Chapter 1 Answers to case study questions

1. 1  Myocardial infraction in a young woman

1. Quite possibly. There are numerous abnormalities in the blood tests, some of which (e.g. raised white blood cell count, neutrophils, ESR, CK, CK-MB, troponin) are very likely to be secondary to the myocardial infarction. Renal function is normal. However, the raised haemoglobin, red blood cell count and haematocrit are unlikely to be a secondary effect, and may be causative. An increased red cell mass may cause a degree of blood congestion which in turn may have precipitated the infarction, perhaps brought on by the intensity of the exercise.
2. As the red cell features point to erythrocytosis (section 4.6.1), this needs to be fully investigated. The family history of cardiovascular disease is a little worrying, and if genuine, suggest a genetic cause. There may be an abnormal haemoglobin variant, and other analyses may be to precisely determine the red cell mass, and levels of erythropoietin. In view of her youth and general good health, smoking and lung disease (leading to hypoxia) may be excluded. Molecular genetics are likely to focus initially on VHL and JAK2.