paroxysms, it may be rigid; and later in the course of the illness, it may become distended with signs of peritonitis. Careful palpation after an attack has subsided may reveal an ill-defined or “sausage-shaped” mass.

With early ileocolic intussusception, the mass is typically found in the right upper quadrant or abdomen. The right lower quadrant may seem empty upon examination, a finding known as the Dance sign. This mass may be difficult to locate in inconsolable infants because of abdominal rigidity from muscle straining. If episodes of cramping are witnessed, the careful examiner may auscultate peristaltic rushes in the area of the intussusception.

The rectal examination should commence with inspection of fecal material in the diaper. Normal-appearing stool should be tested for occult blood. The presence of mucoid or frankly bloody stool supports the diagnosis.

Rarely, inspection of the anus may reveal the prolapsed tip of the intussusception. Prolapse of the intussusceptum from the anus is a rare event (1-3%). A digital rectal examination should be performed routinely, looking for blood or a mass higher in the anal canal.

Fever and leukocytosis are common findings. Tachycardia becomes more prominent as hypovolemia ensues.

The babies with intussusception are usually well nourished and are generally above average in physical development. This fat and healthy appearance is apt to mislead the physician if he or she sees the baby in the early hours of illness.

 

Diagnosis

Tests include:

§ Blood and urine tests

§ Fecal occult blood test, which checks the stool for blood

§ Abdominal x-ray, ultrasound, or CT scan

 

Obtain CBC count with differential and chemistry profile. Blood chemistry abnormalities are not specific for intussusception. Depending on the duration of illness and associated vomiting and blood loss, laboratory investigations may reflect dehydration, anemia, leukocytosis, or a combination of these.

Early in the course of the illness, findings on plain radiographic examination of the abdomen (supine and upright) may show a normal or nonspecific bowel gas pattern. Later, findings suggestive of intussusception include dilated loops of small bowel with or without air-fluid levels, an airless or opacified right lower quadrant, or both. In 25-60%, abdominal plain films demonstrate a right upper quadrant soft tissue density that displaces air-filled loops of bowel. Occasionally, the intussusceptum may be apparent on plain abdominal radiography.

Ultrasonography of the abdomen is a reliable means to identify intussusception. Two ultrasonographic signs of intussusception are: the “doughnut” or “target” sign on transverse views, and the “pseudokidney” sign on longitudinal views.

The evaluation of abdominal pain often leads to CT examination. Although not indicated for the diagnosis of intussusception, intussusception can be found incidentally on CT scan.

 

Diagnostic Procedures:




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