Anemia of Prematurity - Portal Neonatal

multiple organisms) that lead directly to tissue cell death, enzymatic destruction of
supporting connective tissue, and destruction of host humoral and cellular immune
responses to infecting organisms.
� Certain organisms are well known to invade tissue and proliferate in necrotic areas.
Group A Streptococcus, S aureus, and Clostridium species may elaborate extracellular
enzymes and toxins that can damage tissue, may facilitate movement of organisms
through soft tissue planes, and may limit host defenses and penetration of systemic
antimicrobial agents.
o Myonecrosis refers to infectious involvement of muscle.
� In infants with omphalitis, development of myonecrosis usually depends on conditions
that facilitate the growth of anaerobic organisms. These conditions include the
presence of necrotic tissue, poor blood supply, foreign material, and established
infection by aerobic bacteria such as staphylococci or streptococci. C perfringens, in
particular, does not replicate under conditions of an oxidation-reduction potential (Eh)
greater than -80 mV; the Eh of healthy muscle is 120-160 mV. In infections with
mixtures of facultative aerobes and anaerobes, the aerobic organisms use oxygen
available in tissue, thereby further reducing the Eh in tissues inoculated by Clostridium
species or other anaerobic bacteria, often to less than -150 mV, allowing anaerobic
bacterial growth.
� The toxins produced in the anaerobic environment of necrotic tissue allow rapid
spread of organisms through tissue planes. Local spread of toxins extends the area of
tissue necrosis, allowing continued growth of organisms and increasing elaboration of
toxins. Because of progressive deep tissue destruction and subsequent systemic
spread of toxins, anaerobic infections, in particular, may be fatal if not treated
promptly. In addition, rapid development of edema, which constricts the muscle within
its fascia, may lead to ischemic myonecrosis.
o Septic embolization: If septic embolization arises from infected umbilical vessels, it may
lead to metastatic foci in various organs, including the liver, lungs, pancreas, kidneys, and
skin.
o Sepsis: This is the most common complication of omphalitis. In a study by Mason and
colleagues, bacteremia was a complication in 13% of infants with omphalitis. In these
infants, DIC and multiple organ failure may occur.
o Other complications related to omphalitis are much less common.
Prognosis: The prognosis for infants with omphalitis is variable.
Patient Education: Referral for psychosocial counseling may assist the family in coping with a
critically ill infant.
MISCELLANEOUS Section 9 of 10
Medical/Legal Pitfalls:
• Failure to recognize necrotizing fasciitis or myonecrosis may result in delay of appropriate
surgical intervention.
Special Concerns:
• The relatively high incidence of necrotizing fasciitis following omphalitis in the newborn, with its
attendant morbidity and mortality, requires close observation and early surgical intervention if
any question exists regarding the diagnosis.