Effect of octreotide on refractory AIDS-associated diarrhea. A prospective, multicenter clinical trial

Diarrhoea of unknown cause: medical treatment in a stepwise manner

The basic principle for the treatment of idiopathic diarrhoea (functional diarrhoea K59.1) is to delay transit through the gut in order to promote the absorption of electrolytes and water. Under mild conditions, bulking agents may suffice. With increasing severity, antidiarrhoeal pharmaceuticals may be added in a stepwise manner. In diarrhoea of unknown aetiology, peripherally-acting opioid receptor agonists, such as loperamide, are first-line treatment and forms the pharmaceutical basis of antidiarrheal treatment. As second-line treatment opium drops have an approved indication for severe diarrhoea when other treatment options fail. Beyond this, various treatment options are built on experience with more advanced treatments using clonidine, octreotide, as well as GLP-1 and GLP-2 analogs which require specialist knowledge the field.

Past, current, and potential treatments for cryptosporidiosis in humans and farm animals: A comprehensive review

The intracellular protozoan parasite of the genus Cryptosporidium is among the leading causes of waterborne diarrheal disease outbreaks throughout the world. The parasite is transmitted by ingestion of infective oocysts that are highly stable in the environment and resistant to almost all conventional disinfection methods and water treatments. Control of the parasite infection is exceedingly difficult due to the excretion of large numbers of oocysts in the feces of infected individuals that contaminate the environment and serve as a source of infection for susceptible hosts including humans and animals. Drug development against the parasite is challenging owing to its limited genetic tractability, absence of conventional drug targets, unique intracellular location within the host, and the paucity of robust cell culture platforms for continuous parasite propagation. Despite the high prevalence of the parasite, the only US Food and Drug Administration (FDA)-approved treatment of Cryptosporidium infections is nitazoxanide, which has shown moderate efficacy in immunocompetent patients. More importantly, no effective therapeutic drugs are available for treating severe, potentially life-threatening cryptosporidiosis in immunodeficient patients, young children, and neonatal livestock. Thus, safe, inexpensive, and efficacious drugs are urgently required to reduce the ever-increasing global cryptosporidiosis burden especially in low-resource countries. Several compounds have been tested for both in vitro and in vivo efficacy against the disease. However, to date, only a few experimental compounds have been subjected to clinical trials in natural hosts, and among those none have proven efficacious. This review provides an overview of the past and present anti-Cryptosporidium pharmacotherapy in humans and agricultural animals. Herein, we also highlight the progress made in the field over the last few years and discuss the different strategies employed for discovery and development of effective prospective treatments for cryptosporidiosis.

Treatment of human intestinal cryptosporidiosis: A review of published clinical trials

The global burden of diarrhea caused by Cryptosporidium parasite is underestimated. In immunocompromised hosts, chronic and severe presentation of intestinal cryptosporidiosis can result in long-term morbidity and high illness costs. The evidence of effective treatments for cryptosporidiosis has been lacking. We reviewed the published clinical trials to bring forward the feasible therapeutic options of human cryptosporidiosis in various populations and settings according to clinical improvement and parasite clearance rates. A total of 42 studies consisting of the use of nitazoxanide, paromomycin, macrolides, somatostatin analogues, letrazuril, albendazole, rifaximin, miltefosine, clofazimine, and colostrum were included in the review. The trials were mostly conducted in small number of individuals infected with human immunodeficiency virus (HIV), and there is inadequate data of controlled trials to suggest the use of these treatment modalities. Nitazoxanide was reported to be highly efficacious only in immunocompetent hosts and was found to be superior to paromomycin in the same group of patients. Macrolides showed no effective results in both clinical and parasitological improvement. Human bovine colostrum should possibly be administered as one of complementary therapeutic modalities along with other antimicrobials to reach optimal parasite eradication. Other trials of therapeutic modalities were terminated due to futility. Currently, available data is intended to aid the development of strategies for improving access to treatments in different clinical settings, as well as to help guide further studies on treatments of human intestinal cryptosporidiosis.

Lanreotide Autogel in the Treatment of Idiopathic Refractory Diarrhea: Results of an Exploratory, Controlled, Before and After, Open-label, Multicenter, Prospective Clinical Trial

PURPOSE

Chronic idiopathic diarrhea is the passage of loose stools >3 times daily, or a stool weight >200 g/d, persisting for >4 weeks without clear clinical cause. Patients refractory to standard anti-diarrhetics have limited treatment options. Somatostatin analogues have the ability to reduce gastrointestinal secretions and motility. This study evaluated the efficacy and safety of lanreotide Autogel(*) 120 mg in chronic idiopathic diarrhea.

METHODS

Other anti-diarrhetics were not allowed during the study and were stopped at screening. Patients received lanreotide Autogel 120 mg at baseline and day 28. Stool frequency and consistency (Bristol Stool Scale) were recorded; quality of life (QoL) was assessed using the 36-item Short Form Health Survey and irritable bowel syndrome QoL questionnaires; adverse events were monitored. The primary outcome was the proportion of patients with a reduction of ≥50% or normalization to a mean of ≤3 stools/d at day 28.

FINDINGS

Thirty-three patients with >3 stools/d at baseline were included; mean (SD) age was 55.2 (16.4) years. Fourteen patients (42.4%) had a response to lanreotide Autogel at day 28 and 17 (51.5%) at day 56. Mean (SD) number of stools decreased significantly from 5.7 (2.2) at baseline to 3.7 (2.2) at day 56 overall (n = 32; P < 0.001). Significant and clinically meaningful improvements in disease-specific QoL were found in the overall populations. No new safety signals emerged.

IMPLICATIONS

Lanreotide Autogel 120 mg decreased symptoms in these patients with chronic idiopathic refractory diarrhea, and meaningfully improved QoL. These finding have to be confirmed in further clinical trials. ClinicalTrials.gov

IDENTIFICATION

NCT00891371; Eudract CT 2009-009356-20.

The role of octreotide in symptom management in oncology and palliative care

Objective. To provide an overview of the role of octreotide for managing symptoms in oncology and palliative care.

Data Sources. A search of MEDLINE and IDIS databases from 1985 to 1999 and CANCERLIT from 1993 to 1999 was conducted using the terms octreotide, cancer and palliative care. The reference lists from selected articles were also reviewed. Clinical trial databases on the Internet were searched. Oncology and palliative care textbooks were also used to obtain additional references.

Data Extraction. The retrieved literature was reviewed to discuss the pharmacology, pharmacokinetics, adverse effects, indications and principally, the clinical use of octreotide for controlling a number of symptoms encountered in the oncology and palliative care population.

Data Synthesis. The unique inhibitory activity of octreotide lends itself to many possible indications, including diarrhoea from a number of causes, bowel obstruction, nausea and vomiting, bleeding, death rattle, gastrointestinal fistulae, pain and hypercalcaemia. However, convincing pieces of evidence from large prospective clinical trials are required to realise its full potential in oncology and palliative care. Completed studies and clinical experience suggest that octreotide has a role in the treatment of a number of difficult-to-manage conditions, particularly bowel obstruction and diarrhoea due to disease or treatment-related causes. Proposed benefits of octreotide must be weighed against the possible adverse effects and cost effectiveness of treatment.

Noninfectious Diarrhea in HIV Seropositive Individuals: a Review of Prevalence Rates, Etiology, and Management in the Era of Combination Antiretroviral Therapy

Introduction

Diarrhea poses a substantial burden for patients with human immunodeficiency virus (HIV), negatively impacting quality-of-life (QoL) and adherence to antiretroviral therapy. During the combination antiretroviral therapy (cART) era, as incidence of opportunistic infection as a cause of diarrhea decreased, incidence of noninfectious diarrhea (including diarrhea as an adverse event [AE] of cART and HIV enteropathy) increased proportionately. A literature search was conducted for information on prevalence, etiology, and treatment options for noninfectious diarrhea in patients with HIV.

Results

For marketed antiretroviral therapies, up to 28% of patients live with >4 loose or watery stools per day. The US Food and Drug Administration (FDA) does not require pharmaceutical manufacturers to include, within approved prescribing information, prevalence rates for all grades of diarrhea. Traditionally, noninfectious diarrhea management focused on avoiding use of diarrhea-associated cART; symptom management (nonpharmacologic and/or pharmacologic); and, as a last resort, changing cART. Examining the evidence upon which this approach is based reveals that most strategies rely upon anecdotal information and case reports. This review summarizes the literature and updates clinicians on the most recent options for management of noninfectious diarrhea in patients with HIV.

Conclusion

Diarrhea in patients with HIV is a significant unmet clinical need that contributes to worsening QoL and complicates medical management. Approaching management using a stepwise method of nonpharmacologic (diet), nonprescription (over-the-counter) and, finally, prescription agent changes (modification of cART or addition of an evidence-based antidiarrheal) appears reasonable, despite a lack of clear scientific evidence to support the initial two steps of this approach. If diet modifications, including psyllium and fiber introduction, fail to resolve noninfectious diarrhea in patients with HIV, loperamide followed by crofelemer should be considered. Clinicians are encouraged to review the most recent literature, not rely upon prescribing information. Continued vigilance by HIV providers to the presence of gastrointestinal AEs, even in patients taking the most recently approved antiretroviral agents, is warranted. Additional research is justified in identifying the etiology and management of HIV-associated diarrhea in patients on successful cART regimens.

Electronic supplementary material

The online version of this article (doi:10.1007/s40121-014-0047-5) contains supplementary material, which is available to authorized users.

Review article: the aetiology, investigation and management of diarrhoea in the HIV-positive patient

BACKGROUND

Diarrhoea is a common presentation throughout the course of HIV disease.

AIM

To review the literature relating to aetiology, investigation and management of diarrhoea in the HIV-infected adult.

METHODS

The PubMed database was searched using major subject headings 'AIDS' or 'HIV' and 'diarrhoea' or 'intestinal parasite'. The search was limited to adults and to studies with >10 patients.

RESULTS

Diarrhoea affects 40-80% of HIV-infected adults untreated with antiretroviral therapy (ART). First-line investigation is by stool microbiology. Reported yield varies with geography and methodology. Molecular and immunological methods and special stains have improved diagnostic yield. Endoscopy is diagnostic in 30-70% of cases of pathogen-negative diarrhoea and evidence supports flexible sigmoidoscopy as a first line screening procedure (80-95% sensitive for CMV colitis), followed by colonoscopy and terminal ileoscopy. Radiology is useful to assess severity, distribution, complications and to diagnose HIV-related malignancies. Side effects and compliance with ART are important considerations in assessment. There is a good evidence base for many specific therapies, but optimal treatment of cryptosporidiosis is unclear and only limited data support symptomatic treatments.

CONCLUSIONS

The immunological response to HIV infection and Antiretroviral therapy remains incompletely understood. Antiretroviral therapy regimens need to be optimised to suppress HIV while minimising side effects. Effective agents for management of cryptosporidiosis are lacking. There is an urgent need for enhanced regional diagnostic facilities in countries with a high prevalence of HIV. The ongoing roll-out of Antiretroviral therapy in low-resource settings will continue to change the aetiology and management of this problem, necessitating ongoing surveillance and study.

Pharmacological management of diarrhea

According to the World Health Organization, there are approximately 2 billion annual cases of diarrhea worldwide. Diarrhea is the leading cause of death in children younger than 5 years and kills 1.5 million children each year. It is especially prevalent in the developing world, where mortality is related to dehydration, electrolyte disturbance, and the resultant acidosis, and in 2001, it accounted for 1.78 million deaths (3.7% of total deaths) in low- and middle-income countries. However, diarrhea is also a common problem in the developed world, with 211 million to 375 million episodes of infectious diarrheal illnesses in the United States annually, resulting in 73 million physician consultations, 1.8 million hospitalizations, and 3100 deaths. Furthermore, 4% to 5% of the Western population suffers from chronic diarrhea. Given the high prevalence of diarrhea, research has been directed at learning more about the cellular mechanisms underlying diarrheal illnesses in order to develop new medications directed at novel cellular targets. These cellular mechanisms and targets are discussed in this article.

Idiopathic AIDS enteropathy and treatment of gastrointestinal opportunistic pathogens

Diarrhea in patients with acquired immune deficiency syndrome (AIDS) has proven to be both a diagnostic and treatment challenge since the discovery of the human immunodeficiency virus (HIV) virus more than 30 years ago. Among the main etiologies of diarrhea in this group of patients are infectious agents that span the array of viruses, bacteria, protozoa, parasites, and fungal organisms. In many instances, highly active antiretroviral therapy remains the cornerstone of therapy for both AIDS and AIDS-related diarrhea, but other targeted therapies have been developed as new pathogens are identified; however, some infections remain treatment challenges. Once identifiable infections as well as other causes of diarrhea are investigated and excluded, a unique entity known as AIDS enteropathy can be diagnosed. Known as an idiopathic, pathogen-negative diarrhea, this disease has been investigated extensively. Atypical viral pathogens, including HIV itself, as well as inflammatory and immunologic responses are potential leading causes of it. Although AIDS enteropathy can pose a diagnostic challenge so too does the treatment of it. Highly active antiretroviral therapy, nutritional supplementation, electrolyte replacements, targeted therapy for infection if indicated, and medications for symptom control all are key elements in the treatment regimen. Importantly, a multidisciplinary approach among the gastroenterologist, infectious disease physician, HIV specialists, oncology, and surgery is necessary for many patients.

Resolution of refractory chemotherapy-induced diarrhea (CID) with octreotide long-acting formulation in cancer patients: 11 case studies

PURPOSE

Subcutaneous (SC) octreotide has been shown to effectively relieve chemotherapy-induced diarrhea (CID) refractory to conventional therapy but requires t.i.d. injections. A microencapsulated, long-acting formulation (LAR) of octreotide has been developed for once-monthly intramuscular (IM) dosing. Efficacy in resolving severe diarrhea and preventing further episodes of diarrhea in cancer patients was explored.

PATIENTS AND METHODS

Patients with advanced cancer who developed CID and failed conventional antidiarrheal therapy (loperamide + diphenoxylate-atropine) received octreotide LAR IM. The starting dose was either 20 or 30 mg with possible dose escalation from 20 to 30 mg and from 30 to 40 mg. Treatment was repeated every 28 days during chemotherapy.

RESULTS

Complete resolution of diarrhea within 1 to 4 weeks from injection time was seen in all cases with octreotide LAR 30 mg. With a subsequent prophylactic injection once every 28 days, CID was limited to NCI grade 1. This resulted in increased patient quality of life (QOL) and allowed better patient compliance with therapy. Therapy could then be completed at full dose and on schedule after resolution of often debilitating diarrhea.

CONCLUSION

The ability of octreotide LAR 30 mg to speed the resolution of CID and limit further episodes of diarrhea to infrequent NCI grade 1 controlled with loperamide (prn) suggests that long-acting somatostatin homologues have the potential to be useful in the secondary prevention of diarrhea in patients undergoing chemotherapy.

Some aspects of protozoan infections in immunocompromised patients- a review

Protozoa are among the most important pathogens that can cause infections in immunocompromised hosts. These microorganisms particularly infect individuals with impaired cellular immunity, such as those with hematological neoplasias, renal or heart transplant patients, patients using high doses of corticosteroids, and patients with acquired immunodeficiency syndrome. The protozoa that most frequently cause disease in immunocompromised patients are Toxoplasma gondii, Trypanosoma cruzi, different Leishmania species, and Cryptosporidium parvum; the first two species cause severe acute meningoencephalitis and acute myocarditis, Leishmania sp. causes mucocutaneous or visceral disease, and Cryptosporidium can lead to chronic diarrhea with hepatobiliary involvement. Various serological, parasitological, histological and molecular methods for the diagnosis of these infections are currently available and early institution of specific therapy for each of these organisms is a basic measure to reduce the morbidity and mortality associated with these infections.

Systematic review: the use of somatostatin or octreotide in refractory diarrhoea

BACKGROUND

Somatostatin and octreotide have multiple effects which make them ideal for treating diarrhoea of different aetiologies. Their use in a variety of conditions with refractory diarrhoea, however, is based on a limited number of studies.

AIM

We undertook a systematic review of the available English literature to maximize an evidence-based approach to the treatment of refractory diarrhoea. We tested the hypothesis that efficacy is independent of aetiology.

METHODS AND RESULTS

A Medline and individual article search from 1965 to 2000 was undertaken on the use of somatostatin and octreotide in diarrhoea. All reports containing at least five subjects were included. The percentage response in case series and randomized controlled trials was compared, and a meta-analysis of randomized controlled trials where patient level data were provided was carried out. There were 30 publications found (18 case series, 12 randomized controlled trials). The response percentage was 73% overall in case series and 64% in randomized controlled trials (not significant). A meta-analysis of nine randomized controlled trials revealed significant heterogeneity despite an overall relative risk of 0.5 (95% confidence interval, 0.27-0.91). Subgroup analysis of the largest aetiological groups showed that acquired immunodeficiency syndrome studies were homogeneous, but somatostatin and octreotide were less effective. Post-chemotherapy studies remained heterogeneous and somatostatin and octreotide were highly effective.

CONCLUSIONS

While this review strengthens the consensus guidelines on the use of somatostatin and octreotide for refractory diarrhoea, evidence-based support requires additional studies.

Infectious diarrhea in human immunodeficiency virus

Chronic HIV-associated diarrhea is currently a field in flux. Improved noninvasive diagnostic tests, improved pathogen-specific regimens, and better empiric therapies may change some of the assumptions used to select algorithms for diagnostic evaluation and management. Any shift in the cause of diarrhea from pathogen-associated to idiopathic or a reduction in the overall incidence of diarrhea would have considerable impact. It is unclear how significant the problem of pathogen relapse in previous responders will become. Existing studies reviewed in this article show that the high diagnostic yield of endoscopy when stool tests are negative, coupled with significantly better outcomes when pathogens are identified, support the current practice of routine endoscopic evaluation. There currently are scant data on the economic impact of HIV-associated diarrhea as it relates to pathogen-specific and empiric therapy in the era of protease inhibitors. Such data would be integral to future evaluation of the impact of diagnostic and therapeutic strategies.

Drug treatment of microsporidiosis

Microsporidia are ubiquitous organisms that are emerging pathogens in humans. These are most likely zoonotic and/or waterborne infections. In the immunosuppressed host, such as those treated with immunosuppressive drugs or infected with human immunodeficiency virus particularly at advanced stages of the disease, microsporidia can produce a wide range of clinical diseases. The most common manifestation is gastrointestinal tract infection; however, encephalitis, ocular infection, sinusitis, myositis and disseminated infection have also been described. In addition, these organisms have been reported in immune competent individuals. Multiple genera are involved in these infections and different organisms can result in distinct clinical pictures. Differences in clinical and parasitologic response to various therapeutic agents have emerged from clinical, as well as in vitro and in vivo studies. Currently there are no precisely defined guidelines for the optimal treatment of microsporidial infections. This article reviews the available data on compounds with in vitro activity and/or in vivo efficacy for microsporidial infections. Copyright 2000 Harcourt Publishers Ltd.

Antisecretory agents in gastrointestinal obstruction

Gastrointestinal obstruction is associated with nausea, vomiting, and abdominal pain. Antisecretory agents can relieve these symptoms, even in the absence of surgical or mechanical intervention. These medical management approaches are outlined, and recommendations are made.

Management of cancer treatment-related diarrhea. Issues and therapeutic strategies

The cancer treatment-related diarrhea caused by acute graft-versus-host disease (GVHD) and chemotherapeutic agents, particularly fluoropyrimidines and irinotecan, significantly affects patient morbidity and mortality. The mechanisms causing cancer treatment-related diarrhea are not fully understood, but histopathologic evidence points to a multifactorial process that causes an absorptive and secretory imbalance in the small bowel. Cancer treatment-related diarrhea could be life-threatening, yet assessment and treatment are not currently standardized. Several clinicians participated in a closed roundtable meeting to review the mechanisms of chemotherapy-induced diarrhea (CID) and GVHD-induced diarrhea, management issues in cancer treatment-induced diarrhea, and pharmacologic approaches to treatment. The meeting produced a proposal for new treatment guidelines and an algorithm, which include the use of octreotide for the management of CID- and GVHD-induced diarrhea. The development of diarrhea assessment guidelines that expand on the current National Cancer Institute criteria and allow for better patient management was also proposed.

Encephalopathy and cytomegalovirus colitis in an AIDS child

A 2-year-old girl, who had prolonged thrush and spastic diplegia, was found to have a mother-to-child vertical transmission of human immunodeficiency virus type-1 (HIV). A brain computed tomography scan revealed a symmetrical calcification on the bilateral basal ganglia and periventricular white matter. She had an acquired immune deficiency syndrome (AIDS) encephalopathy of pure dominant pyramidal tract disorder without an intellectual deficit. Helper cell lymphocyte count (CD4) increased with the beginning of zidovudine (ZDV, also known as AZT) monotherapy but began to decrease after the 4th week to reach the baseline at 20th week. Zidovudine plus didanosine combination therapy was started at the 68th week, but because of intolerance, the combination was changed to ZDV plus lamivudine at the 98th week. By the 80th week, neither severe opportunistic infection nor deterioration of the neurological status was recognized, but chronic diarrhea appeared. The diarrhea advanced to the wasting syndrome at the age of 4 years and cytomegalovirus genome was confirmed in a biopsied specimen of the colon. Ganciclovir treatment was effective in stopping the diarrhea and increasing her bodyweight, but after the age of 5, resumption of diarrhea was followed by progressive emaciation and weakness. This work may provide some clues in treating children's AIDS.

Ultra-rapid, antagonist-precipitated opiate detoxification under general anaesthesia or sedation

Ultra-rapid opiate withdrawal precipitated by naloxone or naltrexone during general anaesthesia or varying degrees of sedation, usually with the addition of α-2 adrenergic agonists, is an increasingly popular technique. As with anaesthesia or effective analgesia for dentistry or obstetrics, it can be justified on general humane principles. It also simplifies and speeds the transition to treatment programmes involving naltrexone. This paper reviews its development and the current range of techniques, including the use of octreotide to prevent diarrhoea. The prospect of avoiding or shortening the worst discomforts of withdrawal may encourage more opiate addicts to attempt detoxification and opiate-free management, including patients who have been successfully rehabilitated on long-term methadone maintenance treatment (MMT). Despite good motivation and preparation, a significant minority of MMT patients consistently fail to complete conventional withdrawal programmes because of increasing physical discomfort. It is emphasized that there is usually more to the treatment of opiate dependence than withdrawal.

The pancreas in AIDS

Although autopsy studies reveal significant pancreatic lesions in about 10% of AIDS patients, pancreatic lesions infrequently produce symptoms and are rarely recognized premortem. Patients with AIDS can develop pancreatic disease from causes not related to AIDS or AIDS-specific lesions. AIDS-specific causes include opportunistic infection, AIDS-associated neoplasia, and medications used to treat complications of AIDS. Pancreatic involvement is usually part of a widely disseminated tumor and rarely produces clinical symptoms.

Review article: the therapy of gastrointestinal infections associated with the acquired immunodeficiency syndrome

Although there have been dramatic strides in the therapy of human immunodeficiency virus infection over the last few years, the number of infected people world-wide is tremendous and, at least in developing countries, continues to expand. Complications which involve the gastrointestinal tract are common in these patients, because the gut is a major site for involvement by opportunistic infections and neoplasms in patients with the acquired immunodeficiency syndrome. It is important to recognize the clinical spectrum of gastrointestinal diseases, as well as the appropriate and most cost-effective diagnostic strategies, as therapies for a number of these disorders are both widely available and high effective. This review summarizes the major gastrointestinal infections which are seen in patients with the acquired immunodeficiency syndrome, and their treatment.

Pathophysiology of HIV-associated diarrhea

Considerable advances have been made in the evaluation and treatment of diarrhea in HIV-infected individuals, although gaps in knowledge still exist. The availability of newer and more powerful antiretroviral agents should allow a better definition of the effect of local HIV infection on intestinal function. Further attention to the pathophysiology of diarrhea should lead to improvements in diagnosis and treatment.

Diarrheal diseases associated with HIV infection

Diarrhea is a major complication of HIV infection and adversely impacts health care costs, quality of life, and even survival of patients. There is a wide variety of potential causes of diarrhea in HIV-infected patients, and the number of pathogens found continues to increase with time. In addition, there is some controversy concerning the role of some organisms in the pathogenesis of diarrhea and the appropriate diagnostic evaluation of affected patients. This article reviews our current understanding of these pathogens and some of the diagnostic and therapeutic approaches for diarrhea associated with HIV infection.

Cryptosporidiosis in Houston, Texas. A report of 95 cases

Cryptosporidiosis is an important cause of diarrhea. We identified 95 patients with cryptosporidiosis over a 6-year period in our county hospital system, including 9 children and 86 adults infected with the human immunodeficiency virus (HIV). Risk factors included male-to-male sexual practices and Hispanic race. Diarrhea, weight loss, and gastrointestinal complaints were the most common symptoms at presentation. Among the HIV-infected adults, 20 (23%) developed biliary tract disease. Biliary involvement was associated with low CD4 counts. Treatment with paromomycin and antimotility agents was effective in reducing diarrheal symptoms in 54 of 70 (77%) patients with the acquired immunodeficiency syndrome (AIDS), although there was a high rate of relapse. Paromomycin did not prevent the development of biliary disease. Biliary disease responded to cholecystectomy or sphincterotomy with stent placement. Though often a cause of morbidity, cryptosporidiosis was only rarely the cause of death, even among patients with HIV. Cryptosporidiosis continues to be an important medical problem even in developed-countries. Current methods of prevention and treatment are suboptimal.

Incidence and morbidity of cholelithiasis in patients receiving chronic octreotide for metastatic carcinoid and malignant islet cell tumors

BACKGROUND

Octreotide, a long-acting somatostatin analogue, has demonstrated clinical utility in patients with carcinoid syndrome and malignant islet cell tumors of the pancreas. Prior studies have reported a greater than expected incidence of cholelithiasis in patients treated with octreotide for acromegaly. This study attempted to determine the incidence and morbidity of cholelithiasis in a group of patients with metastatic carcinoid or malignant pancreatic islet cell tumors who were receiving chronic therapy with octreotide.

METHODS

Forty-four of 55 patients on investigational protocols with octreotide were eligible for chart review; 10 patients were excluded due to prior cholecystectomy and 1 patient due to asymptomatic cholelithiasis at presentation. Patients fell into three treatment groups. The low dose (LD) group was comprised of 17 patients receiving 150 microg of subcutaneous octreotide 3 times a day. Twenty-one patients received high dose (HD) therapy comprised of 500 microg given 3 times a day. The low dose-high dose (LD-HD) group was comprised of 6 patients who had their dose escalated from 150 microg to 225-500 microg of octreotide 3 times a day.

RESULTS

The overall incidence of cholelithiasis and/or gallbladder sludge was found to be 52.3% in all 3 treatment groups. Three of the 44 patients (6.8%) had symptomatic disease requiring emergency cholecystectomy. Five other patients underwent elective or incidental gallbladder surgery. The incidence of cholelithiasis in the LD, LD-HD, and HD groups was 35.3%, 66.6%, and 61.9%, respectively. The incidence of acute cholecystitis in the three groups was 11.8%, 0%, and 4.8%, respectively.

CONCLUSIONS

Although greater than 50% of patients receiving octreotide developed cholelithiasis, a much smaller percentage of patients had symptomatic gallbladder disease. Patients receiving chronic octreotide treatment require monitoring for the development of gallstones. However, prophylactic cholecystectomy is not indicated, unless it is performed in conjunction with bowel resection or cytoreductive hepatic surgery.

Endocrine implications of human immunodeficiency virus infection

Endocrine abnormalities occur frequently in HIV-infected patients. Although the majority of endocrine disorders reflect chronic infection, stress, and malnutrition, some disorders are characteristic of HIV infection or AIDS and deserve particular clinical attention. Identification of HIV patients at risk of frank endocrine disorders, rapid and correct diagnosis, and appropriate management are essential steps to minimize morbidity and mortality. Finally, increasing evidence from in vitro studies suggests that various hormones may influence HIV replication as well as the course of HIV disease and associated disorders. Future studies on the molecular mechanisms of hormones on HIV action and clinical studies on the effects of hormones as adjunctives to established forms of therapy may stimulate development of novel therapeutic strategies that will benefit HIV-infected patients.

Steatorrhea: a common manifestation in patients with HIV/AIDS

Multiple infectious causes of diarrhea are known in patients with HIV/AIDS. Maldigestion and malabsorption have been reported in patients with HIV/AIDS and may be independent of infectious etiologies. Among ambulatory patients with HIV/AIDS, we examined the prevalence of fat malabsorption (steatorrhea). Sixty-one patients with unexplained diarrhea (defined as > 2 stools/d) and/or weight loss despite adequate caloric intake (and without clinical evidence of chronic pancreatitis) were evaluated in our outpatient Gastroenterology-Nutrition Clinic between March 1, 1993, and July 1994. Patients were instructed by a dietitian to follow a > or = 100 g/d fat diet for 24 h before submitting a stool sample for qualitative (or quantitative) fecal fat determination. Forty-five patients, 32 with ongoing diarrhea and 13 without diarrhea, submitted stool samples. Twenty-two of 45 patients (49%) had qualitative or quantitative steatorrhea, 16/32 with diarrhea (50%) and 6/13 patients without diarrhea (46%). Thirty of 32 patients with diarrhea had had extensive microbiologic and/or endoscopic evaluations. Only 9 patients had a detectable intestinal pathogen, 5 patients had cytomegalovirus (4 treated), 4 patients had cryptosporidia (3 treated), and 1 patient had microsporidia. Steatorrhea, as determined by abnormal qualitative fecal fat, is detectable in nearly 50% of patients with HIV/AIDS. Fat malabsorption appears to be a primary defect in these patients independent of detectable pathogens. Assessment of fat malabsorption should be considered in patients with unexplained weight loss or diarrhea before extensive evaluation for opportunistic infections.

Lanreotide inhibits human jejunal secretion induced by prostaglandin E1 in healthy volunteers

1. Somatostatin inhibits hormonal secretions in the gastrointestinal tract. Somatostatin analogues are used in the treatment of VIPome-related watery diarrhoea. In addition, more than 10% of patients with AIDS suffer from diarrhoea likely due to the increased intestinal secretion of water and ions. However, the direct effect of somatostatin on the flux of water and ions in the intestine has not been, so far, analyzed in vivo. The aim of the present study was to evaluate the effect of lanreotide, a somatostatin analogue, on the movements of water and ions in the jejunum in man. 2. Accordingly, 10 healthy volunteers (age 18-35 years, mean 27) and two patients with AIDS (26 and 33 years) suffering from water diarrhoea (> 800 ml day-1) underwent intestinal perfusion using a four lumen tube with proximal occluding balloon. The segment tested was 25 cm long. The jejunum was infused by an isotonic control saline solution containing polyethylene glycol (PEG) as nonabsorbable marker. Basal jejunal secretions were measured in all subjects. Prostaglandin E1 (PGE1) was administered intraluminally to stimulate jejunal secretion in healthy volunteers. The effect of intravenous lanreotide on the jejunal PGE1-induced secretions of water and electrolytes was analysed in healthy subjects and on the basal secretions in AIDS patients. Each period was analyzed on the basis of three (10 min) successive intestinal juice collections after 20-30 min equilibration time. The antisecretory effect of lanreotide was evaluated in each subject as the difference between fluxes compared to the control period. 3. In healthy volunteers, PGE1 induced secretion of H2O, Na+, K+ and Cl- in the jejunum and lanreotide reduced significantly PGE1-induced response. In both AIDS patients basal fluxes of water and ions were reduced by lanreotide in a dose-dependent manner. 4. Somatostatin can reduce stimulated-jejunal secretion of ions and water in normal subjects and may improve water diarrhoea in AIDS patients.

Human cryptosporidiosis

Cryptosporidium parvum is a protozoan which can cause severe debilitating disease in immunocompromised individuals. Animal models have shown that cellular immunity is the most important factor against the development of the disease. Individuals with a humoral immune deficiency are also at risk. In HIV-infected patients there is a clear relationship between disease severity and CD4 cell counts. Insight into the pathogenesis and development of new agents is hampered by the lack of an in vitro culture system. Prevention is of the utmost importance due to the difficulties of therapy and the severity of clinical disease which can develop. Oocysts are highly resistant to commonly used disinfectants. In HIV-infected patients with cryptosporidiosis, antiretroviral therapy should be instituted or modified. Moreover, non-specific therapy with antidiarrhoeal agents should also be instituted. If no effect is seen, therapy with paromomycin 500 mg 4 times daily for 2-3 weeks should be initiated, followed by maintenance therapy with 500 mg twice daily to prevent relapse.

Treatment of non-HIV cryptosporidial diarrhea with azithromycin

OBJECTIVE

To report a patient with non-HIV-related cryptosporidial diarrhea who was treated effectively with a regimen of high-dose azithromycin therapy.

CASE SUMMARY

A 42-year-old immunocompetent man contracted cryptosporidiosis from an ailing calf that he had purchased. He finally was admitted to the hospital because of excessive weight loss and profuse diarrhea. The patient was started on a course of high-dose azithromycin therapy and symptoms resolved within 48 hours. Follow-up stool cultures were negative for the parasite.

DISCUSSION

Although usually associated with immunocompromised patients, cryptosporidiosis occurs in immunocompetent hosts in a significant portion of the reported cases each year. Although self-limiting in most cases in this population, the disease can be severe at times and require treatment. Paromomycin therapy has been used in the past with good results. Although macrolides have had erratic effects against this parasite in the past, azithromycin (an azalide) demonstrated good efficacy in this patient.

CONCLUSIONS

Azithromycin has demonstrated that it may be an effective option for the treatment of cryptosporidiosis in immunocompromised patients. Studies involving its use in immunocompromised patients are currently underway.

Somatostatin receptors mediating inhibition of basal and stimulated electrogenic ion transport in rat isolated distal colonic mucosa

The aim of this study was to examine the potencies of several recently identified selective somatostatin (SRIF)-receptor ligands as inhibitors of electrogenic ion transport in the rat distal colonic mucosa with the view to identifying the SRIF receptor type involved. Under basal conditions, cumulative administration of SRIF and SRIF28 decreased short circuit current (SCC), a measure of electrogenic ion transport, with EC50 values of 4 nM and 9 nM respectively. The peptidase inhibitors, phosphoramidon (1 microM) and amastatin (10 microM), has no effect on the potencies of either SRIF or SRIF28. The inhibitory action of SRIF on basal SCC was suppressed by piretanide and diphenylamine-2-carboxylate, compatible with the assumption that the Na+K+2Cl- co-transporter and Cl- channels, respectively, may be involved in this antisecretory action of SRIF. Tetrodotoxin (1 microM) had no effect on the antisecretory action of SRIF, suggesting that the process was not neuronally mediated. All of the SRIF analogues examined, with the exception of BIM-23056, maximally inhibited basal SCC to a similar extent as SRIF. Seglitide and octreotide were both more potent antisecretory agents than SRIF (respective EC50 values, 0.4 nM and 1.5 nM) suggesting that this effect was mediated by a receptor belonging to the SRIF1 receptor group. The most distinguishing feature of the rank order of agonist potencies was the high potency of the selective sst2 receptor ligand, BIM-23027 (EC50 value 0.32 nM), the weaker potency exhibited by the selective sst5 receptor ligand, L-362855 (EC50 value 21 nM), and the lack of agonist activity displayed by the selective sst3 receptor ligand, BIM-23056 (EC50 value > 1000 nM). This profile is comparable with that observed in binding studies on the recombinant sst2 receptor. Forskolin-stimulated secretion was suppressed by SRIF analogues with the rank order of agonist potencies BIM-23027 > SRIF > L-362855 >> BIM-23056 which resembled that exhibited under basal conditions. However, the absolute potencies of these agonists were lower (respective EC50 values 2 nM, 14 nM< 38 nM and > 1000 nM) whilst the magnitude of inhibition was about three fold greater. BIM-23027 and SRIF (both 30 nM) also inhibited carbachol-stimulated increases in basal SCC by 60-70%, while a similar concentration of L-362855 inhibited these responses by 11%. BIM-23056 (1 microM) had no effect on carbachol-simulated secretion. Radioligand binding studies on rat colonic mucosal membranes using [125I]-Tyr11-SRIF suggested heterogeneity of SRIF binding sites. Thus, SRIF and SRIF28 competed for binding (IC50 values, 0.32 and 0.63 nM, respectively) with Hill slopes less than unity; while seglitide and BIM-23027 both maximally displaced only 30-40% of specific binding with apparent high affinity (respective pIC50 values, 10.1 nM and 10.0). In conclusion, SRIF decreases basal as well as both cAMP and Ca(2+)-dependent Cl- secretion in rat colonic mucosa. The rank order of agonist potencies suggests that receptors resembling the recombinant sst2 receptor mediate inhibition of basal and forskolin-stimulated secretion. Radioligand binding studies suggest that BIM-23027 interacts with a sub-population of [125I]Tyr11-SRIF binding sites in rat colonic mucosal membranes which probably corresponds to the receptors mediating the antisecretory effects described here.

Consensus statement: octreotide dose titration in secretory diarrhea. Diarrhea Management Consensus Development Panel

Octreotide is an effective therapeutic option in controlling secretory diarrhea of varied etiology. However, marked patient-to-patient differences in the antidiarrheal effects necessitate titration of octreotide dose in individual patients to achieve optimal symptom control. A consensus development panel established guidelines for octreotide dose titration in patients with secretory diarrhea. Overall, the panel recommended an aggressive approach in selecting the initial octreotide dose and in making subsequent dose escalations in patients with secretory diarrhea due to gastrointestinal tumors (eg, carcinoids, VIPomas), AIDS, dumping syndrome, short bowel syndrome, radiotherapy, or chemotherapy. To avoid hypoglycemia in patients with diabetes mellitus-associated secretory diarrhea, the panel recommended a low initial octreotide dose and a conservative titration regimen with close monitoring a blood glucose levels. The end point of therapy should focus on a reduction in diarrhea (frequency of bowel movements or stool volume) rather than normalization of hormonal profile. Overall, octreotide is well tolerated; principal side effects are transient injection site pain and gastrointestinal discomfort. For many patients with secretory diarrhea, octreotide therapy is expected to improve the overall health and quality of life and in the long run will lessen health care costs.

Multicenter trial of octreotide in patients with refractory acquired immunodeficiency syndrome-associated diarrhea

BACKGROUND/AIMS

Diarrhea is a significant problem in patients with acquired immunodeficiency syndrome (AIDS). The aim of this study was to determine octreotide effectiveness in refractory AIDS-associated diarrhea.

METHODS

In a 3-week protocol, 129 patients with a stool weight of > 500 g/day despite standard antidiarrheal therapy were randomized to receive octreotide or placebo (3:2 ratio). Octreotide dose was increased 100 micrograms weekly to a maximum of 300 micrograms three times a day based on weekly 72-hour stool collections. Subsequently, patients received open-label octreotide at doses of up to 500 micrograms three times a day.

RESULTS

A 30% decrease in stool weight defined response. After 3 weeks, 48% of octreotide- and 39% of placebo-treated patients had responded (P = 0.43). At 300 micrograms three times a day, 50% of octreotide- and 30.1% of placebo-treated patients responded (P = 0.12). At a baseline stool weight of 1000-2000 g/day, 57% of octreotide- and 25% of placebo-treated patients responded (P = 0.06). Response rates based on CD4 counts, diarrhea duration, body weight, human immunodeficiency virus risk factor, and presence or absence of pathogens showed no benefit of octreotide. Adverse events were more frequent in the octreotide-treated group.

CONCLUSION

In the doses studied, octreotide was not more effective than placebo in patients with refractory AIDS-associated diarrhea. This lack of effectiveness may be attributable to inadequate sample size, doses, and duration of study treatment.

Octreotide in the treatment of diarrhoea induced by coeliac plexus block

Prolonged and severe diarrhoea after alcohol celiac plexus block is a rare, but life-threatening, complication if not recognized. This type of diarrhoea may be considered an autonomic neuropathy due to sympathetic denervation. A 65-year-old pancreatic cancer patient developed serious diarrhoea after celiac plexus block which was unresponsive to traditional treatment such as loperamide, dyphenoxylate and opioids. Subcutaneous octreotide, 0.1 mg twice a day, achieved a complete resolution of the symptom. This drug was maintained at the same dosage and was well tolerated for 4 months until death. Octreotide, an analogue of somatostatin, reduces diarrhoea by suppression of intestinal motility and secretion and offers a useful option in the treatment of this complication of celiac plexus block.

A rare case of primary skeletal muscle lymphoma: the value of octreotide scintigraphy

We report a case of non-Hodgkin lymphoma presenting as a painless mass of the quadriceps femoris muscle that was detected by a somatostatin analogue (octreotide) scintigraphy. We review the few reported cases of primary muscular lymphoma and discuss the potential value of octreotide imaging as a new diagnostic tool.

Small intestinal manifestations of HIV infection

The small intestine is a common site of involvement in patients infected with the human immunodeficiency virus (HIV). Although there are numerous mechanisms by which small intestinal disease may occur in HIV infected patients, the resulting clinical manifestations of these disorders are remarkably similar and include the development of diarrhoea, weight loss and nutrient deficiencies. In fact, the original designation of AIDS in African countries as the 'slim disease' underlines the importance of small intestinal involvement (most likely secondary to parasitic infections) which commonly occurs in Third World Countries. The current review will provide a clinically oriented overview of small intestinal disease in patients infected with HIV. Because specific data on treatment of small intestinal diseases in AIDS is often lacking, some presented information is based on the author's experience and opinions.

Human microsporidial infections

Microsporidia are obligate intracellular spore-forming protozoal parasites belonging to the phylum Microspora. Their host range is extensive, including most invertebrates and all classes of vertebrates. More than 100 microsporidial genera and almost 1,000 species have now been identified. Five genera (Enterocytozoon spp., Encephalitozoon spp., Septata spp., Pleistophora sp., and Nosema spp.) and unclassified microsporidia (referred to by the collective term Microsporidium) have been associated with human disease, which appears to manifest primarily in immunocompromised persons. The clinical manifestations of microsporidiosis are diverse and include intestinal, pulmonary, ocular, muscular, and renal disease. Among persons not infected with human immunodeficiency virus, ten cases of microsporidiosis have been documented. In human immunodeficiency virus-infected patients, on the other hand, over 400 cases of microsporidiosis have been identified, the majority attributed to Enterocytozoon bieneusi, an important cause of chronic diarrhea and wasting. Diagnosis of microsporidiosis currently depends on morphological demonstration of the organisms themselves. Initial detection of microsporidia by light microscopic examination of tissue sections and of more readily obtainable specimens such as stool, duodenal aspirates, urine, sputum, nasal discharge, bronchoalveolar lavage fluid, and conjunctival smears is now becoming routine practice. Definitive species identification is made by using the specific fluorescein-tagged antibody (immunofluorescence) technique or electron microscopy. Treatment options are limited, but symptomatic improvement of Enterocytozoon bieneusi infection may be achieved with the anthelmintic-antiprotozoal drug albendazole. Preliminary observations suggest that Septata intestinalis and Encephalitozoon infections may be cured with albendazole. Progress is being made with respect to in vitro propagation of microsporidia, which is crucial for developing antimicrosporidial drugs. Furthermore, molecular techniques are being developed for diagnostic purposes, taxonomic classification, and analysis of phylogenetic relationships of microsporidia.

Update on the management of intestinal cryptosporidiosis in AIDS

OBJECTIVE

To update readers on the pharmacotherapeutic management of cryptosporidiosis in patients with AIDS.

DATA SOURCES

A MEDLINE search was used to identify pertinent literature. Additionally, programs and abstracts from the 33rd Interscience Conference on Antimicrobial Agents and Chemotherapy; the 1st International Conference on Macrolides, Azalides, and Streptogramins; the 93rd American Society for Microbiology Meeting; and the 6th and 7th International Conferences on AIDS were used.

DATA EXTRACTION

Available data from in vitro, animal, and human experiments were reviewed.

DATA SYNTHESIS

Intestinal cryptosporidiosis in patients with AIDS can be a life-threatening opportunistic infection. However, there can be significant variability in disease expression, including spontaneous remission. Supportive care with hydration and nutritional supplementation remains a hallmark of therapy. Unfortunately, there is no proven specific pharmacotherapy of cryptosporidiosis in patients with AIDS. Numerous agents have been analyzed for in vitro activity and efficacy in experimental animal models and actual human cases of the infection, including paromomycin, azithromycin, clarithromycin, octreotide, hyperimmune bovine colostrum, bovine transfer factor, and many others. Because limited numbers of controlled trials have been conducted with potential therapeutic agents, the majority of the information to date is preliminary in nature.

CONCLUSIONS

Despite the availability of some evolving and potentially promising treatment modalities, further controlled clinical trials are necessary to evaluate the role of pharmacotherapy for intestinal cryptosporidiosis in patients with AIDS.