What are the causes and treatment options for bilateral parietal headaches?

Bilateral Parietal Headache: Causes and Treatment

For bilateral parietal headaches, migraine is the most common primary cause and should be treated with NSAIDs or triptans acutely, while tension-type headache is another frequent benign etiology; however, you must first rule out dangerous secondary causes including cerebral venous thrombosis, intracranial hypotension, and increased intracranial pressure before initiating treatment. 1, 2

Primary Causes

Migraine

• Bilateral location occurs in migraine and does not require strict unilaterality for diagnosis 1
• Migraine affecting the parietal region typically presents with moderate to severe throbbing pain, worsening with routine activity, and may include nausea, vomiting, or photophobia 1, 2
• The parietal location can be part of the typical migraine distribution pattern 1

Tension-Type Headache

• Presents with bilateral pressing or tightening (non-pulsatile) character of mild to moderate intensity 1
• Does not worsen with routine physical activity and lacks the severe associated symptoms of migraine 1
• Affects approximately 38% of the population, making it the most prevalent primary headache disorder 2

Nummular Headache

• A rare primary headache disorder characterized by chronic, persistent pain in a coin-shaped area, which can occur in the parietal region 3
• The specific round or elliptical shape of the pain site (typically 2-6 cm in diameter) is characteristic 3
• Diagnosis requires ruling out structural pathology with appropriate imaging 3

Critical Secondary Causes (Must Rule Out First)

Cerebral Venous Thrombosis (CVT)

• This is a life-threatening condition that can present with bilateral parietal headache, particularly when the superior sagittal sinus is involved 1
• The headache may be non-orthostatic initially and can progress to severe symptoms including focal neurological deficits 1
• CT venography or MR venography is essential for diagnosis when suspected 1
• Requires immediate anticoagulation even in the presence of hemorrhagic transformation 1

Spontaneous Intracranial Hypotension (SIH)

• Can present with bilateral headache affecting the parietal region, though typically orthostatic in nature 1
• MRI shows characteristic smooth, diffuse dural and leptomeningeal enhancement 1
• May paradoxically lead to CVT as a complication 1
• Treatment includes epidural blood patch and surgical repair of CSF leak 1

Increased Intracranial Pressure

• Bilateral frontal and temporal headache with parietal involvement can indicate pseudotumor cerebri or other causes of raised intracranial pressure 4
• Associated symptoms include papilledema, sixth nerve palsy, nausea, and vomiting 4
• Lumbar puncture with opening pressure measurement is diagnostic 4
• Growth hormone use is a potential iatrogenic cause that must be considered in the medication history 4

Red Flags Requiring Urgent Evaluation

You must immediately investigate for secondary causes if any of these features are present: 2, 5

• Abrupt onset or "thunderclap" presentation
• Neurological signs or symptoms (weakness, visual changes, altered consciousness)
• Age 50 years or older with new-onset headache
• Presence of cancer or immunosuppression
• Provocation by Valsalva maneuver or postural changes
• Progressive worsening pattern
• Awakening from sleep due to headache
• Papilledema on examination

Acute Treatment for Primary Headache

First-Line: NSAIDs

NSAIDs are the initial treatment for mild to moderate bilateral parietal headache presumed to be migraine or tension-type 1, 6

• Aspirin, ibuprofen, or naproxen sodium have the most consistent evidence for efficacy 1
• Acetaminophen alone is ineffective for migraine 1
• The combination of acetaminophen-aspirin-caffeine is effective 1
• Begin treatment as early as possible after headache onset to improve efficacy 1

Second-Line: Triptans

Triptans should be used when NSAIDs provide inadequate relief or for moderate to severe attacks 1, 6, 2

• Options include sumatriptan, rizatriptan, zolmitriptan, and naratriptan with good evidence for efficacy 1, 6
• Combination therapy with a triptan plus an NSAID improves efficacy over monotherapy 1
• Triptans are contraindicated in patients with uncontrolled hypertension, cardiovascular disease, or hemiplegic/basilar migraine 1
• Eliminate pain in 20-30% of patients by 2 hours but cause transient flushing, tightness, or tingling in 25% 2

For Severe Nausea/Vomiting

• Use a nonoral route of administration (intranasal or subcutaneous) and add an antiemetic such as metoclopramide 1, 6

Medications to Avoid

Do not use opioids or butalbital for acute episodic migraine treatment 1

• These medications increase the risk of medication overuse headache and dependency 1
• Opioids may be considered only if other medications cannot be used and abuse risk has been addressed 1

Preventive Treatment

Indications for Prevention

Preventive therapy should be initiated if: 7, 6

• Two or more migraine attacks per month with disability lasting 3+ days
• Using acute medications more than 2-3 days per week (to prevent medication overuse headache)
• Contraindications to or failure of acute treatments
• Patient preference for prevention over frequent acute treatment

First-Line Preventive Medications

The following have the strongest evidence for migraine prevention: 1, 7

• Propranolol 80-240 mg/day or timolol 20-30 mg/day (beta-blockers with FDA approval) 1, 7
• Topiramate 50-100 mg/day (particularly effective for chronic migraine and patients with obesity due to weight loss effect) 1, 7
• Candesartan (especially useful for patients with comorbid hypertension) 7

Second-Line Options

• Amitriptyline 30-150 mg/day (particularly effective for mixed migraine and tension-type headache, or patients with depression/sleep disturbances) 1, 7
• Divalproex sodium 500-1500 mg/day or sodium valproate 800-1500 mg/day (strictly contraindicated in women of childbearing potential due to teratogenic effects) 1, 7

Implementation Strategy

• Start with low dose and titrate slowly until clinical benefits achieved or side effects limit increases 7
• Allow an adequate trial period of 2-3 months before determining efficacy 7, 6
• Use headache diaries to track frequency, severity, and treatment response 7, 6

Critical Pitfalls to Avoid

Medication Overuse Headache

Limit acute medications to no more than 2-3 days per week to prevent medication overuse headache 1, 6

• Threshold varies: ≥15 days/month with NSAIDs; ≥10 days/month with triptans 1
• Defined as headache occurring ≥15 days/month for at least 3 months in patients with preexisting headache disorder 1
• Management requires explanation and withdrawal of overused medication (abrupt withdrawal preferred except for opioids) 1

Inadequate Diagnostic Workup

• Failing to obtain neuroimaging when red flags are present can miss life-threatening conditions like CVT 1, 2
• Not checking opening pressure during lumbar puncture when increased intracranial pressure is suspected 4
• Missing medication-induced causes (growth hormone, vitamin A derivatives) in the history 4

Treatment Errors

• Starting preventive medications at too high a dose, leading to poor tolerability and discontinuation 7
• Inadequate duration of preventive trial (less than 2-3 months) before declaring treatment failure 7, 6
• Using valproate in women of childbearing potential without addressing contraception 7
• Prescribing triptans to patients with cardiovascular risk factors or uncontrolled hypertension 1, 2