Omphalitis is an infection of the umbilicus and/or surrounding tissues, occurring primarily in the neonatal period. It is a true medical emergency that can rapidly progress to systemic infection and death, with an estimated mortality rate between 7% and 15%. Early recognition and treatment are essential to prevent the morbidity and mortality associated with omphalitis.
Immediately after birth, the umbilicus becomes colonized with many different types of bacteria. Gram-positive cocci are present within hours, followed shortly by the presence of many enteric microorganisms. The devitalized tissues of the umbilical stump promote rapid growth of these bacteria, and the thrombosed blood vessels allow entry into the bloodstream, potentially leading to systemic infection.
Omphalitis is uncommon outside of the neonatal period. Symptoms typically begin at an average age of 3 days. It is a rare disease in developed countries, with an incidence of 0.7%. However, in developing countries, the incidence of neonates delivered at hospitals can approach 8%, and if born at home, the incidence can be as high as 22%. Risk factors for the development of omphalitis include the following: low birth weight, prolonged rupture of membranes, maternal infection, umbilical catheterization, nonsterile delivery, maternal infection, prolonged labor, home birth, and improper cord care. Cultural application of cow dung is also associated with higher rates of omphalitis. In addition, immune system abnormalities such as defects in leukocyte adhesion, neutrophil or natural killer lymphocyte function, and interferon production have been associated with an increased risk of omphalitis.
The umbilical cord is the lifeline between the baby and mother during pregnancy and is cut after birth. The umbilical cord stump then gradually dries and typically falls off within 5 to 15 days. Both skin and enteric bacteria may colonize the devitalized tissue of the stump and lead to infection. Omphalitis is, therefore, a polymicrobial infection and the most common pathogens are Staphylococcus aureus, Streptococcus pyogenes, and gram-negative bacteria such as Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis. If maternal infection with chorioamnionitis is suspected, anaerobic bacteria such as Bacteroides fragilis, Clostridium perfringens, and Clostridium tetani can also contribute to infection.
Omphalitis is primarily a disease of the neonate and is characterized by tenderness, erythema, and induration of the umbilicus and surrounding tissues. Early on, patients may only have superficial cellulitis but, if untreated, this can progress to involve the entire abdominal wall. Patients may also have purulent drainage or be bleeding from the umbilical cord stump. Foul-smelling drainage should raise the suspicion of anaerobic infection. Systemic symptoms such as lethargy, poor feeding, fever, and irritability suggest sepsis and portend a worse prognosis. If there is a rapid progression of abdominal wall erythema or gas in the surrounding tissues, necrotizing fasciitis should be considered, and acute surgical consultation is needed.
Laboratory evaluation with complete blood count and culture should be obtained for all patients with suspected omphalitis. In addition, cultures of any purulent material from the umbilical stump should be sent prior to initiation of antibiotics if possible. If the patient has systemic symptoms, a full neonatal septic workup including chest radiograph, urinalysis, urine culture, and cerebrospinal fluid culture should be obtained.
Broad spectrum parenteral antibiotics are required to treat omphalitis. Antibiotic coverage should be directed against both gram-positive and gram-negative organisms. Initial empiric treatment with antistaphylococcal penicillin and aminoglycoside is recommended. If there is a high prevalence of methicillin-resistant Staphylococcus aureus, vancomycin should be administered while awaiting culture results. If there is suspicion for maternal chorioamnionitis or the patient has foul-smelling discharge from the stump, clindamycin or metronidazole is indicated to cover for anaerobes. The duration of antibiotic therapy depends on the patient's clinical response and any complications that may develop during hospital admission. For uncomplicated cases of omphalitis, the recommended course of parenteral therapy is ten days, followed by a switch to oral therapy depending on culture results.
In most cases, the clinical picture of omphalitis is sufficient to make the diagnosis. A patent urachus, which results in direct communication between the bladder and umbilicus can be mistaken for infection due to the persistent drainage from the umbilicus. Umbilical granulomas may also be misdiagnosed as an umbilical infection because the friable tissue can cause serous or serosanguinous drainage and easy bleeding with trauma. These typically occur after the first week of life and can be distinguished by their soft, velvety texture and pinkish color. Umbilical polyps are firm masses comprised of urachal embryologic remnants that often require surgical excision but do not cause infection. If inflammation of the umbilical cord alone is present, then funisitis and not omphalitis is the diagnosis. Funisitis, which is caused by maternal chorioamnionitis, involves only the external surface of the cord and not the umbilical vessels. A wet, foul-smelling umbilical cord without any surrounding cellulitis characterizes funisitis.
Early recognition and treatment of omphalitis are essential to prevent the serious complications of this disease. Sepsis is the most common complication and can progress to septic shock and death. Other rare complications include peritonitis, intestinal gangrene, small bowel evisceration, liver abscess, septic umbilical arteritis, and portal vein thrombosis. Although uncommon, necrotizing fasciitis can occur and should be suspected if there is a rapid progression of infection and signs of systemic toxicity. It should also be suspected if there is no clinical improvement with intravenous antibiotics in 24 to 48 hours. Mortality rates as high as 60% to 85% have been reported in patients with omphalitis complicated by necrotizing fasciitis. If suspected, in addition to broad-spectrum antibiotics, prompt surgical consultation for debridement of the umbilical structures and the involved abdominal wall is essential.
Prevention of omphalitis requires both aseptic techniques during delivery services and proper cord care. The umbilical cord should be cut with a sterile blade or scissors. In the hospital setting where aseptic care is routine, and the risk of omphalitis is low, dry cord care is recommended. In developing countries with a higher risk of omphalitis, chlorhexidine as a topical agent has been shown to reduce the risk of omphalitis inexpensively. In a meta-analysis of studies conducted in community settings of developing countries, the use of chlorhexidine reduced all-cause mortality and the risk of omphalitis when compared to dry cord care. Inappropriate cord care has also been shown to increase the risk of umbilical infection. Cultural application of cow dung or bentonite clay to the umbilical stump has resulted in neonatal tetanus.