Trochleitis is an inflammation of the trochlea and peritrochlear region. This disease may be isolated (occur alone or with migraine) or develop in association with an inflammatory or immunologic condition. Diagnosis is based on clinical findings and confirmed with radiologic images. A typical pain in the superior and inner angle of the orbital region is pathognomonic. Treatment may involve oral or locally injected corticosteroids.
Trochleitis is an inflammation of the trochlea and peritrochlear region, particularly the sheath of superior oblique muscle.
Most of the trochleitis are idiopathic. However, it can be associated with paranasal sinus inflammation, trauma, tumor, but rarely to rheumatologic (Rheumatoid Arthritis, Systemic Lupus Erythematosus, Entheropathic Arthropathy) or immune diseases (sarcoidosis, psoriasis).
The trochlea is a saddle-like cartilaginous structure in the superior and medial region of the orbita, which contains the tendon of the superior oblique muscle. Histologically, the trochlea is envolved by a synovial membrane and innervated by an ophthalmic nerve branch. In trochleitis, the main problem is a stenosing tenosynovitis at the level of the superior oblique tendon sheath. The chronic microtrauma related to continuous friction of the tendon through a narrowed cartilaginous ring (trochlea) may lead to self-induced local inflammation. The movement becomes restricted, and it can cause further trauma of the tissue, thus perpetuating the cycle.
It is necessary to take a precise patient's history to rule out immunologic or inflammatory diseases, including rheumatoid arthritis, juvenile idiopathic arthritis and systemic lupus erythematosus.
A complete neurologic and ophthalmologic examination is necessary, with special attention to the supraorbital notch and the course of the supraorbital nerve. Palpation of affected trochlear region demonstrates a painful, swollen and endured trochlea. If the patient looks down and up, these movements increase the pain due to a functional pseudorestriction induced in a pathologic trochlea. Examination of supratrochlear, supraorbital, and infraorbital nerves has to be done by testing the presence of tenderness by palpation on the emergence and trajectory of the nerves. Anesthetic block of these nerves may be necessary to rule out a periorbital neuralgias.
Patients complain of pain in the superior and inner angle of the orbital region, spreading to the ipsilateral forehead. Pain is exacerbated with vertical movements, especially in supraduction or with palpation of the trochlear region on the symptomatic side. This trochlear pain is called trochleodynia. Near work asthenopia (convergence insufficiency) and diplopia are also described in some patients.
- Inflammation of the superior oblique tendon/trochlear pulley in the superonasal aspect of anterior orbit
- Orbital pain and tenderness to palpation in that region
- Often pain with vertical eye rotations (especially in adduction)
Radiologic images are important for the confirmation of the diagnosis.
Non-invasive investigations, such as orbital ultrasonography and CT scanning or MRI are required for precise diagnosis. Standardized A-scan ultrasound shows the swelling of the peri-trochlear tissue and thickening of the superior oblique muscle with low internal acoustic reflectivity of the trochlea. In atypical cases, biopsy of the trochlear region may be necessary to confirm the etiology of any inflammatory/structural lesion.
Routine blood tests, with search for biologic markers of inflammatory (erythrocyte sedimentation rate, Reactive C Protein) and immunologic (rheumatoid factor, antinuclear antibodies, thyroid hormones, and antithyroid and antimicrosomal antibodies) disorders are mandatory.
- Primary trochlear headache, as another cause of trochleodynia, is a specific headache that originates in the trochlear region with no signs of local or systemic inflammation. The pain is not controlled until local treatment on the sore trochlea is performed
- Orbital headaches with oculomotor cranial palsies (painful ophthalmoplegias)
- Orbital headaches with clinical ocular signs or symptoms like cavernous sinus thrombosis, carotid cavernous fistula and pseudotumour
- Horner syndrome
- Other disorders affecting the anterior cranial fossa
- Thyroid ophthalmopathy with superior oblique involvement
- Orbital myositis
- Metastatic or inflammatory trochlear infiltration (sarcoidosis)
- Other clinical causes of supraduction limitation, like elevation monocular palsy, or Brown syndrome. Brown syndrome is an ocular motility disorder with fibrosis and shortening of the superior oblique tendon. It is associated with a restriction of active and passive elevation in adduction. In the entity trochleitis there is an inflammation that can be accompanied by restriction in this movement or not, while in Brown syndrome there is always a restriction in the movement and diplopia. Most cases of Brown Syndrome are congenital and there is no pain associated. Only the acquired Brown’s Syndrome of inflammatory nature may cause pain and tenderness in the superior nasal orbita, but this pain is usually less intense than in isolated trochleitis.
- Talosa-Hunt syndrome
Many patients are treated with oral NSAIDs and/or topical medication (including topical NSAIDs, corticosteroids and antibiotics), but there is no scientific evidence to support this therapeutic. One study suggest that oral NSAIDs are effective when pain is the isolated symptom and there is no diplopia or motility limitations. The non-responders to oral treatment start with a single injection of corticosteroids in the symptomatic trochlear region. Patients with a trochleitis secondary to an immunologic or inflammatory disease should be treated for the underlying cause.
A benign local traumatic hemorrhage was reported in only a few patients treated with injections of corticoids.
Long-term outlook is good with symptoms resolving within weeks to months in most cases. 95% of the patients have a rapid and complete improvement (usually within 24–48 hours). In most cases, the patients remain pain-free for months, even years. Sometimes, it is necessary a second and third injection.
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