Neonatology

·         Pustular melanosis is benign neonatal rash on a pigmented macular base. The flaccid vesicles contain neutrophils, which is in contrast to the eosinophils seen in erythemia toxicum.

·         The Apgar score helps to rapidly assess the need to resuscitate neonates after birth. Although it has some value in predicting neonatal mortality and cerebral palsy, it has a poor positive predictive value. Most children with cerebral palsy have had normal Apgar scores, while neonates with low Apgar scores do not universally get cerebral palsy.

·         The best screening tool to assess fetal growth is fundal height, which is measured from the upper edge of the symphysis pubis to the top of the uterine fundus. Between 20 and 34 weeks' GA, fundal height measurements (in cm) approximate GA (in weeks). A discrepancy between measured and expected fundal height measurements of 3 cm or more is suggestive of fetal growth restriction.

Abdominal circumference is the most sensitive single measurement, in determining the degree of impaired fetal growth, Once fetal growth restriction is suspected based on history and clinical assessment of fundal height.

·         IUGR: failure to meet growth potential

SGA: <10th percentile for GA based on population norms

LBW: birth weight <2500 gm

Prematurity: normal or altered growth at <37 weeks' GA

·         The ponderal index (PI) is a widely used measurement of the infant's relative thinness or fatness independent of race, gender, and GA:

PI= Wt(gm) x 100/ Ht(cm)³

Normal PI values range between 2.32 and 2.85. The PI is normal in symmetric IUGR, low in asymmetric IUGR, and high in the macrosomic fetus.

·         Barker hypothesis: impaired fetal growth may be a key determinant of later development of adult diseases such as obesity, insulin resistance, type 2 diabetes mellitus, and cardiovascular disease. Poor fetal nutrition results in developmental adaptations that permanently alter subsequent postnatal physiology and thereby "program" an infant's future predisposition to disease.

·         The Quintero staging system grades the severity of TTTS and may aid in determining the prognosis and selection of treatment modalities.

·         Ex utero intrapartum treatment (EXIT) is a technique by which a mother undergoes partial cesarean delivery so that placental support to the fetus can be maintained while airway identification, stabilization, and, if necessary, mass resection is performed. The procedure is currently used for the delivery and management of fetal airway compromise from extrinsic mass compression or intrinsic airway defect.

·         Lung-to-head ratio (LHR) is an ultrasonographic measurement used in fetuses between 24 and 26 weeks' GA with congenital diaphragmatic hernia.

LHR =1.4 is considered a good prognostic indicator.

LHR <1.0 is associated with poor outcomes.

·         Congenital cystic adenomatoid malformation volume ratio (CVR) is an ultrasonographic measurement used as a prognostic tool in the management of CCAM. The CVR identifies fetuses at high risk for developing hydrops. These infants may benefit from closer surveillance and possible fetal intervention.

CVR >1.6 is associated with an 80% risk of developing hydrops.

Neonatal survival approaches 100% in the absence of hydrops.

·         "Triple edema" (fetus, placenta, and mother) is pathognomonic for maternal mirror syndrome. Other terms that are used interchangeably are Ballantyne syndrome and pseudotoxemia.

·         Fetal fibronectin is an extracellular matrix protein, the presence of which in cervicovaginal secretions is a predictor of preterm labor. This predictor has a high negative predictive accuracy (>99%; the absence of fetal fibronectin indicates delivery is not imminent) but only a mediocre positive predictive accuracy.

·         MODIFIED CREASY SCORE has been used to identify patients who are destined to deliver prematurely.

·         Waveform analysis of umbilical artery flow using ultrasound-guided Doppler warns the clinician of increased resistance to flow within the placenta. This test is expressed as systolic-to-diastolic ratio. When the situation is severe enough, the flow during diastole either becomes absent or goes in the reverse direction, indicating marked resistance to flow. This form of testing is principally of value in the severely growth-restricted fetus and can give a very early warning of impending fetal demise.

·         The senses develop in the following order: touch > balance > taste > smell > hearing > sight.

·         Triple dye consists of an aqueous solution of brilliant green proflavine hemisulphate and crystal violet that is bactericidal against Staphylococcus aureus.

·         Unconjugated bilirubin has potent antioxidant and free-radical scavenger properties that may protect cells during the sudden exposure to high ambient oxygen levels at birth. Small intracellular concentrations of bilirubin, continually recycled from oxidized biliverdin, form a highly efficient mechanism to protect cell membranes from lipid peroxidation.

·         Ampicillin, cefotaxime, and vancomycin can be safely given to an infant with jaundice.

·         Harlequin color change is a demarcated erythema forming on the dependent half of the body of newborns. In some cases, the baby appears as if a line were drawn right down the midline. The more superior half of the body appears pale. This appearance can occur in any position and commonly lasts from seconds up to 20 minutes. It is rarely seen after 10 days of life. Harlequin color change is explained by immature autonomic vasomotor control because it is more common in premature infants and is reversible. If the baby is flipped over during an episode, the newly dependent portion will become erythematous.

·         KID syndrome is a rare disorder characterized by keratitis, ichthyosis, and congenital neurosensory deafness. Newborns have erythematous, thickened skin that eventually peels. The face and extremities then become ichthyotic; scaly keratoconjunctivitis usually develops during infancy.

·         Sclerema is likely a result of lipoenzyme dysfunction and occurs in infants who are stressed with severe illnesses. More specifically, dysfunction of enzymes regulating the conversion of saturated fatty acids to unsaturated fatty acids results in excess saturated fatty acids. This dysfunction promotes fat solidification.

·         Renal ultrasound has been recommended in patients with preauricular skin tags because they can be associated with urinary tract abnormalities (8.6% of cases according to one prospective study).

·         Anetoderma of prematurity is the term for focal depressions or outpouchings, which are presumed to be a response to mechanical or thermal injury to the skin.

·         Coiling of the umbilical cord occurs in approximately 95% of newborns, and most are twisted in a sinistral manner.

·         The second-born twin has a twofold to fourfold increased risk of developing respiratory distress syndrome and is more likely to be asphyxiated. However, the risks for sepsis and necrotizing enterocolitis may be increased in first-born twins.

·         Funisitis is inflammation of the umbilical cord vessels and Wharton's jelly, and it has been described as either an acute exudative or subacute necrotizing process that accompanies chorioamnionitis. The predominant organisms that have been identified as etiologic agents are gram-negative bacteria, including Escherichia coli, Klebsiella, and Pseudomonas. Gram-positive organisms (e.g., streptococci, staphylococci) and candidal species are less-commonly responsible.

·         Up to 25% of newborns have palpable nodes, particularly in the inguinal and cervical regions. By 1 month of age, the prevalence is nearly 40%.

·         Throckmorton's sign is the extension of the suspensory ligament of the penis before micturition in newborn infants. However, thousands of house officers have come to believe that this sign relates to the radiographic finding in a male in which the penis points to the side of pathology.

·         Labor length for boys is about 1 hour longer than that of girls.

·         Pupillary reaction to light may appear as early as 29 weeks into gestation but is not consistently present until approximately 32 weeks.

By 32 weeks of gestation, normal premature infants respond to concentrated odor.

·         The Kleihauer-Betke test detects the presence of fetal cells in the maternal circulation. Because fetal hemoglobin is resistant to elution with acid, the treatment of a maternal blood smear with acid will result in darkly stained fetal cells among the maternal "ghost" cells. From the percentage of fetal red cells and the estimated maternal blood volume, the size of the hemorrhage can be determined. One percent fetal cells in the maternal circulation indicates a bleed of approximately 50 mL.

·         Apt-Downey test is used to determine whether swallowed maternal blood is the cause for gastrointestinal bleeding in the neonate.

·         Vigintiphobia, translated from the Latin, is the "fear of 20." Traditionally, it has been common to do exchange transfusions in term infants without evidence of isoimmunization or hemolysis at bilirubin levels of 20 mg/dL to prevent kernicterus. Critics argue that this practice is without scientific evidence, and there is support for tolerating higher levels of bilirubin (in infants without ABO incompatibility or other causes of hemolysis) before intervention has grown.

·         Infants with a family history of light-sensitive porphyria should not receive phototherapy. The presence of direct hyperbilirubinemia is not considered a contraindication, but it will decrease the effectiveness of phototherapy.

·         Nonnutritive sucking is a mode of sucking that is unique to humans and that is characterized by a highly regular, burst-pause pattern. Nonnutritive sucking occurs in all sleep and awake states, although it is seen less often during quiet sleep and crying. It assumes a recognizable rhythmic pattern after 33 weeks of gestation.

·         Although 30% of newborn infants breathe through their mouth or nose and mouth, the remaining 70% are obligate nose breathers until the third to sixth week of life.

·         ECMO is prolonged cardiopulmonary bypass that is used to treat newborn infants (<1 week old) with reversible pulmonary disease that has been complicated by persistent pulmonary hypertension.

Contraindications to ECMO include uncontrolled bleeding, grade II or greater IVH, pulmonary hemorrhage, irreversible pulmonary disease, history of severe asphyxia, prolonged mechanical ventilation (>7-14 days), lethal genetic condition, and significant prematurity (birthweight <2,000 gm; gestational age <35 weeks).

·         Apnea is the cessation of respiration for >20 seconds or for a shorter duration if it is associated with cyanosis and/or bradycardia. Periodic breathing is commonly seen in preterm infants, and it is defined as a pattern of three or more respiratory pauses of >3 seconds' duration with <20 seconds of respirations between pauses. Periodic breathing is not associated with bradycardia. Both apnea and periodic breathing reflect a lack of maturation of respiratory control centers in the preterm infant.

·         Premature infants are particularly susceptible to vitamin E deficiency because there is significant transfer of vitamin E during the last trimester of pregnancy. Vitamin E deficiency in premature infants causes thrombocytosis, edema, and hemolysis potentially causing anemia.

·         Constriction ring syndrome (i.e., Streeter's dysplasia) is a rare syndrome that is characterized by ring-like constriction bands around the upper and lower extremities or the trunk. The etiology is unknown, and it is not hereditary. The extent and depth of the rings vary. The bands may be subcutaneous or may extend down to bone. These bands may interfere with lymphatic and venous return. This causes edema and enlargement of the distal part with decreased capillary refill. If there is great disruption to the local circulation, the part may undergo autoamputation in utero. Often there are other concomitant anomalies of the hand including syndactyly, acrodactyly, hypoplasia, camptodactyly, and symphalangia. Other associated anomalies include cleft palate and lip and talipes equinovarus deformity of the foot.