Can an arachnoid cyst cause headache with nausea?

Can an Arachnoid Cyst Cause Headache with Nausea?

Yes, an arachnoid cyst can cause headache with nausea, but only when the cyst is large enough to cause mass effect, increased intracranial pressure, or has complications such as rupture or hemorrhage. 1, 2

When Arachnoid Cysts Are Symptomatic

The key determinant is cyst size and associated complications, not merely the presence of the cyst itself:

• Large cysts that compress neurovascular structures or cause increased intracranial pressure present with headache, nausea, vomiting, and may even mimic subarachnoid hemorrhage. 1
• Ruptured cysts with midline shift and subdural collections present acutely with headache, vomiting, photophobia, and phonophobia. 2
• Intracystic hemorrhage (traumatic or spontaneous) can cause sudden symptom onset with headache, nausea, and vomiting due to increased intracranial pressure from ball-valve mechanisms. 3
• Symptoms requiring urgent intervention include drowsiness, papilledema, and signs of obstructive hydrocephalus. 4

When Arachnoid Cysts Are Asymptomatic

Most arachnoid cysts remain asymptomatic throughout a patient's lifespan and are discovered incidentally on neuroimaging:

• Small cysts without mass effect are typically asymptomatic and account for 1-2% of intracranial pathologic masses on neuroimaging. 1
• In a pediatric headache clinic study, 9 of 11 patients (82%) with arachnoid cysts had only mild mass effect without midline shift, and their headache symptoms were considered unrelated to the cyst. 2
• These asymptomatic patients often have a family history of migraine, suggesting their headaches represent primary headache disorders rather than cyst-related symptoms. 2

Critical Diagnostic Approach

The clinical distinction between symptomatic and asymptomatic cysts requires specific examination findings and imaging characteristics:

Red Flags Indicating Symptomatic Cyst:

• Altered mental status or drowsiness 4
• Papilledema on fundoscopic examination 4
• Focal neurological deficits 1
• Midline shift on imaging 2
• Large subdural collections 2
• Progressive worsening of symptoms 1

Features Suggesting Unrelated Primary Headache:

• Family history of migraine 2
• Imaging showing only mild mass effect without midline shift 2
• Headache pattern consistent with migraine or other primary headache disorder 2
• Normal neurological examination 2

Management Algorithm

For symptomatic cysts with mass effect or complications:

• Urgent neurosurgical referral for surgical intervention (endoscopic fenestration or cyst wall excision with communication to subarachnoid space). 5, 4
• Surgical outcomes are generally excellent when performed for truly symptomatic cysts. 2, 4

For asymptomatic cysts discovered during headache evaluation:

• Treat the underlying primary headache disorder (migraine, tension-type headache, etc.). 2
• Serial imaging may be considered as arachnoid cysts can undergo spontaneous growth, reduction, or disappearance. 1
• No surgical intervention is indicated for incidental, asymptomatic cysts. 2

Common Pitfalls to Avoid

• Do not automatically attribute headache and nausea to an incidentally discovered arachnoid cyst without evidence of mass effect or complications—most cysts are asymptomatic. 2
• Do not miss a ruptured or hemorrhagic cyst that can present with sudden deterioration mimicking subarachnoid hemorrhage. 1, 5
• Do not delay neurosurgical consultation when imaging shows midline shift, large subdural collections, or the patient has altered mental status. 2, 4
• Consider primary headache disorders (especially migraine) in patients with family history and normal neurological examination, even when an arachnoid cyst is present. 2