Watershed cerebral infarction due to massive pulmonary embolism
Presentation
Diabetic ketoacidosis with a disturbing level of consciousness
Patient Data
Normal CT brain with no abnormlaity.
1 day later, the patient developed hypoxemia and right-sided weakness
CT pulmonary angiography
CT study shows massive pulmonary embolism with bilateral intravascular filling defects significantly compromising vascular lumen seen involving distal main pulmonary arteries and bilateral upper and lower lobar & segmental arteries. Evidence of right heart strain with enlarged right atrium & ventricle and interventricular septal bowing to the left. Bilateral pulmonary multiple wedge-shaped subpleural infarcts.
Newly developed left cerebral hemisphere multiple hypodense lesions seen at the parieto-occipital and fronto-parietal parafalcine region associated with effacement of related cortical sulci consistent with cerebral infarction suspected to be "watershed infarcts" along border zones between MCA/PCA and ACA/MCA respectively.
Further CT cerebral angiography was done to exclude arterial or venous occlusion.
CT angiography shows no arterial or venous stenosis or occlusion.
Case Discussion
Watershed infarcts occur at the border between cerebral vascular territories where the cerebral tissue is distant from the arterial supply and most affected by hypotension and hypoperfusion. Massive pulmonary emboli may be the leading cause of watershed infarcts due to hypotension and low cardiac output. If any new neurological symptoms in embolic patients, this possibility should be considered.