What is Orbital Pseudotumor?
An orbital pseudotumor is an inflammation of the soft tissues and muscles inside of the orbit, the cavity in the skull that holds the eye. It is characterized by the sudden onset of a red, swollen and painful eye. Other symptoms include eyelid swelling, restricted movement of the eyes, double vision and decreased vision. Orbital pseudotumor radiology is helpful in making the diagnosis, along with a clinical exam.
- Orbital pseudotumor is inflammation of the tissues surrounding the eye, which can appear to look like a “tumor,” but is not cancerous.
- Symptoms of orbital pseudotumor may include acute onset eye pain, double vision, swelling, redness, or blurry vision.
- Orbital pseudotumor is diagnosed with an MRI, CT scan, or biopsy, and it is treated with oral corticosteroids.
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Understanding Orbital Pseudotumor
Orbital pseudotumor is inflammation of the eye’s orbit that causes the development of a benign, space-occupying lesion. The inflammation targets the lacrimal gland, extraocular muscles, and orbital fat. Orbital pseudotumor usually affects one eye, but may also affect both eyes.
Orbital pseudotumor is also known as idiopathic orbital inflammatory syndrome. ‘Idiopathic’ implies that there is no identifiable cause of the inflammation of the orbit. It is important to rule out other causes of inflammation before determining that the inflammation is ‘idiopathic’ or has no cause. Sometimes systemic conditions such as sarcoidosis, thyroid disease, or rheumatoid arthritis cause inflammation of the orbital tissues. Bloodwork or radiology tests may be ordered by the eye doctor to determine the root cause of the inflammation, and decide whether the condition is actually orbital pseudotumor.
Orbital pseudotumor vs. pseudotumor cerebri are two different entities and should not be confused. Orbital pseudotumor is due to inflammation of the orbit and extraocular eye muscles. Pseudotumor cerebri is likely due to elevation of intracranial pressure, and typically manifests with swelling of the optic nerve.
In orbital pseudotumor, an inflammatory mass (“tumor” but not cancerous) can cause the eye to protrude and become immobile, causing pain.
The symptoms of orbital pseudotumor may include:
- Swelling around the eye and eyelids (most common, 75%)
- Severe pain in one eye (60%)
- Anterior displacement of the eye, known as proptosis (40%)
- Double vision (35%)
- Restricted eye movement (54%)
- Red eye (48%)
- Swelling of the conjunctiva, the white part of the eye (29%)
- Decreased vision (20%)
This condition typically affects adults between 30 to 60 years of age, and usually women more than men. Children with orbital pseudotumor are more likely to have concurrent systemic symptoms such as fever, headache, and vomiting. Children are also more likely to have both eyes affected.
Adults with orbital pseudotumors frequently have sudden onset of pain, proptosis, and swelling in the area around the eye and orbit. The eye doctor or neurologist will order an Orbital CT scan or MRI imaging to examine structural changes. Orbital pseudotumor radiology via MRI is important to rule out serious concerns for vision loss such as a cancerous space-occupying tumor. Common findings on CT scans in patients with orbital pseudotumor include enlargement of the lacrimal gland, enlargement of the extraocular muscles, and inflammation surrounding the optic nerve.
Because of the need to rule out other conditions that can cause orbital inflammation, the doctor will frequently order blood work. The blood work may include complete blood count (CBC), thyroid function (T3, T4), rheumatoid factor, and angiotensin-converting enzyme (ACE). Rarely, a biopsy may be done to confirm the diagnosis of orbital pseudotumor. However, in many patients, a biopsy is not required.
The preferred treatment for orbital pseudotumor is systemic oral corticosteroids. High-dose steroid therapy will cause the orbital pseudotumor to respond quickly. Unfortunately, the inflammation frequently returns when the steroids are stopped. To prevent the disease from returning, doctors gradually reduce the steroid dosage.
In some circumstances, low-dose radiation therapy or NSAIDs (nonsteroidal anti-inflammatory drugs) may also be considered to reduce the inflammation. With steroid medication, most patients recover well, although they are always at risk for recurrent orbital pseudotumor.