Haw River syndrome

1) Disease Description (Causes and Symptoms)

• Summary: CADASIL (Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy), an autosomal dominant small-vessel disease, is caused by abnormalities in vascular smooth muscle cells due to mutations in the NOTCH3 gene. It causes chronic ischemia and microinfarctions in the cerebellar blood vessels and white matter, resulting in migraine, cerebral infarction, cognitive impairment (vascular dementia), and other conditions in young adults.
• Cause / Inheritance pattern: Usually caused by mutations that cause changes in cysteine residues in the NOTCH3 gene, located on chromosome 19 (19p13.1) (most cases). Autosomal dominant inheritance (a 50% risk of transmission from a directly related parent to a child). Osmiophilic granular material (GOM) may be observed in the basement membrane of vascular smooth muscle cells on skin biopsy.
• Pathophysiology: Abnormalities in the NOTCH3 protein cause vascular smooth muscle cell dysfunction and the accumulation of extracellular deposits, thickening the walls of small arteries and narrowing their lumens → chronic hypoperfusion of the white matter, microinfarctions, and degeneration of the cerebral white matter.
• Main clinical symptoms and course:
  • Migraine (particularly migraine with aura; average onset in the 20s to 30s)
  • Recurrent ischemic cerebral infarctions (often beginning in the 40s; many patients show ischemic lesions)
  • Cognitive impairment/vascular dementia that progresses slowly or worsens in steps (experienced in the advanced stage by many patients)
  • Mood disorders (depression, and sometimes mania), epilepsy (seizures in approximately 10%)
  • Focal neurological deficits such as motor paralysis, speech impairment, and visual field impairment
• Epidemiology (reported): Reported worldwide in several white populations (>400 families); a relatively rare disease (epidemiological estimates are on the order of several per 100,000 people).

2) Treatment Methods and Precautions

• General principles: There is currently no definitive cure, and treatment focuses on preventive and symptomatic management and reducing complications.
• Acute cerebral infarction: Follow standard acute stroke treatment guidelines (thrombolysis, thrombectomy, etc. are determined according to the individual patient’s condition and bleeding risk). CADASIL itself is not an absolute contraindication.
• Prevention of recurrence
  • Thromboprophylaxis: Antiplatelet agents such as aspirin are commonly used, but unconditional benefit has not been proven. Anticoagulation (such as warfarin) should be decided cautiously, taking into account the balance with bleeding risk (when microbleeds are present) and other factors.
  • Blood pressure management: Hypertension increases the risk of cerebral infarction, and strict blood pressure control is recommended.
  • Modification of other cardiovascular risk factors: Smoking cessation, appropriate weight and lipid management, diabetes control, and regular exercise.
• Migraine treatment:
  • Acute: Standard migraine treatments such as NSAIDs and antiemetics. Avoid ergotamine preparations. Triptans should be discussed with the treating physician before use because patients are at high risk for cerebrovascular disease (caution).
  • Prevention: Standard migraine preventive therapies, such as beta-blockers, anticonvulsants (such as topiramate), and calcium channel blockers, may be used.
• Cognitive and psychiatric symptoms: Antidepressants (such as SSRIs), cognitive rehabilitation, and social and psychological support. Functional assistance and rehabilitation when dementia progresses.
• Epilepsy (seizures): Use standard anticonvulsants, taking into account drug interactions and adverse effects in the patient.
• Rehabilitation: Post-stroke rehabilitation (including physical therapy, speech therapy, and occupational therapy) is important.
• Genetic counseling: Family screening and genetic counseling are recommended (predictive testing is recommended only for adults; predictive testing in children should be approached cautiously).
• Clinical trials: Research on pathophysiology-targeted treatments (such as NOTCH3-targeted therapy) is ongoing, but these have not been established as standard treatments.
• Summary of precautions:
  • Avoid smoking, hypertension, hyperlipidemia, and excessive alcohol consumption
  • In women of childbearing age with migraine, combined oral contraceptives (containing estrogen) require caution and consultation because they increase the risk of stroke
  • Driving and operating heavy machinery: May be restricted according to local regulations if there is a risk of stroke or seizures

3) Checklist Before an Outpatient Visit (Including Preparation Items and Example Questions)

• Items to prepare (recommended to bring)
  • A list of medications currently being taken (including prescription drugs, OTC drugs, and herbal medicines) and recent doses
  • A summary of family history (including stroke, dementia, and migraine)
  • Previous brain imaging (MRI/CT) and test results (the original images or a CD, if possible)
  • A record of the timing, characteristics, frequency, and duration of seizures, migraines, and neurological symptoms (symptom diary)
  • Printouts of recent blood pressure, blood glucose, and cholesterol levels, if available
  • Possibility of or plans for pregnancy (for women of childbearing age)
• Information to tell the doctor in advance during the outpatient visit
  • Any focal neurological symptoms that have recently developed (such as paralysis or speech impairment)
  • A history of seizures or decreased consciousness
  • Whether a genetic disease has been diagnosed in the family (especially whether a NOTCH3 variant has been confirmed)
• Simple example questions (questions that can be presented to the doctor first)
  • "Are the white matter changes on my MRI consistent with CADASIL?"
  • "Do you recommend genetic testing? What are the cost and procedure?"

4) Examples of General Questions to Ask the Doctor

• What are the common side effects and precautions for this medication (for example, aspirin, antidepressants, or anticonvulsants)?
• What prognosis (course over time) can be expected for my symptoms (migraine/seizures/cognitive decline)?
• What specific precautions should I take in daily life (driving, work, pregnancy plans, etc.)?
• What are the criteria and procedure for recommending genetic testing for family members?

5) Examples of Disease-Specific Questions

• Are white matter lesions in the frontotemporal region and around the lateral cortex (particularly the anterior temporal region and external capsule) common findings in CADASIL on my MRI? (Request for interpretation of MRI findings)
• A diagnosis in a family member (first-degree relative) has been confirmed. Do you recommend predictive genetic testing for my children (including adult children)? If so, when would be an appropriate time?

(Note: The information above is a guide compiled based on general medical knowledge, and individual diagnosis and treatment decisions should be made through consultation with the treating medical team.)