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[Anemia-induced focal cerebral symptoms in carotid stenoses. Observations of pathophysiology]
1Neurochirurgische Klinik, Universitätsspital Bern.
Insights
Anemia and hemodilution can cause cerebral ischemic events by inducing embolism in patients with carotid stenosis. Lowering hematocrit may increase stroke risk through this mechanism.
Area of Science:
- Neurology
- Hematology
- Vascular Medicine
Background:
- Cerebral ischemic events can be linked to reduced hematocrit.
- Anemia and therapeutic hemodilution are common causes of decreased hematocrit.
Observation:
- Four patients presented with cerebral ischemia over 10 months.
- Causes included upper gastro-intestinal hemorrhage, chronic polyarthritis with gastritis, and therapeutic hemodilution for polycythemia.
- All patients had significant carotid stenosis.
Findings:
- Transcranial Doppler detected emboli in the middle cerebral or ophthalmic arteries in two patients.
- Reduced hematocrit, particularly from blood loss, appears to contribute to cerebral ischemia via induced embolism.
- Carotid stenosis is a critical factor in these events.
Implications:
- This suggests a mechanism where decreased hematocrit can precipitate embolic stroke in stenotic arteries.
- Understanding this link is crucial for managing patients with anemia, polycythemia, or carotid stenosis.
- Further research into hematocrit thresholds and embolic risk is warranted.
Abstract:
Four patients with cerebral ischemic events related to anemia or therapeutic hemodilution were observed within a 10-month period. Upper gastro-intestinal hemorrhage was responsible in 2 patients. The 3rd suffered from chronic polyarthritis and erosive gastritis, and in the 4th instance, the decrease of hematocrit was the result of a therapeutic hemodilution for polycythemia. A significant carotid stenosis corresponding to the symptoms was diagnosed in all patients. Passage of emboli in the middle cerebral or ophthalmic artery respectively was detected in two patients during the transcranial Doppler exam. Analysis of the effect of a decrease of hematocrit on arterial stenoses suggests that cerebral ischemic events related to blood loss are partially due to induced embolism.