Connective tissue dysplasia

Objective markers of connective tissue dysplasia

The phenotype of a patient with undifferentiated connective tissue dysplasia has a number of prominent features that are evident even upon visual inspection.

• Musculoskeletal system: characterized by an asthenic build, tall stature with an obvious body weight deficit. The musculature is poorly developed, and joints are characterized by hypermobility. Postural disorders, scoliosis, chest deformities, flat feet, and protruding («winged») scapulae are common.
• Skin: the skin is characterized by increased elasticity (hyperelasticity).
• Stigmata of dysmorphogenesis (minor anomalies): ocular and nipple hypertelorism, high «gothic» palate, sandal gap on the foot, abnormal shape of the auricles.
• Visceral and ophthalmological manifestations: systemic tissue weakness leads to myopia, nephroptosis (drooping kidney), and anatomical anomalies in gallbladder development.

Valvular heart disease

Dysplasia is a leading cause of mitral valve prolapse (MVP). Hemodynamic shifts in this pathology occur due to incomplete leaflet closure, leading to mitral regurgitation (backflow of blood). Two factors are distinguished in the pathogenesis:

1. Valvular factor: separation of the leaflets during systole, which auscultically produces a systolic murmur.
2. Subvalvular factor: pathological elongation of chordae tendineae and decreased contractility of the papillary muscles exacerbate the blood backflow.

In addition to MVP, dysplasia causes tricuspid valve (TV) disease. Other etiological factors of TV involvement include rheumatic heart disease, congenital heart defects (e.g., Ebstein's anomaly), infective endocarditis, radiation, carcinoid syndrome, and blunt chest trauma. TV disease can also result from iatrogenic trauma during right ventricular myocardial biopsy or due to implanted device leads (pacemakers, cardioverter-defibrillators).

Clinical presentation and autonomic dysfunction

Subjective symptoms in prolapse against the background of dysplasia are quite polymorphic. They are based on two main components: the systemic anomaly itself and autonomic dysfunction. Three main clinical syndromes are distinguished:

• Asthenovegetative: fatigue, reduced exercise tolerance, regular headaches, dizziness, and syncopal states (fainting).
• Cardiac: cardialgia, subjective sensations of skipped heartbeats, palpitations, episodes of shortness of breath.
• Psychoemotional: emotional lability, irritability, tendency toward anxiety, hypochondriacal, and depressive reactions.

Features of the objective cardiovascular examination

The boundaries of relative cardiac dullness in such patients generally remain within normal limits. However, due to hypersympathicotonia, hemodynamic instability is revealed — lability of heart rate (HR) and blood pressure (BP).

Auscultation is the most informative method. A typical picture consists of isolated systolic clicks or their combination with a late systolic murmur. Rarer is a harsh-sounding murmur alone (late systolic or holosystolic). Clicks usually occur in mid- or late systole, are no louder than the second heart sound, and do not radiate beyond the cardiac borders; the locus morbi for them is the apex of the heart or Erb's point. An important feature of these acoustic phenomena is their variability. They appear or intensify upon transition to an upright position (orthostasis) and after physical exertion.

In children, the presence of undifferentiated dysplasia (asthenic constitution, cardiac and renal microanomalies) coupled with autonomic dysfunction often serves as a premorbid background for moderate arterial hypertension. At the same time, hypertension can be latent, manifesting only as fatigue, irritability, and rare headaches.

Multiaxial classification of mitral valve prolapse

There is no single classification of MVP. The diagnosis is formulated using a multiaxial method, describing a number of parameters:

• Etiology: primary (idiopathic) or secondary.
• Auscultatory manifestations: auscultatory form or «silent» (without acoustic phenomena).
• Prolapse anatomy: involvement of the anterior, posterior, or both leaflets.
• Relation to systole: early, late, holosystolic.
• Hemodynamics: severity of regurgitation.
• Additionally: state of the autonomic nervous system, complications, clinical course.

Echocardiographic grades, which assess the depth of prolapse, are of particular importance:

• Grade I: 3 to 6 mm.
• Grade II: 6 to 9 mm.
• Grade III: greater than 9 mm.

Class and exam questions

What else to study on this topic

• Criteria and limits of arterial hypertension in children depending on age.
• Features of using percentile charts for recording pediatric hypertension.
• Signs of myocardial remodeling in severe arterial hypertension.
• Complications of hypertensive crises involving target organs (CNS, kidneys, heart).
• Mechanisms of malignant arterial hypertension development.

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.