OMPHALOMESENTERIC (VITELLINE) REMNANT

 

OMPHALOMESENTERIC (VITELLINE) REMNANT

Partial or complete failure of involution of the omphalomesenteric duct can lead to a spectrum of anomalies in the newborn infant due to varying degrees and location of duct patency:

A.   An umbilical cyst containing intestinal tissue.

B.   Umbilical sinus with a band.

C.   A persistent omphalomesenteric duct at the umbilicus with no intestinal connection results in an umbilical polyp.

D.   Patent mid-duct with closure at both the umbilical and ileal ends of the omphalomesenteric duct results in an omphalomesenteric duct cyst. Because the two ends are fixed, this can lead to small bowel obstruction if loops of bowel twist around the cyst.

E.   Persistent tissue at the ileum, with no connection to the umbilicus results in Meckel's diverticulum.

F.   Complete patency results in the omphalomesenteric duct directly connecting the umbilicus to the terminal ileum. This can lead to intermittent drainage from the umbilicus " omphalomesenteric fistula". These infants will often appear to have a "stoma" in the umbilicus after cord separation.

G.  Persistent fibrous cord (band)  between the umbilicus and the ileum, which can lead to small bowel obstruction.

OMPHALITIS

OMPHALITIS

 Def : Infection of the umbilicus and/or surrounding tissues.
Incidence : approximately 1 in 1,000 infants in developed countries where aseptic delivery and hygienic dry cord care are practiced.

The risk factors associated with the development of omphalitis include:

• prolonged rupture of membranes
• maternal infection
• nonsterile delivery practices
• home delivery
• umbilical catheterization
• low birth weight
• improper cord care or cultural practices of cord care (such as application of cow dung, charcoal dust, or products such as cooking oil and baby powder to the cord stump, and lotus births)
• delayed cord separation
• immunologic conditions such as defects in leukocyte adhesion, neutrophil or natural killer lymphocyte function, and interferon production.

Clinical features:
Mild discharge from the umbilical stump in the absence of inflammatory signs may be a normal occurrence, even when accompanied by some odor.

Unhealthy, discolored, and craggy-appearing umbilical stump; purulent drainage; periumbilical erythema; and induration.

Umbilical stump bleeding may occur with omphalitis because the infection delays thrombosis of the umbilical vessels.

Systemic signs, including lethargy, fever, irritability, temperature instability and poor feeding are suggestive of more severe infection or complication. The most common complication of omphalitis is sepsis.

Other complications include septic umbilical arteritis, portal vein thrombosis, liver abscess, peritonitis, intestinal gangrene, small bowel evisceration, necrotizing fasciitis, and death (Mortality rate is estimated between 7 and 15 percent)
 

Omphalitis is a polymicrobial infection. Historically, the predominant pathogens included Staphylococcus aureus, Streptococcus pyogenes, and Gram-negative bacteria such as Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis. However, with the routine use of antistaphylococcal cord care regimens, Gram-negative infections of the umbilicus have increased . In addition, anaerobic bacteria such as Bacteroides fragilis, Clostridium perfringens, and Clostridium tetani can contribute to umbilical infections, especially in infants born to mothers with chorioamnionitis . In these infants, foul smelling umbilical drainage is a typical finding.

-Predictive (Presymptomatic) Genetic testing in pediatrics .

 

Predictive (Presymptomatic) Genetic testing in pediatrics

Children may be referred because they are at increased risk of developing a genetic disorder in childhood or adult life (i.e the individual is clinically normal now).

n  If the condition is likely to manifest in childhood (e.g. Duchenne muscular dystrophy) or if there are useful medical interventions available in childhood (e.g. screening by colonoscopy for colorectal tumours in children at risk of familial adenomatosis polyposis coli), then genetic testing is appropriate in childhood.

n  If the child is at risk of a late-onset and untreatable disorder (e.g. Huntington disease), then deferring genetic testing until the child becomes an adult, or at least sufficiently mature to be actively involved in seeking the test and can make the decision for himself/herself, is usually preferred.

n  If the child is not at risk of developing the condition but may be a carrier at risk of transmitting the disorder to their future children, then there is also a good case for deferring testing until the young person can participate actively in the decision. There may be less at stake with these reproductive carrier tests than with predictive tests for untreatable disorders, but there are still good grounds for caution and for careful discussion before proceeding with such tests.

These difficult issues are often best handled through a process of genetic counselling supporting open and sustained communication within the family and especially between parents and children.

Predictive testing is not usually offered without a formal process of genetic counselling over more than one consultation with time built in for reflection. Written consent for predictive testing is required by most laboratories.

So, Presymptomatic testing of disorders which manifest in adult life should not be performed until the individual can consent on their own behalf unless there is clear clinical benefit from testing earlier.

Meckel's diverticulum

 

Meckel's diverticulum

Meckel diverticulum is the most common congenital anomaly of the GI tract and is caused by the incomplete obliteration of the omphalomesenteric duct during the 7th wk of gestation.

Meckel diverticulum has been conveniently referred to by the “rule of 2s,”:

• Occurs in 2% of the population.
• Appears within 2 feet (50-75 cm) of the ileocecal valve.
• approximately 2 inches in length
• Approximately 2% to 4% of patients develop complications over the course of their lives.
• Typically presents before age 2 years.
• Two-thirds of patients with MD have 2 types of heterotopic mucosa (gastric and pancreatic), although colonic heterotopic mucosa has also been reported.
•  Is twice as likely to be symptomatic in boys than girls

Meckel diverticulum is typically lined by ileal mucosa.

Clinical presentations:

The majority are asymptomatic.

It is often found incidentally on imaging studies.

Hematochezia:

• Cause of bleeding is ectopic gastric mucosa (acid-secreting mucosa)
• Intermittent painless rectal bleeding (hematochezia) occurs suddenly and tends to be massive in younger patients.
• Bleeding occurs without prior warning and usually spontaneously subsides.
• The color of the stool is typically described as brick colored or currant jelly colored.
• Bleeding can cause significant anemia but is usually self-limited (resolves without intervention) because of contraction of the splanchnic vessels, as patients become hypovolemic.
• Bleeding from a Meckel diverticulum can also be less dramatic, with melanotic stools.

It should be suspected in children with recurrent or atypical intussusception, a patient with symptoms of appendicitis after their appendix has been removed, and patients with an unclear source of GI bleeding.

Periumbilical necrotizing fasciitis in the newborn

 Periumbilical necrotizing fasciitis in the newborn

Neonatal necrotizing fasciitis is a rare complication of omphalitis.

Necrotizing fasciitis starts initially as periumbilical cellulitis and rapidly spreads to the subcutaneous tissues, with the overlying skin appearing edematous with purplish blue discoloration.

Necrotizing fasciitis may also present with bullae, crepitus and peau d’orange appearance.

Necrotizing fasciitis should be recognized early and treated aggressively by debridement, broad-spectrum antibiotics, and supportive care.

In addition to debridement of the involved abdominal wall, it is important to resect the umbilical vein, both umbilical arteries, and any urachal remnant that is present, as these may be involved in the necrotizing infection (even if they look normal).

Reported mortality rates are as high as 60 to 85 percent.

References:

1. Cilley R. Disorders of the umbilicus. In: Pediatric Surgery, Grosfeld J, O'Neill J, Coran A, Fonkalsrud E (Eds), Mosby Inc., Philadelphia 2006.
2. Pomeranz A. Anomalies, abnormalities, and care of the umbilicus. Pediatr Clin North Am 2004; 51:819.