Sign Up for a Free Account
  • Updated 10.08.2023
  • Released 01.12.2000
  • Expires For CME 10.08.2026

Isolated fourth nerve palsy

Introduction

Overview

Isolated fourth nerve palsy is a typically benign condition that causes vertical or oblique binocular diplopia. The most frequent etiologies for isolated fourth nerve palsy are decompensation of a congenital weakness, head or surgical trauma, extra-axial nerve ischemia, nerve inflammation, and local compression by tumor. Thyroid-related orbitopathy, skew deviation, myasthenia gravis, and sagging eye syndrome may mimic fourth nerve palsy. Spectacle prisms and strabismus surgery can be effective treatments for cases that do not resolve spontaneously.

Key points

• Isolated fourth nerve palsy is usually benign and typically does not require an extensive evaluation.
• Isolated fourth nerve palsy typically causes ipsilateral hypertropia in primary gaze that increases on contralateral gaze and ipsilateral head tilt.

• Non-isolated fourth nerve palsy should undergo neuroimaging and evaluation directed to the topographically localizing symptoms and signs.

• The most common etiologies for a fourth nerve palsy are decompensation of a congenital weakness, head or surgical trauma, extra-axial nerve ischemia, nerve inflammation, and local compression by tumor.

• Thyroid-related orbitopathy, skew deviation, myasthenia gravis, and sagging eye syndrome can mimic fourth nerve palsy.

• Spectacle prisms and strabismus surgery can be effective treatments for most unresolved cases.

Historical note and terminology

The terms “superior oblique paralysis,” “trochlear nerve palsy,” and “fourth nerve palsy” are essentially interchangeable for the purposes of this review.

This is an article preview.
Start a Free Account
to access the full version.

  • Nearly 3,000 illustrations, including video clips of neurologic disorders.

  • Every article is reviewed by our esteemed Editorial Board for accuracy and currency.

  • Full spectrum of neurology in 1,200 comprehensive articles.

  • Listen to MedLink on the go with Audio versions of each article.

Questions or Comment?

MedLink®, LLC

3525 Del Mar Heights Rd, Ste 304
San Diego, CA 92130-2122

Toll Free (U.S. + Canada): 800-452-2400

US Number: +1-619-640-4660

Support: service@medlink.com

Editor: editor@medlink.com

ISSN: 2831-9125