Y5 - Superior vena cava obstruction Flashcards
what is superior vena cava obstruction also known as
superior vena cava syndrome
most common cause
malignancy
why has there been an increase in benign causes
due to intravascular devices
def
obstruction of SVC which causes interrupted venous return from the head, thorax, and upper extremities to the right atrium
what does increased venous pressure cause
oedema in the head, neck, arms, and cynosis
aetiology
majority of cases are due to malignancy
what is the most common malignancy causing SVC obstrucion
1 lung cancer
- non-small cell lung cancer (50%)
- small cell lung cancer (25%)
is SVC obstruction more common on the right or left
right (80%)
what are other malignancies causing SVC obstruction
1 lung cancer
2 lymphoma
3 thymoma
what metastatic tumours cause SVC obstruction
1 breast cance
2 colon cancer
3 kaposis sarcoma
what are benign causes of SVC obstruction
iatrogenic causes
-central venous catheters
-pacemakers
mediastinal fibrosis by radiotherapy or infections
what is the most common cause of SVC obstruction
non-hodgkins lyphoma
what happens to the cervical venous pressure in SVC obstruction
is increased to 20-40mmHg from normal range of 2-8mmHg
what is the most important collateral venous return pathway with an obstructed SVC
the azygous venous system
epi
increase in benign causes of SVC obstruction due to intravascular devices however malignant causes are most common
elderly males
RFs
Hx of smoking
intravascular device
>50yrs
signs and symptoms
oedema in face and upper extremities dyspnoea -worsens by bending forward or lying down facial plethora distended neck and chest veins
investigations
CXR
-widened mediastinum or mass lesion
CT chest
what is the most useful imaging test
CT chest with IV contrast
what may be seen on a CT chest with SVC obstruction
full or partial obstruction
collateral vessels
what may be found on ultrasound of upper extremities
dilated SVC; monophasic flow
what is the initial investigation
CXR
what is the management for acute airway obstruction in SVC obstruction
1 secure airway by intubation/surgery
2 radiotherapy and corticosteroids if life threatening
what corticosteroids may be used in life threatening SVC obstruction
dexamethasone 10mg IV bolus plus 4mg per 6hrs
