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91

SIDS

Congenital differentials 

– Congential aortic stenosis

– Anomalous origin of coronary artery from pulmonary artery

92

SIDS (Differential diagnosis)

• Genetic/Metabolic Defects

– Long QT syndrome (SCNSA + KCNQ1 mutations)(Sodium and potassium channel abnormalities.) 1%

– Fatty acid oxidation disorders (MCAD, LCHAD, SCHAD mutations) 5%

– Histiocytoid cardiomyopathy (MTCYβ mutations)

– Abnormal inflammatory responsiveness

(Partial deletion of C4a and C4b)

93

After how many weeks does the female amniotic fluid become bacteriocidal

20 wks 

94

Fetal and Perinatal Infections - Pathways

• Ascending from the vagina and cervix.

• Hematogenous dissemination from the placenta.

• Maternal to fetal transfusion at delivery(Hepatitis B and HIV)

• Direct contact at birth.

• From the environment post-partum.

• Accidental introduction at the time of

procedures - amniocentesis.

95

Ascending Infection

Fetus acquires infection by

– Inhalation of infected amniotic fluid

– Passage through birth canal

96

• Fetal birth infections

– Chorioamnionitis

– Funisitis

– Pneumonia

– Sepsis

– Meningitis

 

97

Infections Acquired by the Hematogenous Route

• TORCHinfections.

• Congenital syphilis.

• Parvovirus B19.

• Human Immunodeficiency  Virus(HIV).

• Other infections(Listeria, parasitic  infections).

98

O= OTHER INTRAUTERINE INFECTIONS

Syphilis

Listeria monocytogenes (late-onset sepsis)

Adenovirus (rare)

Varicella (rare)

Enterovirus

SLAVE

99

TORCH Agents

Transmission

• Hematogenous through the placenta.

• Herpes simplex infection is an exception to this as most infections are due to:

– Direct contact at the time of delivery.

– Ascending infection.

100

TORCH Infections

Common Manifestations

 SGA infants.

 CNS changes:

 Hydrocephalus.

 Microcephaly.

 Periventricular calcification.

Pneumonitis

 Petechiae

Hepatomegaly with jaundice

 Splenomegaly

 Bony changes resembling osteomyelitis

 Chorioretinitis

101

Rubella Embryopathy

 Eye and heart Manifestations 

• Ocular lesions:

– Cataracts.

– Corneal changes. 

– Microphthalmia.

• Cardiac lesions:

– Patent ductus arteriosus.

– Septal defects.

102

Cystic Fibrosis

An autosomal recessive systemic disorder of exocrine glands characterized by

– Chronic pulmonary disease

– Deficient exocrine pancreatic function

– Other complications of inspissated mucus in a number of organs, including the small intestine, liver and the reproductive tract.

103

Cystic fibrosis pathogenesis

• Gene on chromosome 7 (7q31.2) encodes for a protein called the CF transmembrane conductance regulator (= CFTR).

• Phosphorylation of CFTR by protein kinase A using cAMP controls the chloride channel in the apical membranes of eccrine glands.

104

Types of Mutations in cystic fibrosis

 In 70 % cases – 3 base pair deletion that results in loss of a phenylalanine residue at amino acid position 508(∆F508).

• The remaining patients exhibit multiple (more than 800) different mutations.

105

Cystic Fibrosis

Lung

 Plugging of submucosal tracheobronchial mucous glands and ducts.

• Obstruction of bronchioles with mucus, associated with marked hyperplasia and hypertrophy of the mucus-secreting cells.

106

LUng infections from CF

– Chronic bronchitis.

– Bronchiectasis.

– Lung abscesses.

107

Cystic Fibrosis

Pancreas

• In this organ, there is the same mucous obstruction of ducts accompanied by:

– Secondary dilatation and cystic changes of the distal ducts and atrophy of secretory cells.

– Fibrosis.

– Destruction of parenchyma.

• These effects result in chronic pancreatitis in 85% of patients with CF.

108

Cystic Fibrosis

Clinical Features

• Discovered between age of 2-12 months.

• Child presents with symptoms of malabsorption secondary to pancreatic insufficiency:

– Foul-smelling steatorrhea.

– Malnutrition • Edema

• Hypoalbuminemia

– Failure to thrive.

109

CYSTIC FIBROSIS

CLINICAL (CONTD.)

• Two clinical clues in children:

– Nasal polyps

– Rectal prolapse

110

Cystic Fibrosis

Diagnosis

• Pilocarpine sweat test

– Normal sweat: chloride = 10 mEq/L.

– CF sweat, severe variant: chloride >60 mEq/L.

– CF sweat, mild variant: chloride = 40-60 mEq/L

• Genetic diagnosis

111

Phenylketonuria

• Autosomal recessive disorder characterized by

– Progressive mental retardation caused by a deficiency of the hepatic enzyme phenylalanine hydroxylase.

112

PKU pathogenesis

• Point mutation in the PAH gene on 12q.

• Deficiency of Phenylalanine Hydroxylase (PAH) results in

– Hyperphenylalaninemia

– Formation of Phenylketones

• Hyperphenylalaninemia causes irreversible brain damage

– Complete interference with amino acid transport system in brain

– Inhibiting the synthesis of neurotransmitters

113

PKU clinical features 

• Affected infant is normal at birth

• Mental retardation develops within few months

• Tend to have fair skin, blond hair and blue eyes.

• Mousy odour

114

Galactosemia

An autosomal recessive deficiency of Galactose -1-phosphate uridyl transferase, the enzyme that catalyzes the conversion of galactose to glucose.

 

Infants fed milk rapidly develop hepatosplenomegaly, jaundice and hypoglycemia.

• Cataracts and Mental retardation.

115

Galactosemia

• M/E –

extensive and uniform fat

accumulation in liver and marked bile ductal proliferation, cholestasis and fibrosis.

 

116

Dubin-Johnson syndrome

Autosomal recessive disease characterized by chronic or intermittent jaundice and accompanied by a „black‟ liver.

• Defective transport of conjugated bilirubin from hepatocytes to canalicular lumen

• Associated defect in hepatic excretion of

coproporyphrins

117

Dubin-Johnson syndrome

pathology m.e

accumulation of coarse, iron free, dark brown granules in hepatocytes and Kupffer cells.

118

Dubin-Johnson syndrome 

path EM 

pigment is located in lysosomes and it appears to be composed of polymers of epinephrine metabolites, not bilirubin pigment

119

Rotor Syndrome

• Familial conjugated Hyperbilirubinemia

defect in the excretion of conjugated bilirubin into the biliary canaliculi with the bilirubin being absorbed into the blood.

120

Rotor Syndrome

jaundice, attacks of intermittent epigastric discomfort and occasionally abdominal pain, and fever.