Symptom Finder - Double Vision
DOUBLE VISION
Most physicians know that double vision is a neurologic condition and may refer these cases immediately to a neurologist, but what about the cases of double vision with one eye closed? Surprisingly enough, this condition really does exist. Monocular diplopia results from dislocation of the lens (e.g., from injury and Marfan syndrome), the incipient stage of cataracts, corneal opacities, double pupils (from surgery or trauma), or hysteria. Fortunately for us but unfortunately for the patient, double vision is usually binocular and due to paralysis of the extraocular muscles. The causes can be recalled best by anatomically grouping them into those that involve the muscles themselves, the myoneural junction, the peripheral portion of the cranial nerve, and the nucleus of the cranial nerve in the brainstem and supranuclear causes.
1. Extraocular muscle: Using the mnemonic MINT the following differential can be developed.
M—Malformations such as myotonic dystrophy and congenital ophthalmoplegia belong here.
I—Inflammatory conditions such as dermatomyositis and orbital cellulitis are considered here.
N—Neoplasms of the orbit and exophthalmic goiter are classified here.
T—Trauma suggests orbital fractures and contusions or lacerations of the muscles.
2. Myoneural junction: This suggests the important condition of myasthenia gravis.
3. Peripheral portion of the cranial nerve: Recall of these conditions is assisted by the mnemonic VINCE.
V—Venous sinus thrombosis (cavernous sinus in this case) is suggested.
I—Inflammatory conditions remind one of syphilis and tuberculous meningitis, post diphtheritic neuritis, sphenoid sinusitis, petrositis, and increased intracranial pressure.
N—Neoplasms suggest pituitary tumors, suprasellar tumors, nasopharyngeal carcinomas, chordomas, and sphenoid ridge meningiomas.
C—Congenital lesions suggest aneurysms.
E—Endocrine disorders suggest diabetic neuropathy, a common cause of sudden extraocular muscle palsy.
4. Brainstem: Recall of these conditions is best undertaken with the mnemonic VINDICATE.
V—Vascular lesions include basilar artery thrombosis, hemorrhages, emboli, and aneurysms. Migraine may belong here, too.
I—Inflammatory lesions include syphilis, tuberculosis, and viral encephalitis.
N—Neoplasms include brainstem gliomas, metastatic carcinomas, and Hodgkin lymphoma.
D—Deficiency diseases suggest Wernicke encephalopathy.
I—Intoxication suggests botulism, bromide, and iodide poisoning.
C—Congenital conditions suggest hydrocephalus and Arnold– Chiari malformation.
A—Autoimmune disease suggests MS, postinfectious encephalitis, and lupus.
T—Traumatic conditions suggest subdural hematomas, basilar skull fractures, and pontine hematomas.
E—Endocrine reminds one of the increased incidence of basilar artery thrombosis in diabetes.
5. Supranuclear causes (including cortical): These recall a pineal tumor, the conjugate palsy of cerebral thrombosis or hemorrhage, the conjugate gaze in focal cortical epilepsy, and the dilated pupil in early herniation through the tentorium.
Approach to the Diagnosis
This is similar to that for all neurologic disorders and depends on the association of other signs. Isolated palsies of the third (oculomotor) or sixth (abducens) nerve without pupillary changes suggest diabetic neuropathy, so a glucose tolerance test would be done. A thyroid profile is useful to rule out hyperthyroidism. An isolated palsy of the third nerve with pupillary changes (mydriasis) suggests an aneurysm and angiography is indicated. X-rays of the skull and orbits, a spinal tap, and CT scans would all be useful under certain circumstances, but a neurologist is in a better position to determine this. A cavernous sinus thrombosis is possible if the patient is febrile and has more than one cranial nerve palsy along with loss of the corneal reflex, chemosis, ecchymosis, and distended retinal veins. Treatment should be started immediately.
Other Useful Tests
1. VDRL or FTA-ABS test (neurosyphilis)
2. Sedimentation rate (cerebral abscess)
3. Tensilon test (myasthenia gravis)
4. Acetylcholine receptor antibody titer (myasthenia gravis)
5. X-ray of the skull and orbits (orbital abscess or tumor, brain
tumors)
6. X-ray of the sinuses (trauma, sinusitis)
7. Visual field examination (MS)
8. Serum growth hormone, corticotropin, LH, and FSH levels
(pituitary tumor)
9. CT scan of the brain and sinuses (brain tumor, abscess)
10. MRI of the brain (space-occupying lesion, MS)
DOUBLE VISION
Most physicians know that double vision is a neurologic condition and may refer these cases immediately to a neurologist, but what about the cases of double vision with one eye closed? Surprisingly enough, this condition really does exist. Monocular diplopia results from dislocation of the lens (e.g., from injury and Marfan syndrome), the incipient stage of cataracts, corneal opacities, double pupils (from surgery or trauma), or hysteria. Fortunately for us but unfortunately for the patient, double vision is usually binocular and due to paralysis of the extraocular muscles. The causes can be recalled best by anatomically grouping them into those that involve the muscles themselves, the myoneural junction, the peripheral portion of the cranial nerve, and the nucleus of the cranial nerve in the brainstem and supranuclear causes.
1. Extraocular muscle: Using the mnemonic MINT the following differential can be developed.
M—Malformations such as myotonic dystrophy and congenital ophthalmoplegia belong here.
I—Inflammatory conditions such as dermatomyositis and orbital cellulitis are considered here.
N—Neoplasms of the orbit and exophthalmic goiter are classified here.
T—Trauma suggests orbital fractures and contusions or lacerations of the muscles.
2. Myoneural junction: This suggests the important condition of myasthenia gravis.
3. Peripheral portion of the cranial nerve: Recall of these conditions is assisted by the mnemonic VINCE.
V—Venous sinus thrombosis (cavernous sinus in this case) is suggested.
I—Inflammatory conditions remind one of syphilis and tuberculous meningitis, post diphtheritic neuritis, sphenoid sinusitis, petrositis, and increased intracranial pressure.
N—Neoplasms suggest pituitary tumors, suprasellar tumors, nasopharyngeal carcinomas, chordomas, and sphenoid ridge meningiomas.
C—Congenital lesions suggest aneurysms.
E—Endocrine disorders suggest diabetic neuropathy, a common cause of sudden extraocular muscle palsy.
4. Brainstem: Recall of these conditions is best undertaken with the mnemonic VINDICATE.
V—Vascular lesions include basilar artery thrombosis, hemorrhages, emboli, and aneurysms. Migraine may belong here, too.
I—Inflammatory lesions include syphilis, tuberculosis, and viral encephalitis.
N—Neoplasms include brainstem gliomas, metastatic carcinomas, and Hodgkin lymphoma.
D—Deficiency diseases suggest Wernicke encephalopathy.
I—Intoxication suggests botulism, bromide, and iodide poisoning.
C—Congenital conditions suggest hydrocephalus and Arnold– Chiari malformation.
A—Autoimmune disease suggests MS, postinfectious encephalitis, and lupus.
T—Traumatic conditions suggest subdural hematomas, basilar skull fractures, and pontine hematomas.
E—Endocrine reminds one of the increased incidence of basilar artery thrombosis in diabetes.
5. Supranuclear causes (including cortical): These recall a pineal tumor, the conjugate palsy of cerebral thrombosis or hemorrhage, the conjugate gaze in focal cortical epilepsy, and the dilated pupil in early herniation through the tentorium.
Approach to the Diagnosis
This is similar to that for all neurologic disorders and depends on the association of other signs. Isolated palsies of the third (oculomotor) or sixth (abducens) nerve without pupillary changes suggest diabetic neuropathy, so a glucose tolerance test would be done. A thyroid profile is useful to rule out hyperthyroidism. An isolated palsy of the third nerve with pupillary changes (mydriasis) suggests an aneurysm and angiography is indicated. X-rays of the skull and orbits, a spinal tap, and CT scans would all be useful under certain circumstances, but a neurologist is in a better position to determine this. A cavernous sinus thrombosis is possible if the patient is febrile and has more than one cranial nerve palsy along with loss of the corneal reflex, chemosis, ecchymosis, and distended retinal veins. Treatment should be started immediately.
Other Useful Tests
1. VDRL or FTA-ABS test (neurosyphilis)
2. Sedimentation rate (cerebral abscess)
3. Tensilon test (myasthenia gravis)
4. Acetylcholine receptor antibody titer (myasthenia gravis)
5. X-ray of the skull and orbits (orbital abscess or tumor, brain
tumors)
6. X-ray of the sinuses (trauma, sinusitis)
7. Visual field examination (MS)
8. Serum growth hormone, corticotropin, LH, and FSH levels
(pituitary tumor)
9. CT scan of the brain and sinuses (brain tumor, abscess)
10. MRI of the brain (space-occupying lesion, MS)
