Parinaud Syndrome

What is a parinaud syndrome?

It is the supranuclear vertical gaze disturbances secondary to tectal plate compression. It is also known as parinaud dorsal midbrain syndrome.

It is a term used to denote multiple eye abnormalities, specifically dysfunctional pupil and eye movement. The term parinaud syndrome is named after Henry Parinaud, a French ophthalmologist. He is the father of French ophthalmology. ^{(1, 2)}

Image 1: A young adult with clinical manifestations of parinaud dorsal midbrain syndrome.
Picture Source: images.slideplayer.com

Photo 2: A two year old patient with a clinical manifestation of parinaud syndrome.
Image Source: upload.medbullets.com

Parinaud Syndrome Symptoms

The clinical manifestations of parinaud syndrome include the following:

• Upgaze paralysis – The patient complains of upward gaze palsy. Usually, the downward gaze is preserved. The vertical palsy is supranuclear. The upward gaze mechanism is not functioning.
• Pseudo-Argyll Robertson pupils – The pupil of the patient is mid-dilated and demonstrates a light near dissociation. The pupils respond well to near stimuli but they do not response to light.
• Collier’s sign (Eyelid retraction) – It is the abnormal elevation of the upper eyelids and lowering of the lower eyelids.
• Convergence-Retraction nystagmus – An upward gaze causes this phenomenon. If you suddenly up gaze, the eyes pull in and the globes retract.
• Setting sun sign – It is also known as a sunset eye sign. It is common in children which results from upward gaze paresis. The eyes are driven downward and the sclera is usually positioned in between the iris and upper eyelid. A portion of the lower pupil is covered by the lower lid. It is usually seen in patients with botched ventriculoperitoneal shunts.
• Other clinical manifestations include nerve palsy at third position, skew divergence, see-saw nystagmus (intorsion and elevation of one eye), diplopia (double vision), oscillopsia (illusion of an unstable visual world), and near vision becomes blurry. ^{(2, 3, 4, 5)}

Causes of parinaud syndrome

Parinaud syndrome is usually associated with pineal gland tumor and infarction in the midbrain. Other possible causes of parinaud syndrome include the following:

• Mesencephalic hemorrhage
• A/V malformation
• Obstructive hydrocephalus
• Multiple sclerosis
• Trauma ⁽⁵⁾

Parinaud syndrome is commonly mistaken for conjunctivitis because the clinical manifestations are the same. However, parinaud syndrome usually affects one eye and occurs with a swollen lymph node and fever. The source of infection is usually viral, bacterial, fungi, and parasite.

The common causes are tularemia and cat scratch disease. The bacteria causing disease can directly enter the eye or can be transmitted to the eyes via droplets. ^{(6, 7)}

Diagnosis

The doctor will conduct a thorough physical examination of the affected eye. He/she will watch for any signs of irritation and redness. The presence of swollen lymph nodes near the ears should be checked as well. The cornea will also be checked for the presence of ulcers.

A blood test is ordered to check for any signs of infection. Culture and sensitivity of the eye secretion can also help come up with the most accurate diagnosis. Various neuroimaging studies should be done to correctly and accurately diagnose the condition of the patient.

The doctor will usually order for a CT scan and MRI scan. There are also instances when an angiography is needed to as to detect arteriovenous malformation. ^{(7, 8, 9)}

Who are at risk?

People who are at risk for parinaud syndrome include the following:

• Women with multiple sclerosis, especially in their 20s to 30s.
• Geriatric patients, especially those with stroke of the upper brainstem.
• Young patients suffering from brain tumor in the midbrain and pineal gland. ⁽⁹⁾

Parinaud Syndrome Treatment

The focus of care and treatment approach depends on the clinical manifestations and underlying cause. Hence, it is important to come up with a detailed diagnosis including a CT scan and MRI scan. It is important to diagnose the disease at an early stage so that treatment will be initiated the soonest time possible.

A positive prognosis for recovery is more likely to happen if the disease is diagnose and treated at an early stage. If there is an ongoing infection, the doctor will prescribe antibiotics. If the ocular tissues are infected, then it should be removed surgically.

For eye-related symptoms such as upgaze palsy, retraction nystagmus, and convergence movement, they can be improved using bilateral inferior rectus recessions. The overall condition of the eye usually improve after a few months. The improvement is slow but steady, especially when proper treatment and care is observed. ^{(3, 4, 10)}

Conclusion

A parinaud syndrome is an umbrella term for multiple eye abnormalities. The term is named in honor of Henry Parinaud, a well-known French ophthalmologist and neurologist. He was known in these fields in the second half of the 19th century.

He was the one who gave the disease a clear view and understanding. Parinaud syndrome is characterized by the patient’s inability to perform eye movements, especially controlling gaze in the vertical direction. This manifestation is associated with dorsal midbrain damage primarily because the movements of the eyes are controlled by the superior colliculus of the tectum, which is found in the dorsal portion of the midbrain. That is why parinaud syndrome is also called dorsal midbrain syndrome. ^{(2, 7, 8)}

Parinaud syndrome can compromise other surrounding structures particularly the pretectal area, rostral interstitial nucleus of the medial longitudinal fasciculus, and posterior commissure. Of all the possible causes of parinaud syndrome, the two most common are tumor of the pineal gland and tumor of the midbrain structures.

Hence, it is of great importance to detect the disease the earliest time possible so that the patient will be able to receive proper care and treatment. It is difficult to treat the disease once it is already in its advanced stage. If you feel like something is not right in your body, you should actively take measures to treat the disease.

The best thing to do is to consult your doctor so that proper assessment, accurate diagnosis, and the best treatment will be received by the patient. ^{(1, 4, 5)}

References:

1. https://en.wikipedia.org
2. https://radiopaedia.org
3. www.eneurosurgery.com
4. webeye.ophth.uiowa.edu
5. https://syndromespedia.com
6. https://healthmaza.com
7. https://www.ncbi.nlm.nih.gov
8. www.sciencedirect.com
9. www.gpnotebook.co.uk
10. www.medigoo.com