2.disorders of prematurity; pediatric pathology

transcript

Pediatric PathologyPediatric Pathology

Dr. Krishna Tadepalli, MD, www.mletips.com

2. Disorders of Prematurity2. Disorders of Prematurity

Disorders of Prematurity• Depends on birth weight( 2,300gm) and gestational age (34weeks), infants are

classified into1. Appropriate for gestational age ( AGA) = between 10th to 90th percentile2. Small for gestational age (SGA) below 10th percentile3. Large for gestational age (LGA) = above 90th percentile

• Pre- term = born before 37 weeks • Post – term = after 40 (?)weeks

• Causes of Prematurity = 2nd MCC of neonatal mortality, • Preterm premature rupture of membranes (PPROM) ;- 1/3rd of preterm

deliveries, risk factors are many ( previous episode, vaginal bleeding, smoking, poor nutrition etc.,)

• Intrauterine infection ;- 25% of all preterm labors, mainly due to placental infection, MC organisms Ureaplasma, Mycoplasma, Gardnerella, Trichomonas, Gonorrhea, Chlamydia; TLRs (TLR4) are key factors;

• Uterine, cervical & placental abnormalities ;- • Multiple gestations ( twin pregnancy)

Disorders of Prematurity1. Fetal Growth Restriction (FGR) = low birth weight (<2500 gm); same as SGA;

also called intra uterine growth retardation (IUGR); – Risk factors (Fetal chromosomal, congenital anomalies or infections; Placental

Uteroplacental insufficiency, genetic mosaicism of placenta (Trisomy 7); Maternal toxemia of pregnancy, chronic HTN, malnutrition and Drugs & chemicals ( smoking and alcohol)

2. Neonatal RDS = DAD or Hyaline Membrane Disease; MCC of RDS Hyaline Membrane Disease (others – maternal sedation, fetal head injury etc.,); almost always preterm and AGA babies; other associations – male baby, Maternal Diabetes, C-section; X-ray of lungs ground glass like; the most important underlying factor = immaturity of lungs (lack of surfactant); – surfactant is important for innate immunity and decrease surface tension;

hyaline membrane = protein and fibrin rich exudate with necrotic type II pneumocytes, never seen in still born; hormones increase (Glucocorticoids) or decrease (insulin) surfactant synthesis;

– Grossly = solid (atlectatic) lungs, liver like, sink in water – Rx = exogenous surfactant + Oxygen; antenatal Glucocorticoids to mother;

delay labor; – Complications of Rx = Retinopathy of prematurity and Broncho-pulmonary

dysplasia, PDA, Intraventricular H.age, Necrotizing Enterocolitis

RDS - PathogenesisRDS - Pathogenesis

Anderson

Patchy Atelectasis – Neonatal LungsPatchy Atelectasis – Neonatal Lungs

Hyaline MembraneHyaline Membrane

Anderson Dr. Krishna Tadepalli, MD, www.mletips.com

Disorders of Prematurity3. Necrotizing Enterocolitis (NEC)• MC in Premature babies• Pathogenesis – unknown (? Multifactorial)• Associated with prematurity, enteral feeding or formula milk

(bacterial introduction), inflammatory mediators (PAF) are important ( increased mucosal permeability);

• Clinically bloody stools, abdominal distention, CVS collapse• Diagnosis = air in the intestinal walls (Pneumatosis intestinalis)

involves terminal ileum and large intestines; • Microscopy mucosal or mural necrosis, ulceration, bacterial

colonization, gas in walls, • Rx = needs bowl resection with high mortality, • Complication post – NEC strictures ( due to healing by fibrosis)

NECNEC

2.disorders of prematurity; pediatric pathology

Health & Medicine