Darleen R. Powars

The natural history of stroke in sickle cell disease

Abstract The occurrence and progression of strokes in patients with sickle cell disease and the resultant structural and functional defects were investigated by an indepth study of 35 patients, 32 of whom are part of a natural history study of 537 patients. The relative frequency for all ages is 6 per cent. Strokes are predominantly seen in patients with sickle cell anemia (33 with sickle cell anemia and two with heterozygous hemoglobin S and C (SC) disease). Twenty-five of the patients were less than 20 years old at the time of the first stroke—9.1 per cent of all patients observed during this age range. The actuarial or predictive risk of an initial stroke during the first two decades is 0.761 episodes per 100 person years whereas after age 20 the risk is 0.524 episodes per 100 person years. Children significantly at risk (p

Outcome of Sickle Cell Anemia: A 4-decade Observational Study of 1056 Patients

Abstract: Based on a prospective cohort study of 1056 patients with sickle cell anemia (Hb SS) initiated in 1959, we investigated the influence of calendar era, age, sex, and prior medical conditions on the subsequent development of irreversible organ damage and survival using the Cox regression model with time-dependent covariates adjusting for all prior occurrences. We studied 30 acute clinical events, and focused on 8 prototypic forms of irreversible organ damage. Childhood survival to age 20 years has improved from 79% for those born before 1975 to 89% for children born in or after 1975. Bone infarction was a significant risk factor for avascular necrosis (p = 0.01), and infantile dactylitis was a significant risk factor for stroke (p = 0.01). Prior hospitalized vaso-occlusive sickle crisis in adults was significantly associated with the increased rate of avascular necrosis (p < 0.001), leg ulcers (p < 0.001), sickle chronic lung disease (p < 0.001), renal failure (p < 0.005), and early death (p < 0.001). The diagnosis of clearly evident clinical conditions such as leg ulcer, osteonecrosis, and retinopathy predicted an increased likelihood of developing a more lethal form of organ damage and earlier death: 77% of patients with chronic lung disease, 75% of those with renal insufficiency, and 51% of those with stroke had a prior chronic condition. Of the 232 patients who died, 73% had 1 or more clinically recognized forms of irreversible organ damage. By the fifth decade, nearly one-half of the surviving patients (48%) had documented irreversible organ damage. End-stage renal disease (glomerulosclerosis), chronic pulmonary disease with pulmonary hypertension, retinopathy, and cerebral microinfarctions are manifestations of arterial and capillary microcirculation obstructive vasculopathy. The current study underscores the need for preventive therapy to ameliorate the progression of the sickle vasculopathy. Abbreviations: CVA = cerebral vascular accident.

Sickle Cell Chronic Lung Disease: Prior Morbidity and the Risk of Pulmonary Failure

Sickle cell chronic lung disease (SCLD) is a prime contributor to mortality in young adult patients with sickle cell disease, especially those with sickle cell anemia (SS). Both perfusion and diffusion defects have been demonstrated, with generalized pulmonary fibrosis and disabling restrictive lung failure. We report 28 cases (25 SS, 1 S beta(0) thalassemia, 1 S beta(+) thalassemia and 1 SO-Arab) which began during the second decade of life and which ended in death by the fourth decade, after an ordered progression to pulmonary failure and cor pulmonale. Myocardial hypoxia with multifocal fibrosis and segmental infarction occurred in more than one-third of the cases and sudden death was a frequent final event. We define 4 stages of SCLD, based on pulmonary function tests, chest roentgenograms, blood gases, and noninvasive cardiac studies; each stage is 2 or 3 years in length, until death ensues in Stage 4. Case-control analysis showed that the significant risk factors associated with SCLD are 1) the total number of acute chest syndrome events in an individual before the onset of SCLD, (p = 0.0001), 2) sickle cell crisis marked by chest pain (p = 0.03) and 3) aseptic necrosis (p = 0.005). Temporal clustering of acute chest syndrome episodes frequently heralds the onset of SCLD. The pulmonary arterial bed, which has low oxygen tension and low pressure in a slow-flow system, is ideally suited to facilitate the polymerization of sickle hemoglobin, causing endothelial damage and culminating in an obstructive arteriolar vasculopathy. Identification of the significant risk factors predictive of SCLD can lead to early diagnosis of the disease; this is the only hope for effective intervention therapy.

Lack of influence of fetal hemoglobin levels or erythrocyte indices on the severity of sickle cell anemia.

Persons with sickle cell anemia who have elevated fetal hemoglobin or lowered erythrocyte mean corpuscular volume are reputed to have less severe clinical manifestations and a greater probability of survival. This study examines the relationship between seven clinical indicators of morbidity in sickle cell anemia and seven hematological parameters that were collected from 214 patients. Risks of sickle cell crisis, acute chest syndrome, hospital admissions, cerebrovascular accident, aseptic necrosis, meningitis/septicemia, and death were used as indicators of morbidity. The hematological parameters included percent fetal hemoglobin, absolute fetal hemoglobin, percent hemoglobin A2, hemoglobin concentration, packed cell volume, mean corpuscular volume, and mean corpuscular hemoglobin concentration. Statistical analyses of the data showed no relationship between the hematological parameters and six of the seven clinical indicators of the severity of sickle cell anemia. The only significant finding was an increased risk of stroke in those patients with lower levels of fetal hemoglobin. Therefore, with this exception, there is no predictable relationship between morbidity and mortality in sickle cell anemia and levels of fetal hemoglobin or erythrocyte indices. Thus, the general belief that there is an association between severity of sickle cell anemia and the levels of fetal hemoglobin has not been established.

Anxiety, Self-Concept, and Personal and Social Adjustments in Children with Sickle Cell Anemia.

The psychologic effect of sickle cell anemia, a life-long chronic illness, on the self-concept, anxiety level, and personal and social adjustments of school-aged children was investigated by using a battery of standard psychologic tests. Two groups of children were evaluated: a study group of 29 children with sickle cell anemia (hemoglobin SS) and a comparison group of 26 black inner city schoolchildren without sickle cell disease or other known chronic illness. The youngsters with sickle cell anemia did not differ from a peer group of schoolchildren in personal, social, and total adjustments. The self-concept scores of the patient group were lower than those of the comparison group. An unexpected finding of the study was the observation that the anxiety scores (measuring acute anxiety) were significantly lower in the study group than those in the comparison group.

βS-gene-cluster haplotypes in sickle cell anemia : clinical implications

Restriction endonuclease analysis was used to detect alpha-gene deletions and to determine the haplotypes in the DNA of the beta S-gene-cluster [Benin, Central African Republic (CAR), and Senegal] in 221 patients with sickle cell anemia (SS). The clinical expression of SS was modified by the beta S-gene-cluster polymorphisms and the alpha-gene status (alpha-thalassemia-2). The overall risk of soft tissue organ failure caused by the obliterative sickle vasculopathy (including stroke, renal failure, chronic lung disease with cor pulmonale, leg ulcers, and young adult death) was increased threefold in those with a CAR haplotype and was decreased in those with a Senegalese chromosome (p = 0.003). In the presence of a Senegalese haplotype, the patients health is better, and with the CAR haplotype it is always worse. With the Benin, it is intermediate. Acute recurrent clinical events including hospitalized sickle cell crisis, bone infarction, and infection are decreased in frequency in those with a Senegalese haplotype. The risk of most acute events including acute chest syndrome is equivalent in those with Benin or CAR haplotypes. In the United States, alpha-thalassemia-2 is co-inherited randomly among the beta S-gene-cluster haplotypes. Acute events occurring during childhood are minimally effected by this co-inheritance. The risk of soft tissue organ failure is decreased. After the age of 20 years, painful episodes of the lumbar dorsal area are increased in patients who had alpha-thalassemia-2 in association with degenerative bone disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Separation of peptides by high-pressure liquid chromatography for the identification of a hemoglobin variant.

High-pressure liquid chromatography on a reversed-phase column has been used to separate the tryptic peptides of a human hemoglobin variant which was then identified as hemoglobin E.

Sickle cell anemia and major organ failure.

Major organ failure in sickle cell anemia is the direct consequence of the sickle cell evoked vasculopathy. Major organ failure is first clinically apparent as autosplenectomy, then during childhood presents as cerebral infarction and atrophy, and finally culminates in young adulthood as end stage renal failure (glomerulosclerosis), sickle chronic lung disease, intracranial hemorrhage, retinopathy, disabling leg ulcers, and generalized osteonecrosis. The vascular damage begins years before the overt clinical symptoms are apparent with no pain to act as a signal. Organ damage is progressive and irreversible. The rate of progression is genetically controlled from birth. Except for the management of life-threatening infections that are associated with the non-functioning spleen, disease expression has not been altered by therapy. The focus of future clinical investigations must be the prevention of the vasculopathy and tissue damage which is induced by the sickle red cell.

Small noncleaved follicular center cell (FCC) lymphoma: Burkitt and non‐Burkitt variants in the United States. I. Clinical features

With the understanding that Burkitts lymphoma was of follicular center cell (FCC) derivation, Lukes and Collins classified the tumor, descriptively, as small noncleaved FCC lymphoma. Two subtypes were described: Burkitt and non‐Burkitt. Attempting to define the clinicopathologic features of the subtypes, we studied 42 patients: 25 Burkitt and 17 non‐Burkitt. Histologically, the Burkitt tumor demonstrated remarkable uniformity of nuclear size and contour, whereas the non‐Burkitt variant had greater variability. Immunoglobulin monoclonality was demonstrated in 83% of Burkitt and 81% of non‐Burkitt cases. Burkitt patients tended to be younger. Gastrointestinal disease was seen in 15 Burkitt and only four non‐Burkitt patients (P < 0.05). Disseminated disease was found in the majority of both variants. Marrow involvement was demonstrated in 4.5% of Burkitt and 37.5% of non‐Burkitt patients (P < 0.05). Median survival of Burkitt patients was 10.5 months versus 7.7 months in the non‐Burkitt group. The authors believe that significant biologic differences between the variants have been demonstrated, which may be of potential value to the clinician.

Multisystem damage associated with tricorporal priapism in sickle cell disease

PURPOSE Priapism is an uncommon but debilitating complication of sickle cell disease (SCD). Recent observations among adult males regarding the abysmal failure of medical and surgical therapy encouraged us to review our 25-year experience identifying the prognostic features that might determine outcome. PATIENTS AND METHODS As part of a prospective 25-year longitudinal demographic and clinical cohort study, a subset of 38 (8.2%) patients with priapism were identified among a cohort of 461 men with SCD. The patients with priapism were compared with the nonaffected men with respect to severity of disease expression, hematologic status, beta s globin gene haplotype, and the incidence of sickle-related major organ failure. The influence of the treatment modalities on outcome was also evaluated. RESULTS Priapism occurred as a single episode in 24 patients, and in 14 as temporally clustered repeat episodes. Eighty-seven percent of those with priapism had sickle cell anemia (SS), an increased risk as compared with other variants of SCD (p = < 0.05). There were two distinct age-related patterns of disease expression. Eight patients were prepubertal; they experienced shorter episodes, involvement of the corpora cavernosa only, few recurrent episodes, and a good prognosis for future erectile function. Non-surgical therapy in children was associated with excellent results. In contrast, the 29 postpubertal adults often had involvement of the corpora cavernosa and corpus spongiosa (tricorporal disease) and half had prolonged episodes that lasted longer than 8 days. One pubescent patient had repeated episodes and became impotent. Prolonged or repeated episodes eventuated in impotence in 56%. Surgical intervention was not beneficial. Sickle cell-related organ failure such as stroke, chronic restrictive lung disease, chronic renal failure, and nonhealing leg ulcers was observed more frequently in men who had priapism. Death occurred in nine adult patients (25%) within 5 years of the first episode of priapism. CONCLUSION Priapism in adult males identifies those at high risk for other sickle cell-related organ failure syndromes and, as such, is another complication indicative of severe disease. The dismal prognosis in SS adults requires better understanding of the precise pathophysiology of low-flow tricorporal priapism. Clarification of the mechanisms inducing the priapic state should lead to specific therapeutic maneuvers and an improved prognosis for this disabling condition.