Day #264 Sickle Cell Anemia

Today we discussed a patient with sickle cell anemia (previous blogs) who presented with acute onset chest pain, bilateral chest xray infiltrates and profound hypoxemia.

This patient had a compound heterozygote of sickle and beta-thalassemia. A review of the various compound heterozygotes is available here.

This patient may have had chest crisis. We did not see the initial xray. The definition of acute chest crisis/syndrome:

• New Chest Xray Infiltrate with chest pain
  AND


• One of: cough, fever, hypoxemia, tachypnea, sputum

A review of the ACS is available here. A more detailed review of the pulmonary complications in sickle cell anemia is available here.

We discussed red cell exchange (review here) which should be considered in ACS.

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The patient also complained of crushing retrosternal chest pain with a new left bundle branch block on the ECG. This turned out *not* to be myocardial ischemia; although this was diagnosed retrospectively. Interpreting STEMI in the context of LBBB is difficult. This article discusses the relationship of bundle branch block to MI and suggests means of diagnosis that are relatively specific but not sensitive.

A further meta-analysis is available here.

Clearly we need to do better at picking up ischemia in the context of LBBB. I suggested that a STAT echo may have been helpful in this case in picking up LV dysfunction which would be expected with an ischemic LBBB. This is in keeping with the recomendations of the American college of cardiology.