Pupillary abnormalities and anisocoria: an overview

Horner syndrome is an oculosympathetic palsy causing the ipsilateral triad of miosis, partial ptosis, and anhidrosis from a lesion anywhere along the three-neuron sympathetic pathway to the eye and face. Diagnosis is clinical, confirmed with apraclonidine or cocaine eye drops; management targets the underlying cause, which ranges from benign to an emergent carotid dissection or Pancoast tumor.

Third nerve palsy is dysfunction of the oculomotor nerve producing ptosis, a down-and-out eye, and often a dilated pupil; a non-pupil-sparing or painful presentation is a posterior communicating artery aneurysm until emergent CT or MR angiography and neurosurgical evaluation prove otherwise, while pupil-sparing cases are managed with vascular risk-factor control.

Syphilis is a sexually transmitted infection with the spirochete Treponema pallidum that progresses through painless chancre (primary), disseminated rash and condyloma lata (secondary), latent, and tertiary stages including neurosyphilis, diagnosed by paired nontreponemal and treponemal serology and treated with a single dose of intramuscular benzathine penicillin G for early disease.

Lung cancer is the leading cause of cancer death worldwide, split into non-small cell lung cancer (NSCLC, 80% of cases: adenocarcinoma, squamous cell, large cell) and small cell lung cancer (SCLC, 10-15%), both driven overwhelmingly by cigarette smoking. Diagnosis requires tissue histopathology, staging drives treatment (TNM staging for NSCLC, limited versus extensive stage for SCLC), and management ranges from lobectomy in early-stage disease through concurrent chemoradiation and consolidation immunotherapy in locally advanced disease to targeted tyrosine kinase inhibitors, immune checkpoint inhibitors, or platinum-based chemotherapy in metastatic disease.

Septic thrombosis of the cavernous sinus from spreading facial, sinus, or orbital infection, marked by fever, proptosis, chemosis, and cranial nerve palsies that classically become bilateral. It is a neuro-ophthalmic emergency treated with immediate broad-spectrum IV antibiotics, source control, and consideration of anticoagulation.

Subarachnoid hemorrhage is sudden bleeding into the subarachnoid space, most often from a ruptured saccular (berry) aneurysm, presenting as the worst headache of a patient's life. Diagnosis is noncontrast head CT, then lumbar puncture if CT is negative, then catheter angiography to define the aneurysm; management is early aneurysm securement, blood pressure control, and nimodipine to reduce delayed cerebral ischemia from vasospasm.

Ischemic stroke is sudden focal neurologic deficit from arterial occlusion confirmed by infarction on neuroimaging. Diagnosis relies on urgent noncontrast head CT to exclude hemorrhage; treatment is IV alteplase within 4.5 hours and mechanical thrombectomy for large-vessel occlusion within an extended window, followed by antiplatelet therapy and risk-factor control.

Myasthenia gravis is an autoimmune disorder of the postsynaptic neuromuscular junction, most often caused by acetylcholine receptor antibodies, producing fluctuating, fatigable weakness of ocular, bulbar, and limb muscles. Diagnosis rests on antibody testing and electrodiagnostics; first-line treatment is pyridostigmine, with glucocorticoids and steroid-sparing immunosuppression for generalized disease and thymectomy for eligible patients.

Acute angle-closure glaucoma is a pupillary-block emergency in which sudden closure of the iridocorneal angle blocks aqueous outflow, causing severe eye pain, halos, and rapidly rising intraocular pressure that can blind the eye within hours if not treated. Diagnosis is clinical plus tonometry and gonioscopy; treatment is immediate topical and systemic IOP-lowering therapy followed by laser peripheral iridotomy.

Cluster headache is a trigeminal autonomic cephalalgia causing severe unilateral orbital or temporal pain lasting 15 to 180 minutes, up to eight times daily, with ipsilateral autonomic features. First-line acute treatment is 100% oxygen inhalation or subcutaneous sumatriptan; verapamil is first-line prevention.