orbital amyloidosis


A brief introduction of orbital amyloidosis Orbital amyloidosis can occur in the lacrimal gland area of the orbit, in the eyelid and conjunctiva tissue. It is a disease caused by amyloid protein deposition. It is relatively rare clinically. The disease can cause exophthalmos, ptosis, eye movement disorders, orbital hemorrhage (spontaneous), and vision loss. Basic knowledge Prevalence rate: 0.05% Susceptible group: no special group Mode of infection: non infectious Complications: eye movement disorder


Etiology of orbital amyloidosis


The cause is unknown. This lesion is a plasma cell involved lesion, which may be related to the immune dysfunction of the body. Some cases are secondary to long-term eye infection and chronic inflammation, vasculitis, cavernous angiopathy, etc., and some cases are secondary to myeloma (multiple), macroglobulinemia, B-cell malignant lymphoma, etc.

(2) Pathogenesis

The pathogenesis is unknown. Plasma cells are involved in the process of pathological changes, whether secondary or primary amyloidosis, so it may be related to the immune dysfunction of the body. Some cases have a certain family tendency, indicating that it is related to heredity. The high peak of IgM in protein immunoelectrophoresis indicates macroglobulinemia.


Prevention of orbital amyloidosis

Prevention of orbital amyloidosis:

1. Because the cause of amyloidosis is not clear, there is no way to prevent primary amyloidosis.

2. Secondary amyloidosis can only be prevented or effectively treated by inflammatory diseases that cause amyloidosis, such as tuberculosis and rheumatoid arthritis. If drugs can be used to control rheumatoid arthritis, the possibility of developing into secondary amyloidosis will be reduced.


Complications of orbital amyloidosis complication Ocular Motility Disorders

It is often accompanied by eye muscle hypertrophy, eye movement disorder, etc. Since amyloid lesions are not limited to local areas and can occur in multiple systems and organs, the following complications may occur:

1. Complicated with renal diabetes insipidus, hyperkalemia and renal failure.

2. Clinically, congestive heart failure is often associated with progressive and intractable attacks. Heart failure caused by amyloidosis is difficult to deal with, and some patients are extremely sensitive to digitalis, leading to serious or even fatal arrhythmia. If the conduction system is involved, it may cause conduction block, atrial fibrillation, atrial flutter and ventricular arrhythmia. This is often the late manifestation of primary amyloidosis, and the prognosis is very poor.

3. Complicated with portal hypertension, esophageal vein bleeding and spontaneous liver rupture. In addition, the gallbladder and pancreas may also have amyloid deposits.

4. Complicated with airway obstruction, dyspnea, atelectasis, pleural effusion, and secondary infection.


Symptoms of orbital amyloidosis common symptom Visual impairment Amyloid protein deposition Lacrimal gland enlargement Yellow nodule ptosis Bulging

Primary amyloidosis is a common type, and eye lesions are part of systemic amyloidosis, that is, amyloid deposition occurs in conjunctiva, orbit and other anatomical parts such as skin, pharynx, bronchial branches, heart, liver, kidney, muscles, nerves and blood vessels, resulting in lesions; When the heart is involved, it will cause heart failure. When the tongue is invaded, it will become enlarged, making it difficult to swallow and speak; Intestinal diseases lead to intestinal peristalsis and absorption dysfunction. When amyloid protein is deposited on the eyelid, it shows that the skin has waxy yellow nodules. Because amyloid protein is deposited around the blood vessels, the blood vessels are fragile. The eyelid can bleed due to minor trauma. The involvement of the eyelid skin is always related to systemic amyloidosis, limited to the lesions of the conjunctiva, lacrimal gland and orbit, The absence of eyelid skin damage generally indicates that there is no systemic disease. In these cases, the results of systemic amyloidosis examination are often negative.

Amyloidosis limited to the orbit is very rare. Generally, amyloid protein is deposited in the conjunctiva first, and then spreads back to the fascia sac and orbit along the periphery of the blood vessels. The most typical lesions are amyloid protein deposited in the upper and lower fornix conjunctiva and subconjunctival tissue, upper tarsal plate, levator muscle tendon of the upper eyelid, muscle and M ü ller muscle, which thickens and thickens the upper eyelid and causes ptosis, such as opening the eyelid, We can see brittle and bleeding solid vegetations. Amyloid protein deposition in the lacrimal gland causes the lacrimal gland to swell, muscle invasion causes extraocular muscle hypertrophy, and eye movement is limited. If multiple extraocular muscles are involved, it may lead to frozen eyes, sclera and around the optic nerve are involved, which may affect visual function, and may also invade other orbital tissues, causing exophthalmos, orbital bleeding, etc, The mass can compress the orbital bone to produce compressive absorption of the orbital bone, but there is no bone destruction.

Secondary amyloidosis is mainly caused by infection and chronic stimulation of inflammation. Plasma cells involved in the inflammatory process may be related to amyloid deposition. Tuberculosis, rheumatoid arthritis, leprosy and osteomyelitis cause amyloid deposition in the liver, kidney, spleen and adrenal gland and other substantive organs; It can also affect the eyelids, but the orbit is rarely invaded. Local amyloid deposition caused by local inflammation or infection of the eye is rare, such as chronic inflammation of the cornea. Infection sometimes causes amyloid deposition of the cornea, but it is very rare to see deposition in the orbit.

Systemic plasma cell hyperplasia, multiple myeloma, megaglobulinemia and B-cell lymphoma may lead to the deposition of amyloid protein in the orbit due to the excessive synthesis of immunoglobulin fragments; Amyloidosis is also regarded as a part of aging. Autopsy shows that the elderly often have amyloidosis.

CT examination can show solid space occupying lesions in the lacrimal gland area of the orbit, with irregular shape and uneven density accompanied by calcification.


Examination of orbital amyloidosis

1. Urine examination: urine Bence Jones protein examination and protein immunoelectrophoresis examination to exclude plasma cell disease and multiple myeloma.

2. Histopathological examination: Amyloidosis is a kind of acellular, transparent and amorphous material deposition, which causes foreign body granuloma reaction. In routine HE staining, the amorphous material is mostly distributed around the blood vessels, which is eosinophilic. Fibroblasts and inflammatory cells can be seen in the whole lesion, most of which are plasma cells, It can also be seen that the characteristic multinuclear foreign body tissue cells are scattered in the lesion area or distributed at the edge of the amyloid deposition area. In the acidophilic mass, lymphoid follicles are occasionally seen. Amyloid protein is positive in PAS, Congo red, methyl violet and thioflavin T staining. Polarized light microscopy shows birefringence and dichroism. Electron microscopy shows that amyloid protein is acyclic, Fine fibers without branches.

The chemical composition of amyloid protein varies from disease to disease. The raw materials for synthesizing amyloid protein come from blood circulation or local proteins, which are spontaneously fused into β Folding configuration, which converts protein into fiber, and its dyeing characteristics are purely due to fiber rigidity and fold configuration, β Fracture exists in all amyloidosis lesions, so the author suggested that the disease be renamed as β Fibrosis, protein AL exists in patients with primary systemic amyloidosis and multiple myeloma, which may be related to amyloid deposition of eyelid and vitreous body; It is also the main protein in primary localized orbital lesions. Chemical analysis shows that protein AL represents λ and κ The N-terminal segment of immunoglobulin light chain or all light chains, protein AA exists in patients with secondary amyloidosis. It is a group of heterotypic proteins. There is a common sequence of 9 amino acids at the N-terminal of light chain. There is an immune cross reaction between protein AA and protein SAA. Protein AA seems to be the degradation product of protein SAA in the blood circulation. Under normal circumstances, the content of protein SAA is low, In the process of chronic inflammation and infection, it is significantly increased due to emergency response.

Other fibrins separated from amyloid protein are: protein AFP, which exists in patients with a certain family genetic tendency; Protein AEt is associated with APUD tumor; Protein AP exists in all patients with amyloidosis and is related to PAS amyloprotein staining.

CT examination: the lacrimal gland was enlarged, extraocular muscles were thickened, or soft tissue mass shadow in the orbital anterior segment was found, and spotty calcification was occasionally seen.


Diagnosis and differential diagnosis of orbital amyloidosis

The waxy yellow mass on the eyelid skin, the hard and brittle dome conjunctiva, and the easily bleeding vegetation have diagnostic value. CT examination found that the lacrimal gland was enlarged, the extraocular muscles were thickened, or the soft tissue mass shadow in the orbital anterior segment was occasionally seen, which can judge the scope, size, and location of the disease, but can not determine the nature of the disease. To make a clear diagnosis, histopathological examination is required, Protein immunoelectrophoresis should be performed for patients with plasma cell diseases. Patients with suspected multiple myeloma should collect 24h urine for Bence Jones protein examination. If plasma cell myeloma is considered, bone marrow examination should be performed. The high peak of IgM in protein immunoelectrophoresis indicates macroglobulinemia.

To differentiate from multiple myeloma and macroglobulinemia, urine Bence Jones protein test and protein immunoelectrophoresis should be performed, and attention should be paid to whether other organs in the body have amyloid changes.

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