NBME CBSE ACTUAL TEST (usmle step 1)|QUESTIONS AND
CORRECT VERIFIED ANSWERS (LATEST 2026 UPDATE)
|ALREADY GRADED A+
CO2 transport to lungs - Answer -*carbonic anhydrase*
Cl shift
*Haldane*: CO2 released to lung
(*Bohr*: O2 release to tissue)
CO poisoning causes - Answer -carboxyhemoglobin
no affect on PaO2
Cyanide poisoning causes - Answer -lactic acidosis
How to treat cyanide poisoning - Answer -*Amyl nitrite* -->
Methemoglobin
THEN *Thiosulfate* (hydroxycobalamin)
Normal A-a gradient - Answer -5-15
Hypoventilation: Heroin OD or high altitude
Increased A-a gradient - Answer –
*Diffusion impairment* (fibrosis)
*R-L shunt* (aspiration, ARDS)
*V/Q mismatch* (pulmonary edema
AT --> AT II
where and how - Answer –
pg. 1
,ACE
(- high in sarcoidosis)
In small pulmonary bV
C5a induces what - Answer -PMN influx (ie: in lungs)
Korotkoff sound - Answer -BP cuff - appear and disappear
in inflation/deflation
Pulsus Paradoxus - Answer -10mmHg difference in
Korotkoff sound
Pulsus Paradoxus occurs in - Answer -Cardiac Tamponade
Kussmaul sign - Answer -JVP rises *during inspiration*
Constrictive Pericardiditis
Restrictive/Interstitial Lung Disease:
A-a, FVC, FEV1, EFR - Answer –
Airway widening due to *radial traction* from fibrosis
*increase Aa*
decreased FVC & FEV1
*Increased EFR*
Sarcoidosis - Answer –
pg. 2
,*Th1 *noncaseating granulmona
bilateral hilar adenopathy
increased *ACE*
increased IL2, IFNg
1-a-hydroxylase in macrophages: vit D --> *HyperCa*
Hyper Ca causes - Answer -stones, thrones, groans, psych overtones
1-a-hydroxylase in macrophages - Answer –
PTH independent conversion of
Calcifediol to *calcitriol* (bioactive Vit D)
Vit D --> Hyper Ca
Idiopathic pulmonary fibrosis - Answer –
*Honeycomb* pattern
loss of Type 1 pneumocytes
*hyperplasia Type II* pneumocytes
Goodpasture - Answer –
HS II
Auto-Ab against BM destroys lung alveoli (*restrictive*) and renal
glomeruli
Obstructive Lung Disease - Answer –
DECREASED FEV1, Decreased FVC
pg. 3
, increased RV, FRC, TLC
**different shape
COPD - Answer -PMN, mo, CD8
*V/Q mismatch:* O2 induced hypercapnia;
physio dead space
Myeloperoxidase causes - Answer -Green sputum/pus
Do not give O2 supplement to - Answer –
COPD patient
Decreased stimulation of
*carotid bodies* = decreased RR
TX COPD with - Answer –
*Fluticasone* (glucocorticoid)
inhibit cellular reaction
a1-antitrypsin deficiency - Answer –
Serine protease inhibitor
*LIVER*
*LUNG*: inc PMN elastase --> emphysema
Asthma dx - Answer –
*Methacholine* (maCh) challenge
pg. 4
CORRECT VERIFIED ANSWERS (LATEST 2026 UPDATE)
|ALREADY GRADED A+
CO2 transport to lungs - Answer -*carbonic anhydrase*
Cl shift
*Haldane*: CO2 released to lung
(*Bohr*: O2 release to tissue)
CO poisoning causes - Answer -carboxyhemoglobin
no affect on PaO2
Cyanide poisoning causes - Answer -lactic acidosis
How to treat cyanide poisoning - Answer -*Amyl nitrite* -->
Methemoglobin
THEN *Thiosulfate* (hydroxycobalamin)
Normal A-a gradient - Answer -5-15
Hypoventilation: Heroin OD or high altitude
Increased A-a gradient - Answer –
*Diffusion impairment* (fibrosis)
*R-L shunt* (aspiration, ARDS)
*V/Q mismatch* (pulmonary edema
AT --> AT II
where and how - Answer –
pg. 1
,ACE
(- high in sarcoidosis)
In small pulmonary bV
C5a induces what - Answer -PMN influx (ie: in lungs)
Korotkoff sound - Answer -BP cuff - appear and disappear
in inflation/deflation
Pulsus Paradoxus - Answer -10mmHg difference in
Korotkoff sound
Pulsus Paradoxus occurs in - Answer -Cardiac Tamponade
Kussmaul sign - Answer -JVP rises *during inspiration*
Constrictive Pericardiditis
Restrictive/Interstitial Lung Disease:
A-a, FVC, FEV1, EFR - Answer –
Airway widening due to *radial traction* from fibrosis
*increase Aa*
decreased FVC & FEV1
*Increased EFR*
Sarcoidosis - Answer –
pg. 2
,*Th1 *noncaseating granulmona
bilateral hilar adenopathy
increased *ACE*
increased IL2, IFNg
1-a-hydroxylase in macrophages: vit D --> *HyperCa*
Hyper Ca causes - Answer -stones, thrones, groans, psych overtones
1-a-hydroxylase in macrophages - Answer –
PTH independent conversion of
Calcifediol to *calcitriol* (bioactive Vit D)
Vit D --> Hyper Ca
Idiopathic pulmonary fibrosis - Answer –
*Honeycomb* pattern
loss of Type 1 pneumocytes
*hyperplasia Type II* pneumocytes
Goodpasture - Answer –
HS II
Auto-Ab against BM destroys lung alveoli (*restrictive*) and renal
glomeruli
Obstructive Lung Disease - Answer –
DECREASED FEV1, Decreased FVC
pg. 3
, increased RV, FRC, TLC
**different shape
COPD - Answer -PMN, mo, CD8
*V/Q mismatch:* O2 induced hypercapnia;
physio dead space
Myeloperoxidase causes - Answer -Green sputum/pus
Do not give O2 supplement to - Answer –
COPD patient
Decreased stimulation of
*carotid bodies* = decreased RR
TX COPD with - Answer –
*Fluticasone* (glucocorticoid)
inhibit cellular reaction
a1-antitrypsin deficiency - Answer –
Serine protease inhibitor
*LIVER*
*LUNG*: inc PMN elastase --> emphysema
Asthma dx - Answer –
*Methacholine* (maCh) challenge
pg. 4
