Specific radiographic signs of NEC are associated with specific Bells stages of the disease:
Bells stage 1 (suspected disease):
Mild systemic disease (apnea, lethargy, slowed heart rate, temperature instability)
Mild intestinal signs (abdominal distention, increased gastric residuals, bloody stools)
Nonspecific or normal radiological signs
Bells stage 2 (definite disease):
Mild to moderate systemic signs
Additional intestinal signs (absent bowel sounds, abdominal tenderness)
Specific radiologic signs (pneumatosis intestinalis or portal venous gas)
Laboratory changes (metabolic acidosis, too few platelets in the bloodstream)
Bells stage 3 (advanced disease):
Severe systemic illness (low blood pressure)
Additional intestinal signs (striking abdominal distention, peritonitis)
Severe radiologic signs (pneumoperitoneum)
Additional laboratory changes (metabolic and respiratory acidosis, disseminated intravascular coagulation)Ultrasonography has proven to be useful, as it may detect signs and complications of NEC before they are evident on radiographs, specifically in cases that involve a paucity of bowel gas, a gasless abdomen, or a sentinel loop. Diagnosis is ultimately made in 5–10% of very-low-birth-weight infants (<1,500g). Diagnosis of NEC is more challenging in premature infants, due to inexplicit symptoms and radiographic signs. The most preterm infant is at highest risk of developing NEC. Prevention
Prevention includes the use of breast milk and probiotics. A 2012 policy by the American Academy of Pediatrics recommended feeding preterm infants human milk, finding "significant short- and long-term beneficial effects," including reducing the rate of NEC by a factor of one-half to three-quarters.Small amounts of oral feeds of human milk starting as soon as possible, while the infant is being primarily fed intravenously, primes the immature gut to mature and become ready to receive greater intake by mouth.
Patients experience optic atrophy due to progressive cranial nerve compression, which may lead to nystagmus or even blindness in severe cases.Other neurological abnormalities include intellectual disability, speech and psychological deterioration. Convulsions and status epilepticus are also present in patients, however the mechanisms for the development of these features are unknown. Patients also experience cranial nerve damage resulting from progressive cranial pressure. Pathogenesis
DSS is classified as an autosomal recessive disease(OMIM 224300), but it is also identified as an X-linked recessive inheritance in certain families. The total number of genes that are responsible for causing the disease and the correlation between genotype and phenotype remains unclear. Multiple gene mutations were identified in different patients via whole genome sequencing, therefore it is presumed that DSS is genetically heterogeneous. TCIRG1 mutation
The TCIRG1 gene is present in chromosome locus 11q13, which encodes for the a3 subunit of vacuolar H+ ATPase (V-ATPase) that is unique to osteoclasts. The a3 subunit is responsible in anchoring the vacuolar proton pump to the ruffled membrane of osteoclasts. The V-ATPase is important in mediating the transport of hydrogen ions into the resorption lacunae, which is a pit on the bone surface enclosed by the osteoclast for bone resorption. The accumulation of ions in the lacuna facilitates the decomposition of hydroxyapatite crystals by creating an acidic environment, resulting in bone resorption. Mutation of the gene results in osteoclast-rich osteopetrosis due to poor translation and altered structure of proton pump structure, which is normally involved in large amounts of osteoclast activity leading to absorption of bone tissue.