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Ischemic brain disease, cerebrovascular thrombosis and embolism

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Ischemic Brain Disease: Cerebrovascular Thrombosis and Embolism Overview

Ischemic brain disease develops when blood flow to the brain is insufficient, usually because the arteries supplying it become narrowed (stenosis) or blocked [1, 2]. Blockages are typically caused by either thrombosis (a blood clot forming locally, often at a site of underlying vessel wall disease) or embolism (obstruction by a clot or debris that traveled from another part of the body) [1, 2]. This section delves into cerebral vessel thrombosis, exploring the diverse pathological processes that lead to its formation.

Occlusion of cerebral arteries can be caused by an embolus (often originating from the heart) or by local thrombosis resulting from atherosclerosis within the vessel wall [1, 2].

Clinically, cerebral embolism often presents with symptoms very similar to those of thrombosis [1]. Specific differentiating factors are detailed in the section covering embolism of the neck and brain arteries.

Common types of thrombotic and embolic events leading to ischemic brain disease include:

Differential Diagnosis of Symptoms Suggesting Ischemic Brain Disease [1, 3]

Condition Key Features / Distinguishing Points Typical Investigations / Findings
Ischemic Stroke / TIA (Thrombotic/Embolic) Sudden onset focal neurological deficit corresponding to vascular territory. Risk factors often present. TIA resolves completely (<24h, often <1h). CT head excludes hemorrhage. MRI (DWI) confirms ischemia early. Vascular imaging (US, CTA, MRA) identifies cause (stenosis, occlusion, embolism source).
Intracerebral Hemorrhage (ICH) Sudden onset focal deficit, often with headache, vomiting, decreased consciousness, severe hypertension. Non-contrast CT head shows hemorrhage.
Seizure with Todd's Paralysis Post-ictal focal weakness mimicking stroke. History of seizure. Transient (resolves <48h). History. EEG may show abnormalities. Imaging usually normal unless underlying lesion. Transient nature.
Migraine with Aura (esp. Hemiplegic) Transient neurological symptoms (often spreading gradually) followed by/accompanying headache. History of similar episodes. Full recovery. Clinical diagnosis. Normal exam between attacks. Imaging usually normal.
Hypoglycemia Can cause focal neurological deficits, confusion, seizures. History of diabetes relevant. Low blood glucose. Symptoms improve with glucose.
Brain Tumor Can present acutely with hemorrhage/seizure causing focal signs, but often progressive symptoms precede. MRI with contrast shows mass lesion.
Subdural Hematoma Can cause focal signs due to compression. Headache, altered mental status. History of trauma (may be minor). CT/MRI shows subdural collection.
Metabolic Encephalopathy Diffuse dysfunction (confusion, lethargy). Focal signs uncommon unless superimposed issue. Identifiable systemic cause. Specific lab abnormalities. Imaging non-specific.
Peripheral Vertigo (e.g., Labyrinthitis) Acute vertigo, nausea, vomiting. No other brainstem/cerebellar signs usually. Can mimic posterior circulation TIA/stroke. Clinical exam (HINTS). Normal brain imaging.
Syncope Brief loss of consciousness due to global hypoperfusion. Often prodrome. Rapid recovery. Can mimic TIA if brief focal symptoms occur. History. Cardiac evaluation (ECG, Holter), orthostatic vitals. Normal neurological exam post-event.
Functional Neurological Disorder Symptoms inconsistent with organic patterns. Positive clinical signs. Diagnosis of exclusion. Normal imaging/labs.

References

  1. Ropper AH, Samuels MA, Klein JP, Prasad S. Adams and Victor's Principles of Neurology. 11th ed. McGraw Hill; 2019. Chapter 34: Cerebrovascular Diseases.
  2. Grotta JC, Albers GW, Broderick JP, et al. Stroke: Pathophysiology, Diagnosis, and Management. 7th ed. Elsevier; 2021. Chapter on Mechanisms of Ischemic Stroke.
  3. Caplan LR. Stroke Mimics. Semin Neurol. 2016 Apr;36(2):203-12. (Or relevant chapter in Adams/Victor or Grotta).

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