Lymphatic system

Questions on General Surgery Lymphatic System .

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Q) Thoracic duct drains into?

a) Left IJV

b) Right IJV

c) Cisterna chyli

d) Abdominal cavity

Ans a)

Lymph sacs develop at 6–7 weeks. These cisterns enlarge and develop communications that permit lymph from the lower limbs and abdomen to drain via the cisterna chyli into the thoracic duct, which  drains into the left internal jugular vein at its confluence with the left subclavian vein.

Lymph from head and right arm drains via a separate lymphatic trunk, the right lymphatic
duct, into the right internal jugular vein.

Q2) Prograde lymphatic flow does not depend on 

a) Muscle contraction and external pressure

b) Contraction and relaxation of lymphangions

c) Prevention of reflux due to valves

d) Serum oncotic pressure

Ans d 

It depends on : 

  1. Transient increases in interstitial pressure secondary to
    muscular contraction and external compression;
    2 the sequential contraction and relaxation of lymphangions;
    3 the prevention of reflux because of valves.

Transport in the thoracic and right lymph ducts also depends upon intrathoracic (respiration)
and central venous (cardiac cycle) pressures.

ref Bailey 996

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Q3) Acute lymphadenitis most commonly caused by

a) bacteroids

b) Streptococcus pyogenes

c) Atypical bacteria

d) E coli

Ans b

Acute lymphangitis is an infection, often caused by Streptococcus pyogenes or Staphylococcus aureus

Q) Lymphedema which subsides on elevation and bed rest is Brunner grade

a) Subclinical

b) I

c) II

d) iii

Ans b Grade I

Brunner Grade of Lymphedema

Subclinical - Not clinical apparent 

Grade 1- Oedema pits on pressure and swelling largely or completely disappears on elevation and bed

Grade 2 Oedema does not pit and does not significantly reduce upon elevation, positive Stemmer’s sign

grade 3 - Oedema is associated with irreversible skin changes, i.e. fibrosis, papillae

ref Bailey page 998

Q) Not seen in lipoedema as compared to lymphedema

a) More common in women

b) Does not pit

c) feet are involved

d) No response to compression

Ans c 

Features of lipoedema that help differentiate it from
● Occurs almost exclusively in women
● Onset nearly always coincides with puberty
● Nearly always bilateral and symmetrical
● Involvement of trunk
● The feet are not involved, leading to an inverse shouldering
effect at the malleoli
● No pitting
● No response to elevation or compression
● No skin changes of lymphoedema (negative Stemmer’s sign)
● MRI shows subcutaneous fat but no fluid accumulation