Peter Tormey. Hirschsprung Associated Enterocolitis, Don't Forget the Bubbles, 2020. Available at:
https://doi.org/10.31440/DFTB.28496
Michelle is a 5-year-old girl with a background of Hirschsprung’s Disease. She had a pull through procedure performed 6 months ago. She is on daily PR washouts.
She presents to ED acutely unwell with multiple episodes of brown vomiting. On examination she is lethargic, grey in colour and peripherally shut down. Her abdomen is distended.
What is Hirschprung’s Disease?
Hirschprung’s Disease (HD) is caused by the failure of neural crest cells to migrate completely during intestinal development.
The neural crest cells are progenitor cells for the enteric nervous system, which controls peristalsis, blood flow to the gut and secretions. The enteric ganglia are interconnected to form 2 plexi that extend along the length of the bowel: an out myenteric (Auerbach) plexus running the full length of the gut and an inner submucosal (Meissner) plexus, found in the small and large intestine. The absence of these plexi results in an aganglionic segment of colon, which fails to relax, causing a functional obstruction.
Interestingly, the timing of the arrest in migration of the neural crest cells influences the severity of disease. The cells migrate in a craniocaudal fashion, therefore, early arrest results in a longer segment of aganglionosis.
The incidence of HD is 1 in 5000 live births. The male-to-female ration is 4:1 in short segment disease but it is 1:1- 2:1 in long segment disease.
How do children with Hirschprung’s present?
How these children present depends on whether they have short or long-segment disease. Short-segment disease only involves the rectosigmoid colon and accounts for 80-85% of cases. In long-segment disease, the aganglionosis extends proximally to the sigmoid colon.
Those with long-segment disease are more severely affected and tend to present earlier, usually in the first few days after birth. They can present with any of the following features:
- Abdominal distension
- Bilious vomiting
- Delayed passage of meconium
- Enterocolitis
Those with short-segment disease may present later in childhood with constipation and failure to thrive.
What is “delayed” passage of meconium?
There is a big variation in the timing of first meconium passage in neonates, however, most healthy newborns will pass stool within the first 24 hours. All healthy newborns should pass their first stool within 48 hours.
Clark studied 395 term infants and found that 98.5% of them passed stool within the first 24 hours and 100% within 48 hours.
It is generally acknowledged that term infants who don’t pass stool within the first 48 hours should undergo careful evaluation and investigation. 60-90% of patients with HD will not pass meconium within 48 hours.
The differentials of delayed passage of meconium are listed below:
- Meconium plug syndrome
- Meconium ileus
- Hirschsprung’s disease
- Anorectal malformation
- Intestinal atresia
- Malrotation, volvulus
- Hypoplastic left colon syndrome
- Opioid use
- Hypothyroidism
- Sepsis
- Prematurity, low birth weight
Hirschprung Associated Enterocolitis
Hirschsprung Associated Enterocolitis (HAEC) is a serious complication of HD. Patients can present critically unwell with haemodynamic instability, fever, vomiting, explosive diarrhoea and abdominal distension. An explosive release of gas or stool during rectal examination strongly supports a diagnosis of HD.
The incidence of HAEC ranges from 6-60% prior to pull-through surgery and 25-37% after surgery. HAEC can be potentially life-threatening. Swenson was one of the first to report on mortality in HAEC, reporting a mortality rate of 33% after HAEC, compared with 4% in HD patients without EC. The reported mortality in other studies varies greatly from 0 to 39%.
Mortality rates have improved in recent years, most likely due to improved supportive care in PICU and improved surgical expertise. The mortality rate in HAEC is now 1%.
Poor prognostic factors are: HAEC present at diagnosis of HD and postoperative HAEC.
While it can be seen in all children with HD, several features appear to be associated with an increased risk:
- Trisomy 21
- Long-segment disease
- Previous HAEC
- Post-op obstruction
The cause of HAEC is unknown. Several hypothesis have been proposed:
- Dysbiosis of the intestinal microbiome
- Impaired mucosal barrier function
- Altered innate immune response
- Bacterial translocation
Mild cases can present with symptoms of viral gastroenteritis, fever, mild abdominal distension and diarrhea. If it is not promptly recognized and treated it can progress to toxic megacolon, which can be fatal.
It is important to remember that HAEC can also occur in children who have had surgical repair for HD. It is due to obstruction, which can be due to:
- Retained aganglionosis
- Transition zone pull-through
- Dysmotility following pull-through
- Anastamotic stricture
A high index of clinical suspicion is required to make the diagnosis. Abdominal x-ray is also helpful and usually shows significantly dilated bowel loops and air-fluid levels.
HAEC is an emergency. Prompt treatment is required with IV antibiotics, (e.g metronidazole, gentamicin, amoxicillin) fluid resuscitation and surgical evaluation, which may include rectal washouts or an emergency colostomy.
Which children with constipation do we need to worry about?
Constipation is a very common presentation to ED. When assessing these patients it is important to screen for any underlying abnormalities, including HD.
Constipation, with the following features should raise your suspicions for undiagnosed HD:
- Neonates
- History of delayed passage of meconium
- Chronic, refractory constipation
- Failure to thrive
- Presence of other urogenital abnormalities
- Family history of HD (the risk for a sibling is 200 times higher than the general population, (4% vs. 0.02%)
- Associated syndromes:
- Down Syndrome
- Bardet-Biedl syndrome
- Cartilage-hair hypoplasia
- Congenital central hypoventilation syndrome
- Multiple endocrine neoplasia type 2
- Mowat Wilson syndrome
- Smith-Lemli-Opitz syndrome
- Waardenburg syndrome
How is Hirschprung’s diagnosed?
Abdominal x-ray may show dilated bowel loops, thickened bowel loops or air fluid levels. These findings, however, are non-specific.
Contrast enema is useful to demonstrate the functional obstruction seen with HD, as seen in the film below.
Case courtesy of Dr Mohammad Farghali Ali Tosson. From the case https://radiopaedia.org/cases/50255 rID: 50255
Definitive diagnosis is by rectal suction biopsy.
It is important to consider HD in children presenting to ED with constipation. You should have a low threshold for surgical referral, particularly if they have any risk factors listed above.
How is Hirschprung’s treated?
Treatment involves surgical resection of the aganglionic segment and anastomosis of the normal bowel to the anus, while preserving sphincter function.
Long term complications include:
- Chronic constipation
- Incontinence
- Recurrent HAEC
- Psychosocial issues
Did you know?
HD was first described by Harald Hirschsprung in 1886. He described 2 children with severe constipation, due to dilation and hypertrophy of the colon.
Lennander in 1900 was the first to suggest that the pathogenesis may be neurogenic in origin. Tittel then demonstrated in 1901 histiological findings indicating aganglionosis of the colon. In 1948 Swenson used motility studies to demonstrate absence of peristalsis in the aganglionic colon.
The history of Hirschsprung’s Disease is an interesting and colourful one with many false starts and conflicting opinion. If you’re interested in reading more, look no further than this American Academy of Surgeons history of surgery article.
Michelle was fluid resuscitated and commenced on IV antibiotics. She was transferred to PICU due to haemodynamic instability. She was managed conservatively by the surgical team with regular rectal washouts.
Michelle has had several episodes of HAEC previously. This episode, in particular, was life-threatening. Her parents are finding it harder to perform the daily rectal washouts as she gets older. As a result, it was decided to perform an ileostomy to improve bowel management and to try and prevent HAEC.
References
1. Butler Tjaden NE, Trainor PA. The developmental etiology and pathogenesis of Hirschsprung disease. Vol. 162, Translational Research. Mosby Inc.; 2013. p. 1–15.
2. Congenital aganglionic megacolon (Hirschsprung disease) – UpToDate [Internet]. [cited 2020 Jul 7]. Available from: https://www-uptodate-com/contents/congenital-aganglionic-megacolon-hirschsprung-disease?search=hirschsprung disease children&source=search_result&selectedTitle=1~76&usage_type=default&display_rank=1
3. Haricharan RN, Georgeson KE. Hirschsprung disease. Semin Pediatr Surg [Internet]. 2008 Nov [cited 2020 Jul 20];17(4):266–75. Available from: https://pubmed.ncbi.nlm.nih.gov/19019295/
4. Ryan ET, Ecker JL, Christakis NA, Folkman J. Hirschsprung’s disease: Associated abnormalities and demography. J Pediatr Surg [Internet]. 1992 [cited 2020 Jul 20];27(1):76–81. Available from: https://pubmed.ncbi.nlm.nih.gov/1552451/
5. Clark DA. Times of First Void and First Stool in 500 Newborns [Internet]. Vol. 60, PEDIATRICS. 1977 [cited 2020 Jul 28]. Available from: www.aappublications.org/news
6.Loening-Baucke V, Kimura K. Failure to Pass Meconium: Diagnosing Neonatal Intestinal Obstruction. Am Fam Physician. 1999 Nov 1;60(7):2043.
7. Gosain A, Frykman PK, Cowles RA, Horton J, Levitt · Marc, David ·, et al. Guidelines for the diagnosis and management of Hirschsprung-associated enterocolitis. Pediatr Surg Int. 2017;33:517–21.
8. Swenson O, Davidson FZ. Similarities of Mechanical Intestinal Obstruction and Aganglionic Megacolon in the Newborn Infant. N Engl J Med [Internet]. 1960 Jan 14 [cited 2020 Jul 28];262(2):64–7.
9. Vieten D, Spicer R. Enterocolitis complicating Hirschsprung’s disease. Semin Pediatr Surg. 2004 Nov 1;13(4):263–72.
10. Murphy F, Puri P. New insights into the pathogenesis of Hirschsprung’s associated enterocolitis. Pediatr Surg Int [Internet]. 2005 Oct 30 [cited 2020 Jul 28];21(10):773–9. Available from: https://link-springer-com.proxy.library.rcsi.ie/article/10.1007/s00383-005-1551-1
11. Badner JA, Sieber WK, Garver KL, Chakravarti A. A genetic study of Hirschsprung disease. Am J Hum Genet [Internet]. 1990 [cited 2020 Jul 20];46(3):568–80. Available from: /pmc/articles/PMC1683643/?report=abstract
12. Hirschsprung disease • LITFL • Medical Eponym Library [Internet]. [cited 2020 Jul 20]. Available from: https://litfl.com/hirschsprung-disease/
Polycythaemia
Jilly Boden. Polycythaemia, Don't Forget the Bubbles, 2021. Available at:
https://doi.org/10.31440/DFTB.30144
Its 3 am and you are called by a midwife on the postnatal ward to review a ‘jittery baby’ with a respiratory rate of 70. The midwife informs you that Alice is a term baby born via Cat 2 LSCS (failure to progress, Apgar 9,9) following an uncomplicated pregnancy (although she does note that mum has admitted to smoking cannabis occasionally during pregnancy). She is currently establishing breastfeeding.
On examination, Alice is settled but does have some mild tremors on handling. They settle on containment and don’t appear to be rhythmic or jerking in nature. She is centrally pink, with a red face and purple hands and feet. All observations, other than the respiratory rate are within normal limits.
You decide its likely Transient Tachypnoea of the Newborn but as part of your assessment, you obtain a capillary blood gas.
The decision is made to give the baby a full top-up of formula feed (with mum’s consent) and to do formal, free-flowing venous bloods in an hour’s time to re-assess, but what is the next step?
Some definitions
The term polycythemia refers to a raised red cell concentration >2 standard deviations above the expected normal values. It can either be defined as a haematocrit from a peripheral venous sample being >65 percent or the haemoglobin is >22 g/dL however the former is more commonly used in clinical settings.
Haematocrit peaks maximally at the mean age of 2.8hrs. Although capillary blood gas samples are a helpful guide to the diagnosis, the sample on which treatment should be based must be from a peripheral venous sample. Studies have shown that the haematocrit from true venous samples (depending on capillary gas sample technique) can be up to 15% lower than the capillary sample.
Causes
Most cases of polycythaemia occur in normal healthy infants and may result from a variety of reasons, which can be broadly categorised into:
Increased red cell volume from increased transfusion, causes include:
Placental insufficiency with increased foetal erythropoiesis secondary to intra-uterine hypoxia. This may occur in association with:
Other causes of polycythaemia include:
* A note on delayed cord clamping:
Interestingly, although delayed cord clamping in IUGR babies has been shown to double the likelihood of polycythemia, a recent study found there was no increase in babies with symptomatic polycythemia and nor was there any increase in the need for partial exchange transfusion. Delayed cord clamping as also been found not to have an effect on hyperbilirubinemia.
Complications
An increased red cell mass results in an increased blood viscosity and reduced blood flow, impaired tissue oxygenation and a tendency to microthrombus formation. This is exacerbated by hypoxia, acidosis and/or poor perfusion.
Thrombosis may result in:
Hyperviscosity of blood results in increased resistance to blood flow and decreased oxygen delivery. Viscosity exponentially increases when an infant has polycythemia. In the neonate, this can lead to abnormalities of central nervous system function, hypoglycemia, decreased renal function, cardiorespiratory distress, and coagulation disorders. Hyperviscosity has been reported to be associated with long-term motor and cognitive neurodevelopmental disorders.
Signs and symptoms
The majority of newborns with polycythemia as asymptomatic (74-90%). In symptomatic infants, the hyperviscosity causes a decrease in tissue perfusion and metabolic complications such as hypoglycemia and hypocalcemia. They are responsible for clinical signs and symptoms including:
The most commonly encountered problems in severely symptomatic newborns with polycythemia are central nervous system disorders.
Pathophysiology
In addition to cerebral blood flow, glucose carrying capacity also decreases in polycythemia. As a result, plasma glucose concentration, especially venous is lower than normal. Hypocalcemia and hyperbilirubinemia may also be seen in polycythemic newborns. The level of calcitonin gene-related peptide (CGRP) has been shown to be high in polycythemic newborns. This peptide regulates vascular tone, stimulates vasodilatation, and leads to hypocalcemia. High levels of CGRP suggest a role in response to polycythemia.
Management
A 2010 cochrane review found there to be:
‘No proven clinically significant short or long‐term benefits of PET (Partial Exchange Transfusion) in polycythemic newborn infants who are clinically well or who have minor symptoms related to hyperviscosity. PET may lead to an increase in the risk of NEC. The data regarding developmental follow‐up are extremely imprecise due to the large number of surviving infants who were not assessed and, therefore, the true risks and benefits of PET are unclear.’
With this in mind, it is broadly accepted that PET should only be undertaken if it is thought to be the primary cause of the symptoms, rather than a byproduct of dehydration from other causes e.g. feeding difficulties or metabolic disorders.
The formal bloods reported as Hb 215 g/L with a Hct of 69% and a repeat gas shows a glucose of 3.2 mmol/L. The midwifery staff report she seems less ‘jittery’ and a plan is made for full formula top-ups and daytime review to ensure resolution of symptoms.
References
Garcia-Prats, J. A. (2019, September 1). Neonatal Polycythemia. Retrieved October 19, 2019, from https://www.uptodate.com/contents/neonatal-polycythemia.
Wu, A. H. B. (2006). Tietz clinical guide to laboratory tests (3rd ed.). St. Louis, MO: Saunders/Elsevier
Alsafadi, T. R., Hashmi, S., Youssef, H., Suliman, A., Abbas, H., & Albaloushi, M. (2014). Polycythemia in neonatal intensive care unit, risk factors, symptoms, pattern, and management controversy. Journal of Clinical Neonatology, 3(2), 93. doi: 10.4103/2249-4847.134683
Safer Care Victoria. (2018, October). Polycythaemia in neonates. Retrieved from https://www.bettersafercare.vic.gov.au/resources/clinical-guidance/maternity-and-newborn-clinical-network/polycythaemia-in-neonates.
Özek, E., Soll, R., & Schimmel, M. S. (2010). Partial exchange transfusion to prevent neurodevelopmental disability in infants with polycythemia. Cochrane Database of Systematic Reviews, 20(1). doi: 10.1002/14651858.cd005089.pub2
Sarici, S. U. (2016). Neonatal Polycythemia: A Review. Clinical Medical Reviews and Case Reports, 3(11). doi: 10.23937/2378-3656/1410142
Jeevasankar, M., Agarwal, R., Chawla, D., Paul, V. K., & Deorari, A. K. (2008). Polycythemia in the newborn. The Indian Journal of Pediatrics, 75(1), 68–72. doi: 10.1007/s12098-008-0010-0
A., D. A. P., Werner, E. J., & Christensen, R. D. (2013). Neonatal hematology pathogenesis, diagnosis, and management of hematologic problems. Cambridge: Cambridge Univ. Press. 171-186.
Saggese, G., Bertelloni, S., Baroncelli, G. I., & Cipolloni, C. (1992). Elevated calcitonin gene-related peptide in polycythemic newborn infants. Acta Paediatrica, 81(12), 966–968. doi: 10.1111/j.1651-2227.1992.tb12155.x