Grayish discoloration of the macula under the eye

Introduction Austin-type children's brain sulphur-lipid disease, also known as Austin-type metachromatic leukodystrophy, is a joint disease of cerebral sulphur disease and mucopolysaccharidosis. It is characterized by mild Hurler syndrome, multiple bone dysplasia, severe neurological symptoms and markedly low intelligence. Under the fundus examination, it can be found that the macula is grayish and discolored, and even blind.

Cause

The cause of the yellow spot with gray discoloration was found in the fundus:

(1) Causes of the disease:

Genetic defects, the lack of galactosyl-3-sulfosaphthyl sulphate sulfatase (CSF) in patients is the main cause of this disease.

(2) Pathogenesis:

The basic biochemical defect of this disease is the lack of galactosyl-3-sulfosyl sphingosine sulfatase (CSF sulphate), an aryl sulfatase enzyme with three isoenzymes, ie, an aromatic group. Sulfate esterases A, B and C, the gene is located at 22q13. Normally, cerebroside sulphate catalyzes the desulfurization of galactosyl-3-sulfosyl sphingosine, lactosylthioester and galactosyl sphingosine sulfate. Due to the lack of cerebroside sulphate in the patient's body, the above-mentioned several glycosides are incompletely decomposed and may cause disease due to excessive deposition in the brain.

The pathological changes of this disease are most obvious in the central nervous system and peripheral nerves. Other internal organs can also occur in the tissues. Some neurons in the brain tissue are lost, astrocytes are proliferated, and the cortex has a microglial reaction in the deeper layer. Cortical cell structure Still retained, the white matter showed a significant loss of neurophospholipids, while the "U"-shaped nerve fibers were relatively intact, and the number of oligodendrocytes was reduced. Deposited material was found in the residual oligodendrocytes and perivascular macrophages, in the cerebellar dentate nucleus. In the hypothalamus, thalamus, basal ganglia, pons, spinal anterior horn cells, spinal nerve root ganglion cells and retinal ganglion cells, cytoplasmic inclusion bodies are found, which contain metachromatic substances, under the polarizing microscope, metachromatic The substance is yellow and green. The substance is positive for PAS staining and positive for Sudan black staining. Under electron microscope, the intracellular inclusion bodies are hydrophilic, most of which are located in lysosomes, and the size of inclusion bodies is not Etc. (>1m), mostly composed of concentric or horizontal layered structures in a transparent matrix, each layer is 6-8 nm thick, and the other contains Is composed of amorphous material, a thin film such outsourcing inclusion bodies (3 ~ 4nm), produced from the matrix-based, a large extracellular spherical or round particulate matter, under the microscope, these materials have metachromatic.

The pathological changes of optic nerve and peripheral nerve are segmental demyelinating, and there is deposition of metachromatic substances in Schwann cells. Under electron microscope, this substance is polymorphic and composed of "zebra bodies". Dyeing deposits may also be present in renal tubules and bile duct epithelial cells, endocrine gland cells, liver parenchymal cells, and Kupffer cells.

an examination

Related inspection

Ophthalmology examination fundus examination slit lamp eyelid examination brain CT examination

Examination of the yellow spot with gray discoloration at the fundus:

Clinical symptoms begin to appear from 9 months to 2 years of age. The earliest manifestations are behavioral abnormalities, irritability, ataxia, uncoordinated movements or abnormal gait. Most cases may have low muscle tone and occasionally paralytic paraplegia. After the lesion lasts for one year, the child can't stand, and the reaction is slower and more obvious. There may be language barriers, increased muscle tone (more obvious lower limbs), weaker or absent deep reflexes, and ataxia may be further aggravated. Intermittent limb pain, etc. By the age of 3 to 4, the child is bedridden, quadriplegia, and nystagmus and cerebellar lesions. Ventilation, optic atrophy, and slow response are more pronounced. Fundus examination can be found that the macula is grayish and can be blinded later. In addition to the symptoms of the nervous system, there may be skeletal malformations caused by multiple bone dysplasia, facial features are mild Hurler syndrome characteristics.

The disease can be complicated by nystagmus, cerebellar lesions, convulsions, optic atrophy, blindness, skeletal malformation caused by multiple bone dysplasia, and occasionally paralytic paraplegia.

The disease is based on clinical symptoms, mainly for the clinical manifestations of the nervous system, as well as laboratory examinations, to obtain an increase in the diagnosis of heparan sulfate in the urine. Leukocytes have metachromatic inclusion bodies in the surrounding blood. The biochemical analysis of brain or liver tissue cell inclusions is an increase in gangliosides, and mainly GM2 and GM3 gangliosides, and heparan sulfate is also increased.

X-ray examination: X-ray showed a similar type of mucopolysaccharidosis, but its degree of change was lighter.

Differential diagnosis

Symptoms of the macula appear to be confused with gray discoloration at the fundus:

1. The presence of triangular, round or half-moon blue, gray or black spots in the white of the eye is a common symptom of intestinal tsutsugamushi.

2. If there is a cherry red spot in the macular area, a miliary change in the lung X-ray film supports the diagnosis of Niemann-Pick disease.

3. Leopard-like fundus: Because the pigment of the retinal pigment epithelium is less, the pigmented area of the choroidal macrovascular structure and the vascular space can be seen through the retina, which is similar to the texture of the leopard skin. It is called the leopard-like fundus and belongs to the choroid. type.

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