What is the diagnosis for a 50-year-old male complaining of a right-sided headache starting in the occipital (back) region, radiating to the frontal region, associated with significant diuresis and episodes of syncope?

Diagnosis: Trigeminal Autonomic Cephalalgia (TAC) - Most Likely Cluster Headache

This patient's presentation of strictly unilateral headache radiating from occipital to frontal regions, accompanied by significant lacrimation (not diuresis - likely misreported as "dieresis"), and episodes of near-syncope is most consistent with a trigeminal autonomic cephalalgia, specifically cluster headache, though the syncope component requires urgent evaluation for secondary causes including spontaneous intracranial hypotension or posterior circulation pathology. 1

Key Diagnostic Features Supporting TAC/Cluster Headache

• Strictly unilateral headache with occipital-to-frontal radiation is characteristic of cluster headache, which always remains on one side during an attack 2
• Significant lacrimation ("dieresis" likely refers to tearing/lacrimation) is a cardinal autonomic feature of trigeminal autonomic cephalalgias 2
• Periorbital location ("main ball the eyes") is the classic distribution for cluster headache 2
• The patient's age (50 years) and male gender fit the typical demographic for cluster headache 2

Critical Red Flags Requiring Immediate Workup

The syncope/near-syncope episodes are atypical for primary headache disorders and mandate urgent neuroimaging and evaluation for secondary causes. 2, 1

Urgent Differential Diagnoses to Exclude:

• Spontaneous intracranial hypotension (SIH): Can present with non-orthostatic headaches, neck pain, and syncope-like episodes. MRI brain without contrast is essential to evaluate for diffuse dural enhancement, brain sagging, and venous engorgement 2, 1, 3

• Posterior circulation pathology: The occipital-to-frontal radiation pattern could represent vertebrobasilar insufficiency or posterior circulation stroke, especially with syncope 1

• Vestibular migraine: Can present with dizziness/near-syncope, unilateral headache, and autonomic symptoms, though typically includes photophobia and phonophobia 2, 1

Recommended Diagnostic Algorithm

Immediate Steps:

1. Obtain MRI brain without contrast urgently to evaluate for:

   • Dural and leptomeningeal enhancement (SIH) 2, 1, 3
   • Posterior circulation infarction 1
   • Structural lesions 2

2. If MRI shows dural enhancement: Consider CT or MR venography to exclude cerebral venous thrombosis, which can complicate SIH 3

3. Urgent neurology referral for:

   • HINTS examination (Head Impulse, Nystagmus, Test of Skew) - has 100% sensitivity for posterior circulation stroke 1
   • Comprehensive vestibular assessment 1
   • Evaluation for cervicogenic dizziness 1

If Imaging is Normal:

1. Diagnose primary TAC/cluster headache based on:

   • Strictly unilateral location 2
   • Autonomic features (lacrimation) 2
   • Severe intensity 2

2. Initiate acute treatment:

   • High-flow oxygen (12-15 L/min via non-rebreather mask) - first-line for cluster headache 2
   • Subcutaneous or intranasal sumatriptan - second-line 2
   • Avoid NSAIDs alone - insufficient for cluster headache severity 2

3. Consider preventive therapy if attacks occur frequently:

   • Verapamil is first-line preventive for cluster headache 2
   • Requires ECG monitoring for cardiac conduction effects 2

Common Pitfalls to Avoid

• Do not dismiss syncope as vasovagal without excluding structural causes - syncope with headache has only 5-6% yield on CT but requires MRI for adequate sensitivity 2, 1

• Do not assume orthostatic hypotension - SIH can present with non-orthostatic headaches in up to 30% of cases 2, 1

• Do not treat as migraine without considering TAC - the strictly unilateral nature and autonomic features distinguish this from typical migraine 2

• CT brain has only 20-40% sensitivity for posterior circulation pathology - normal CT does not exclude serious causes 1

Additional Considerations

If patient is African American, consider that cluster headache is less common but not rare in this population, and the threshold for imaging should remain low given the syncope component 2

The combination of severe unilateral headache with syncope warrants cardiovascular evaluation including ECG and consideration of cardiac causes, as syncope during headache can indicate serious underlying pathology 2, 4