OMPHALITIS UMBILICAL STUMP INFECTION
Category: Child Health
Abstract :
Omphalitis is an infection of the umbilical stump. Omphalitis typically
presents as a superficial cellulitis that may progress to necrotizing fasciitis,
myonecrosis, or systemic disease. The introduction of aseptic umbilical cord
care has greatly reduced the occurrence of omphalitis in newborn infants.
Omphalitis has become rare in industrialized countries; however, it remains a
common c
Omphalitis is an infection of the umbilical stump. Omphalitis typically
presents as a superficial cellulitis that may progress to necrotizing fasciitis,
myonecrosis, or systemic disease. The introduction of aseptic umbilical cord
care has greatly reduced the occurrence of omphalitis in newborn infants.
Omphalitis has become rare in industrialized countries; however, it remains a
common cause of neonatal mortality in less developed areas.
Omphalitis is
predominantly a disease of the neonate. Although several cases have been
reported in adult patients, adult omphalitis is extremely uncommon and is not
discussed in this article.
Approximately 85% of cases are polymicrobial
in origin. Aerobic bacteria are present in approximately 85% of infections,
predominated by Staphylococcus aureus, group A Streptococcus, Escherichia coli,
Klebsiella pneumoniae, and Proteus mirabilis. In the past, studies emphasized
the importance of gram-positive organisms (eg, S aureus and group A
Streptococcus) in the etiology of omphalitis; however, more recent studies have
highlighted gram-negative organisms as the cause. These studies suggest that the
change in etiology may be caused by the introduction of prophylactic umbilical
cord care using antistaphylococcal agents, such as hexachlorophene and triple
dye, and the subsequent increase in gram-negative colonization of the umbilical
stump. In addition, anaerobic bacteria colonize the maternal genital
tract.
When techniques adequate for the recovery of anaerobic bacteria
were used in studying newborns with omphalitis, anaerobes were recovered from
one third of patients. The predominant anaerobic isolates were Bacteroides
fragilis and Clostridium perfringens. Several mothers whose newborns had
omphalitis caused by B fragilis also had amnionitis caused by this organism.
Isolated cases due to other anaerobic organisms, including Clostridium
sordellii, also are reported. Neonatal tetanus caused by Clostridium tetani
usually results from contamination of the umbilical cord during improperly
managed deliveries outside of a medical facility or the cultural practice of
placing cow dung on the umbilical stump after delivery. Neonatal tetanus is rare
in the United States but is common in developing
countries.
Pathophysiology:
• The umbilical stump represents a unique
but universally acquired wound, in which devitalized tissue provides a medium
that supports bacterial growth. Normally, the cord area is colonized with
potential bacterial pathogens during or soon after birth. These bacteria have
the potential to invade the umbilical stump, leading to omphalitis. If this
occurs, the infection may progress beyond the subcutaneous tissues to involve
fascial planes (necrotizing fasciitis), abdominal wall musculature
(myonecrosis), and the umbilical and portal veins (phlebitis). The factors that
cause colonization to progress to infection are not well
understood.
Frequency:
Internationally:
• Overall incidence varies
from 0.2-0.7% in industrialized countries. Incidence is higher in hospitalized
preterm infants than in full-term infants. Episodes of omphalitis are reported
and usually are sporadic, but rarely, epidemics occur, eg, due to group A
Streptococcus.
Mortality/Morbidity:
• Outcome usually is favorable in
infants with omphalitis associated with cellulitis of the anterior abdominal
wall. In a study by Sawin and colleagues, no deaths occurred among 32 infants
with omphalitis in the absence of necrotizing fasciitis and myonecrosis. The
mortality rate among all infants with omphalitis, including those who develop
complications, is estimated at 7-15%. The mortality rate is significantly higher
(38-87%) after the development of necrotizing fasciitis or myonecrosis.
Suggested risk factors for poor prognosis include male sex, prematurity or being
small for gestational age, and septic delivery (including unplanned home
delivery); however, data are limited and conclusions cannot be drawn regarding
the role of these factors in the mortality rate.
• Sequelae of omphalitis
may be associated with significant morbidity and mortality, including
necrotizing fasciitis, myonecrosis, endocarditis, portal vein thrombosis,
sepsis, septic embolization, and death.
Sex: No sex predilection has been
reported, although male may have a worse prognosis than female
Age:
•
In full-term infants, the mean age at onset is 5-9 days.
• In preterm
infants, the mean age at onset is 3-5 days.
History:
• A detailed
review of the pregnancy, labor, delivery, and the neonatal course is important.
A history of poor feeding or feeding intolerance may be an early indication of
infection. A history of change in mental status, such as irritability, lethargy,
and somnolence, or a history of a decreased level of activity may be an
important indicator of systemic dissemination of the infection.
• Anaerobic
bacteria are part of the normal flora of the female genital tract and are
commonly involved in ascending infections of the uterus and in septic
complications of pregnancy; therefore, the higher incidence of omphalitis caused
by anaerobes (especially B fragilis) in infants with adverse perinatal
histories, such as premature or prolonged rupture of membranes and amnionitis,
may relate to exposure to maternal infection.
• History of urine or stool
discharge from the umbilicus suggests an underlying anatomic
abnormality.
Physical:
• Local disease:
Physical signs vary with
the extent of disease. Signs of localized infection include the following:
o
Purulent or malodorous discharge from the umbilical stump
o Periumbilical
erythema
o Edema
o Tenderness
•Extensive local disease:
The
following signs indicate more extensive local disease, such as fasciitis or
myonecrosis. These signs also may suggest infection by both aerobic and
anaerobic organisms and include the following:
o Periumbilical
ecchymoses
o Crepitus
o Bullae
o Progression of cellulitis despite
antimicrobial therapy
• Systemic disease:
Signs of sepsis or other
systemic disease are nonspecific and include disturbances of thermoregulation or
evidence of dysfunction of multiple organ systems. Examples include the
following:
o Disturbances of thermoregulation - Fever (temperature >38°C),
hypothermia (temperature <36°C), or temperature instability
o
Cardiovascular disturbances - Tachycardia (pulse >180 beats per minute
[bpm]), hypotension (systolic blood pressure <60 mm Hg in full-term infants),
or delayed capillary refill (<2-3 s)
o Respiratory disturbances - Apnea,
tachypnea (respirations >60/min), grunting, flaring of the alae nasi,
intercostal or subcostal retractions, or hypoxemia
o Gastrointestinal tract
disturbances - Rigid or distended abdomen or absent bowel soundso Cutaneous
abnormalities - Jaundice, petechiae, or cyanosis
o Neurologic abnormalities -
Irritability, lethargy, weak sucking, hypotonia, or
hypertonia
Causes:
• Omphalitis is a polymicrobial infection typically
caused by a mixture of aerobic and anaerobic organisms. Associated risk factors
include the following:
o Low birthweight (<2500 g)
o Prior umbilical
catheterization
o Septic delivery (as suggested by premature rupture of
membranes, nonsterile delivery, or maternal infection)
o Prolonged rupture of
membranes
• Omphalitis occasionally manifests from an underlying
immunologic disorder. Several infants with chronic omphalitis were subsequently
diagnosed with leukocyte adhesion deficiency, a rare immunologic disorder with
an autosomal recessive pattern of inheritance. These infants typically present
with the following:
o Leukocytosis
o Delayed separation of the umbilical
cord
o Recurrent infections
• Omphalitis also may be the initial
manifestation of neutropenia in the neonate. Infants with neonatal alloimmune
neutropenia have presented with omphalitis. Neonatal alloimmune neutropenia is a
disease analogous to Rh-hemolytic disease and results from maternal
sensitization to fetal neutrophils bearing antigens that differ from the
mother's. Maternal immunoglobulin G antibodies cross the placenta and result in
an immune-mediated neutropenia that can be severe and last for several weeks to
6 months. Affected infants may present with other cutaneous infections,
pneumonia, sepsis, and meningitis. Since omphalitis complicated by sepsis also
can be associated with neutropenia, the underlying immune-mediated neutrophil
destruction may not be immediately appreciated in affected newborns.
•
Rarely, an anatomic abnormality may be present, such as a patent urachus or
patent omphalomesenteric duct.
• Other abnormalities associated with
serious systemic infection include the following:
o Hypoglycemia
o
Hypocalcemia (often related to saponification with fatty acids released by
bacterial lipases in subcutaneous tissue)
o Metabolic acidosis
Other
Problems to be Considered:
The clinical picture of omphalitis is sufficiently
characteristic that diagnosis can be made with fair certainty on clinical
grounds. Determining whether associated complications are present, such as
systemic infection or necrotizing fasciitis, myonecrosis, endocarditis, or
portal vein thrombosis, is important. In neonates with omphalitis and either
delayed separation of the umbilical cord or neutropenia, the presence of a
predisposing anatomic abnormality (eg, patent urachus) or an immunologic problem
(eg, leukocyte adhesion deficiency or neonatal alloimmune neutropenia) must be
considered.
Persistence of a portion of the embryonic tract between the
bladder and the umbilicus results in a variety of urachal anomalies. A patent
urachus, a free communication between the bladder and umbilicus, may result in
persistent drainage from the umbilicus, which can be mistaken as a sign of
infection. Incomplete obliteration of the urachal remnant may lead to the
formation of an isolated extraperitoneal cyst, which can present with a
secondary bacterial infection mimicking omphalitis. However, these cysts rarely
present with secondary infections in the neonatal period.
Lab
Studies:
• Obtain specimens from umbilical infection routinely, and submit
specimens for Gram stain and culture for aerobic and anaerobic organisms. If
myonecrosis is suspected, obtain specimens from the involved muscle rather than
the wound surface.
• Obtain a blood culture for aerobic and anaerobic
organisms.
• Obtain a complete blood count with manual differential.
o
Neutrophilia or neutropenia may be present in acute infection. An
immature-to-total neutrophil ratio greater than 0.2 may be a useful indicator of
systemic bacterial infection in the first few days of life.
o
Thrombocytopenia may be present.
• Other nonspecific laboratory tests,
either alone or in combination with a defined scoring system, have been
evaluated for their usefulness in rapid detection of bacterial infection in
neonates, although none has demonstrated sensitivity or specificity sufficiently
high to dictate clinical care. The tests include the following:
o C-reactive
protein levels
o Erythrocyte sedimentation rate
o Limulus lysate test,
which detects endotoxin
• The following laboratory studies are suggested
in neonates in whom sepsis and disseminated intravascular coagulation (DIC) are
suspected:
o Prothrombin time
o Activated partial thromboplastin time
o
Fibrinogen
o Fibrinogen split products or D-dimer
Imaging
Studies:
• Abdominal radiographs may reveal intra-abdominal wall gas.
•
Computed tomographic (CT) scan of the abdomen may determine the presence and
extent of muscle involvement.
Procedures:
• Lumbar puncture may be
warranted in infants in whom sepsis is suspected.
Histologic
Findings:
• Analysis of biopsy specimens may reveal necrotizing fasciitis,
which is an acute inflammatory infiltrate found in subcutaneous fat and
connective tissue, or myonecrosis, which is an acute inflammatory process
surrounding muscle bundles, many of which are no longer viable.
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