Early symptoms of the condition include [6]:

• Nausea 
• Vomiting (often green in colour indicating bile stain)
• Pulling of legs to the chest area
• Intermittent and moderate to severe abdominal pain
• Rectal bleeding
• Stool mixed with blood and mucus
• A sausage shaped mass can be felt in the abdomen following physical examinations 

In children who are too young to communicate symptoms, major presentations include constant crying and pulling up of knees to the chest and paroxysms of pain [7].

Fever is not a symptom of intussusception except when there is compression of arterial blood supply. This brings about perforation and sepsis and consequently, fever.

• Fever

  An eight-month-old female infant, who initially presented with a single episode of vomiting and fever (37.8 °C), was examined as an outpatient at the department of pediatrics of a general hospital. [ncbi.nlm.nih.gov]

  Fever is not a symptom of intussusception except when there is compression of arterial blood supply. This brings about perforation and sepsis and consequently, fever. [symptoma.com]

  It is normal during this time to have a fever and your child may be given Tylenol (Acetaminophen) to bring down the fever. For the first 12 hours after the enema, your child will not be allowed to eat or drink. [chop.edu]

• Crying

  (note: many other causes of infant crying are associated with facial redness rather than pallor) Pallor and lethargy may be the predominant presenting signs, may be persistent rather than episodic, and in some the crying episodes may not be very vigorous [emed.ie]

  Episodes typically occur 2-3 times/hour and may increase over the next 12-24 hours During these episodes of crying the child may look pale. (note: many other causes of infant crying are associated with facial redness rather than pallor). [rch.org.au]

  Symptoms Children The first sign of intussusception in an otherwise healthy infant may be sudden, loud crying caused by abdominal pain. Infants who have abdominal pain may pull their knees to their chests when they cry. [mayoclinic.org]

  He awoke at 0400 crying. His mother carried him and he settled down after a few minutes and then fell back asleep. Over the next few hours, he woke up intermittently crying. His appetite has been poor since the onset of these symptoms. [hawaii.edu]

• Gangrene

  He was referred to pediatric surgical department and underwent laparotomy confirming ileocecal intussusception with resection of gangrenous part of his large and small bowel with end-to-end anastomosis. [ncbi.nlm.nih.gov]

  If this is not treated quickly, it can lead to bowel gangrene. Gangrene can cause tissue in the intestinal wall to die. [cancercarewny.com]

  The telescoping segment obstructs the intestine and ultimately impairs blood flow to the intussuscepting segment (see Figure: Intussusception. ), causing ischemia, gangrene, and perforation. Intussusception. [msdmanuals.com]

  The blood supply to the engulfed segment may become impaired and result in gangrene and severe constriction or complete blockage of the canal. Treatment is usually surgical removal of the growth and of the affected part of the intestine. [britannica.com]

  Death is caused by complications from gangrene and massive infection. Individuals who are successfully treated for intussusception recover, usually without complications. [encyclopedia.com]

• Collapse

  It folds into itself like a collapsible tube. This creates a blockage. It causes the intestines to not work properly. Intussusception is most common in infants and young children. It is a medical emergency. [familydoctor.org]

  One part of the intestine slides into another, much like the parts of a collapsible telescope. As a result, the intestine is blocked. [msdmanuals.com]

  The invaginating portion of the intestine or the intussusceptum collapses into the receiving portion or the intussuscipiens. The process goes on and more proximal areas get involved. [symptoma.com]

• Pallor

  (note: many other causes of infant crying are associated with facial redness rather than pallor) Pallor and lethargy may be the predominant presenting signs, may be persistent rather than episodic, and in some the crying episodes may not be very vigorous [emed.ie]

  (note: many other causes of infant crying are associated with facial redness rather than pallor). [rch.org.au]

  The most common presenting features are colicky abdominal pain, vomiting, pallor, lethargy and listlessness. [ncbi.nlm.nih.gov]

  Vomiting (initially nonbilious) Lethargy, pallor, and other symptoms of shock or altered mental status may be present. [amboss.com]

• Abdominal Pain

  A 37-year-old man with abdominal pain 3 weeks after lumbar spine surgery following a motor vehicle accident. [web.archive.org]

  CONCLUSION Although intussusception is a rare cause of abdominal pain in adults, it is an important diagnosis to consider in patients with recurrent abdominal pain because it may be a harbinger of malignancy. [ncbi.nlm.nih.gov]

  Abdominal pain in children. Pediatr Clin North Am. 2006;53:107-137. http://www.ncbi.nlm.nih.gov/pubmed/16487787?tool=bestpractice.com [4] Hackam DJ, Saibil F, Wilson S, et al. [bestpractice.bmj.com]

• Vomiting

  The factors associated with recurrent intussusception with lead points present were vomiting and mass location in the right abdomen (P CONCLUSIONS: Age (>1 year), symptom duration (≤12 hours), the absence of vomiting, mass location (right abdomen) and [ncbi.nlm.nih.gov]

  Following persistent vomiting and fluid sequestration in obstructed bowels, dehydration and electrolyte imbalance often occur. [symptoma.com]

  Approximately equal in males and females · In developing nations Incidence is higher in adults than it is in developed nations Fewer are associated with malignancy, and fewer have pathologic lead points · Children o Cyclical, colicky abdominal pain o Vomiting [learningradiology.com]

• Diarrhea

  Herein, we report a 5-year-old male preschool child who presented symptoms of infectious diarrhea, and ileocecal type intussuscepton and Campylobactor jejuni bacteremia were found after a series of investigations. [ncbi.nlm.nih.gov]

  An 88-year-old man was seen at the hospital because of diarrhea. There was a previous history of undergoing sigmoidectomy for retrograde intussusception due to a cancer of the sigmoid coin in the hospital 6 years earlier. [doi.org]

  After surgery, watch for problems such as stomach upset, diarrhea, and fever. Take care of your child's incision. It may need to be cleaned or checked for infection. References Citations Kaiser AD, et al. (2007). [myhealth.alberta.ca]

• Nausea

  He presented with nausea, vomiting, poor appetite, and intermittent, cramping abdominal pain for over 1 wk. [ncbi.nlm.nih.gov]

• Abdominal Mass

  […] pain o Vomiting o “Currant jelly” stools (diarrhea with mucus and blood) or other blood in stool § Classic triad occurs in about 1/3 of patients; most have 2 of the 3 o Palpable abdominal mass, often in right upper quadrant o Dance’s sign: RUQ mass [learningradiology.com]

  C.P Children (6M-2Y) Adults Abrupt onset of violent crampy abdominal pain. Vomiting. Redcurrant jelly stool. Bloody stool. Recurrent abdominal pain. Palpable abdominal mass. Palpable Abdominal mass. 6. Types Children Adults Ileo-ileal. Ileo-colic. [slideshare.net]

  Distended abdomen later in the course Stool: Bloody stool/occult blood positive PR unnecessary if good evidence of intussusception; abdominal mass or PR bleeding, but otherwise should be done for signs of PR blood or mass Signs of an acute bowel obstruction [emed.ie]

  Distended abdomen later in the course Stool Bloody stool/occult blood positive PR unnecessary if good evidence of intussusception; abdominal mass or PR bleeding, but otherwise should be done for signs of PR blood or mass. [rch.org.au]

• Tachycardia

  Pallor, tachycardia, and diaphoresis indicate shock. About 5 to 10% of children present without the colicky pain phase. Instead, they appear lethargic, as if drugged (atypical or apathetic presentation). [merckmanuals.com]

  Upon admission, the patient still suffered from abdominal pain without symptoms of fever, tachycardia, nausea or vomiting. The abdominal plain film showed a mass with clear border on the left upper quarter (Fig 2 ). [casesjournal.biomedcentral.com]

• Purpura

  […] intussusception that spontaneous disappeared in a few hours Intussusception: Small bowel intussusception in a 12 year old girl Intussusception: Small bowel intussusceptions with intussusceptions at 2 different sites Intussusception: Henoch Schonlein purpura [ultrasoundcases.info]

  Examples include polyps, lymphoma, Meckel diverticulum, and immunoglobulin A–associated vasculitis (formerly called Henoch-Schönlein purpura) when purpura involve the bowel wall. Cystic fibrosis is also a risk factor. [merckmanuals.com]

  •Purpura. 5. C.P Children (6M-2Y) Adults Abrupt onset of violent crampy abdominal pain. Vomiting. Redcurrant jelly stool. Bloody stool. Recurrent abdominal pain. Palpable abdominal mass. Palpable Abdominal mass. 6. Types Children Adults Ileo-ileal. [slideshare.net]

  Abstract The real cause of intussusception is not fully understood and a variety of conditions have been associated with it (Meckel diverticulum, polyps, duplication cysts, parasites, Henoch-Schönlein purpura, cystic fibrosis, hemolytic-uremic syndrome [ncbi.nlm.nih.gov]

• Sweating

  Other symptoms include: Bloody, mucus-like bowel movement, sometimes called a "currant jelly" stool Fever Shock ( pale color, lethargy, sweating) Stool mixed with blood and mucus Vomiting Your doctor will perform a thorough exam, which may reveal a mass [nlm.nih.gov]

  Other symptoms include: Bloody, mucus-like bowel movement, sometimes called a "currant jelly" stool Fever Shock ( pale color, lethargy, sweating) Stool mixed with blood and mucus Vomiting Exams and Tests Your doctor will perform a thorough exam, which [mountsinai.org]

• Flank Pain

  We describe the case of a fibroepithelial polyp located in the distal right ureter, which occurred in a 42-year-old man with lower urinary tract symptoms, haematuria and flank pain. [ncbi.nlm.nih.gov]

• Lethargy

  (note: many other causes of infant crying are associated with facial redness rather than pallor) Pallor and lethargy may be the predominant presenting signs, may be persistent rather than episodic, and in some the crying episodes may not be very vigorous [emed.ie]

  Additionally, significant somnolence and lethargy can be seen with intussusception! Numerous cases have been reported that highlight this fact. Cause of the lethargy is unclear. [pedemmorsels.com]

  Pallor and lethargy may be the predominant presenting signs, may be persistent rather than episodic, and in some the crying episodes may not be very vigorous. [rch.org.au]

  […] from profound dehydration; therefore, intussusception should always be in the differential for pediatric lethargy. 1,2 The imaging workup for suspected intussusception includes plain film radiography, ultrasound, and contrast enema. [appliedradiology.com]

• Irritability

  Clinical examinations and investigations may not be conclusive and another working diagnosis such as irritable bowel syndrome would be made. [ncbi.nlm.nih.gov]

  A baby might also vomit several times or have blood in the stool, or could appear weak or very irritable. [cdc.gov]

  The walls of the two sections of intestine press on each other, causing irritation and swelling. Eventually, the blood supply to that area is cut off, which can cause damage to the intestine. [childrenshospital.org]

  The walls of the two "telescoped" sections of intestine press on each other, causing irritation and swelling. Eventually, the blood supply to that area is cut off, which can cause damage to the intestine. [luriechildrens.org]

• Altered Mental Status

  Altered Mental Status? Augment your exam with POCUS. It may be intussusception. Tags: Altered Mental Status Bedside Ultrasound change in mental status Intussusception Point of Care Ultrasound Sean M. [pedemmorsels.com]

  Vomiting (initially nonbilious) Lethargy, pallor, and other symptoms of shock or altered mental status may be present. [amboss.com]

Laboratory studies are often not helpful in the evaluation of patients with intussusception [8]. However, leukocytosis may be present with gangrene in advanced cases of intussusception. Following persistent vomiting and fluid sequestration in obstructed bowels, dehydration and electrolyte imbalance often occur.

Ultrasonographic imaging has also been found to have a relatively high sensitivity and specificity when it comes to detection of ileocolic intussusception. Abdominal radiographs may also show diagnostic characteristics of intussusception but their specificity and sensitivity is still in doubt.

• Bowel Distention

  Ultrasound examination found a normally evolving pregnancy and a bowel obstacle, without bowel distention. Because it was not a surgical emergency at the time of evaluation, she was sent to the hospital's Obstetrics Department. [ncbi.nlm.nih.gov]

  If left untreated, it will progress to bowel distention, damage, necrosis and rupture, followed by peritonitis (inflammation of the abdominal cavity), severe infection and shock. [lifespan.org]

The treatment often recommended in this condition includes a barium or air enema and in some cases surgery [9].

A barium or air enema can be a diagnostic procedure and also a treatment. When this procedure works, there is usually no need to continue with further treatment. It is the treatment of choice in children as it is highly effective with them. It is rarely used in adults. Recurrence following barium or air enema is seen 15-20% of the time and when it happens, the treatment is often repeated.

Surgery is recommended when the intestine is torn or a lead point is suspected [10]. Portion of the trapped intestine is freed, obstruction is cleared and dead intestinal tissues are also removed. This is the treatment used for most adult cases. In rare scenarios, intussusception is temporary without requiring medical intervention.

Prognosis is excellent in patients with this condition as long as it is diagnosed and treated early [5]. Otherwise, severe complications and death may occur.

After non-operative reduction, the recurrence rate of intussusception is often less than 10% however it has been reported to be as high as 15% in other cases. Most intussusceptions recurrences happen after 72 hours of correction but there have been cases where it occurred 3 years down the line. When there is more than 1 recurrence, a lead point is suspected. A recurrence often starts with the same symptoms as the initial event. Except when lead point suggestion is very strong, treatment for recurrence is often same as treatment for initial event.

In a few cases, the condition is caused by abnormal growth in the intestine such as polyp or a tumor [2]. This is known as the lead point. The normal wave-like contractions of the intestine may grab this lead point, pulling it into the lining of the intestine and then into the bowel that is ahead of it. In many cases however, there is no clear cause of intussusception.

It is difficult to determine the true prevalence of this disease due to the wide geographic variation in the incidence of the condition among countries and also in cities within countries [3]. There are no official documents showing the prevalence of intussusception in the United States. It is believed though that incidence is 1 case for every 2000 live births. In Great Britain, incidence varies from 1.6 to 4 cases per 1000 live births.

On average, the male-female ratio is set at approximate 3:1. With advancing age, the gender difference becomes further clear. In patients older than 4 years, male-to-female ratio is 8:1. Two out of three children with intussusception are < 1 year old and the most common occurrence is in people aged 5 to 10 months. It is also the most common cause of intestinal obstruction in patients within the ages of 5 months to 3 years.

The pathogenesis of idiopathic intussusception is not clear [4]. It is however, believed to follow an imbalance in the longitudinal forces along the walls of the intestine. 

As a result of imbalance in the intestinal wall forces, an area of the intestine enters into the lumen of adjacent bowel. The invaginating portion of the intestine or the intussusceptum collapses into the receiving portion or the intussuscipiens. The process goes on and more proximal areas get involved. 

The intussusceptum may proceed to the distal colon or sigmoid and even prolapse out of the anus in rare cases. The classic pathologic process seen with most bowel obstruction cases arises when the mesentery of the intussusceptum gets invaginated with the intestine.

There is no clear prevention path for this condition.

Intussusception refers to a situation where a part of the intestine invaginates into the bordering intestinal lumen bringing about an obstruction in the bowel [1]. It is a well-known cause of abdominal pain in children. Intussusception is suspected in pediatric medicine when the 3 main symptoms (vomiting, abdominal pain, and passage of blood) are present.

There are two variants of intussusception, the idiopathic intussusception which often starts at the ileocolic junction (affects infants and toddlers mostly) and the enteroenteral intussusception which is jejunojejunal, jejunoileal or ileoileal (occurs in older children). The latter condition is seen in people with special medical conditions such as Henoch-Schönlein purpura (HSP), cystic fibrosis and hematologic dyscrasia. It may also be secondary to a lead point and often occurs in the postoperative period.