Description

Omphalitis, an infection of the umbilical stump, begins in the neonatal period as a superficial cellulitis but may progress to necrotizing fasciitis, myonecrosis, or systemic disease.

Epidemiology

• Episodes of omphalitis are usually sporadic, but rare epidemics occur.
• Mean age of onset is 5–9 days in term infants and 3–5 days in preterm infants.
• Incidence varies from 0.2 to 0.7% of live births in developed countries and up to 21% of live births in developing countries.

Risk Factors

• Low birth weight
• Prior umbilical catheterization
• Septic delivery
• Male sex

General Prevention

• There are multiple methods used for umbilical cord care, many of which are acceptable.
• Antimicrobial agents applied to the umbilicus may decrease bacterial colonization and prevent omphalitis, particularly in developing countries.
• Effective methods of umbilical cord care:
  • Clean, dry cord care (AAP/WHO recommended)
  • Triple dye
  • Topical 4% chlorhexidine
  • 70% alcohol solution
• There is significant evidence to support the use of topical 4% chlorhexidine to prevent omphalitis in developing countries, although it does delay time to cord separation.
• 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

• Potential bacterial pathogens normally colonize the umbilical stump after birth.
• These bacteria invade the umbilical stump, leading to omphalitis.
• Established aerobic bacterial infection, necrotic tissue, and poor blood supply facilitate the growth of anaerobic organisms.
• Infection may also extend beyond the subcutaneous tissues to involve fascial planes (fasciitis), abdominal wall musculature (myonecrosis), and umbilical and portal veins (phlebitis).

Etiology

• Most cases of omphalitis are polymicrobial.
• The most common organisms include gram-positive cocci (Staphylococcus aureus, group A streptococci) and gram-negative enteric bacilli (Escherichia coli, Klebsiella pneumoniae, 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 cow dung is used in cord care.

Commonly Associated Conditions

• Leukocyte adhesion deficiency
  • Omphalitis may be the initial manifestation of one of the leukocyte adhesion deficiencies (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 5th 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.