What is the focus of the clinical history to evaluate trochlear nerve palsy (fourth nerve palsy)?

Updated: Oct 08, 2019
  • Author: Zafar A Sheik, MD, MD; Chief Editor: Andrew G Lee, MD  more...
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Answer

Obtain a detailed history concerning characteristics of the diplopia: onset, duration, vertical or horizontal, monocular or binocular, and positions that improve or worsen the diplopia. This can help differentiate a new onset of fourth nerve palsy from a congenital condition that has decompensated. Patients with trochlear nerve palsy typically have worse diplopia on downgaze and gaze opposite the affected eye. If the onset is due to trauma, determine the mechanism of injury. Blunt trauma to the head, especially directly at the orbit, is a common cause of acquired trochlear nerve palsy.

A detailed medical history and review of systems can aid in detecting the root cause of the palsy. Determine risk factors for stroke, including any history of hypertension, dyslipidemia, diabetes mellitus, smoking, and past cardiovascular incidents. Surgical history should be assessed for past intracranial or orbital surgeries. Constitutive symptoms such as fever, malaise, and neck stiffness suggest meningitis. Neurologic findings can indicate a compressive lesion of the trochlear nucleus, fascicle, or nerve. Diagnosis of other diseases such as HIV infection and demyelinating diseases is pertinent as they have also been associated with fourth nerve palsy. In older patients, giant cell arteritis should also be ruled out. [19, 20]


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