Inherited connective tissue disorder characterized by progressive calcification and fragmentation of elastic fibers in skin, retina, and cardiovascular system leading to multiple vascular lesions caused by medial calcification of medium-sized and major arteries. Severe cardiovascular complications must be expected.
Pseudoxanthoma Elasticum; PXE Syndrome.
First described by Ester Elizabeth Groenblad, a Swedish ophthalmologist, and James Victor Strandberg, a Swedish dermatologist, in 1929.
Incidence in the general population is estimated at 1:100,000. Male-to-female ratio is 2:1.
Various patterns: two autosomal dominant forms (Type II, characterized by isolated skin manifestations) and two autosomal recessive forms (Type I, represents 95% of patients), caused by mutations in the ABCC6 gene (adenosine triphosphate-binding cassette, subfamily C, member 6) probably mapped on 16p13.1. Sporadic cases have also been observed.
Unknown; an abnormal secretion of glycosaminoglycans by fibroblasts may result in coating of the elastic fibers. Another hypothesis is the presence of an abnormal protease that renders elastic fibers prone to calcification.
Based on the clinical findings of skin lesions, which are almost always present, and start in the teen years at the neck, progressing to armpits, elbows, and groins and consisting of yellow papules, followed by visual impairment at approximately 25 years of age, but never leading to blindness (peripheral vision is preserved).
Features involve skin (small, yellow papules in mouth, neck, axilla, elbow, groin, and periumbilical region; orange peel appearance, elastosis perforans serpiginosa), eyes (angioid streaks of the retina in Bruch membrane, macular degeneration, decreased visual acuity, myopia, blue sclerae, retinal hemorrhages), heart and vessels (mitral valve prolapse, angina pectoris from premature occlusive vascular disease, arteriosclerosis, medial calcification of medium-sized and major arteries, diminished or absent peripheral pulses, claudication, congestive heart failure, restrictive cardiomyopathy myocardial infarction), gastrointestinal system (gastrointestinal hemorrhage, gastric and duodenal microaneurysms, arteriovenous malformations), skeleton (pectus deformities, kyphosis, scoliosis), and central nervous system (stroke, cerebral hemorrhage calcification of falx cerebri).
Precautions before anesthesia
Assess for occult blood loss (red blood cell count, fecal test, urine analysis). Evaluate cardiovascular function (clinical, ECG, Doppler ultrasonography, echocardiography). Evaluate ophthalmologic lesions (clinical, ophthalmologic examination).
Vascular risk is major and requires appropriate perioperative cardiac monitoring. Arterial blood pressure should be strictly controlled, but invasive monitoring is often difficult because of frequent loss of peripheral pulses and calcifications of the arteries. Avoid arterial hypotension. Regional anesthesia is not contraindicated, but vascular resistance response to sympathetic blockade is unpredictable. Renal failure may occur, so kidney function should be assessed.