Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Kendig > Lung In Sickle Cell Disease > Flashcards

Lung In Sickle Cell Disease Flashcards

1
Q

HbS gene is protective against:

A

Malaria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Most severe form of SCD

A

Sickle cell anemia (HbSS)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Amino acid substitution in HbSS

A

Valine for glutamic acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Structural changes in HbS

A

When deoxygenated, beta subunit of HbS is exposed and polymerizes with other Hgb tetramers, causing aggregates (crystals) that distort RBC membrane. After exposure to hypoxic or acidic environment, there is loss or K and increases in free Ca, causing dehydration. These cause membrane to stiffen and the RBC to be sickle shaped, subject to hemolysis and causing obstruction in small blood vessels.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Pathogenesis of SCD

A

-Sickle cell is deficient in antioxidant and produces oxidant species.
-Hemolysis produces free Hb and extra cellular heme, which is proinflammatory and a damage-associated molecular pattern molecule (DAMP).
-Release of neutrophil extracellular traps (NET)
-Inhibition of NO causes increased cellular adhesion and diminished vasodilation
-Enhanced adhesion of sickle cells to each other, endothelium, and neutrophil causes VASO-OCCLUSIVE CRISIS (VOC)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

SCD in newborns

A

Asymptomatic due to HbF
Manifestations at 10-12 weeks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Age group with highest incidence of ACS

A

2-4 years old

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Most important risk factor for development of SCLD

A

Recurrent ACS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

ACS is more common and more severe in this subtype

A

HbSS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Incidence of ACS is inversely proportional to __ and directly proportional to __

A

Inverse:
HgF

Direct:
Steady state WBC - release free radicals and inflammatory mediators

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Increased risk of ACS in children with fever

A

ANC > 9
Hgb < 8.6
Previous ACS
URTI
Noncompliance to penicillin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Common infections causing ACS

A

C. pneumoniae
M. pneumoniae
RSV
Parvovirus B19 - marrow necrosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Common cause of ACS

A

Pulmonary fat embolism - activates SPLA2 which liberates fatty acids, causing acute pulmonary toxicity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Wheezing in SCD

A

Increased risk of ACS, decreased lung function, death

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

ACS symptoms

A

Chest pain
Productive cough
Dyspnea
Bone pain if from fat embolism
Fever, tachypnea, crackles, wheezes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

CXR of ACS

A

NEW PULMONARY INFILTRATE, commonly in lower and middle lobes

17
Q

Presentation of SCLD

A

Hypoxemia
RLD due to recurrent damage to parenchyma
Cor pulmonale
Diffuse interstitial fibrosis in CXR

18
Q

Risk factors for SDB/OSA in SCD

A

Compensatory adenotonsillar hypertrophy in functional asplenia
Altered facial bone structure due to extramedullary hematopoiesis

19
Q

PFT in SCD

A

Obstructive becoming restrictive with age
Can be obstructive, restrictive, mixed

20
Q

Causes of LFT abnormalities

A
  1. Asthma
  2. Hyperdynamic pulmonary circulation due to raised cardiac output from chronic anemia
  3. Transfusion causes increased pulmonary capillary blood volume
21
Q

Diagnostics

A

Sickle test (HbS solubility test, sodium metabisulfite test)
Tests to separate hemoglobins
Molecular testing

22
Q

Management of ACS

A

Broad spectrum antibiotics including atypicals
Hydration not more than 1.5x FM (can cause vascular leak)
Simple BT if low Hgb
Exchange transfusion if high Hct to avoid increased viscosity
Supplemental O2; escalate if increased hypoxia, dyspnea, pH < 7.25
Analgesia
Bronchodilator, dexamethasone
Inhaled NO if with PH

23
Q

Management of PH in ACS

A

Anticoagulation
Hydroxyurea
Prostacyclin agonist or ET-1 antagonist NOT PDD5 inhibitor

24
Q

LFT monitoring

A

Bronchodilator challenge if <70%
Cold air or exercise challenge if >70%
AVOID methacholine (can precipitate ACS)

Annual monitoring
Impulse oscillometry in young children

25
Q

Pulse oximetry inaccuracy

A

COHb may be raised in some
Light absorption is different in HbS and HbA

26
Q

Prevention of ACS

A

Hydroxyurea - raises HbF; NO donor; reduces adhesion to endothelium
Chronic transfusion
Incentive spirometry
Stem cell

27
Q

Prognosis

A

Short life expectancy
Common COD: pulmonary embolism, pneumonia

Kendig (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions