Normal or abnormal CXR?

Source:  Normal or abnormal CXR?    Tag:  cxr normal

You are on the cardiology floor and have been asked to pick up a chest x-ray on a 22-year-old male. There is no other history available because the patient is yet to be discussed. You pick up the x-ray and look at it. It is shown below.


Q. The patient’s may have an abnormality at what letter?
a. A
b. B
c. C
d. D
e. E

Answer D
Explanation below

Q. The most likely abnormality is-
a. Small cardiac silhouette
b. Central line placed too deep in the vein
c. Presence of left superior vena cava
d. Presence of left subclavian vein

Answer C
Explanation below

Q. If this patient has a persistent left superior vena cava, what other abnormality would you suspect?
a. Varicose veins
b. Congenital heart disease
c. Azygous lobe
d. Hepatic vein occlusion

Answer B
1. Persistent left superior vena cava (LSVC) is seen in 0.3 to 0.5 % of the normal population and 3 to 10 % of patients with other congenital heart abnormalities.
2. It is a persistent remnant of a vessel that is present as an embryological counterpart of the normal right-sided superior vena cava.
3. Persistent left superior vena cava is rare but important congenital vascular anomaly. It results when the left superior cardinal vein caudal to the innominate vein fails to regress.
4. It is most commonly observed in isolation but can be associated with other cardiovascular abnormalities including atrial septal defect, bicuspid aortic valve, coarctation of aorta, coronary sinus ostial atresia, and cor triatriatum.

Q. Blood returning to the heart from the left superior vena cava usually enters the-
a. Right ventricle
b. Coronary sinus
c. Left ventricle
d. Thebesian veins

Answer B
1. Blood returning from the left upper extremity and head through the left subclavian and left internal jugular veins drain into the LSVC to the coronary sinus and thence into the right atrium.
2. The coronary sinus dilates secondary to this large volume of blood.

Q. Which vascular structure is usually absent in people who have a left superior vena cava?
a. Innominate artery
b. Innominate vein
c. Left subclavian vein
d. Right superior vena cava

Answer B
1. The left innominate vein is either absent or small.

Q. On echocardiography, presence of what anomaly will alert the cardiologist for the presence of a left superior vena cava.
a. Enlarged left atrium
b. Enlarged right atrium
c. Enlarged coronary sinus
d. Enlarged  right superior vena cava

Answer C
1. Presence of a dilated coronary sinus on echocardiography should alert the clinician towards the possibility of PLSVC.
2. The diagnosis should be confirmed by saline contrast echocardiography. Cardiologists and critical care physicians should consider presence of PLSVC whenever a catheter or guide wire inserted via left subclavian vein takes an unusual left-sided downward course.