A double-blind randomized trial of low-dose oral urea to prevent sickle cell crises

Seventy-nine homozygous SS patients were randomly assigned to control or oral prophylactic urea treatment in a double-blind trial designed to determine whether prophylactic oral urea, in low doses, prevents sickle cell crises. The average follow-up time for these patients was 13.7 months and 33 patients were diagnosed as having one or more crises during the study. No statistically significant treatment differences were found in weight changes, bilirubin changes, or hemoglobin changes over the course of the study or in the distribution of time to first crises or time to second crisis. This study gives no evidence in favor of the hypothesis that prophylactic oral urea, in low doses, prolongs time to crisis.     

A prospective, randomized, double-blind crossover study on the use of 5% citrate lock versus 10% citrate lock in permanent hemodialysis catheters

Central venous catheters are used as permanent vascular access for chronic hemodialysis when construction of an arteriovenous fistula is not possible or contraindicated. We prospectively evaluated the efficacy and safety of a 5% citrate versus 10% citrate catheter lock for permanent single-lumen dialysis catheters in a double-blind, crossover study of 28 patients during 1,876 dialysis sessions. There was a slightly higher number of dialysis sessions with clot formation in the 5% citrate group; entirely attributable to the formation of small clots. There was no statistically significant difference in the formation of large clots, complete obstruction of the catheter or the need for urokinase between the 2 study groups. In view of the ongoing debate on the safety of high-concentration citrate catheter locks, we conclude that a 5% citrate lock is equally efficient in preventing catheter dysfunction compared with a 10% citrate lock and is therefore the preferred citrate catheter-locking solution.     

Thrombotic microangiopathy in sickle cell disease crisis

Thrombotic microangiopathy (TMA) in patients with sickle cell disease (SCD) is a rare complication. These patients manifest microangiopathic hemolytic anemia (MAHA) with laboratory evidence of hemolytic anemia, schistocytosis, and thrombocytopenia. This is the first report of the syndrome in a group of these patients. A retrospective chart analysis of 10 consecutively diagnosed patients in SCD crisis who were referred for therapeutic plasma exchange (TPE) after developing MAHA was done. Patients had chest pain, respiratory distress, fever, pulmonary infiltrates, jaundice, and neurological dysfunction with abnormal liver function and coagulation tests. MAHA was diagnosed after a median hospital stay of 5 days. Nine patients recovered completely following TPE with fluid replacement by fresh frozen plasma with or without cryo-poor plasma. Incomplete response to TPE in one case was due to the development of fresh complications. During a median follow-up period of 77 months, there was one recurrent episode and one death in SCD crisis but without evidence of MAHA. TMA is not a very rare complication among Bahraini SCD patients in crisis. Characteristic features of this disorder are acute chest syndrome, organ failure, leuco-erythroblastosis, and a combination of thrombocytopenia, LDH level >1,000 U/l, and schistocytes in blood smears. Management with TPE usually leads to complete recovery with little chance of short-term recurrence. Multiple pathogenetic mechanisms leading to increased von Willebrand factor and its multimers may form the basis of this syndrome.     

Ischemic colitis complicating sickle cell crisis

Abdominal pain is quite common in sickle cell crisis, although the cause of abdominal pain is seldom determined and remains controversial. We have recently seen an 18-yr-old man with sickle cell disease who developed acute abdominal pain during a crisis. Rebound tenderness on physical exam and "thumbprinting" on barium enema examination suggested possible colon infarction. Histopathologic review of the resected ascending colon demonstrated mucosal necrosis and submucosal edema consistent with ischemic colitis. Hypotheses regarding the cause of abdominal pain in sickle crises are reviewed; the pathophysiology of sickle-cell induced vasocclusion and its relation to the development of ischemic colitis in our patient is discussed.     

The management of crisis in sickle cell disease

Abstract: The symptoms and signs of sickle cell disease are exacerbated in times of crisis, characterized by tissue infarction or worsening anaemia. Prompt medical intervention is required in these distressing situations to provide relief and comfort to the patient. Effective analgesia is crucial in treating the painful crisis of sickle cell disease. The haemoglobinopathy may cause hyposthenuria with reduced ability to excrete the sodium load in normal saline. A 5% dextrose solution or 5% dextrose in 25% normal saline is therefore recommended for intravenous hydration. As the leading cause of morbidity and mortality in sickle cell disease, infections call for vigorous antibiotic therapy. Oxygen administration should be reserved for hypoxic patients, and blood transfusion given only when really indicated. Acute chest syndrome and cerebrovascular accidents are life-threatening complications of sickle cell disease whereas priapism can cause important long-term sequelae; all deserve urgent attention. In the long term, comprehensive care is cost-effective in reducing the frequency and adverse effects of sickle cell crisis.     

Patient-controlled analgesia versus continuous infusion of morphine during vaso-occlusive crisis in sickle cell disease, a randomized controlled trial

Intravenous morphine is the treatment of choice for severe pain during vaso- occlusive crisis in sickle cell disease (SCD). However, side effects of morphine may hamper effective treatment, and high plasma levels of morphine are associated with severe complications such as acute chest syndrome. Furthermore, adequate dosing remains a problem since no objective measurement of pain severity exists and analgesia should be titrated upon the patient's reported pain. Patient-controlled analgesia (PCA) may therefore be an interesting alternative since patients can titrate the level of analgesia themselves. In this randomized controlled study, the efficacy of intravenous morphine administration with PCA was compared with continuous infusion (CI) of morphine in patients with SCD during vaso-occlusive crisis. Twenty five consecutive episodes of vaso-occlusive crisis in 19 patients with SCD were included in the study. Patients in the PCA-group had a markedly and significant lower mean and cumulative morphine consumption when compared with the patients in the CI-group (0.5 mg/hr versus 2.4 mg/hr (P < 0.001) and 33 mg versus 260 mg (P = 0.018, respectively). The mean daily pain scores were comparable (4.9 versus 5.3). The lower mean and cumulative morphine consumption in the PCA-group led to significant less nausea and constipation during treatment when compared with the CI-group (area under the curve, respectively, 11 versus 18 (P = 0.045) and 30 versus 45 (P = 0.021). Furthermore, a nonsignificant reduction in the duration of hospital admission of 3 days was observed in the PCA-group. PCA results in adequate pain relief at a much lower morphine consumption and should considered to be the first choice in morphine administration to sickle cell patients admitted with vaso-occlusive crisis.     

The painful crisis of homozygous sickle cell disease. A study of the risk factors

Some epidemiologic features of the painful crisis in homozygous sickle cell disease were examined in a retrospective study of 995 painful crises. Previously reported associations with cold weather and pregnancy were confirmed. There was a striking increase in painful crises in male patients between the ages of 15 and 25 years, whereas female patients showed little age-related change. The frequency of painful crises correlated positively with hemoglobin levels and reticulocyte counts in both sexes and negatively with mean corpuscular volume in female patients. There was a striking increase in painful crises in male patients with hemoglobin levels above 8.5 g/dL (greater than 85 g/L). High hemoglobin levels appear to be an important risk factor for painful crises.     

Increased circulating endothelial cells in sickle cell crisis

To determine whether increased numbers of circulating endothelial cells, a possible indicator of endothelial injury, are present in subjects with sickle cell disease, we measured circulating endothelial cells in 30 normal subjects and in 23 subjects with sickle cell anemia. Mean circulating endothelial cells were significantly higher (P less than 0.025) in the sickle cell subjects than in the normal subjects. Circulating endothelial cells were significantly higher than normal in 10 sickle cell subjects studied during painful crisis (P less than 0.01) but not in 13 sickle cell subjects studied while in the steady state. To control for the known stimulatory effect of cigarette smoking on circulating endothelial cells, we analyzed the results for smokers and nonsmokers separately. Mean circulating endothelial cells were not significantly higher in sickle cell subjects who smoked (n = 10) than in normal subjects who smoked (n = 8), but were significantly higher (P less than 0.05) in sickle cell nonsmokers (n = 13) than in normal nonsmokers (n = 22). Among nonsmoking sickle cell subjects, mean circulating endothelial cells were significantly higher than normal (P less than 0.01) during painful crisis (n = 7), but not in the steady state (n = 6). We conclude that circulating endothelial cells are significantly increased in sickle cell crisis, and may indicate the occurrence of acute endothelial injury during episodes of microvascular occlusion.     

Lead toxicity masquerading as sickle cell crisis

We recently saw a 12-year-old black boy with known sickle cell disease who had been seen many times for abdominal pain thought to be secondary to a vasoocclusive crisis. The patient eventually was admitted, after a seizure and the onset of obtundation. The etiology of his acute encephalopathy remained unclear until bone films of his knees fortuitously revealed "lead lines." The patient was treated and did well subsequently. This case emphasizes the importance of considering other diagnoses when a sickle cell patient presents with a crisis.     

A double-blind, placebo-controlled, randomized study of infliximab in primary sclerosing cholangitis

GOALS: To evaluate the safety and efficacy of infliximab in patients with primary sclerosing cholangitis. STUDY: In this double-blind, placebo-controlled study, 24 patients with primary sclerosing cholangitis were screened and randomly assigned in a 2:1 ratio to receive infliximab (5 mg/kg) or placebo at weeks 0, 2, 6, 12, 18, and 24; patients were followed through week 52. The primary efficacy end point was a decrease of at least 50% in the serum alkaline phosphatase level from baseline to week 18. A blinded histologic assessment of liver biopsy samples, obtained at weeks 0 and 26, was performed using a predefined scoring system, including scores for inflammation, fibrosis, and cholestasis. RESULTS: Patient enrollment was prematurely stopped when results of an interim analysis showed no significant treatment benefit. Of the 24 patients screened, 10 were enrolled (6 patients received infliximab). Mean alkaline phosphatase levels at weeks 0, 18, and 52 were 349, 330, and 389 U/L, respectively, for the infliximab group and 481, 438, and 391 U/L, respectively, for the placebo group. Liver biopsy samples were analyzed in 7 patients (4 infliximab); no apparent differences could be detected in any of the histologic parameters. In 3 of 4 infliximab-treated patients and 2 of 3 placebo-treated patients, the disease stage did not change after 6 months of treatment. No meaningful changes were detected in the symptom score. No serious drug-related adverse events were observed. CONCLUSIONS: Study findings failed to demonstrate efficacy of infliximab in this small group of patients with established primary sclerosing cholangitis.     

Red cells in sickle cell crisis: observations on the pathophysiology of crisis

The pathophysiology of the occurrence and resolution of sickle cell crisis is unknown. The molecular abnormality is constant, while crisis is episodic. In the present study, red cell filterability and sickling with deoxygenation have been measured during sickle cell crises. Recovery from sickle crisis is associated with an increased filterability of the circulating red cell and a decreased susceptibility of the red cell to sickle with deoxygenation (p less than 0.05). The possibility that these changes are responsible for the resolution of crisis is suggested.     

Patient-controlled analgesia in patients with sickle cell vaso-occlusive crisis

Pain control using intramuscular analgesia is often unsatisfactory in sickle cell patients. In a pilot study, 15 patients with sickle cell anemia (SS) and one patient with SB thalassemia in vaso-occlusive crisis were treated with the Patient-Controlled Analgesia (PCA) technique using a Pharmacia Deltec Programmable pump (CADD PCA). Age range was 19-50 years (median = 27); there were nine females and seven males. The protocol consisted of 3 days of therapy using a background of continuous infusion meperidine. The starting dose was 20 mg/hr and was escalated to 30 mg/hr. The average amount given was 25.8 mg/hr. One to two boluses of 2.5-5.0 mg/dose (mode = 5.0) were also allowed each hour. In addition, patients number 8 through 16 were given hydroxyzine (Vistaril) 50 mg PO q6h. The number of days in pain prior to study entry (mean +/- SD) was 3.3 +/- 1.6. The number of pain sites per patient was 3.6 +/- 1.2. Using categorical and analog pain scales, patients' pain scores decreased only about 30%. However, most patients were fairly satisfied with the treatment and rated it overall as follows: 1 poor, 1 fair, 3 good, 6 very good, 4 excellent, 1 no comment. Patients number 8 through 16 gave higher ratings probably because a more idealized dosage regimen was being used by that time in the study. There were no adverse effects or major problems noted. It is our impression that PCA, when optimized, will be a safe and effective alternative method for providing patients with sickle cell vaso-occlusive crisis pain relief.     

Acute pancreatitis during sickle cell vaso-occlusive painful crisis

Sickle cell disease is characterized by chronic hemolytic anemia and vaso-occlusive painful crisis. The vascular occlusion in sickle cell disease is a complex process and accounts for the majority of the clinical manifestations of the disease. Abdominal pain is an important component of vaso-occlusive painful crisis and may mimic diseases such as acute appendicitis and cholecystitis. Acute pancreatitis is rarely included as a cause of abdominal pain in patients with sickle cell disease. When it occurs it may result form biliary obstruction, but in other instances it might be a consequence of microvessel occlusion causing ischemia. In this series we describe four cases of acute pancreatitis in patients with sickle cell disease apparently due to microvascular occlusion and ischemic injury to the pancreas. All patients responded to conservative management. Acute pancreatitis should be considered in the differential diagnosis of abdominal pain in patients with sickle cell disease.