Shortness of Breath

Mr. CV is a 22 year-old graduate student who presents with chest pain, shortness of breath and hemoptosis.
  • Mr. CV says he was working in his lab when he suddenly felt a warm feeling in the right side of his chest, followed by a sharp pain.
  • He coughed and noticed blood in his sputum.
  • He felt short of breath and light headed.
  • Friends brought him to the emergency room.
  • Physical exam reveals a tachypnic, anxious man.
    ----BP = 138/88 mmHg
    ----Respirations = 36 and mildly labored.
    ----Pulse = 96/min and regular
    ----Chest clear to auscultation with no abnormal heart sounds.
  • Arterial blood gases:
  • PO2 = 82 mmHg, (ref = 80 -100)
  • PCO2 = 26 mmHg (ref = 35-45)
  • pH = 7.28 (ref = 7.36 - 7.44)
  • Upon further questioning he says he remembers some right calf tenderness over the past two days, but thought it was due to jogging.
Not much of a challenge here. This sounds like a pulmonary embolus.

Of course it sounds like a pulmonary embolus, that's what it is.
  • But the question is, why does a healthy, skinny, 22 year-old have a PE?
  • This guy's a runner for crying out loud.
  • He's certainly not immobilized.
  • No long car trips or plane rides.
  • How about the basic clotting stuff:
    ----PT = 11 seconds (ref = 11)
    ----aPTT = 29 seconds (ref =24 - 34)
  • CBC
The numbers don't look so bad. Better remind me about hypercoagulation again.

Reason for the clot
1. Too many clotting proteins
2. Abnormal clotting proteins
3. Too little thrombolysis
4. Endothelial damage
5. Other stuff

Location of the clot
1. Arterial = platelet activation or endothelial damage
2. Venous = stasis and factor activation, APS
3. Both = abnormal clotting proteins or homocysteine

Let's check for factor V Leiden first.
  • This is by far the most common protein abnormality leading to thrombosis.
    ---It occurs in approximately 5% of the Caucasian population.
    ---The DNA sequence for both wild-type and Leiden factor is known.
  • DNA probe of Mr. CV's genome reveals he has the Leiden variant of factor V.

Once activated, V Leiden cannot be degraded by protein C. It's a runaway train.

Condition ------ ---- ------------------ Incr. risk

Heterozygosity ------------------------------------7X

Heterozygosity + birth control pills --------------- 35X
Homozygosity ----------------------------------- 80X