Lung Devo (both lectures) Flashcards

1
Q

Precursor of: epithelial lining of the larnyx, trachea, bronchi and lungs

A

Endoderm

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2
Q

Precursor of: cartilage, smooth muscle, elastic and fibrous CT of larynx, trachea and bronchi

A

Splanchnic mesoderm

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3
Q

Lung devo occurs in recognizable phases: What happens week 4-7?

A

(week 4 -7)

  • Lung primordium appears from splanchnic mesoderm
  • Initial airway branching

laryngotracheal tube–> seperated by transeosphageal septum into : primitive trachea and primitive esophagus (look at diagram)

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4
Q

Anomalies Occurring During the Embryonic Phase
• Inadequate Partitioning perhaps due to abnormal or insufficient development of the

A

Tracheoesophageal Septum

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5
Q

The following are all examples of :

absence of the lungs, extra lobes, ectopic lobes or absence of lobes, abnormal or insufficient branching, an accessory lung, bronchogenic cysts, pulmonary vascular anomalies

A

• Anatomic Anomalies

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6
Q

• 39 week male
• 3.2 kg
• Prenatal ultrasound –
normal
• Excess secretions and
respiratory distress 30
minutes after birth
• Unable to pass NGT

A

Problem with tracheoesophageal septum; could be cystic or atresia

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7
Q

What is the most common type of esophageal atresia?

A

Listed as Type A in notes which = Gross type C

85%

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8
Q

Symptoms and diagnosis of distal TEF

A

air in bowel on xray will confirm distal TEF, no contrast necessary

*perform a bronchoscopy to identify fistula

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9
Q

Associated anomalies in TEF or EA

  • Occur in___% of patients
  • Most common with ______ and least common with_____
A

50%

isolated EA

isolated TEF

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10
Q

In TEF and EA _________are main determinants of survival

A

Associated anomalies

(Smaller infants have more associated anomalies such as severe associated cardiac anomalies)

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11
Q

Newborn has distal TEF with EA. What makes them canidates for primary repair?

A

– Healthy
– Near Term
– No major cardiac anomalies
– No significant pulmonary disease

• Removes threat of aspiration PNA

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12
Q

Recomended pre-op mamagement for isolated EA

A

Gastrostomy for feeding
• Drain upper pouch
• Wait 6-12 weeks for pouch growth
• May utilize dilation methods to “stretch”pouch
• Re-evaluate the pouch prior to OR

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13
Q

During repart of TEF with EA, how do we access the trachea?

A

Via extra pleura right thoracotamy (watch for azygous vein!)

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14
Q
A
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15
Q

Week 6-16 is the Psuedoglanular phase… what happens?

A

airway branching continues

increased epithelial-mesenchyme interactions and see pirmordia dev for respiratory passages.

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16
Q

Respiratory diverticulum is made from:

A

endoderm

(surounded by splanchinc mesenchyme)

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17
Q

Week 16-26 is the Canalicular Phase. What occurs?

A
  • Capillary density increases
  • Avelolar Cells (Pneumocytes) begin to differentiate
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18
Q

What is the limit of extrauterine viability?

A

kid needs to be in for at least 22-24 weeks to support life outside and will need assistance

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19
Q

weeks 26-birth: Terminal Sac phase

What is going on during this phase?

A

• Distal airways dilate, forming Terminal Sacs (primitive alveoli)

surrounded by splanchinc mesenchyme

epithelium starts to thin

get elsatin fibers

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20
Q

Congenital Cystic Adenomatoid Malformation (CCAM) is an example of:

A

Congenital bronchopulmonary malformation

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21
Q

Mass of pulmonary tissue in which there is proliferation of bronchial structures at the expense of alveolar development.

A

CCAM; Congenital Cystic Adenomatoid Malformation

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22
Q

** Asynchronous maturation** of the developing lung bud and the surrounding mesenchyme between the 16th and 20th weeks, resulting in:

A

overgrowth of the terminal airway structures or CCAM

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23
Q

Histology of CCAM:

Alveolar spaces lined by a combination of _______ and ______, forming
glandular (“adenomatoid”) architecture

A

both respiratory and mucus-secreting epithelium

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24
Q

Classification of CCAM

Type I

Type II

Type III

A

Type I: large macroscopic cysts

Type II: small macro cysts

Type III: microscopic cysts

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25
Q

Clincal Presentaiton of CCAM

______ respiratory distress

_______pulmonary infections

asymptomatic but detected:

A

rarely respiratory distress

recurrent pulmonary infections

no symptoms but seen on x-tray or ultrasound

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26
Q

CCAM

ususally affects ______ lobe(s), has communication with ______ system and progressive air trapping leads to ________

A

affects single lobe

communicates with bronchial system

trapping air leads to distension

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27
Q

Respiratory distress as neonate
• Day of Life 1 in this infant with tachypnea and hypoxia, requiring intubation. CXR shows LLL hyperlucency with herniation across midline

What conclusions can be drawn from this vignette?

A

they hyperlucency in LLL is indicitive of fluid in the lung (hydrops)

(CCAM will result in fluid filled cysts)

*child requires thoracotomy and lobectomy right away

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28
Q

Consequences of mass effect and timing of arrest of development from CCAM:
• pulmonary______ and _______
• distortion of______ and impaired _____

A

hypertension and hypoplasia

mediastinum

venous return

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29
Q

Can result in hydrops, severe respiratory failure,
pulmonary infection, or no symptoms

A

CCAMs

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30
Q

Tx options for PRE-natal hydrops

A
  • Thoracentesis
  • Thoraco-amniotic shunt
  • Fetal lobectomy
  • Induce delivery and perform resection
31
Q

While doing rotations, a first time mother delivers a healthy apperaing baby. During a chest Xray, the baby was found to have CCAM in the LLL. The attending asks you if surgery is still required… your response?

A
  • They will likely cause recurrent infections, making the resection of a symptomatic lesion more difficult.
  • There is always some amount of diagnostic uncertainty before the pathologic specimen is available.
  • There have been reports of cancers developing in CCAMs, at as little as 1 year of age.
  • The procedure of choice is an anatomic lobectomy
32
Q

What is the process for a nonemergent ‘elective’ Treatement of CCAM?

A

• Plain Film Chest Xray in neonatal period
• Follow – up CT Scan within 1-2 months
• Elective resection within first 3-6 months of life
– Thoracoscopic
– Open

33
Q

Alveolar Phase (32 weeks - 8 years)
• Alveolar formation begins by ________
• Alveolar septum (walls) become_____

A

subdivision of terminal sacs - Septation

thinner

34
Q

Postnatal Development
• Most alveoli form after birth
• Formation proportional to_____

A

body growth

35
Q

Each phase of devo blends into the next phase in Lungs (T/F)

• Formation of airways in the lung proceeds in a proximal to distal direction or distal to proximal direction

A

True

devos in proximal to distal direction

36
Q

The prenatal lung contains:

A

Fluid!

*insufficient fluid in lungs leads to HYPOPlastic lung

37
Q

Prenatal lung has _____

Respiratory movements are ______

pulmonary vascular resistance is______

A

fluid

shallow, episodic

high resistance

38
Q

What changes after birth allow breathing?

A

**Pulmonary Changes **
• Fluid replaced by air

Circulatory Changes
• Cardiac shunts close
• Pulmonary vessels fill
Neural
• Breathing
• Sympathetic activation

39
Q

If a newborn has ‘wet lung’ or issues with fluid removal from the lungs, may get:

A

transient tachypnea

40
Q
A
41
Q

Characteristics of the new air/liquid interface within the alveoli
• Thin_____ wall
• Subjected to _____

A

compliant

surface tension

42
Q

Production of surfactant by _____ begins toward the end of ______ period with a significant increase at ____ weeks

A

Type 2 pneumocytes

canalicular

35 weeks

43
Q

What prevents a baby from breathing on it’s own if it’s born prior to 35 weeks?

A

insufficient pulmonary surfactant production

44
Q

3 Functions of Pulmonary Surfactant

A
  • Decrease surface tension
  • Stabilize alveolar surface
  • Decrease fluid transfer
45
Q

Pulmonary Surfactant is a mixture of 3 Components

A
  • Phospholipid
  • Protein
  • Antioxidant
46
Q
  • Rapid breathing (>60 breaths/min)
  • Flaring nostrils
  • Chest retractions
  • Expiratory grunt
  • Often cyanotic (blue)
  • Rapid heart rate
  • Anxious expression
A

Clinical Signs Respiratory Distress

***this is a MEDICAL EMERGENCY!**

47
Q

Respiratory Distress Syndrome/Hyaline Membrane Diseas = clinical condition where newborn babies experience Respiratory Distress
• Are usually _____
• Have_____ Lungs
• Often develop a________in their lungs

A

Premature

Immature

Hyaline Membrane

48
Q

HMD and RDS are two different diseases and yet…

A

these guys often overlap. Very likely that if you have one, you have the other

49
Q

Hyaline membrane formation:

Type ____ alveolar injury–> breakdown of caplilary/air barrier–> ____ leaks into alveolar lumen–> hyaline forms and ____ is disrupted

A

Type I alveolar cells

Serum leaks to lumen

Surfactant fnx is disrupted

50
Q

Cuases of Respiratory Distress Syndrome:

A

An inability to keep alveoli filled with air
A Decrease in Surfactant Production

51
Q
  • Poor Compliance of Lung Tissue
  • Atelectasis due to alveolar collapse
  • Engorgement of Pulmonary Capillaries
  • Formation of a Hyaline Membrane

These are all from:

A

Decreased surfactant production

52
Q

Premature infants who experience RDS may develop

A

Bronchopulmonary Dysplasia (chronic lung disease of infancy)

53
Q
A
54
Q
A
55
Q
  • 1.2-kg male infant born vaginally at 32 weeks EGA
  • Apgars 6, 8
  • Required bulb suctioning, brief PPV.
  • Grunting, retractions, nasal flaring, acrocyanosisimmediately after birth.
  • VS: HR 178, RR 79, Mean BP 39 mmHg. O2 74-78% in room air

What is concerning for RDS?

A

Grunting, retractions, nasal flaring, acrocyanosis

low O2 saturation

increased RR and low BP

born at 32 weeks

56
Q

What is the pathology of RDS?

A

Due to structural and functional immaturity of lungs.
• Underdeveloped parenchyma
• Surfactant deficiency–:Type II pneumatocytes
• Results in decreased lung compliance, unstable alveoli

57
Q
A
  • Prematurity
  • <28 weeks GA (≈100%)
  • 28-34 weeks GA (33%)
  • >34 weeks GA (5%)
  • Perinatal depression
  • Male predominance
  • Maternal diabetes
  • C-section
  • Multiple birth
58
Q

What do you see on chest xray in infant with RDS?

A

• Low lung volumes
• Diffuse atelectasis: “ground
glass opacities”
• Air bronchograms
• Difficult to distinguish from
pneumonia

59
Q

Lab findings concerning for RDS?

A
  • Moderate hypoxia
  • Respiratory acidosis
  • Metabolic acidosis (delayed)
60
Q

Tx for RDS in infant?

A
  • Oxygen supplementation
  • Assisted ventilation
  • nCPAP
  • mechanical ventilation
  • FiO2 > .40
  • Exogenous surfactant replacement
  • Fluid restriction
61
Q

Prevention of RSD

A
  • Antenatal bethamethasone
  • Arrest of preterm labor
62
Q
  • Peak severity ___days
  • Recovery coincides with____ beginning at 72 hrs
  • Severe cases evolve into _________
A

1-3

diuresis (getting water out of lungs)

bronchopulmonarydysplasia (chronic lung disease)

63
Q
  • Tachypnea immediately after birth or within two hours, with other predictable signs of respiratory distress.
  • Symptoms can last few hours to two days
A

Transient tachypnea

64
Q

What do we see in xray in TTN?

A

Chest radiography shows diffuse parenchymal infiltrates, a “ wet silhouette” around heart, or intralobar fluid accumulation

65
Q

Meconium Aspiration Syndrome is seen in _____% in term or post term infants.
Why is it a bad deal?

A

1.5- 2

  • Meconium is locally irritative, obstructive & medium for for bacterial culture
  • Meconium aspiration causes significant respiratory distress. Hypoxia occurs because aspiration occurs in utero.
  • CXR- Patchy atelectasis or consolidation.
66
Q

What does xray for child with RDS look like compared to normal?

A

RDS has patchy, whitish looking lungs while normal lungs are clear

67
Q

Issues with RDS when we have premature lungs with insufficient surfactant. We can measure this using:

A

Lecithin/sphingomyelin ratio (Phosphatidylglyerol ismore accurate measurement)

68
Q

LS ratios

>2.0 is 98%:

1.5-1.9 is 50%:

<1.5 is 73%:

A

normal

RDS

RDS

69
Q

How can doctors enhance fetal lung maturation?

A
  • Administer glucocorticoids to the mother before delivery
  • Administer artificial surfactant to the newborn
70
Q

• The lower portion of the respiratory system develops from a

A

ventral foregut diverticulum (endoderm)

71
Q

Interaction between endoderm and splanchnic mesoderm results in
airway branching which proceeds

A

proximal-distal

72
Q
  • A air/liquid interface is established in alveoli which is subject to_____
  • Adequate surfactant reduces the surface tension
A

surface tension

73
Q

Inadequate____ levels lead to immature lungs and respiratory distress syndrome (hyaline membrane disease

A

surfactant