Sun21November0437PM 14

A 61-year-old man with a history of nephrotic syndrome related to membranous nephropathy comes to the Emergency department with pleuritic chest pain. He had no significant improvement in proteinuria in response to steroids and cyclophosphamide and is now managed with high dose furosemide and ramipril.

Examination reveals a BP of 105/60 mmHg, pulse is 94 and regular. There is bilateral pitting oedema of the lower limbs. His chest is clear.

Investigations reveal:

Hb 125 g/L (130-180)

WCC 9.3 ×109/L (4-10)

PLT 192 ×109/L (130-400)

Na 137 mmol/L (135-145)

K 4.9 mmol/L (3.5-5.5)

Cr 145 µmol/L (70-120)

Albumin 20 g/L (35-50)

ECG Sinus rhythm, S1 Q3 T3 pattern

VQ scan Left sided pulmonary embolus

Which of the following is the most likely contributing factor to his pulmonary embolism?

(Please select 1 option)

Peripheral oedema

Loss of antithrombin III Correct

Increased fibrinolytic activity

Loss of beta-2-microglobulin

Underlying malignancy

Explanation

Nephrotic syndrome results in the loss of several different proteins into the urine, including free protein S and antithrombin III. There are also increased levels in plasma of beta-2-microglobulin and reduced fibrinolytic activity. The degree of hypercoagulability is proportional to the reduction of albumin. For this reason, when patients with nephrotic syndrome are admitted to hospital for an intercurrent illness, thromboprophylaxis is very important. Where an event has occurred, long term anticoagulation should be considered.

In this situation fibrinolytic activity is reduced and beta-2 microglobulin levels are increased. Whilst peripheral oedema may be associated with venous stasis, loss of clotting factors would be a greater contributor to risk of VTE.

Malignancy is responsible for only 5-10% of cases; as we are not given a history of other symptoms consistent with an underlying tumour it seems an unlikely factor here.

Answer Statistics

1

7%

2

72%

3

4%

4

11%

5

8%

Times answered: 293