Marfan syndrome in children
Introduction
Introduction to Pediatric Ma Fang Syndrome Ma Fang syndrome also has congenital mesoderm dysplasia, called Marchesani syndrome, spider indications, limb slenderness, characterized by surrounding connective tissue malnutrition, skeletal abnormalities, internal eye diseases and cardiovascular abnormalities. A hereditary disease characterized by connective tissue. basic knowledge Sickness ratio: 0.05% Susceptible people: young children Mode of infection: non-infectious Complications: aortic stenosis, crystal dislocation, brain subarachnoid hemorrhage, epilepsy, spina bifida
Cause
Causes of Pediatric Ma Fang Syndrome
(1) Causes of the disease
The disease is autosomal dominant, and Dietz et al. (1991) localize the disease gene to 15q15~q21.3 through family linkage analysis, in many tissues such as endocardium, heart valve, large blood vessels, bones, etc. There are accumulations of mucopolysaccharides such as chondroitin sulfate A or C, which affect the structure and function of elastic fibers and other connective tissue fibers, causing corresponding organ dysplasia and dysfunction. Abraham et al. (1982) proposed aortic elasticity. The protein is abnormal, the desmosome protein and the isopontin protein are decreased, and the lysyl residue is correspondingly increased, which is the main change of the disease. The urinary hydroxyproline excretion is increased, and the blood mucin and mucopolysaccharide are also Increase.
(two) pathogenesis
Through the family's linkage gene localization dominant inheritance, it can be proved from the increase of urinary hydroxyproline excretion in patients, this disease is elastic fiber defect, that is, abnormal collagen metabolism, connective tissue fiber is a very important component in the body tissue structure Therefore, when it is abnormal, it will affect the organs of the whole body (mesoderm tissue), especially the bones and cardiovascular system. The spider bones and the chest or the chest of the boat are all represented by the limbs. The excessive growth of the longitudinal axis of the fingers and ribs may be due to defects in the composition of the periosteal fibers. There is an acidic mucopolysaccharide deposit in the middle layer of the aorta and pulmonary artery. The disease has a family tendency and is autosomal dominant.
Pathology: gross eye changes, ascending aorta dilatation, chronic aortic dissection, heart valve showed mucinous edema, valve balloon, chord thickening, cardiac hypertrophy and mitral calcification and dermatoglyph Abnormalities, etc., the pathological changes of this syndrome are most prominent and representative of the cardiovascular system. Microscopically, the aortic middle layer elastic tissue is sparse and fragmented, with smooth muscle changes in irregular thread shape, and the amount of collagen increases. It can be seen that the metachromatic substance is scattered in the middle layer, and the aortic dissection is formed. It shows cystic middle necrosis and moderate degeneration of elastic fibers, accompanied by smooth muscle bundle disorder. The histopathological changes of the aortic valve are Normal structural destruction and loss, cystic degeneration and loss of tissue fibroblasts, pathological changes in the skin manifested as vacuolar degeneration and elastic fiber arrangement disorder, joint synovial changes are also elastic fibrosis, collagen increase and metachromatic substances It is scattered in the sac.
Prevention
Pediatric Ma Fang Syndrome Prevention
Prevent the birth of children:
(1) Pre-marital examination: including detailed inquiries about the medical history and treatment of both men and women and their family members, especially the presence or absence of congenital malformations, genetic history and close relatives. Family surveys, blood test chromosomal examinations or genetic diagnosis should be performed to detect carriers;
(2) Genetic counseling: One of the couples or their relatives has a genetic disease or congenital malformation, asking about the occurrence of similar diseases in the offspring; if a genetic disease or congenital malformation has been made, ask about the offspring when the child is born again. The situation and how to prevent the birth of the child. Have a disease, take a medicine, or come into contact with toxic substances or radiation during pregnancy to ask about the possible condition of the fetus.
Complication
Complications of Pediatric Ma Fang Syndrome Complications aortic stenosis, crystal dislocation, subarachnoid hemorrhage, epilepsy, spina bifida
1. Cardiovascular is most likely complicated by aortic idiopathic dilatation, aortic stenosis, aortic dissection and mitral anomalies.
2. Eye lesions can be complicated by crystal dislocation or subluxation, high myopia, glaucoma, retinal detachment, iritis and so on.
3. Nervous system lesions can be complicated by subarachnoid hemorrhage and internal carotid aneurysm, epileptic seizures, in addition, patients with Ma Fang syndrome can also have spina bifida, spinal cord bulging, syringomyelia.
Symptom
Symptoms of Pediatric Ma Fang Syndrome Common Symptoms Spinal posterior joint relaxation of lens dislocation or subluxation wrist sign sacral metacarpal index and phalanx... Ventricular septal defect atrial septal defect cortical bone thinning patent ductus arteriosus
It can be found after birth. According to statistics, the incidence rate is more than that of men.
1. The bone is abnormally tall and thin, the skull is long and narrow, the limb is long, the thigh and forearm are obvious, the finger distance is longer than the body length, especially the finger, the toe is slender like a spider's foot, and the foot often has obvious eversion, individual There is a hammer-shaped deformity, the chest is often funnel chest with pterygoid scapula, sometimes flat chest, posterior spine, lateral curvature, often limited to the thoracic vertebrae.
2. The ligament and joint relaxation muscle tension is significantly reduced, the joint is overstretched, and the wrist sign is positive (that is, the patient holds the other wrist in one hand, the thumb is placed on the styloid process of the humerus, and the thumb and the little finger do not force to form a circle. Normal people have a distance between the thumb and the little finger, which is not easy to form a ring. It is not uncommon for the dislocation of the patella and the natural dislocation of the hip joint. There are also inguinal hernias and diaphragmatic hernias.
3. Appearance is sturdy, weak, but the intelligence is normal, the ear is large and the position is low, the outer ear is more deformed, the high sacral bow, the eyebrow arch is more prominent, and the eye is subsided.
4. Eye manifestations 50% to 80% of the symptoms of children with ocular changes, common lens dislocation or subluxation, cataract, high refractive error, corneal size variation and turbidity; rare glaucoma, uveal pigment Abnormal distribution, eyeball depression, oblique eye tilt, amblyopia, color blindness, etc.
5. Cardiovascular changes are more common. Even 1940 review literature, 1/3 cases may have cardiovascular changes, such as mitral regurgitation, atrial septal defect, ventricular septal defect, patent ductus arteriosus, tetralogy of Fallot.
6. Other abnormalities include secondary sexual dysplasia, abnormal ear shell, slender teeth, etc., and there may be abnormalities such as abnormal lung lobulation, dysplasia of the lung, migration kidney, ureteral stricture and the like.
Examine
Examination of Pediatric Ma Fang Syndrome
The basal metabolic rate is low, the serum mucin is lower than normal, the urinary hydroxyproline is increased, the mucopolysaccharide is increased, especially the sulfate gum A or C is increased, and the hyaluronic acid in the urine is excessive.
Regarding the determination of 24h urinary hydroxy citrate, some scholars have suggested that as a diagnostic indicator, the results of domestic Tongji Medical University data for 24h urinary hydroxy acid normal adults and children are (24.41±17.02) mg, patients (including adults, children) The difference between (44.84±36.12) mg is very significant. Although the test is less specific and less sensitive, it is obvious if the disease and other factors that can affect the urinary hydroxyproline test value are excluded. Increased is meaningful for diagnosis.
X-ray inspection
(1) The phalanx is slender.
(2) Determination of metacarpal index, that is, the ratio of the right and left 2nd to 5th metacarpal length and width, normal is 5.5 to 8.0; 8.1 to 8.3 prompt (possible) diagnosis, 8.4 confirmed the disease.
(3) Determination of the phalanx index, that is, the ratio of the length and width of the proximal phalanx of the right hand ring, female > 4.6, male > 5.6, can diagnose the disease.
(4) The aortic root width was significantly dilated, and the aortic retrograde angiography showed that the ascending aorta expanded in a vase-like manner and the left ventricle increased.
2. Echocardiography reported a diagnostic coincidence rate of 92.3%.
(1) Aortic root dilatation: according to Brown et al.: 1 aortic width > 22 mm / m 2 body surface area; 2 measured aortic diameter > 37 mm; 3 left aorta diameter < 0.7 cm; with 2 of 3 items Can diagnose the disease.
(2) Aortic valve dysfunction.
(3) signs of mitral valve prolapse and mitral insufficiency signs.
(4) Those with aortic dissection can find the corresponding signs.
(5) Other cardiovascular malformations.
3. CT and or MRI examination can clearly identify the presence or absence of aortic lesions, vessel wall thickness, aortic dissection and tear, occlusion in the lumen.
4. Slit lamp examination can reveal lens dislocation.
Diagnosis
Diagnosis and diagnosis of pediatric horse syndrome
Diagnose based on
(1) Special bone changes, that is, the tubular bone is slender, especially the metacarpal bone, the cortical bone is thin, slender, and changes like a spider.
(2) Congenital cardiovascular abnormalities.
(3) Eye symptoms.
(4) Family history.
Three of the above four clinical criteria can be diagnosed, and only two of the first three changes can be diagnosed as incomplete equine syndrome.
2. Mckusick (1995) lists cardiovascular abnormalities in horse syndrome as
(1) aortic dilatation (ascending aorta, descending aorta), aortic dissection, aortic stenosis, patent ductus arteriosus.
(2) Pulmonary artery abnormalities (pulmonary artery dilatation, pulmonary aneurysm).
(3) septal defect (atrial septal defect, ventricular septal defect).
(4) abnormal valve and accompanied by subacute bacterial endocarditis.
Differential diagnosis
1. Identification with cystineuria The disease must be differentiated from cystineuria, the latter is recessive, the child is mentally retarded, and the urine contains cystine. Urine nitroprusside test was positive.
2. Identification with Ma Fang syndrome should be differentiated from anti-Mafan syndrome, that is, Marchesanis syndrome, and: 1 homocystonia; 2 rheumatic aortic regurgitation; 3 familial mitral valve prolapse or Aortic valve prolapse; 4 familial aortic annulus dilatation; 5 congenital contracture spider-like finger (toe) and other identification.
