Cryptogenic Stroke

  • The stroke may be considered to be crypto- genic after standard evaluation when clinical examination and brain imaging suggest a super- ficial or large, deep cerebral infarct, but none of the above routine vessel-imaging, cardiac, or hematologic tests has revealed a probable cause. 
  • Patients with a small, deep infarct also may be considered to have cryptogenic stroke if they are younger than 50 years of age, have no standard vascular risk factors, and have no white-matter hyperintensities or prior small, deep infarcts. 
Epidemiology and Main features of Cryptogenic Stroke 
  • 10-40 % of strokes are cytoptogenic stroke; 120,000 to 180,000 patients each year in the United States. 
  • More than 200 etiology of strokes have been defined
  • Age of patients influences the likelihood of various causes 
    • 18-30
    • 31-60
    • >60
  • Better prognosis
  • Diffusion sequences of MRI is more sensitive to small lesions and lesions in the brain stem and cerebellum 
  • Imaging features that suggests etiology of stroke
    • infarcts in multiple territories suggest emboli from a proximal aortocardiac source;
    • infarcts of different ages in a single territory suggest emboli of arterial origin; 
    • infarcts along the borders between brain artery territories suggest systemic hypotension or multiple emboli; and 
    • a small deep infarct along with white-matter hyperintensities suggests intrinsic small-vessel disease 
  • USG neck and Transcranial USG are usually done only if MRA neck or CTA neck are contraindicated 
  • TEE identifies potentially salient abnormalities in approximately 50 to 75% of young patients with otherwise cryptogenic stroke, including patent foramen ovale, atrial septal aneurysm, endocarditis, aortic atherosclerosis, regional myocardial-wall dysfunction, dilated left atrium, and atrial appendage thrombi 
  • As compared with the TOAST criteria, both the ASCOD and CCS systems identify fewer patients as having had cryptogenic stroke 

Diagnosis and Work up for Cryptogenic Stroke

Advanced Evaluation for Cryptogenic Stroke