bubble_chart Overview

Endocrine regulation controls the oxidation and metabolism of various organs and tissues in the human body, thereby maintaining normal health. Excessive or insufficient secretion can lead to diseases. Clinically, it is commonly classified into two types: thyrotoxic exophthalmos and thyrotrophic exophthalmos.

bubble_chart Etiology

Thyrotoxic Exophthalmos: The occurrence of thyrotoxic exophthalmos may be attributed to two factors. On one hand, the sympathetic nerves are in a state of excitation, causing the orbital smooth muscles to tense and contract, thereby pulling the eyeball forward. On the other hand, the lateral rectus muscle thickens and relaxes, reducing the backward pull on the eyeball and allowing the tendency for the eyeball to move forward to take effect. Additionally, the subsequent filling of the orbital fat into the space left behind the eyeball means that even under external pressure, the eyeball cannot return to its original position.

Thyrotropic Exophthalmos: Excessive secretion of thyrotropin due to hyperfunction of the anterior pituitary or complete thyroidectomy leads to what is known as pituitary exophthalmos (malignant exophthalmos). Recent research suggests that this may be related to immune factors. Under normal circumstances, the feedback mechanism between thyroid hormone and thyrotropin maintains a state of balance. Therefore, performing a thyroidectomy when exophthalmos is in a progressive state carries the risk of exacerbating the condition.

bubble_chart Clinical Manifestations

Thyroid toxic exophthalmos:

Thyroid toxic exophthalmos is also known as exophthalmic goiter.

Graves' disease is a condition characterized by exophthalmos and thyroid enlargement, and is divided into two types based on thyroid function status:

1. Ocular Graves' disease: Exophthalmos accompanied by diffuse thyroid enlargement, but with normal thyroid function.

2. Graves' eye disease: Diffuse thyroid enlargement with exophthalmos, and either hyperthyroidism or hypothyroidism, each further divided into two subtypes.

Graves' disease is clinically common, particularly among middle-aged women, and is an autoimmune disorder. It represents a hyperactive phenomenon in tissue metabolism and nervous system reactivity, possibly triggered by psychological trauma as a stress response.

Thyrotropic exophthalmos: Mostly bilateral, more common in middle-aged men, with ocular symptoms more prominent than systemic toxic symptoms. Due to the marked and progressive exophthalmos, it is also called exophthalmic ophthalmoplegia. The direction of exophthalmos is straight forward. In the early stages, the upper eyelid often retracts upward, with severe edema of the eyelid and conjunctiva. The eyelid contents feel hard upon palpation, which can lead to incomplete eyelid closure and exposure keratitis, even progressing to suppurative corneal ulcer or perforation. Additionally, it is often accompanied by extraocular muscle paralysis, restricted eye movement, and diplopia. Fundus examination may reveal retinal hemorrhage and optic disc edema, caused by increased orbital pressure leading to retinal venous obstruction. Elevated intraocular pressure can also compress the optic nerve, resulting in central vascular restriction, decreased vision, and glaucoma-type visual field defects, and may even lead to optic nerve atrophy.

bubble_chart Treatment Measures

Thyrotoxic exophthalmos: Medical treatment is the main approach, generally involving antithyroid drug therapy. Radioactive isotope ¹³¹

iodine and subtotal thyroidectomy have equivalent therapeutic effects. For exophthalmos, symptomatic treatment should be adopted, such as protecting the highly exposed cornea to prevent dryness and infection by applying anti-inflammatory ointments and wearing eye patches; partial tarsorrhaphy can reduce corneal exposure, while hormone therapy remains inconclusive.

Thyrotropic exophthalmos: Local care should focus on protecting the cornea and preventing infection. For severe conjunctival edema, corticosteroid eye drops or subconjunctival/retrobulbar injections of dexamethasone can be used. Some advocate the use of 5–10% guanethidine eye drops to treat eyelid retraction or a single retrobulbar injection of hyaluronidase (500 units). Systemic treatment may include high-dose corticosteroids and thyroid extract, primarily to inhibit thyrotropin secretion, with X-ray irradiation of the pituitary-hypothalamic region as an option. Surgical therapy is rarely used nowadays, but orbital decompression may be performed if necessary.