Microanatomy 3

Question 1

What is hyaline membrane disease

Answer 1

 Clinically manifests as neonatal respiratory distress syndrome (RDS)
 Formation of membranes in the peripheral airways (fibrin & cellular debri

Question 2

what leads to hyaline membrane disease

Answer 2

 Architectural & functional immaturity of lungs ◦ preterm babies
◦ babies from diabetic mothers
◦ male gender, caesarean section
 Deficiency of pulmonary surfactant

Question 3

what is pulmonary surfactant made form

Answer 3

Complex mixture of protein and phospholipids

Question 4

what is pulmonary surfactant secreted by

Answer 4

 Synthesised by type II alveolar cells

Question 5

what causes an increase and decrease in pulmonary surfactant

Answer 5

 glucocorticoids, thyroxine & labour increase
 insulin & Caesarean section decrease
 certain genetic polymorphisms SP-A, SP-B

Question 6

when is pulmonary surfactant most abundant

Answer 6

 Most abundant >35 weeks of gestation

Question 7

What happens if pulmonary surfactant is deficient

Answer 7

If deficient
 collapsed, non aerated lungs
 ‘solid’ on chest X-rays

Question 8

What does pulmonary surfactant does

Answer 8

 Reduces surface tension in the alveoli

Question 9

what are the complications of hyaline membrane disease

Answer 9

◦ chronic lung disease (BPD)
◦ pneumothorax,
- pneumomediastinum,
- pneumopericardium

Question 10

What are the causes of prematurity

Answer 10

 PROM (premature rupture of membranes) 30-40%
 Intrauterine infection 25%
 Uterine anomalies (fibroids, bicornuate)
 Cervical incompetence
 Placental problems (abruption, pl. praevia)
 Multiple gestation
 IOL for maternal or fetal disease

Question 11

What are the major causes of death in pre-term babies

Answer 11

 Hyaline membrane disease (HMD)

 Intraventricular haemorrhage (IVH)

 Necrotizing enterocolitis (NEC)

 Neonatal sepsis
◦ early onset (up to 1 week of age)
◦ late onset (>1 week of age)

Question 12

What factors determine survival rates in premature babies

Answer 12

 Gestational age (>35/40)

 Size
◦ BW >2500g
◦ no growth restriction

 Antenatally corticosteroids

 Exogenous surfactant at delivery

 Postnatally
◦ management
◦ treating the underlying disease

Question 13

what useful information can an autopsy provide

Answer 13

 Confirm clinical diagnosis

 Additional pathologies

 Congenital malformations

 Infection

 Assess intrauterine growth restriction (IUGR)

Question 14

when are you small for gestational age

Answer 14

 Birth weight <10th centile

◦ at term <2500g

Question 15

what are the causes of small babies

Answer 15

◦ Constitutional (genetic)

◦ Intrauterine growth restriction
 small
 dysmature

Question 16

what are the two types of intrauterine growth restriction

Answer 16

• Symmetric IUGR

- Asymmetric IUGR

Question 17

Describe symmetric IUGR

Answer 17

◦ Proportional underdevelopment
◦ Early onset
◦ Chromosomal abnormality, chronic infection

Question 18

describe asymmetric IGUR

Answer 18

◦ Disproportional underdevelopment
(“brain sparing” effect)

◦ Late onset >25/40

◦ Causes
 Chronic placental disease  Chronic cord problem

Question 19

How should cot deaths be investigated

Answer 19

 Contact the Coroner
◦ natural death, accident or non-accidental
injury?
 Blood & urine tests in A&E
 Complete autopsy
 Examination of the death scene  Review of the clinical history

Question 20

what are differential diagnosis of cot death

Answer 20

 Infection
 Undiagnosed congenital abnormality
 Undiagnosed tumour
 Undiagnosed genetic or metabolic defect 
 Accident
 Non accidental injury (NAI)

Question 21

what is the risk of SIDS

Answer 21

 Risk of recurrence 1 : 8000
◦ due to other diseases or inherited conditions
◦ same risk factors may be repeated in subsequent pregnancies

Question 22

What is the prevalence of SIDS

Answer 22

 SIDS risk 1-2 per 1000 live births

Question 23

what can a mother do to reduce the risk of SIDS

Answer 23

 Baby on the back  Stable surface
 Safe bedding
 No co-sleeping
 No hyperthermia
 No smoking in the baby’s room

Question 24

what is SUDI

Answer 24

sudden unexpected death in infancy = less than 1 year old

• death is unexpected, sudden and initially unexplained
• apparently occurs during sleep and remains unexplained after a through death scene investigation, including performance of a complete autospy and review of circumstances of death and the clinical history

Question 25

what are unusual SIDS cases

Answer 25

post-resuscitation (‘temporarily interrupted
SIDS’)
 SIDS while awake

Question 26

What are typical autospy fidings in SIDS

Answer 26

• serosal petechiae
• focal lung haemorrhage
• acute stress in thymus
• extramedullary haemopoiesis - mild URTI

Question 27

what happens in meningococcus septicaemia

Answer 27

◦ shock
◦ bilateral adrenal haemorrhage
◦ widespread purpura
◦ meningitis

Question 28

what can be a underlying pathology of meningococcus septicaemia

Answer 28

deranged clotting / Disseminated Intravascular Coagulation(DIC)

Question 29

what is the cause of meningococcus septicaemia

Answer 29

 Neisseria meningitidis
 Streptococcus pneumoniae
 Haemophilus influenzae
 Pseudomonas sp.
 Staphylococcus sp.

Question 30

What are the symptoms of meningitis

Answer 30

• headache
• photophobia
• neck stiffness s
• vomiting
• clouding of consciousness
• rash that won’t go away

Question 31

what is the defect in Edwards syndrome

Answer 31

trisomy 18
◦ karyotype 47,XX,+18 or 47,XY,+18
◦ 1:8000 births
◦ advanced maternal age

Question 32

what investigations do you perform to get a genetic diagnosis

Answer 32

 Antenatally
◦ chorionic villous sampling CVS
◦ amniocentesis

 Postnatally or at PM
◦ blood
◦ skin
◦ sternum