What is the diagnosis for a 70-year-old patient with a recent history of influenza (flu) and coughing fits, presenting with symptoms of diplopia (double vision) and partial blindness?

Differential Diagnosis: Valsalva-Induced Transient Ischemic Attack vs. Giant Cell Arteritis

This patient most likely experienced a transient ischemic attack (TIA) triggered by increased intracranial pressure from coughing fits (Valsalva maneuver), though giant cell arteritis must be urgently excluded given the age and context. 1

Primary Diagnostic Consideration: Cough-Induced TIA

The combination of diplopia and partial vision loss (likely transient monocular blindness or hemianopia) occurring during or immediately after severe coughing fits in a 70-year-old strongly suggests a hemodynamic TIA. 2, 3

Key supporting features:

• Coughing-induced TIA is a recognized hemodynamic phenomenon where Valsalva maneuvers during severe coughing increase intracranial pressure and reduce cerebral perfusion, particularly in patients with compromised cerebrovascular circulation 2
• The temporal relationship between coughing fits and visual symptoms is highly characteristic 2
• Diplopia combined with partial blindness suggests posterior circulation involvement (vertebrobasilar territory) or multiple vascular territories affected simultaneously 1, 3
• Transient visual symptoms occur in 34.5% of TIA patients, with diplopia representing 13.4% and various forms of visual field loss being common 3

Critical Alternative: Giant Cell Arteritis (GCA)

Giant cell arteritis is a medical emergency that must be immediately ruled out in any patient over 70 with new-onset visual symptoms, particularly if accompanied by recent systemic illness. 1

Red flags mandating urgent GCA evaluation:

• Age over 70 years 1
• New-onset diplopia and visual loss (GCA can cause both through ophthalmic artery involvement and cranial nerve palsies) 1
• Recent flu-like illness could mask constitutional symptoms of GCA (fever, malaise) 1
• Permanent visual loss occurs in GCA if not promptly treated 1

Immediate assessment required:

• Presence of scalp tenderness, temporal artery abnormalities (thickening, nodularity, reduced pulse) 1
• Jaw claudication (pain with chewing) 1
• Headache (new or different pattern) 1
• ESR and CRP levels (typically markedly elevated in GCA) 1

Specific Vascular Territories and Mechanisms

The symptom pattern suggests:

• Diplopia indicates cranial nerve involvement (most commonly sixth nerve palsy in vasculopathic disease) or brainstem ischemia 1
• Partial blindness could represent:
  • Transient monocular blindness (38% of transient visual symptoms in TIA) 3, 4
  • Homonymous hemianopia (12.3% of transient visual symptoms) 3
  • Bilateral visual loss (4.5% of cases) 3

In elderly patients with vasculopathic risk factors, sixth nerve palsy is most commonly due to microvascular ischemia (diabetes, hypertension), though the acute onset during coughing suggests hemodynamic compromise rather than pure microvascular disease 1

Urgent Diagnostic Workup Required

Immediate evaluation must include:

• Complete ophthalmologic examination with fundoscopy to assess for papilledema, optic atrophy, or signs of arteritic anterior ischemic optic neuropathy 1
• ESR and CRP to screen for GCA (cannot wait for temporal artery biopsy if GCA suspected) 1
• Vascular imaging (CT angiography or MR angiography) to assess for carotid stenosis, vertebrobasilar insufficiency, or incomplete circle of Willis 2
• Brain MRI with diffusion-weighted imaging to detect acute ischemia (positive in 5-12% of patients with transient visual symptoms) 3
• Assessment for atrial fibrillation (particularly if homonymous hemianopia present, as atrial fibrillation occurs in 23.2% of these cases) 3

Management Algorithm

If GCA cannot be immediately excluded:

• Start high-dose corticosteroids immediately (do not wait for biopsy confirmation if clinical suspicion is high, as delay risks permanent blindness) 1
• Arrange urgent temporal artery biopsy and/or vascular ultrasound 1

If TIA is confirmed and GCA excluded:

• Urgent neurology referral for comprehensive stroke risk assessment 1
• Antiplatelet therapy initiation 3
• Aggressive vascular risk factor management 1
• Consider revascularization if significant carotid or vertebrobasilar stenosis identified 2

Critical Pitfalls to Avoid

• Do not dismiss symptoms as "just flu-related" – the temporal association with coughing suggests true vascular compromise 2
• Do not delay GCA evaluation – permanent visual loss occurs rapidly if untreated 1
• Do not assume symptoms are benign if they resolved – approximately 40% of patients with sixth nerve palsy who don't recover by 6 months have serious underlying pathology 1
• Do not attribute diplopia solely to viral illness – while post-viral cranial nerve palsies occur, they are more common in children and require exclusion of more serious causes in elderly patients 1