Diseases Of Infancy And Childhood Question and Answers

Diseases of Infancy and Childhood

Question 1. Write a short note on neonatal respiratory distress syndrome.
Answer:

Respiratory distress syndrome (RDS)/hyaline membrane disease

• Seen in preterm infants
• Associated with male gender
• Risk factors: Maternal diabetes, cesarean section
• Predisposing factor—lung immaturity
• The incidence of RDS is inversely proportional to the gestational age
• The fundamental defect in RDS is a deficiency of pulmonary surfactant
• Surfactant synthesis is increased by cortisol, insulin, prolactin, thyroxine, and TGF-β and is suppressed by insulin
• Labor increases surfactant synthesis
• Microscopically, eosinophilic hyaline membranes line the respiratory bronchioles, alveolar ducts, and alveoli

Read and Learn More Preparatory Manual of Pathology Question and Answers

Complications due to treatment of RDS

• High concentration and prolonged oxygen administration lead to retrolental fibroplasia (also called retinopathy of prematurity) and bronchopulmonary dysplasia

Question 2. Write a note on the hemolytic disease of newborns.
Answer:

Hemolytic disease of the newborn (immune hydrous)

• Caused by blood group antigen incompatibility between mother and fetus
• Rh and ABO blood groups antigens can induce clinically significant immunologic reactions

Etiology and Pathogenesis

• Occurs when fetal red cells reach maternal circulation
• Results in antibody response
• Among the Rh antigens, the D antigen is a major cause of Rh incompatibility
• Initial exposure to Rh antigen, results in IgM antibody formation
• Rh disease is uncommon after a first pregnancy
• However, during subsequent pregnancy (due to IgG antibody response), the risk of immune hydrous is increased

How to protect?

• Anti-D antibodies (RhIg) usage has reduced the incidence of maternal Rh isoimmunization
• Administration of RhIg to the mother is done at 28 weeks of pregnancy and within 72 hours of delivery
• RhIg is also administered following abortions
• Immunization to Rh-negative mothers decreases the risk for hemolytic disease in Rh-positive neonates in subsequent pregnancies

Question 3. Write a short note on ABO incompatibility.
Answer:

ABO incompatibility

• Seen in 20% to 25% of pregnancies
• Anti-A and anti-B antibodies produced are of IgM type, which does not cross the placenta
• The disease is milder than Rh incompatibility
• There is no effective protection against ABO reactions

The disease is not as severe as Rh incompatibility because

• Neonatal red cells express blood group antigens A and B poorly
• Cells, other than red cells, express A and B antigens, which absorb some of the transferred antibodies

Whom does it affect and why?

• ABO hemolytic disease affects infants with group A or B, who are born to group O mothers
• For some unknown reasons, group O women possess IgG antibodies directed against group A or B antigens, even without prior sensitization, resulting in affected first child

Question 4. Write a note on erythroblastosis fetal.
Answer:

Erythroblastosis fetal is

• In immune hydrops, the fetus will be severely anemic
• The liver and spleen will be enlarged, due to cardiac failure, secondary to anemia
• In the bone marrow, there occurs compensatory hyperplasia of the erythroid precursors
• Extramedullary hematopoiesis is present in the liver, spleen, and lymph nodes
• Increased hematopoietic activity results in increased numbers of immature red cells, including reticulocytes, norm oblasts, and erythroblasts (erythroblastosis fetal is)

Question 5. Write a note on the etiopathogenesis of cystic fibrosis.
Answer:

Cystic fibrosis

• Disorder of ion transport in epithelial cells
• Affects fluid secretion in exocrine glands and epithelial lining of the respiratory, gastrointestinal, and reproductive tracts
• Results from abnormal function of epithelial chloride channel protein encoded by cystic fibrosis transmembrane conductance regulator (CFTR) gene
• CFTR gene is located on chromosome 7q31.2
• Pulmonary manifestations are associated with the mutation of man nose-binding lectin 2 (MBL2) and transforming growth factor β1 (TGFB1)

Question 6. Enumerate the tumors affecting children.
Answer:

Tumors commonly encountered in childhood

• Leukemia, teratomas, Ewing sarcoma, rhabdomyosarcomas, hepatoblastoma, Wilms’ tumor, estrogenic sarcoma, neuroblastomas, retinoblastoma

Question 7. Discuss neuroblastomas about their clinical features, morphology, and prognostic factors.
Answer:

Neuroblastomas

• The most common extra-cranial solid tumor in childhood
• Associated with germline mutations in the anaplastic lymphoma kinase (ALK) gene
• Sites: Adrenal gland (40%), along the sympathetic chain, paravertebral region of the abdomen (25%), and posterior mediastinum
• Tumors can show spontaneous regression

Gross

• Range in size from minute nodules to large masses

Microscopy

• Tumor cells, arranged in solid sheets, have scant cytoplasm with dark nuclei
• Background demonstrates faintly eosinophilic fibrillary material (neuropil)
  Homer Wright pseudo rosettes—tumor cells are concentrically arranged about a central space filled with neuropil
• Ganglioneuroblastoma: Composed of ganglion cells (cells with abundant cytoplasm, large vesicular nuclei, and prominent nucleolus) admixed with primitive neuroblasts
• Ganglioneuromas: Better differentiated lesions, with mature ganglion cells and a few neuroblasts
• The maturation of neuroblasts into ganglion cells is accompanied by the appearance of Schwann cells
• Schwann stroma indicates a favorable outcome

N-MYC amplification—the most important prognostic marker

Question 8. Write a note on the genetics and morphology of Wilms’ tumor.
Answer:

Pathogenesis and genetics

Risk is increased in any of the four groups of congenital malformations

1. WAGR syndrome

• Characterized by Wilms’ tumor, aniridia, genital anomalies, and mental retardation
• Individuals carry germ line deletions of 11p13
• Patients with aniridia show PAX6 gene mutations

2. Deny-Crash syndrome

• Characterized by male pseudohermaphroditism, and diffuse mesangial sclerosis
• Patients show germline abnormalities in WT1
• Increased risk for developing germ cell tumors (gonadoblastoma)

3. Beck with Wiedemann syndrome

• Characterized by enlargement of body organs (organomegaly), macroglossia, hemihypertrophy, omphalocele, and abnormal large cells in the adrenal cortex (adrenal cytometry)
• Chromosomal region implicated—localized to band 11p15.5 (“WT2”)
• Increased risk for developing hepatoblastoma, pancreata, adrenocortical tumors, and rhabdomyosarcoma

Morphology of Wilms’ tumor

Gross

• Present as a large, solitary, well-circumscribed mass
• 10% are bilateral or multicentric at the time of diagnosis

Cut section

• The tumor is soft, homogeneous, and tan to gray with occasional foci of hemorrhage, cyst formation, and necrosis

Microscopy

• Classic tri-physic combination of blaster, stromal, and epithelial cell types are seen
• Blaster component: Sheets of small blue cells
• Epithelial differentiation: In the form of abortive tubules or glomeruli
• Stromal cells: Fibrotic or myxoid in nature