Neonatal Respiratory Distress Syndrome (RDS) 60,000 cases / year in USA with 5000 deaths Incidence is inversely proportional to gestational age The cause is lung immaturity with decreased alveolar surfactant – surfactant decreases surface tension – first breath is the hardest since lungs must be expanded – without surfactant, lungs collapse with each breath

RDS Risk Factors 1) Prematurity – by far the greatest risk factor – affected infants are nearly always premature 2) Maternal diabetes mellitus – insulin suppresses surfactant secretion 3) Cesarean delivery – normal delivery process stimulates surfactant secretion

RDS Pathology Gross – solid and airless (no crepitance) – sink in water – appearance is similar to liver tissue* Microscopic – atelectasis and dilation of alveoli – hyaline membranes composed of fibrin and cell debris line alveoli (HMD former name) – minimal inflammation

Necrotizing Enterocolitis Incidence is inversely proportional to gestational age – approaches 10% with severe prematurity Pathogenesis – not fully understood – intestinal ischemia – inflammatory mediators – breakdown of mucosal barrier

Necrotizing Enterocolitis

Sudden Infant Death Syndrome Definition – sudden death of an infant under 1 year of age which remains unexplained after a thorough case investigation, including performance of a complete autopsy, examination of the death scene, and review of the clinical history Also called crib death

Epidemology of SIDS Leading cause of death in USA of infants between 1 month and 1 year of age 90% of deaths occur ≤ 6 months age, mostly between 2 and 4 months

Risk Factors for SIDS Parental – Young maternal age (age <20 years) – Maternal smoking during pregnancy – Drug abuse in either parent – Short intergestational intervals – Late or no prenatal care – Low socioeconomic group Infant – Brain stem abnormalities, associated defective arousal, and cardiorespiratory control – Prematurity and/or low birth weight – Male sex – Product of a multiple birth – SIDS in a prior sibling – Antecedent respiratory infections Environment – Prone sleep position – Sleeping on a soft surface – Hyperthermia – Postnatal passive smoking

Pathogenesis of SIDS Generally accepted to be multifactorial Triple risk model – Vulnerable infant – Critical development period in homeostatic control – Exogenous stressors Brain stem abnormalities, associated defective arousal, and cardio-respiratory control

Diagnosis of SIDS SIDS is a diagnosis of exclusion Complete autopsy Examination of the death scene Review of the clinical history Differential diagnosis – child abuse – intentional suffocation

TUMORS Benign Malignant

BENIGN Hemangiomas Lymphatic Tumors Fibrous Tumors Teratomas (also can be malignant)

Congenital Capillary Hemangioma At birth At 2 years After spontaneous regression

Teratomas Composed of cells derived from more than one germ layer, usually all three Sacrococcygeal teratomas – most common childhood teratoma – frequency 1:20,000 to 1:40,000 live births – 4 times more common in boys than girls Aproximately 12% are malignant – often composed of immature tissue – occur in older children

Sacrococcygeal Teratoma

Malignant Tumors Cancers of infancy and childhood differ biologically and histologically from their counterparts occurring later in life. The main differences are: – Incidence and type of tumor – Prevalence of underlying familial or genetic aberrations – Tendency of fetal and neonatal malignancies to regress spontaneously or cytodifferentiate – Improved survival or cure of many childhood tumors,

INCIDENCE AND TYPES The most frequent childhood cancers arise in the hematopoietic system (leukemia & lymphoma), nervous tissue (including the central and sympathetic nervous system, adrenal medulla, and retina), soft tissues, bone, and kidney. Histologically, many of the malignant pediatric neoplasms are unique. In general, they tend to have a more primitive (embryonal) These tumors are frequently designated by the suffix - blastoma, for example, nephroblastoma (Wilms' tumor), hepatoblastoma, and neuroblastoma.

Neuroblastomas Second most common malignancy of childhood Neural crest origin – adrenal gland – 40 % – sympathetic ganglia – 60% In contrast to retinoblastoma, most are sporadic but familiar forms do occur Median age at diagnosis is 22 months

Neuorblastoma Morphology Small round blue cell tumor – neuorpil formation – rosette formation – immunochemistry – neuron specific enolase – EM – secretory granules (catecholamine) Usual features of anaplasia – high mitotic rate is unfavorable – evidence of Schwann cell or ganglion differentiation favorable Other prognostic predictors are used by pathologists and oncologists

Neuorblastoma *Neuropil**Homer-Wright Rosettes * **

Clinical Course and Prognosis Hematogenous and lymphatic metastases to liver, lungs and bone 90% produce catecholamines, but hypertension is uncommon Age and stage are most important prognostically – < 1 year age: good prognosis regardless of stage Amplification of N-myc oncogene – present in 25-30% of cases and is unfavorable – up to 300 copies on N-myc has been observed Risk Stratification – low risk: 90% cure rate – high risk 20% cure rate