From the Guidelines
The most appropriate next step in diagnosis for this patient is neuroimaging, including MRI with gadolinium and magnetic resonance angiography (MRA) or computed tomography angiography (CTA), as recommended by the adult strabismus preferred practice pattern 1. This patient presents with symptoms consistent with third nerve palsy, characterized by ptosis and pupillary involvement on the left side. Given her age, hypertension, and smoking history, these findings raise concern for a compressive lesion, such as an aneurysm or tumor, which must be ruled out urgently. The patient's symptoms, including blurred vision and fatigue, also suggest a possible underlying condition that requires prompt evaluation.
Key Considerations
- The patient's ptosis and pupillary involvement are consistent with third nerve palsy, which can be caused by a compressive lesion or microvascular disease 1.
- The patient's smoking history and age increase the suspicion for a compressive lesion, such as an aneurysm or tumor 1.
- Neuroimaging, including MRI with gadolinium and MRA or CTA, is recommended to evaluate for a possible compressive lesion 1.
- If the neuroimaging is normal, serologic testing for infectious diseases and consideration of lumbar puncture may be necessary 1.
Rationale for Recommendation
The recommendation for neuroimaging is based on the most recent and highest quality study, which emphasizes the importance of urgent evaluation for compressive lesions in patients with third nerve palsy 1. The patient's symptoms and risk factors, including smoking history and age, increase the suspicion for a compressive lesion, making neuroimaging the most appropriate next step in diagnosis.
From the Research
Diagnostic Approach
The patient's symptoms of drooping of the left eyelid, blurred vision, and fatigue, along with a history of hypertension and smoking, suggest a possible vascular or neurological condition. The physical examination findings of slight ptosis of the left eyelid and unequal pupil sizes are also indicative of a potential issue with the nerves or blood vessels supplying the eye.
Possible Causes
- The patient's symptoms could be related to a thoracic aortic aneurysm, which is a relatively uncommon disease with an incidence of 10.4/100 000, as reported in a study published in 2019 2.
- Another possible cause is a Pancoast tumor, which is a type of lung tumor that can invade the structures of the apex of the chest, including the nerves and blood vessels, as described in a study published in 2016 3.
Diagnostic Tests
- Carotid duplex ultrasonography (option B) may not be directly relevant to the patient's symptoms, as it is typically used to evaluate the carotid arteries in the neck.
- Cerebral arteriography (option C) is an invasive test that may not be necessary at this stage, as it is typically used to evaluate the blood vessels in the brain.
- Visual evoked potential (option E) is a test that evaluates the function of the visual pathway, but it may not be directly relevant to the patient's symptoms.
- Acetylcholine receptor antibody titer (option A) is a test that is typically used to diagnose myasthenia gravis, which is an autoimmune disorder that can cause muscle weakness and fatigue.
- Chest x-ray (option D) is a non-invasive test that can be used to evaluate the lungs and chest cavity, and may be useful in diagnosing a Pancoast tumor or other conditions that may be causing the patient's symptoms.
Next Steps
Based on the patient's symptoms and physical examination findings, a chest x-ray (option D) may be a reasonable next step in the diagnostic workup, as it can help to evaluate the lungs and chest cavity for any potential abnormalities, such as a Pancoast tumor or thoracic aortic aneurysm, as suggested by studies published in 2019 2 and 2016 3.