Overview
Basal nucleus calcification, i.e. idiopathic basal nucleus calcification, is also known as Fahr’s disease. Symmetrical calcification of the basal nuclei on both sides of the body caused by various reasons is called bilateral symmetrical basal nucleus calcification syndrome or Fahr’s syndrome. Calcification of the pallidum and caudate nucleus is mostly seen in advanced age, and can also be seen in normal people. Calcification spots appearing after 40 years of age are considered to be physiologic and have no clinical significance; however, if calcification of the basal nucleus is found in the early years of life on the cranial X-ray, it should be considered as an abnormality. In addition to basal nucleus calcification, there is also cerebellar calcification. Lesions of the basal nuclei calcinosis can lead to a variety of motor and cognitive disorders, including Parkinson’s disease and Huntington’s disease.
Etiology
The cause of the disease is unknown and is currently thought to be mainly related to the following factors:
1. Genetic factors are mostly circulating, but familial cases have been reported with autosomal recessive or dominant inheritance.
2. Activation of glutamate receptors in the brain by exogenous toxins, resulting in neurotoxicity leading to calcium deposition.
3. Abnormalities in iron and calcium phosphate metabolism play an important role in the pathogenesis of Fahr’s disease.
4. Immune factors.
Symptoms
1. Familial cases mostly start in adolescence or early adulthood, with early genetic findings. Some patients with rare genetic diseases, such as pseudohypoparathyroidism type II, refractory anemia, a variety of autoimmune endocrine gland diseases, etc., the main manifestations of a variety of movement disorders, such as torsion spasms, unilateral or bilateral torsion spastic hand and foot dyskinesia, tremor and ataxia, etc., can be seen to the prominent expression of the Parkinson’s syndrome and torsion spasticity of torsion spasticity, torsion spasticity of torsion spasticity of torsion spasticity of torsion spasticity of torsion spasticity of hand and foot, torsion spasticity of hand and foot may be Parkinson’s syndrome can be seen as a prominent manifestation of myotonia and torsion spasms.
2. Hypoparathyroidism or pseudohypoparathyroidism associated with abnormal calcium and phosphorus metabolism accounts for about 2/3 of the cases of basal nuclear calcification. Fahr syndrome caused by primary hypoparathyroidism has a long course with a history of multiple episodes of tics, chorea, torsades de pointes, or Parkinson’s disease-like manifestations of cerebellar ataxia or in a minority of patients there are positive bilateral limb pyramidal fasciculation signs.
3. Some patients have mental disorders such as depression, mania, obsessive-compulsive behavior, aggressiveness, irritability, indifference, gender dysphoria, delirium, etc. Dementia is one of the most common clinical manifestations of the disease, but the type of dementia of Fahr’s disease is different from that of Alzheimer’s disease and Pick’s disease, and it is a mixture of the two. Early manifestations of mental retardation, mostly insidious, followed by memory and language temporal and spatial disorientation.
Examination
1. Laboratory examination
(1) Serum calcium level is normal, but with hypoparathyroidism or pseudohypoparathyroidism, serum calcium is reduced, and there are clinical manifestations of hypocalcemia.
(2) Routine blood biochemistry, cerebrospinal fluid routine examination is not specific.
(3) Drugs trace elements and biochemical examination help the etiologic diagnosis.
2. Other auxiliary examinations
(1) CT examination, symmetrical basal nucleus calcification spots >800mm2 can be seen, which is an important diagnostic criterion for this disease, and cerebellar dentate nucleus and cerebral cortex can also have calcification spots.
(2) MRI examination can be seen in the basal nuclei of the brain and part of the gray matter T2WI high signal, accompanied by dementia can be seen in the center of the bilateral semiovoid high signal, SPECT examination found that the bilateral basal nuclei of the cerebral blood flow compared with the cerebral cortex is significantly reduced, and the degree of reduction in blood flow is proportional to the severity of the disease.
(3) Cerebrospinal fluid and calcium examination.
Diagnosis
The diagnosis is based on the symptoms of movement disorders with mental retardation, etc. Symmetrical calcified spots in bilateral basal nuclei are seen on CT and MRI, and the family history supports the diagnosis. The cause of Fahr’s syndrome must be actively searched for, and it must be clear that it is idiopathic or some special causes.Moskowitr (1971) proposed new diagnostic criteria for Fahr’s disease:
1. Bilateral symmetrical calcification of the basal nuclei on CT or X-ray;
2. absence of clinical manifestations of pseudohypoparathyroidism;
3. serum calcium and phosphorus within normal limits;
4. normal renal tubular response to thyroxine;
5. absence of infection, poisoning and other etiologies;
6. with or without family history. Fahr syndrome is present when there is an etiology and calcification of the basal nuclei is found.
Differential diagnosis
This disease must be differentiated from Fahr syndrome, which has various causes including
1. Hypoparathyroidism and pseudohypoparathyroidism are the most common causes of Fahr syndrome. Patients with reduced serum calcium levels have tetany and convulsions. Pseudohypoparathyroidism type II is a rare familial genetic disease. In addition to the signs and symptoms of hypoparathyroidism, there are obvious skeletal and physical developmental disorders.
2. Intracranial infections in childhood may cause calcification of the basal nuclei.
3. The main cause of neonatal Fahr syndrome is severe ischemic-hypoxic encephalopathy and intrauterine asphyxia, which can cause a series of manifestations of Fahr syndrome within a few months, and can be identified by medical history.
Complications
Some patients develop psychiatric disorders, dementia is one of the most common clinical manifestations of the disease, early manifestations of mental retardation, mostly insidious, followed by memory language, temporal and spatial disorientation.
Treatment
There is no specific treatment for this disease, the main cause and symptomatic treatment, causing extravertebral system symptoms can be appropriate application of anti-Parkinson’s disease drugs and control of tardive dyskinesia drugs, psychiatric symptoms can be used antipsychotic drugs. It has been reported that platelet coagulation inhibitors or cerebral vasodilators, such as compound sodium ferulate capsule, flunarizine, nimodipine, and elixir, can be used; levodopa/carbidopa or levodopa/benserazide can be used to treat the symptoms of paralysis of tremor; and thiamphenicol (Tebufen) or haloperidol can be used to treat chorea.
Prognosis
The disease has a long course, with some reports of survival to 70 years or more.
Prevention
Fahr’s disease is currently considered a neurodegenerative disorder. Preventive measures for those with a genetic background include avoiding consanguineous marriages, promoting genetic testing for carriers of genetic counseling and prenatal diagnosis and elective abortion to prevent the birth of affected children. Early diagnosis, early treatment and enhanced clinical care are important to improve the quality of life of patients.