S1E18: The distressed infant and Intussusception - PEM
Look at that sun!
Welcome back to our June episode of TheCase.Report, and it’s our long awaited return to PEM.
Orla is joined by the trio of Anna, Roy and Andrew who take us through some tricky twists in the case of a tender tot.
Then Anna sits down with Dr Dani Hall talking about what true allyship for our patients means.
Finally, Dr Rory O’Brien joins us to talk about the PEM journey in the People’s Republic. Any of you out there interested in PEM in CUH, shoot Rory an email and he’ll be happy to chat.
Let’s get to it!
The distressed infant
The ddx of undifferentiated ‘unsettled’ baby - non specific complaints such as lethargy, vomiting without diarrhoea and therefore not a concrete diagnosis of gastro, pallor etc. What are your initial thoughts and The difficulties of examining an abdomen in these children who are actively distressed and crying - how best to do it? What specifically are we looking for? What must we be careful not to miss?
Raised ICP
Injury eg clavicle fracture, non-accidental injury
Incarcerated inguinal hernia
Urinary tract infection
Hair tourniquet
Corneal foreign body/abrasion
Causes of acute abdominal pain
Divide these up into time critical and most likely as per age - in neonates all causes are time critical and potentitally life threatening
What is intussusception?
Widely variable presentations
Intussusception is the telescoping or invagination of one part of the bowel into its distal adjoining part, most commonly at the ileo-caecal valve. It can happen at any age, with most cases occurring between 2 months and 2 years of age. . There is sometimes a preceding viral illness such as URTI or flu-like symptoms before onset which is thought to result in lymphoid hyperplasia causing a ‘lead point’ due to viral illness. Occasionally there is a pathological lead point caused by luminal polyps, tumours, Meckel’s diverticulum or Henoch-Schonlein purpura.
Boys are more commonly affected than girls by between 2:1 to 3:1, with 75% of cases occurring before 12 months of age.
Classic Triad:
Acute crampy colicky or progressive abdominal pain
Currant jelly (dark red mucous filled) stools - a late sign indicative of bowel ischaemia and necrosis
Palpable sausage shaped abdominal mass
This triad is present in between 20-40% of presentations, however at least two of them are present in 60% of patients. . Up to 20% of children have no notable pain or bleeding making it easy to miss.
Other common findings: Vomiting, intermittent crying and discomfort, lethargy, diarrhoea, abdominal distension.
Physical exam Following vital signs to ensure the patient is stable; a thorough abdominal exam should be completed. The most consistent sign in intussusception is an ill-defined palpable mass, which may be sausage shaped and is often in the RUQ. The RUQ mass may be accompanied by the absence of bowel in the RLQ, known as Dance’s sign. However, palpation may be difficult in a crying infant. If there are bloody stools, be sure the check the rectum to look for alternative explanations such as an anal fissure. In all cases check the hernial orifices carefully, in boys, palpate both testes to rule out a testicular torsion, and in girls check carefully for a herniated and/or torted ovary. N
Intussusception usually causes bouts of pain, lasting between 1-3 minutes, so it is best to try to examine the child in between these bouts. Perform the examination with the child lying on the mother’s lap for comfort. If the child does not appear to be settling for a prolonged period of time in the department, with other causes ruled out, consider administration of pain relief, particularly if you are suspecting an acute surgical abdomen.
Great mimick:
If left unresolved for extended periods of time, as we learned in our case, patients can present with shock, sepsis, bowel obstruction or perforation, all of which can have a significant morbidity and mortality associated.
Repeated presentations common.
Imaging:
Imaging is key for the diagnosis of intussusception. Ultrasound is the preferred modality due to its superior safety profile and higher sensitivity and specificity for the diagnosis of intussusception. (PedsCases.com) Andrew to add more on ultrasound- bedside versus departmental. Use of it. Target sign or donut like appearance of borders of each segment of bowel being visible- making diagnosis of intussusception. Ability to assess reducibility of the lesion, and rule out ischaemia by doppler etc.
Discussion of other imaging - AXR - intestinal obstruction, absence of wind in right lower quadrant, free air present will decide future operative management
POCUS can be very helpful in intussusception given that:
Majority of cases are seen in age 2 months - 2 years where obtaining history and physical examination is challenging
Intussusception often present with nonspecific symptoms with the classic triad seen in less 40% of children.
Departmental ultrasound shows high sensitivity (98%) and specificity (98%) with a high negative predictive value of 99.7%. Diagnostic accuracy of POCUS on intussusception is comparable. A 2020 meta-analysis and systematic review published in Western Journal of Emergency Medicine showed that overall POCUS for Paediatric EM physicians was 94.2% sensitive and 97.8% specific. There is a wide range of differences in experience for the PEM physicians, from those who received relatively brief training to those who’ve performed over 100 scans.
There are currently a few varying techniques when utilising POCUS to diagnose intussusception. Ultimately, you are looking for the classic “target sign” on the linear probe in transverse view. This will appear with a peripheral hypoehcoic ring with central echogenicity. Ileocolic intussusception is most commonly found in the right abdomen. A highly specific US finding of intussusception is presence of mesenteric lymph nodes within the lumen of the intussuscipiens.
AXR was historically used for initial investigation, but has much lower sensitivity and specificity than US. Up to 25% of patients with proven intussusception have a normal xray. Even with the addition of a 2-view AXR (supine and lateral decubitus), it’s still inferior to US. Each AXR is equivalent of 4 months background radiation exposure for paeds population.
Role of AXR in suspected intussusception:
Confirmation of diagnosis: sometimes, mass or leading edge of intussusceptum can be seen.
Small bowel obstruction
Pneumoperitoneum, rare.
POCUS is the way forward, potential to shortened door-to-reduction time and overall length of stay. Operator dependent with need for sufficient training, should establish the ideal training protocol and necessary number of POCUS exams for skill maintenance.
Differential diagnosis:
Appendicitis
Gastroenteritis
UTI
Pyloric stenosis- in younger babies
Management:
If it is a typical ileocaecal intussusception with no sign of perforation on AXR, and not peritonitic on examination, primary treatment is with contrast enema (gas or liquid). If there rare signs of peritonitis, early surgery is necessary. Pure small bowel intussusception and those with pathological lead points require different management strategies.
In the ED - the focus is on IV access and adequate isotonic fluid resuscitation. The use of antibiotics is case and centre-dependent, so check with your local antimicrobial guidelines and surgical colleagues. If there is sign of peritonitis or septic shock, broad spectrum antibiotics covering intra-abdominal pathogens should be started without delay.
Other management pearls:
Significant dehydration, manage fluid resus carefully.
NPO and given IV fluids
NG if obstructed.
Predictors of successful reduction by enema are:
Intervention within 24-48 hours
Adequate rehydration
Age of child >3 months
Surgical resection if air enema is contraindicated or if perf. If child is critically ill, signs of sepsis or free air.
Overall mortality for kids with idiopathic intussusception is less than 1%
Intussusception is an emergency which MUST be identified and treated ASAP.
Prognosis
Intussusception has a recurrence rate of 10% post contrast enema (it does not differ significantly between air or contrast), and surgical reduction has a recurrence rate of between 2% and 5%. The mortality related to intussusception is often due to delayed diagnosis and/or failure to recognise or treat septic or hypovolaemic shock. This is a condition not to be missed in the ED, and we must appropriately recognise and treat the physiology of the patient in front of us.
BIAS in Emergency Medicine
Authority Gradient leading to Bias: SHO Roy was reassured by very competent and experienced SpRs initial assessment- though the key is in the red flags explained which prompted parents to return.
Cueing bias from Triage
Confirmation Bias: The tendency to search for, interpret, focus on and remember information in a way that confirms one's preconceptions. A vomiting child- most likely diagnosis? Gastro, Look for signs of gastro and confirm same.
Anchoring Bias: ‘The tendency to rely too heavily, or "anchor", on one trait or piece of information when making decisions (usually the first piece of information acquired on that subject’
‘This kid was here with gastro yesterday, they are back’
Groupthink- Second night, reg and SHO conferred on patient, nursing staff cued their take on it with triage and comments post- convinced no need for further investigations
AND FINALLY: Hindsight bias- it was obvious all along! Bias involving the tendency to see past events as being predictable at the time those events happened. We feel like this at the end of this case because we now know the outcome. The hints along the way are the learning point and what lead us to more nuanced and informed clinical practice.
Debriefing over patient returning sick after first visit. No fault here, but an opportunity to highlight the possible bias, decision fatigue, and situational awareness. Diagnosing intussusception from clinical presentation alone can be challenging, and can easily be passed off as gastroenteritis in the early stages.
In a busy, crowded emergency department, EM doctors often rely on intuitive decision making, aka “Recognition Primed Decisionmaking” model. This is when a situation generates cues that let you recognise patterns which leads to you accessing your preexisting mental models to decide on a plan.
Pros:
Useful when time is limited.
Requires little conscious thought.
Can lead to a satisfactory plan.
Useful in routine situations.
Cons:
Can only be applied in common and routine situations
Does not result in optimal solution
Can lead to confirmation bias
Growing literature to “Optimise the Decision Maker” and the issue of decision fatigue.
Cognitive and mental fatigue after long shift, inadequate break, repeated decisionmaking.
May fail to recognise all potential alternatives, demonstrate bias, experience burden of decision making more intensely, and a higher risk of decision regret.
