Chapter 10- Diseases Of Infancy And Childhood Flashcards
What are the stages of development?
Neonatal- first 4wks
Infancy- first year
1-4
5-14
What are the most prominent disorders associated with each developmental stage?
Infant- congenital disorders
1-4- accidents
5-9- accidents with neoplasms becoming more prominent
10-14- accidents with suicides becoming more prominent
What are congenital anomalies?
Defects present at birth
What is the most common cause of mortality in infants?
Congenital anomalies
What is blighted ovum/anembryonic pregnancy?
No embryo/gestational sac produced
When is miscarriage most common?
First 8wks
What are malformations?
Primary errors of morphogenesis due to abnormal development
Genetic
What are disruptions?
Secondary organ/body region destruction
Extrinsic/environmental
Structure was previously normal
What are deformations?
Localized/generalized compression of the fetus by abnormal biochemical factors
What commonly causes disruptions?
Amniotic bands
What can cause deformations?
Uterine constraint
Multiple fetuses
Bicornate uterus
Leiomyomas
Oligohydroamnios
What is a sequence?
A cascade of anomalies triggered by one event
Single localized aberration in organogenesis sets secondary effects involving other organs into motion
What is a common sequence?
Potter sequence/oligohydroamnios
What are the characteristics of Potter sequence?
Reduced amniotic fluid (multiple possible causes) results in flattened face, positional abnormalities, pulmonary hypoplasia
What is a malformation syndrome?
A constellation of congenital anomalies that can’t be explained by a single initiating event
What is agenesis?
Organ absence (also associated primordium)
What is aplasia?
Organ absence due to failure of growth of the existing primordium
What is atresia?
Absence of an opening
Where is atresia normally seen?
Hollow organs
What is dysplasia (in disorders of infancy)?
Abnormal organization of cells
What are possible causes of dysplasia in development?
Genetic- chromosomal disorders associated with congenital malformations
Environmental
Multifactorial- environment influences and two or more genes of small effect
What environmental factors can cause congenital disorders?
Viral infections
Drugs
DM
Irradiation
What does TORCH stand for? And what do these infections often cause?
Congenital defects in utero
Toxoplasmosis
Other (syphilis, VZ, parvo)
Rubella
CMV
Herpes
What congenital disorders are commonly multifactorial?
Cleft lip/palate
Neural tube defects
When is an embryo/fetus most susceptible to teratogens?
3-9wks
What is the embryonic period of gestation?
1-8wks
At what week of gestation are newborns considered premature?
Earlier than 37 weeks
What is the difference between preterm premature rupture of placental membrane (PPROM) and PROM?
PPROM- occurs before 37wks, higher risk for mortality
PROM- after 37wks, less risk associated
What factors can predispose a pregnancy to PPROM?
Prior hx
Smoking
Vaginal bleeding
Poor nutrition
Low socioeconomic status
How common is intrauterine infection?
Occurs in 25% of preterm births
How do intrauterine infections cause preterm birth?
TLR activation down-regulates prostaglandin, inducing smooth muscle contraction
What is chorioamnionitis?
Placental membrane inflammation
What is funisitis?
Umbilical cord inflammation
What organisms are associated with intrauterine infections?
Ureaplasma urealyticum
M. hominis
G. vaginalis
Trichomonas
Gonorrhea
Chlamydia
What types of structural abnormalities can cause premature birth?
Fibroids (leiomas)
Placenta previa- cervix is blocked by the placenta
Abruptio placentae- premature separation between the placenta and uterus
What are the hazards associated with premature birth?
Neonatal respiratory distress syndrome/hyaline membrane disease
Necrotizing enterocolitis
Sepsis
Intraventricular and germinal matrix hemorrhage
What is intraventricular and germinal matrix hemorrhage?
Lesion, normally starting between thalamus and caudate nucleus
Large- rupture into ventricles (germinal matrix is immature cells under their lining)
Morbidity, cerebral palsy, retardation
Bilateral
What can cause premature birth?
PPROM
Intrauterine infection
Gestation with multiples
Uterine, cervical and placental structural abnormalities
What birth weight is indicative of fetal growth restriction?
<2500g full term
What kind of anomalies can cause fetal growth restriction?
Fetal
Placental
Maternal
Fetal anomalies causing growth restriction are normally what?
Symmetric
What fetal anomalies can cause growth restriction?
Chromosome disorders
Congenital anomalies
Fetal infection (TORCH)
What placental anomalies can cause fetal growth restriction?
Uteroplacental insufficiency
Umbilical placental vascular anomalies
Placental abruptio
Placenta previa
Placental thrombosis and infarction
Placental infection
Pregnancy with multiples
What do most placental abnormalities causing fetal growth restriction stem from?
Heavy demands on blood supply during the third trimester
What is the most common factor in maternal anomalies causing fetal growth restriction?
Conditions reducing placental blood flow
What maternal abnormalities can cause fetal growth restriction?
Pre-eclampsia
Chronic hypertension
Narcotics, alcohol, smoking, malnutrition
What is the cause of neonatal respiratory distress syndrome (NRDS)?
Lung immaturity
Deficiency in pulmonary surfactant secreted by Type II pneumocytes
Alveoli are difficult to fill, collapse on themselves
NRDS is less common with what?
Increasing age
When does surfactant production begin in utero?
35wks
What stimulates surfactant production?
Corticosteroids
What do the lungs of a NRDS neonate look like?
Solid, airless, reddish-purple
Sink in water
What is hyaline membrane disease?
Thick hyaline membranes line the alveoli
What are NRDS neonates at an increased risk of developing?
Patent ductus arteriosus (increased lung BP- more blood)
Intraventricular hemorrhage
Necrotizing enterocolitis
What is necrotizing enterocolitis?
Ischemic necrosis of the intestinal mucosa in portions d the bowel
What is necrotizing enterocolitis inversely proportional to?
Age
What are the characteristics of necrotizing enterocolitis?
Distended, friable, congested or frankly gangrenous bowel
Intestinal perforation with accompanying peritonitis
Pneumatosis intestinalis- gas within intestinal wall
What is the microscopic picture of necrotizing enterocolitis?
Coagulative necrosis
Ulceration
Colonization
Submucosal gas bubbles
How do perinatal infections occur?
Transvertically/ascending- amniotic fluid, birth canal
Transplacentally/hematologically- parasites, viruses, listeria and treponema
What is fetal hydrops?
Accumulation of edema fluid
What are the types of fetal hydrops?
Hydrops fetalis (generalized)
Cystic hygroma
Immune hydrops
Non-immune hydrops
Where does cystic hygroma occur?
Post-nuchally (behind neck)
What is immune hydrops?
Hemolytic disease caused by blood group Ag incompatibility
What Ag group normally causes immune hydrops?
Rh
Why does ABO rarely cause immune hydrops?
IgM (can’t cross placenta)
Ags are poorly expressed on fetal cell
What are the characteristics of immune hydrops?
Anemia (hemolysis)
Heart and liver damage
Jaundice
Kernicterus
Why does jaundice occur in immune hydrops?
Fetus lacks enzyme to conjugate bilirubin, unconjugated bilirubin from hemolysis builds up
What is kernicterus?
Bilirubin binds lipids in the brain causing retardation
What are the major causes of non-immune hydrops?
CV defects
Chromosomal anomalies (Turner syndrome- 45X)
Fetal anemia- pale fetus
How does twin to twin transfusion cause non-immune hydrops?
Blood is shunted from one to another (one has almost none, the other has too much)
What infection can cause non-immune hydrops?
Parvo B19
What does non-immune hydrops caused by Turner syndrome look like?
Abnormalities of lymph fluid drainage from the neck
What are common inborn errors of metabolism?
Phenylketonuria
Galactosemia
Cystic fibrosis
What is deficient in phenylketonuria?
Phenylalanine hydroxylase
What are the characteristics of phenylketonuria?
Mental retardation
Reduced hair and skin pigmentation
Musty/mousy odour
Build up of phenylalanine from mother’s diet
What screen is used for phenylketonuria?
PKU
How is phenylketonuria treated?
Restrictive diets
What is deficient in galactosemia?
Enzyme that metabolizes galactose
What are the characteristics of galactosemia?
Build up of galactose-1-phosphate
Hepatomegaly
Cataracts
CNS alterations
Failure to thrive
Vomiting and diarrhea after milk ingestion
How is galactosemia treated?
Restrictive diets
What is cystic fibrosis?
Inherited disorder if ion transport that affects fluid secretion
What is the most common lethal genetic disease in caucasians?
Cystic fibrosis
What is mutated in cystic fibrosis?
CF transmembrane conductance regulating protein (CFTR)
What ion does the CFTR transport?
Chloride (other membrane transports salt, water follows)
What abnormalities are seen with cystic fibrosis?
Pancreas- mucous accumulation
Intestine- meconium ileus (mucous plugs)
Liver- cirrhosis (mucin plugs)
Salivary glands- duct dilation, atrophy, squamous metaplasia
Lungs- mucous cell hyperplasia, viscous secretions block/dilate bronchioles
Male genital tract- azoospermia, infertility
Cardiorespiratory disease
Sweat glands- extremely concentrated excretions
What is the definitive test for cystic fibrosis?
Sweat chlorides
What is the major cause of death in cystic fibrosis?
Cardiorespiratory disease
What are the cardiorespiratory diseases associated with cystic fibrosis?
Lung infections
Obstructive lung disease
Cor pulmonale
What is SIDS?
Sudden death of an infant that can’t be explained after investigation
What is sudden unexpected infant death syndrome?
Cause is discovered during autopsy
What is the morphology of SIDS?
Multiple petechiae
Evidence of upper respiratory tract infection
Astrogliosis of brain and cerebellum
What is the suggested pathogenesis of SIDS?
Immature critical brain stem regions and environmental influences impair regulatory mechanisms
What risk factors are associated with SIDS?
Maternal age and health
Brain stem abnormalities
Prematurity
Birth of multiples
SIDS in previous sibling
Prone or side sleeping
Soft sleeping surface
What are the most common neoplasms of infancy?
Mesenchymal (sarcomas)
What is the most common tumour of infancy?
Hemangioma
What are hemangiomas sometimes associated with?
von Hippel-Lindau disease
What are the characteristics of hemangiomas?
Vascular tumours
Irregular red-blue masses
Port wine stains
When are lymphatic tumours clinically significant in infants?
When they encroach on viral structures
What fibrous tumour has an excellent prognosis?
Infantile fibrosarcoma (ETV6-NTRK3 fusion gene)
When are the peak incidences of teratomas in children?
2yrs and late adolescence
Where do 40% of teratomas occur in children?
Sacrococcygeal region
What cancer is responsible for the most deaths in children?
Leukemias
What are the common forms of malignant tumours in children?
Small round blue cell tumours
-blastomas
Where do neuroblastic tumours occur?
Medulla or sympathetic ganglion
What is the most common neuroblastic tumour?
Neuroblastoma
What are the characteristics of neuroblastomas?
Neurofibrillary background
Homer Wright pseudorosettes
What are Wilm’s tumours?
Soft, large, well circumscribed renal masses
What is the triphasic histology of Wilm’s tumours?
Blastema
Immature stroma
Tubules
What mutation is associated with Wilm’s tumours?
Bilateral germline mutations in 11p
What syndromes are associated with Wilm’s tumours and what are their characteristics?
WAGR- anirida, genital anomalies, retardation
Denys-Drash- gonadal dysgenesis, nephropathy
Beckwith-Wiedemann- enlarged organs, hemihypertrophy
