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Biomedical subjects

R E Pyeritz

Publications and source records attributed to R E Pyeritz.

At least 109 records · Page 6Linked to original sources
PubMed1988

Systolic expansion of the aortic root: an echocardiographic and angiographic sign of aortic composite graft dehiscence.

Precise diagnosis of aortic composite graft dehiscence may be difficult. We present a case illustrating this problem and its resolution. Two-dimensional echocardiography and contrast ventriculography revealed a space adjacent to the aortic valve conduit that demonstrated marked systolic expansion. The dynamic variation of this space was secondary to communication with the left ventricular cavity caused by disruption of the composite graft valve ring. Thus, systolic expansion of the aortic root is a useful echocardiographic and angiographic sign of composite graft dehiscence.

Adult↗
PubMed1988

Respiratory complications of mucopolysaccharide storage disorders.

Twenty-one patients with the diagnosis of mucopolysaccharidosis or mucolipidosis and a history of respiratory complaints or thorough respiratory evaluation were studied retrospectively. Anatomic factors affecting respiratory status included: (i) upper airway narrowing by hypertrophied tongue, tonsils, adenoids, and mucous membranes; (ii) lower airway narrowing by glycosaminoglycan deposition within the tracheobronchial mucosa; (iii) decreased thoracic dimensions due to scoliosis and thoracic hyperkyphosis; and (iv) decreased abdominal dimensions due to lumbar hyperlordosis, gibbus formation and hepatosplenomegaly. Cardiac and neurologic involvement, while present, did not play primary roles in the development of respiratory disease. The functional consequences of these findings included increased risk of developing: (i) respiratory tract infections; (ii) airway compromise during or after anesthesia or sedation; (iii) dyspnea on exertion; (iv) obstructive lung disease; (v) obstructive sleep apnea; and (vi) cor pulmonale. A management approach is presented which can reduce the morbidity and mortality experienced by these patients.

Adolescent↗
PubMed1988

Spirometry and chest wall dimensions in achondroplasia.

Standard values for pulmonary function in short-limbed dwarfism are not available. Therefore, chest diameters and expiratory spirograms were measured in 58 female and 44 male subjects between 7 and 60 years of age with achondroplasia, the most common form of dwarfism. Standing height in adults was 49.6 +/- 3.2 (SD) inches with a sitting/standing height ratio of 0.66 (normal 0.52-0.53). Despite extremely short stature, only AP chest diameters in males were smaller than control subjects of similar age. The following equations were derived for forced vital capacity (FVC): males (under 25 years), FVC(L) = -3.56 + 0.162 X sitting height (in) + 0.067 X age (yrs); males (over 25 years), FVC(L) = -0.73 + 0.162 X sitting height (in) -0.047 X age (yrs); females (under 20 years), FVC(L) = -3.56 + 0.150 X sitting height (in) + 0.067 X age (yrs); females (over 20 years), FVC(L) = -1.92 + 0.150 X sitting height (in) -0.016 X age (years). Similar prediction equations were derived for FEV1 and FEF25-75%: FEV1/FVC % was 84.2 (+/- 6.5) for females and 88.0 (+/- 6.5) for males. We also compared the observed FVC measurements to values calculated using standing heights derived from the subject's sitting height, assuming a normal body proportion. The observed vital capacity in achondroplasia was only 67.6 (+/- 19.2) percent of that predicted for normally proportioned females and 72.4 (+/- 13.6) percent for males, suggesting reduced vital capacity in achondroplasia, due to reduced chest wall compliance or abnormal lung growth.

Achondroplasia↗
PubMed1988

Dural ectasia is a common feature of the Marfan syndrome.

Widening of the lumbosacral spinal canal was found in 63% of 57 patients with the Marfan syndrome and in none of 57 age- and sex-matched non-Marfan control patients, who underwent CT scanning for routine clinical indications. The bony abnormalities in mild cases consisted of thinning of the pedicles and taminae and erosion of the neural foraminae and were generally limited to L5 and S1. More severe changes were present in 13 patients, two of whom had associated neurologic signs, and included meningoceles or near total erosion of a pedicle. Presence and severity of vertebral abnormalities were associated with neither any other clinical feature nor overall phenotypic severity. Dural ectasia can be added to the list of pleiotropic manifestations of the Marfan syndrome.

Adult↗
PubMed1987

Psychiatric manifestations of homocystinuria due to cystathionine beta-synthase deficiency: prevalence, natural history, and relationship to neurologic impairment and vitamin B6-responsiveness.

Homocystinuria commonly affects the central nervous system (CNS), primarily as mental retardation, seizures, and stroke. Case reports have long suggested a predisposition to schizophrenia, but no careful study of predisposition to psychiatric illness has been performed. Accordingly, we evaluated 63 persons with homocystinuria due to cystathionine beta-synthase deficiency for psychiatric disturbance, intelligence, evidence of other CNS problems, and responsiveness to vitamin B6. The overall rate of clinically significant psychiatric disorders was 51%, predominated by four diagnostic categories: episodic depression (10%), chronic disorders of behavior (17%), chronic obsessive-compulsive disorder (5%), and personality disorders (19%). The average IQ was 80 +/- 27 (1 SD); and an IQ of less than or equal to 79 was two-thirds more common among vitamin B6-nonresponsive patients compared to vitamin B6-responsive patients. Aggressive behavior and other disorders of conduct were particularly common among patients with mental retardation and among vitamin B6-nonresponsive patients.

Cystathionine beta-Synthase↗
PubMed1987

Thoracolumbosacral laminectomy in achondroplasia: long-term results in 22 patients.

Neurologic problems caused by vertebral stenosis in the thoracolumbosacral (TLS) region are common in achondroplasia. Surgical decompression by means of laminectomy is recommended often, but its long-term results have not been assessed. We reviewed the clinical history of 22 achondroplastic patients who had at least one TLS laminectomy performed before 1981. Symptoms predated the first TLS laminectomy by a mean of 2.3 years (range 0.1-17 years). Preoperatively, 91% of patients had motor function impairment, 86% had sensory dysfunction, 86% had neurogenic claudication, 77% had radicular pain, 59% had symptomatic bladder dysfunction, and 32% had fecal incontinence. Only upper motor neurons were affected in 45%, only lower motor neurons in 27%, and both in 27%. Follow-up after the first TLS laminectomy averaged 8 years. Of the 20 patients who initially improved neurologically, 12 had functional improvement for more than 5 years. However, 11 of these 12 subsequently regressed and 10 had additional laminectomies. Long-term neurologic and functional improvement was associated with both a short duration of symptoms preoperatively and absence of cervical stenosis. Because of hypertrophic scarring, 9 patients developed compression at the site of the initial TLS laminectomy and required re-operation 6.4 years (range 1-11 years) later. We conclude that TLS laminectomy is an effective treatment for spinal stenosis if performed early in the course of the neurologic syndrome. However, some patients have, or later develop, compression adjacent to the myelographic site of stenosis, and some develop hypertrophic scarring at the site of initial decompression. We therefore suggest that the first TLS laminectomy extend (1) 3 levels cephalad to the myelographic block, (2) at least to S2, and (3) laterally at least to the facets.

Achondroplasia↗
PubMed1987

The bingo model of survivorship. V. The problems of conformation to the empirical evidence.

We discuss the statistical and biological problems of adapting the theoretical bingo model to the analysis of empirical data. A distinction is made between an idealized pathogenetic model, which aims to represent the disease in as much authentic detail as the present state of knowledge allows and in components that have literal interpretation, and an empirical model, which deals with those effects of the pathogenetic model that one may hope to observe clinically. We review a variety of empirical models distinguishable by the amount of data available on intermediate degrees of damage short of total destruction. The relationship of damage to time is explored, and we consider the criteria and usefulness of linearization of this relationship where the diachronic ("longitudinal") data are few and extend over a comparatively short time. Every time a patient is examined, the degree of cumulative damage is assessed in each of the body systems of interest. Thus the examination will furnish a set of measurements, which is obtained on each of several examinations, taken over a period that for preference is long relative to the survival of the system. Specific disorders discussed include dentition and enlargement of the aorta with age in the Marfan syndrome.

Aorta↗
PubMed1987

The Stickler syndrome: evidence for close linkage to the structural gene for type II collagen.

The Stickler syndrome is an autosomal dominant hereditary disorder of connective tissue with pleiotropic features including premature osteoarthropathy, mild spondyloepiphyseal dysplasia, vitreoretinal degeneration, and the Pierre-Robin sequence. Genetic linkage studies in two families with the Stickler syndrome have been performed using restriction fragment length polymorphisms associated with the structural gene for type II collagen, COL2A1. No recombinants between the Stickler phenotype and COL2A1 were observed. The total LOD score for linkage of the Stickler syndrome and COL2A1 at a recombination fraction (theta) of zero is 3.59. These findings suggest that, at least in some families, the mutation causing Stickler syndrome affects the structural locus for type II collagen.

Collagen↗
PubMed1987

Cervicomedullary compression in young patients with achondroplasia: value of comprehensive neurologic and respiratory evaluation.

We studied prospectively 26 young patients with achondroplasia to test two hypotheses: that respiratory problems may be the result of occult spinal cord compression, and that achondroplastic patients with cord compression might have occult respiratory abnormalities. Respiratory abnormalities were present in 85%, the majority caused by a primary problem of the pulmonary system, such as small thoracic cage or obstructed airway. Three patients had hypoxemia, recurrent cyanotic spells, and episodes of respiratory distress explainable only by cervicomedullary cord compression; in each patient, respiratory problems were alleviated by decompressive surgery. Another six patients with cervicomedullary compression had, in addition, at least one primary pulmonary cause of respiratory problems. After decompressive surgery the respiratory problems improved in three and were unchanged in three. Reconstructed sagittal CT images proved the most sensitive technique for detecting craniocervical stenosis as a cause of cervicomedullary cord compression, although some degree of stenosis was present in nearly all of the patients.

Achondroplasia↗
PubMed1987

Acetabular protrusion in the Marfan syndrome.

The Marfan syndrome is a genetic disorder of connective tissues resulting in ocular, cardiovascular, and musculoskeletal deformities. The authors reviewed 22 cases of Marfan syndrome. Forty-five percent (ten of 22) of the patients had acetabular protrusion, with one-half of these being unilateral and one-half bilateral. Scoliosis was associated with acetabular protrusion in 90% of cases (nine of ten). The authors conclude that acetabular protrusion is a common skeletal finding in the Marfan syndrome.

Acetabulum↗
PubMed1987

Pediatric patients with achondroplasia: CT evaluation of the craniocervical junction.

Twenty-six patients (4 months to 6 years old) with achondroplasia complicated by sleep apnea and/or other neurologic manifestations underwent plain computed tomography (CT) of the craniocervical junction; six also underwent CT myelography. For objectification, multiplanar reconstruction was used to complement axial plane measurements by providing coronal and sagittal measurements; multiplanar reconstruction also improved perception of the longitudinal relationships between the brain stem and subarachnoid space. A narrow subarachnoid space was found in all 26 patients; marked cord compression was present in nine, six of whom underwent CT myelography. These six had marked focal obliteration of the subarachnoid space on both plain CT and CT myelography. Since the subarachnoid space immediately above and below the craniocervical junction is normally capacious, when marked constriction was present, no additional information could have been gained from CT myelography. Thus, plain CT was shown to be sufficient for surgical planning (suboccipital decompression) in nine patients with cord compression due to achondroplasia.

Achondroplasia↗
PubMed1987

Marfan syndrome: evaluation with MR imaging versus CT.

Twenty-five patients with Marfan syndrome underwent computed tomography (CT) and magnetic resonance (MR) imaging. MR images were interpreted in blinded fashion and then the results were compared with findings from CT scans. MR imaging was found to be equivalent to CT in the depiction of aortic, dural, and hip abnormalities in patients who had not undergone surgery. MR imaging was superior to CT in evaluation of postoperative patients because the artifact produced by Bjork-Shiley or St. Jude valves precludes adequate evaluation of the aortic root on CT scans, while producing only a small inferior field distortion, a "pseudo-ventricular septal defect," on MR images. The absence of radiation exposure is another significant advantage for the relatively young Marfan syndrome population, who require serial studies. MR imaging is the modality of choice for evaluation and follow-up of patients with Marfan syndrome and offers an appropriate means of screening their kindred.

Adolescent↗
PubMed1987

Pulmonary function in the Marfan syndrome.

To explore the causes of reported abnormalities in pulmonary function in persons with the Marfan syndrome, we analyzed retrospective anthropometric and pulmonary function tests in 79 patients. For ten subjects, there were matched, related control subjects who did not have a connective tissue disorder. Patients had lower values of FVC and TLC than the values expected for their standing heights (83 and 91 percent). However, when sitting height was used to calculate expected spirometric values, patients free of severe deformity of the thoracic cage did not have significant spirometric abnormalities (FVC 105 percent, FEV1 92 percent). However, patients with moderate-to-severe pectus excavatum or scoliosis (common features of the Marfan syndrome) had marked reductions in total lung capacity as well as in FVC and FEV1, suggesting a restrictive ventilatory defect. The abnormalities of pulmonary function often found in clinical laboratories can be explained in most cases by inappropriate use of standing height to calculate expected values, by thoracic cage deformity, or by both. We have found no evidence from standard tests of pulmonary function for a connective tissue defect of lung parenchyma that is of clinical importance in Marfan patients who lack chest wall deformity.

Adolescent↗