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.

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.

 

Pediatric Umbilical Hernia

 Pediatric Umbilical Hernia

Etiology

Umbilical hernia in children results from incomplete closure of the fascia of the umbilical ring, through which intraabdominal contents may protrude.

 After separation of the umbilical cord, usually, the ring undergoes spontaneous closure through the growth of the rectus muscles and fusion of the fascial layers.

A failure or delay in this process leads to the formation of an umbilical hernia.

 The exact etiology is unknown, but usually, occurs through the umbilical vein component of the ring.

- Prognosis and long-term outcome of IUGR.

Prognosis and long-term outcome of IUGR.

A. Mortality:

-        Mortality ↑ with decreasing gestational age when FGR is also present.

-        Mortality ↓ by 48% for each week that the fetus remains in utero before 30 weeks’ gestation.

B. Postnatal Growth Impairment:

-        usually, Term SGA have adequate catch-up growth during the first 12 months without pharmacologic intervention and in most cases catch-up growth is complete by two years.

-        However, it is having been suggested that SGA children aged 2−4 years with no evidence of catch-up growth and heights less than –2.5 SD should be referred for endocrine evaluation and eligibility for growth hormone (GH) treatment [for a minority, growth hormone therapy (started before 8 years of age and continued for >7 years) can augment growth parameters.

-        Preterm SGA infants can take 4 or more years to achieve heights in a normal range.

-        Many preterm infants show a postnatal growth deficit at the time of hospital discharge, so-called extrauterine growth restriction (EUGR), which is defined as a centile at discharge lower than the birth centile.

-        EUGR is largely due to an inadequate postnatal nutrient intake as well as postnatal morbidities, and it ↑ with decreased gestational age.

-        Premature infants with EUGR also have metabolic abnormalities similar to those observed in term SGA children and these occur irrespectively of whether they are SGA or AGA at birth.

-        SGA term infants suffer from an adverse fetal environment during the last trimester of pregnancy, whereas very preterm infants suffer from an adverse postnatal environment during the first three months, a time biologically equivalent to the third trimester of fetal life.

C. Neurological and developmental delay

-        Neurodevelopmental morbidities are seen 5 to 10 times more often in FGR infants compared with AGA infants and depend not only on the cause of FGR but also on the adverse events in the neonatal course (eg, perinatal depression or hypoglycemia).

-        Even without identified perinatal events, IUGR infants have a higher incidence of long-term neurologic or developmental handicaps.

-        Many studies reveal evidence of minimal brain dysfunction, including hyperactivity, short attention span, and learning problems.

-        Preterm FGR infants also show alterations in early neurobehavioral functions, such as attention-interaction capacity and cognitive and memory dysfunction, that persist.

-        Increased risk of cerebral palsy, a wide spectrum of learning disabilities, mental retardation, developmental delay, and neuropsychiatric disorders are seen in later years.

-        The most important predictor of subnormal performance is the absence of catch-up growth in height and/or head circumference.

-        Long-term exclusive breastfeeding could help to prevent some of the neurological sequelae of being born SGA. Overfeeding with an enriched formula could accelerate growth, but it does not seem to lead to an advantage for intellectual development and could increase metabolic and cardiovascular risks.

- Staging of fetal growth restriction and optimal timing of delivery.

 

Staging of fetal growth restriction and optimal timing of delivery

 

The optimal timing of delivery with FGR is determined by the severity of

fetal compromise and the risk of stillbirth:

1.     Stage I (mild placental insufficiency): Abnormal Doppler studies including CPR ratios.

2.     Stage II (severe uteroplacental insufficiency): There is absent EDV in the UA. Delivery should be after 34 weeks with twice-a-week monitoring.

3.     Stage III (fetal deterioration, low suspicion of fetal acidosis): There is a reversal of EDV in the UA or DV PI >95th percentile. Risks of stillbirth and neurologic handicap are increased. Delivery should be around 32 weeks.

4.     Stage IV (fetal acidosis): Spontaneous fetal decelerations, reduced variability or reversal of atrial flow on DV. Imminent risk of fetal demise. Deliver immediately.

 

Also timing of delivery should be individualized and based on gestational age and fetal condition. The following principles may guide management of pregnancies complicated by IUGR:

·       Remote from term, conservative management to prolong pregnancy may be performed safely with serial antepartum surveillance as described earlier to achieve further fetal maturity.

·       The term or late preterm (>34 weeks) IUGR fetus should be delivered when there is evidence of maternal hypertension, poor interval growth (over 2- to 4-week intervals), nonreassuring antenatal testing (NST, BPP), and/or umbilical artery Doppler testing to demonstrate absence or reversal of flow.

·       When growth restriction is mild, no complicating maternal or fetal factors are present, and the umbilical artery Doppler and fetal testing are reassuring, delivery can be delayed until at least 37 weeks to minimize the risks of prematurity.

·       Each specific clinical scenario requires close consideration and an individualization of management plans.