Thumb sign

Introduction 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. Thumb sign: The thumb is adducted, and the remaining 4 fingers are fists. The tip of the thumb is beyond the lower edge of the palm, and about half of the patients have this sign.

Cause

(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.

(3) Pathology: gross eye changes with abnormal eye, ascending aorta dilatation, chronic aortic dissection, heart valve with mucinous edema, valve balloon, chord thickening, cardiac hypertrophy and mitral calcification As well as abnormal dermatoglyphics, the pathological changes of this syndrome are most prominent and representative of the cardiovascular system. Under the microscope, the aortic middle layer elastic tissue is sparse and fragmented, with smooth muscles showing irregular thread-like changes, collagen volume. Increased, and visible metachromatic substances in the saclike vacuole scattered in the middle layer, aortic dissection tumor formation, showed cystic middle necrosis and elastic fiber moderate degeneration, accompanied by smooth muscle bundle disorder, aortic valve tissue Pathological changes were normal structural destruction and loss, cystic degeneration and loss of tissue fibroblasts. The pathological changes of the skin showed vacuole degeneration and elastic fiber arrangement disorder. Joint synovial changes were also elastic fibrosis, collagen increased and different. The dyeing substance is distributed in a saclike sac.

an examination

Related inspection

Thumb-to-palm muscle strength test thumb-to-palm test thumb small fingertip relative test

Inspection Method:

(1) metacarpal index: the average length of the four metacarpals of the index finger, middle finger, ring finger and little finger divided by the average width of the middle part of the four metacarpals on the anterior slice of the X-ray of both hands. The normal man's metacarpal index is less than 8, and the syndrome is greater than 8 8.4, female is greater than 9.2.

(2) Thumb sign: Let the patient's thumb adduct, cross the palm and straighten and make a fist. Positive if the stretched thumb clearly exceeds the lateral edge of the hand.

(3) Wrist sign: The patient holds the contralateral wrist at the proximal end of the contralateral humeral head with one hand, and surrounds the thumb and little finger for 1 week. If the thumb and the little finger are not stressed, they overlap each other and are positive.

2. Skin changes The most common skin manifestations are widening of the skin lines or atrophic skin lines. These abnormal skin manifestations can be found in many parts of the body, especially in the chest, shoulder deltoid areas and thighs.

3. Cardiovascular abnormalities 30% to 40% of patients have cardiovascular system complications, the most common cardiovascular abnormalities of the aortic idiopathic dilatation, aortic dissection aneurysm and mitral valve abnormalities. Aortic lesions and mitral valve disease can sometimes occur simultaneously. The systolic click sound with late systolic murmur is its most common sign. In addition, trauma, hypertension, and pregnancy can induce acute aortic rupture and dissection aneurysm formation. In addition to aortic and mitral valve disease, tricuspid valve disease can occur in fashion. Although aortic dilation always occurs in the ascending aorta, aneurysmal dilatation, dissection aneurysm formation, or rupture can also occur in the thoracic aorta and abdominal aorta. About 1/3 of patients may have congenital heart disease, common aortic valve stenosis, patent ductus arteriosus, atrial septal defect and other rare cardiovascular complications such as Fossil sinus and pulmonary artery dilatation, the main branch of the aorta For example, the common carotid artery, splenic artery dilation, endocardial fibrosis, aortic aneurysm rupture and heart failure are the main causes of death in this syndrome.

4. The most characteristic manifestation of ocular changes is crystal dislocation or subluxation, and about 3/4 of patients are bilateral. Crystal dislocation can be caused by a variety of factors. Large eyes and small crystals can increase the gap around the crystal, expand the suspensory ligament, develop the ciliary body, and attach the suspensory ligament and its attachment to the crystal. In addition, this syndrome can also occur in high myopia, glaucoma, retinal detachment, iritis and other eye abnormalities. These ocular lesions have a more severe effect on the eye than crystal dislocation. The sclera is abnormally manifested as the blue sclera. Corneal hyperplasia, retinitis pigmentosa, choroidal sclerosis, strabismus, nystagmus, tremors, and anterior chamber swelling can sometimes occur.

5. Nervous system lesions The neurological symptoms of this syndrome, like other congenital rheumatism, are also caused by cerebral vascular malformations, manifested as subarachnoid hemorrhage and compression of aneurysms caused by internal carotid aneurysms. Big attack. In addition, patients with Marfan syndrome can also have spinal cleft lobes and syringomyelia. Low muscle tone associated with muscle atrophy is the most common neuromuscular condition in this syndrome. A small number of patients may have mental retardation or dementia.

complication:

1. Cardiovascular most likely concomitant, aortic idiopathic dilatation, aortic stenosis, aortic dissection and mitral anomalies.

2. Ocular lesions can be complicated by dislocation or subluxation, high myopia, glaucoma, retinal detachment, iritis and so on.

3. Nervous system lesions can be complicated, subarachnoid hemorrhage and internal carotid aneurysm, epileptic seizures. In addition, patients with Marfan syndrome can also have spinal cleft lobes and syringomyelia.

Differential diagnosis

Pain arc sign: It is a chronic shoulder pain syndrome caused by repeated friction and impact between the structure of the subacromial space and the shoulder arch during shoulder abduction. It is a common disease in middle-aged and above. The disease includes acromion bursitis, supraspinatus tendonitis, calcification of the supraspinatus tendon, rotator cuff rupture, and biceps tendon tenosynovitis. The common clinical feature is that there is a pain arc in the active abduction of the shoulder joint, and the passive activity pain is significantly reduced or even completely painless.

Homans sign: examination method: the patient is lying on his back, the knee joint is straight, and the calf is slightly raised. The examiner holds the foot. A manifestation of thrombophlebitis when the Homans sign is positive.

Impact sign: can occur at any age from 10 years old to old age. Some patients have a history of shoulder trauma, and a significant number of patients are associated with long-term overuse of the shoulder joint.

Wrist sign: The patient holds the contralateral wrist at the proximal end of the contralateral humeral head with one hand, and surrounds the thumb and little finger for 1 week. If the thumb and the little finger can overlap each other without pressure, it is positive.

Sexual onset: no ethnic differences, more common in children, can also be seen in most adults with symptoms after birth, face is old, showing a sad appearance, trunk muscles are not developed, subcutaneous fat is thin.

1. Bone changes: The patients in this syndrome have long and thin limbs, especially the fingers. The torso can be shortened by the side bends, making the limbs appear more elongated, like a spider's foot, hence the name of the spider (Figure 1). Reduced muscle tone, increased joint activity, and exceptional range of motion, but dislocation is rare. The head is long, the forehead is rounded, and the sternum deformity is mostly caused by the ribs being too long, and the funnel chest or chicken breast is more common. The shoulder ridge is wing-shaped. Abnormal systemic connective tissue may involve joint capsule, ligament, tendon, and sarcolemma, which may lead to repeated dislocation of the joint, flat foot or high arch foot, high arch and high irregularity. Common Marfan syndrome.

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