Pulmonology - Med Study

Question 1

What % of predicted lung volumes on spirometry are abnormal?

Answer 1

< 80% predicted

>120% predicted may also be significant

Question 2

What Lung Capacities are affected in restrictive lung disease?

Answer 2

Decreased TLC (both VC and RV are decreased)

Question 3

What spirometry values suggest obstructive lung disease

Answer 3

FEV1/FVC is < 0.7

Question 4

What is Residual volume (RV)?

Answer 4

unused space

Question 5

What is expiratory Reserve volume (ERV)?

Answer 5

from full non-forced end expiration to full forced end expiration

Question 6

what is tidal volume (TV)?

Answer 6

normal unforced ventilation

Question 7

What is Inspiratory reserve volume (IRV)?

Answer 7

from normal unforced end-inspiration to full forced end-inspiration

Question 8

Equation for Vital Capacity (VC)

Answer 8

VC = IRV + TV + ERV

Question 9

Equation for Total Lung Capacity (TLC)

Answer 9

TLC = VC + RV

Question 10

Equation for Inspiratory Capacity (IC)

Answer 10

IC = IRV + TV

total capacity available for inspiration after passive exhalation

Question 11

Equation for functional residual capacity (FRC)

Answer 11

FRC = ERV + RV

capacity left in lungs after passive inspiration

Question 12

Causes of intrathoracic & extrathroacic restrictive lung disease

Answer 12

intra: parenchymal disease, interstitial disease
extra: obesity, scoliosis, neuromuscular weakness

Question 13

How does VQ mismatch lead to hypoxemia & what is treatment

Answer 13

some alveoli have more V and some more Q.
major cause in chronic lung disease
responds to 100% O2 supplementation

Question 14

How does R to L shunting cause hypoxemia

Answer 14

perfusion of non-ventilated alveoli

causes: alveolar collapse, intraalveolar filling (pna, pulm edema), intracardiac shunt, AVM

Question 15

how does decreased alveolar ventilation lead to hypoxemia? is PCO2 deranged? How?

Answer 15

low TV or RR

always has high PCO2

Question 16

how does decreased diffusion cause hypoxemia?

Answer 16

doesn’t really unless exercise induced bc it takes tremendous thickening.
occurs with interstitial lung disease
PCO2 may be wnl

Question 17

how does high altitude cause hypoxemia

Answer 17

reduced partial pressure of O2

Question 18

what shifts oxyhemoglobin dissociation curve to the right (or down)

Answer 18

mnemonic TAP
increased Temperature
increased H+ (acidosis or inc PCO2)
increased 2,3-DPG

Question 19

What happens when Hgb dissociation curve shifts right (down)?

Answer 19

decreased affinity for O2 –> promotes offloading

Question 20

what happens when HGb dissociation curve shifts left (up)?

Answer 20

increased affinity for O2

Question 21

how does Carbon Monoxide poisioning affect hgb dissociation curve

Answer 21

binds tightly to Hgb –> O2 cant bind –> already bound O2 binds tightly –> left/up shift in dissociation curve
regular pulse ox can’t differentiate

Question 22

how does methemoglobin affect hgb dissociation curve

Answer 22

Hgb molecule oxidized from Fe2+ to Fe3+ –> cant hold onto O2 or CO2 –> regular Hgb holds O2 more tightly –> left/up shift

Question 23

Clinical Presentation of methemoglobinemia & treatment

Answer 23

> 25%: perioral/peripheral cyanosis
35-40%: fatigue, dyspnea
60%: coma, death

remove offending agent
100% Oxygen
methylene blue
if hereditary - 1-2g/day ascorbic acid

Question 24

Laryngomalacia

Answer 24

most common c/o stridor in newborn
laryngeal cartilage not stiff enough –> luminal narrowing –> inspiratory stridor
heard by 2 weeks of life
stridor worse with agitation, feeding, supine position
most outgrow by 12-24mo, if severe & affecting feeding or nighttime hypoxia, trim supraglottis
Dx with awake flexible laryngoscopy

Question 25

vocal cord paralysis

Answer 25

damage to recurrent laryngeal can be with other neuro abnormalities, after birth trauma (neck stretching), or after CT/thyroid/TEF surgery absent or weak cry, hoarse raspy voice aspiration risk Dx with awake fiberoptic nasopharyngoscopy

Question 26

subglottic stenosis

Answer 26

cause stridor & resp distress in newborn or first few months of life common in Down's Syndrome can present with recurrent croup can be acquired after intubation at any age Dx with direct laryngoscopy or bronch

Question 27

laryngeal cyst

Answer 27

develop from mucous secretion epithelium of supraglottic region stridor & hoarseness usu not congenital and 2'2 prolonged or traumatic intubation tx; remove cyst

Question 28

laryngocele

Answer 28

epithelium lined diverticula from laryngeal saccule (above each vocal cord that lubes the cords) laryngeal obstruction of neck mass excise

Question 29

laryngeal atresia

Answer 29

failure of larynx to recanalize in 10th week gestation | usually incompatible with life

Question 30

laryngeal web

Answer 30

abnormal development of structures in & around laryngeal inlet present with abnormal voice, stridor, resp distress assoc with velocardiofacial syndrome --> test for 22q11 gene deletion Dx: direct laryngoscopy Tx: incision or dilation

Question 31

Tracheal agenesis - 3 types

Answer 31

type 1: proximal trachea closed, distal communicates with esophagus type 2: bronchi meet in midline & communicate with esophagus thru fistula type 3: absent trachea, both main bronchi communicate with esophagus separately RDS + absent cry. suspect if unable to intubate despite visualizing larynx

Question 32

tracheal stenosis

Answer 32

segmental, usu involves complete cartilage rings occuring anywhere along length severe retractions + expiratory stridor bronch, CT, or MRI to confirm mild can observe, if symptomatic dilate or resect

Question 33

Tracheomalacia/bronchomalacia

Answer 33

inadequate cartilagenous tone or external compression --> collapses with breathing --> expiratory stridor usually mild but can be assoc with other things like TEF, cardiac abnormality, cervical/mediastinal masses

Question 34

lobar emphysema

Answer 34

RDS in neonate up to 5-6 months - tachypnea, grunting, expiratory wheezing usually LUL diaphragm down & mediastinum to opposite side if severe, lobectomy

Question 35

Pulmonary hypoplasia

Answer 35

RDS, hypoxic, hypercarbic | assoc/w oligohydramnios, PROM

Question 36

Congenital Pulmonary Venolobar syndrome (Scimitar syndrome)

Answer 36

pulm venous blood flow from all/part of R lung --> IVC just above or below diaphragm which is L to R shunt heart failure or pulm htn transcatheter occlusion of aortopulmonary collaterals

Question 37

AVM - Hereditary Hemorrhagic telangiectasia (aka Osler Weber Rendu)

Answer 37

skin, mucous membrane, organ issues epistaxis by age 20 but can come earlier PAVM uncommon in childhood but incidence increases with age and often asymptomatic R-->L shunting --> dyspnea, bleeding hemoptysis, exervise intolerance risk for CVA/TIA, brain abscess known HHT should get screening echos - positive is air bubble in systemic Tx for symptomatic - surgery or pulm angiography

Question 38

pulmonary sequestration

Answer 38

mass of abnormal, nonfunctioning lung tissue isolated from normal lung, fed by systemic arteries intralobar: lower lobe (m/c posterior basal section of LLL), usually isolated & discovered in childhood/adolescence extralobar: males, just above/below diaphragm, left side communicates with foregut other anomalies common (colon duplication, vertebral anomaly, diaphragm defects) pleuritic CP out of proportion to other findings Dx on CXR/CT. not bronchoscopy bc not connected to airway.

Question 39

Bronchogenic cyst

Answer 39

abnormal budding of tracheal diverticulum of foregut before 16wga m/c cyst in infancy single, unilocular, right sided most filled with mucous incidental on CXR vs RDS d/t compression of airway can get infected - fever, CP, productive cough rupture --> pneumothorax or hemoptysis Tx - excision

Question 40

Eventration of diaphragm

Answer 40

marked elevation, usually congenital but can be 2'2 phrenic nerve injury males, left sided

Question 41

accessory diaphragm

Answer 41

rare. most often right side. can cause lung hypoplasia | surgery if symptomatic

Question 42

Croup

Answer 42

3mo-3yo, peak 2yo boys > girls fall, early winter paraflu > RSV, flu, measles, other low pitched barking cough, inspiratory stridor, steeple sign humidifier, steamy shower, cool air dexamethasone or if moderate stridor at rest/moderate rtx/severe sxs use rac epi (need to observe bc can rebound)

Question 43

Epiglottits

Answer 43

2y-5y abrupt onset fever, sore throat, drooling, stridor, look toxic, tripod positioning abx with anti-staph (clinda, oxacillin, cefazlin) & ceftriaxone or cefotax airway w anesthesia or ENT ppx with rifampin

Question 44

Bacterial Tracheitis

Answer 44

S. aureus > paraflu, moraxella, NtHflu, anaerobes previously healthy child <3yo with recent URI toxic, high fever, brassy productive cough, rapid deterioration fall, winter Tx: nafcillin, usually need hospitalization. vanco if MRSA common in community