DESCRIPTION

Omphalitis, a bacterial infection of the umbilical stump, begins in the neonatal period as a superficial cellulitis but may track along umbilical vessels and progress to systemic illness.

EPIDEMIOLOGY

• Episodes of omphalitis are usually sporadic.
• Mean age of onset is 5 to 9 days in term infants and 3 to 5 days in preterm infants.
• Omphalitis is rare in developed countries, with an incidence of approximately 1 out of 1,000 live births, but in developing countries, incidence may be upward of 8–22% of infants, depending on risk factors.

RISK-FACTORS

• Low birth weight
• Prior umbilical catheterization
• Septic delivery
• Home birth
• Prolonged rupture of membranes
• Chorioamnionitis/funisitis

GENERAL-PREVENTION

• There are multiple methods used for umbilical cord care, including dry cord care, triple dye, 4% chlorhexidine, and 70% alcohol solution.
• Clean, dry cord care is recommended by the American Academy of Pediatrics (AAP) and World Health Organization (WHO) for infants born in a hospital setting in developed countries.
• Aseptic delivery and hygienic cord care, including cutting the cord in a sterile manner (with gloves and sterile instruments), are key to preventing infection.
• There is significant evidence to support the use of topical 4% chlorhexidine in infants born at home in settings with high neonatal mortality (>30 deaths per 1,000 live births).
• There is no evidence that application of an antiseptic to the umbilical cord is better than clean, dry cord care in a hospital setting.

PATHOPHYSIOLOGY

• Once the umbilical cord is cut after birth, the stump dries and falls of within 5 to 15 days.
• The umbilical stump is colonized by microorganisms soon after birth, both pathogenic and nonpathogenic.
• Pathogenic bacteria may invade the umbilical stump, leading to omphalitis.
  • The type of organisms present varies depending on the birth setting and quality of cord care.
  • In high-resource settings, gram-positive organisms are most likely, and gram-negative organisms are more common in low-resource settings.
• Omphalitis may present in varying severity:
  • Funisitis/umbilical discharge—abnormal-appearing umbilical cord and purulent, malodorous discharge
  • Omphalitis with associated cellulitis—periumbilical erythema and tenderness in addition to cord discharge
  • Omphalitis with systemic signs of infection
  • Omphalitis with necrotizing fasciitis—crepitus, bullae, and evidence of involvement of superficial and deep fascia, often associated with septic shock
• Unhygienic cord care, as well as the application of harmful substances to the umbilical cord, can lead to an increased incidence of omphalitis in developing countries.
• Established aerobic bacterial infection, necrotic tissue, and poor blood supply facilitate the growth of anaerobic organisms.

ETIOLOGY

• The most common causative organisms are gram-positive cocci, including Staphylococcus aureus (MSSA and methicillin-resistant S. aureus [MRSA]), group A and group B streptococci.
• Gram-negative pathogens include Escherichia coli, Klebsiella pneumoniae, Pseudomonas species, and Proteus mirabilis.
• Gram-positive organisms predominate; however, antistaphylococcal cord care has led to an increase in colonization and infection with gram-negative organisms.
• Anaerobic bacteria, including Bacteroides fragilis and Clostridium perfringens, are most likely in cases complicated by necrotizing fasciitis or myonecrosis.
• Clostridium tetani and Clostridium sordellii are seen primarily in developing countries when unhygienic instruments may be used to cut the cord and/or cow dung is used in cord care.

ASSOCIATED-CONDITIONS

• Leukocyte adhesion deficiency (LAD)
  • Omphalitis may be the initial manifestation of one of the LADs.
  • LADs are rare, autosomal recessive immunologic disorders affecting leukocyte adhesion to blood vessel walls.
  • Cord separation requires the influx of leukocytes; therefore, this deficiency causes delayed separation and can cause concomitant omphalitis.
  • Infants also may present with leukocytosis, absence of pus formation, impaired wound healing, and recurrent infections localized to the skin and mucosal surfaces.
  • Treatment involves prompt recognition of infection and use of appropriate antibiotics. Severe cases may need hematopoietic stem cell transplantation.
• Neutropenia
  • Omphalitis complicated by sepsis can be associated with neutropenia.
  • Other syndromes of neonatal neutropenia may present initially with omphalitis.
    • Neonatal alloimmune neutropenia: Maternal IgG antibodies cross the placenta and cause immune-mediated destruction of fetal neutrophils bearing antigens differing from mother’s.
    • Other causes of neutropenia: autoimmune neutropenias, X-linked agammaglobulinemia, hyper-IgM immunodeficiency syndromes, HIV, glycogen storage disease type IB, or disorders of amino acid metabolism
• Anatomic abnormalities
  • Patent urachus:
    • The urachus, a tubular structure connecting the bladder to the umbilicus, should obliterate by the fifth gestational month.
    • If it remains patent, a continuous, significant amount of urine can drain from the umbilicus.
  • Persistent omphalomesenteric duct:
    • Congenital malformation where a communication exists between the umbilicus and the gut
    • Drainage consists of intestinal secretions.
  • Excessive granulation tissue:
    • Results from delayed healing of cord stump
    • Drainage is serosanguinous and pink.
• Considerations in preterm infants:
  • Preterm infants are more susceptible secondary to immature immune defenses (including the skin) and possible umbilical catheterization.
  • These infants are more likely to present with omphalitis at an earlier age and with low neutrophil counts.