Cytomegalovirus- and Cryptosporidium-associated acalculous gangrenous cholecystitis

Detection of Cryptosporidium spp. and Giardia spp. in Environmental Water Samples: A Journey into the Past and New Perspectives

Among the major issues linked with producing safe water for consumption is the presence of the parasitic protozoa Cryptosporidium spp. and Giardia spp. Since they are both responsible for gastrointestinal illnesses that can be waterborne, their monitoring is crucial, especially in water sources feeding treatment plants. Although their discovery was made in the early 1900s and even before, it was only in 1999 that the U.S. Environmental Protection Agency (EPA) published a standardized protocol for the detection of these parasites, modified and named today the U.S. EPA 1623.1 Method. It involves the flow-through filtration of a large volume of the water of interest, the elution of the biological material retained on the filter, the purification of the (oo)cysts, and the detection by immunofluorescence of the target parasites. Since the 1990s, several molecular-biology-based techniques were also developed to detect Cryptosporidium and Giardia cells from environmental or clinical samples. The application of U.S. EPA 1623.1 as well as numerous biomolecular methods are reviewed in this article, and their advantages and disadvantages are discussed guiding the readers, such as graduate students, researchers, drinking water managers, epidemiologists, and public health specialists, through the ever-expanding number of techniques available in the literature for the detection of Cryptosporidium spp. and Giardia spp. in water.

Perforation of the gallbladder in a patient with acute cytomegalovirus cholecystitis shortly following renal transplantation

A 74-year-old man with end-stage renal failure secondary to diabetes received a living donor renal transplant (cytomegalovirus [CMV]-seropositive recipient from a CMV-seropositive donor). Computed tomography scan revealed a gallbladder with hemorrhage. On postoperative day 27, cholecystography revealed gallbladder perforation; he underwent an emergency operation. Histological examination of the gallbladder wall was positive for multiple viral inclusion bodies. We report a very rare case of both hemorrhagic and perforated CMV cholecystitis within a month following renal transplantation.

AIDS Cholecystopathy

Several types of biliary tract abnormalities including sclerosing cholangitis, acalculus cholecystitis, and gangrenous cholecystitis have been described in patients with AIDS. Sixteen HIV-positive patients with no previous history of biliary tree abnormality, including no history of jaundice or elevated liver function tests, were reviewed retrospectively. Each patient in our study was examined by abdominal ultrasonography and computed tomography. The results of this study showed that ultrasound may be more accurate than computed tomography in detecting gallbladder abnormalities among patients with AIDS.

Gastrointestinal opportunistic infections in human immunodeficiency virus disease

Gastrointestinal (GI) opportunistic infections (OIs) are commonly encountered at various stages of human immunodeficiency virus (HIV) disease. In view of the suppressive nature of the virus and the direct contact with the environment, the GI tract is readily accessible and is a common site for clinical expression of HIV. The subject is presented based on information obtained by electronic searches of peer-reviewed articles in medical journals, Cochrane reviews and PubMed sources. The spectrum of GI OIs ranges from oral lesions of Candidiasis, various lesions of viral infections, hepatobiliary lesions, pancreatitis and anorectal lesions. The manifestations of the disease depend on the level of immunosuppression, as determined by the CD4 counts. The advent of highly active antiretroviral therapy has altered the pattern of presentation, resorting mainly to features of antimicrobial-associated colitis and side effects of antiretroviral drugs. The diagnosis of GI OIs in HIV/acquired immunodeficiency syndrome patients is usually straightforward. However, subtle presentations require that the physicians should have a high index of suspicion when given the setting of HIV infection.

AIDS cholangiopathy

AIDS is an advanced disease with systemic and infectious complications that can be fatal. When a patient with AIDS presents with right upper quadrant or midepigastric pain, cholestasis, and symptoms of cholangitis, AIDS cholangiopathy should be suspected and appropriate diagnostic and therapeutic interventions should be initiated. Opportunistic infections such as Cryptosporidium and cytomegalovirus are the most common cause of AIDS cholangiopathy. Four distinct cholangiographic abnormalities have been demonstrated by endoscopic retrograde cholangiopancreatography, the most common being papillary stenosis with sclerosing cholangitis. Antimicrobial therapy is often ineffective. Highly active antiretroviral therapy may enhance immune function and offers the best medical therapy to clear the opportunistic infections. Ursodeoxycholic acid has a limited benefit in patients with sclerosing cholangitis and cholestasis. Endoscopic sphincterotomy has been shown to relieve pain and biliary obstruction in patients with papillary stenosis. Balloon dilation of strictures and stent placement decompress the biliary system and may be helpful. Cholecystectomy is recommended to treat acalculous cholecystitis, and celiac plexus block may be offered to patients with terminal disease and intractable abdominal pain.

Gastrointestinal disorders of the critically ill. Biliary sludge and cholecystitis

Biliary sludge develops commonly in critically ill patients and may be associated with biliary colic, acute pancreatitis or acute cholecystitis. Sludge often resolves upon resolution of the underlying pathogenetic factor. It is generally diagnosed on sonography. Treatment of sludge itself is unnecessary unless further complications develop. Acute acalculous cholecystitis also develops frequently in critically ill patients. It may be difficult to diagnose in these patients, manifesting only as unexplained fever, leukocytosis or sepsis. Sonography and hepatobiliary scintigraphy are the most useful diagnostic tests. Management decisions should take into account the underlying co-morbid conditions. For many patients, percutaneous cholecystostomy may be the best management option. Cholecystostomy may also provide definitive drainage as patients recover and underlying critical illness resolves.

Polymerase chain reaction-based diagnosis of infection with Cryptosporidium in children with primary immunodeficiencies

BACKGROUND

Patients with deficient cell-mediated immunity are prone to chronic biliary tract infection with Cryptosporidium, which can lead to the development of sclerosing cholangitis and acute cryptosporidiosis after bone marrow transplantation (BMT). The organism is very difficult to detect during asymptomatic periods.

METHODS

PCR techniques were compared with standard microscopy for detecting the organism in such patients. Amplification targets were two fragments of the 18S ribosomal RNA gene (unnested) and part of the Cryptosporidium oocyst wall protein gene (nested and unnested). Twenty eight-patients with primary immunodeficiencies were studied including: CD40 ligand deficiency (13); undefined combined immunodeficiency (10); major histocompatibility complex II deficiency (2); and other defects (3). Samples analyzed included stool, bile and liver tissue.

RESULTS

Of 25 patients tested prospectively, Cryptosporidium could be detected by PCR but not by microscopy in 12, only 3 of whom had a known history of infection. Five of this group had sclerosing cholangitis. Nine of the PCR-positive patients subsequently underwent BMT and 5 developed acute posttransplant diarrhea and cholangiopathy associated with Cryptosporidium excretion. Of the 13 PCR-negative patients, 3 had cholangiopathy (sclerosing cholangitis in 1 and minor changes in 2). Four of these underwent BMT and none developed cryptosporidiosis. In 3 patients, studied only after developing post-BMT cholangiopathy and diarrhea, Cryptosporidium was detected by PCR but not by microscopy. Genotyping and sequencing showed multiple types of Cryptosporidium in approximately one-third of positive cases.

CONCLUSIONS

These results indicate that PCR-based procedures are more sensitive than microscopy for detecting Cryptosporidium in patients with immunodeficiencies.

[Alithiasic cholecystitis in the adult: etiologies, diagnosis and treatment]

Acalculous cholecystitis represents 2% to 14% of cholecystectomies performed for acute cholecystitis. Its main etiology is ischemia of the gallbladder wall, which mainly occurs in critically ill patients, particularly in case of cardiovascular previous disease or diabetes. Acalculous cholecystitis associated with VIH are rare and have a better prognosis. Other etiologies are exceptional. Diagnosis of acalculous cholecystitis is difficult, with a lack of specificity of abdominal ultrasound for the diagnosis of ischemic cholecystitis. In all cases, cholecystectomy is a definitive treatment allowing certain diagnosis. Percutaneous drainage must be reserved to patients whose general condition does not allow general anesthesia. Medical treatment alone is not indicated in acalculous cholecystitis.

Hepatobiliary and pancreatic infections in AIDS: Part II

In the first part of our review, we discussed the general evaluation and clinical presentation of the various hepatic infections occurring in patients with AIDS. In addition, we focused on specific hepatic parenchymal infections. In this article, we will discuss the major clinical syndromes arising from opportunistic infections affecting the gallbladder (acalculous cholecystitis), biliary tree (AIDS-cholangiopathy), and pancreas (pancreatitis). Acalculous cholecystitis can develop in patients with AIDS who have not experienced the severe precipitating physiologic stresses normally required in patients without AIDS. The most common presentation is with right upper quadrant (RUQ) pain and tenderness. The diagnosis is a clinical one since there is no standard test, other than surgery. Cholecystectomy is the treatment of choice. The most common AIDS-associated infective complication of the biliary tree is AIDS-cholangiopathy. This is best viewed as a form of secondary sclerosing cholangitis resulting from a variety of opportunistic infections within the biliary tree. Affected persons present with RUQ pain and have marked elevations in the canalicular enzymes, alkaline phosphatase, and gamma-glutamyl transferase. Morphologic abnormalities are identified by endoscopic retrograde cholangiopancreatography. These include stricturing, dilatation, and beading of the biliary tract. Endoscopic sphincterotomy of the papilla of Vater may provide symptomatic relief for patients with papillary stenosis. Opportunistic infections within the pancreas gland have been documented in both pre- and postmortem studies. However, the true incidence of pancreatitis related to infections is unknown. The presentation is similar to that of pancreatitis from other causes. A computerized tomogram of the abdomen is the investigation of choice. Tissue aspiration or biopsy of the pancreas is required to demonstrate the presence of an opportunistic infection. The management is usually supportive, as it is rare that a specific infection is identified and treated.

Acalculous cholecystitis and septicemia caused by non-O1 Vibrio cholerae: first reported case and review of biliary infections with Vibrio cholerae

The first case of septicemic acute acalculous cholecystitis caused by non-O1 Vibrio cholerae is described in a healthy traveler, and biliary tract infections from V. cholerae are reviewed. Immediately after a vacation in Cancun, Mexico, a 55-year-old man developed acute cholecystitis. Blood and bile cultures grew non-O1 V. cholerae. At surgery, the gallbladder was acalculous, inflamed, distended, and nearly ruptured. Pathogenetic factors may have included diarrhea prophylaxis with bismuth subsalicylate, distension of the gallbladder from illness-induced fasting, and bacterial toxins in the gallbladder. The patient received i.v. cephapirin, followed by oral cephradine for a total of 10 days, and he made a quick and complete recovery. V. cholerae should be considered in the differential diagnosis of persons from endemic areas who present with cholecystitis or acute jaundice.

Surgical therapy for 101 patients with acquired immunodeficiency syndrome and symptomatic cholecystitis

BACKGROUND

Hepatobiliary disease in patients with acquired immunodeficiency syndrome (AIDS) has been well documented. Cytomegalovirus and Cryptosporidium are the pathogens most frequently associated. Previous reports of cholecystectomies and AIDS have had conflicting results on morbidity and mortality.

METHOD

Retrospective review of 101 patients with AIDS and symptomatic cholecystitis who underwent cholecystectomy from December 1989 to May 1995.

RESULTS

All patients had symptoms characteristic of gallbladder disease, the most common being abdominal pain and fever. Thickening of the gallbladder was the most common diagnostic finding. Fifty-six patients underwent open cholecystectomy and 45 laparoscopic cholecystectomy. Pathologic examination revealed an abnormal gallbladder in all cases and gallstones in 29%. A specific pathogen or malignancy was identified as the etiologic agent in 44% of patients. Perioperative morbidity was similar (<5%) in both surgical groups. Perioperative mortality was 4% among all the patients treated.

CONCLUSIONS

Both open and laparoscopic cholecystectomy improved the quality of life of these patients and should be considered as the treatment for persistent hepatobiliary symptoms in patients with AIDS.

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.

Gallbladder and biliary tract disease in AIDS

Biliary disease occurs in a subset of AIDS patients with CD4 counts of less than 100 per mm3. These patients present with right upper quadrant and epigastric pain, cholestasis, and usually abnormal findings on imaging. In 75% of patients, an associated opportunistic infection can be identified. In patients with biliary disease, pain is often relieved following endoscopic sphincterotomy, whereas cholecystectomy provides pain relief in patients with acalculous cholecystitis.

Gastrointestinal manifestations

Gastrointestinal disease is a common problem in the setting of HIV-1 infection. As patients live longer and other opportunistic pathogens are suppressed, these problems are becoming even more important in the quality of life.

Long-term follow-up of endoscopic retrograde cholangiopancreatography sphincterotomy for patients with acquired immune deficiency syndrome papillary stenosis

PURPOSE

To evaluate the long-term effects on biliary-type pain and changes in biochemical parameters in patients with AIDS-associated papillary stenosis who underwent endoscopic retrograde cholangiopancreatography (ERCP) sphincterotomy.

PATIENTS AND METHODS

Twenty-five consecutive patients were diagnosed by cholangiography with AIDS-associated papillary stenosis using standard criteria. Patients underwent ERCP sphincterotomy and were followed prospectively in the Gastrointestinal or Liver Clinics, San Francisco General Hospital, and by their primary physicians. Post-procedure data was prospectively collected by chart review or in-person or telephone interview, and analyzed using statistical software.

RESULTS

All patients presented with severe right upper quadrant and/or mid-epigastric abdominal pain and had marked elevations of serum alkaline phosphatase. Following ERCP sphincterotomy, pain scores decreased significantly for at least 9 months of follow-up. Serum alkaline phosphatase levels, however, remained essentially unchanged. Overall quality of life was difficult to assess, as patients suffered from other AIDS-associated debilitating diseases.

CONCLUSIONS

ERCP sphincterotomy, while not without risks, provided significant reduction in pain in patients with AIDS-associated papillary stenosis.

Importance of accurate preoperative diagnosis and role of advanced laparoscopic cholecystectomy in relieving chronic acalculous cholecystitis

Between April 1, 1989, and January 1, 1994, 38 patients with chronic acalculous cholecystitis underwent an advanced (3-puncture) laparoscopic cholecystectomy at our institution. The 30 women and 8 men had a mean age of 39 years (range, 23 to 65 years) and represented 4.5% of our overall gallbladder patient population. In each case, the disease produced typical biliary colic, but no gallstones were visualized on ultrasound examination; cholecystokinin-stimulated cholescintigraphy revealed a dysfunctional gallbladder, as evidenced by an ejection fraction of < or = 35% or nonvisualization or nonemptying of the organ. In all 38 cases, cholecystectomy resulted in the complete relief of symptoms. Although an increasing number of physicians are recommending this operation for acalculous gallbladder disease, it should not be performed on the basis of clinical history alone. Rather, objective criteria confirming the need for surgical intervention should be obtained by means of appropriate preoperative testing, including cholecystokinin-stimulated cholescintigraphy.

Acute acalculous cholecystitis due to Vibrio cholerae

The case of a 57-year-old woman admitted with symptoms and signs suggesting an intestinal infection caused by Vibrio cholerae, and who also developed a clinical picture compatible with acute cholecystitis, is presented. Cholera was diagnosed by examining a fresh sample of stools and cultures. An abdominal sonogram disclosed signs of acute acalculous cholecystitis. She underwent cholecystectomy, and cultures of a clear fluid and a "milky" sediment found within the gallbladder were also positive for V. cholerae. This microorganism was seen at the gallbladder mucosa microscopically. The strain was serotyped V. cholerae 01 (El Tor) Ogawa and was the etiology of the acute acalculous cholecystitis in this patient.

AIDS-related cholangiopancreatographic changes

The cholangiographic and pancreatographic appearances of the acquired immunodeficiency syndrome (AIDS) associated cholangitis were evaluated in 26 patients. Twenty-four patients were diagnosed by retrograde cholangiography or endoscopic cholangiopancreatography (ERC or ERCP). One patient was diagnosed by T-tube cholangiography and another patient by transhepatic cholangiography. The radiographic findings ranged from intrahepatic ductal abnormalities with or without involvement of the extrahepatic biliary tree (eight patients) to irregularities and strictures involving the ampulla of Vater or the intrapancreatic portion of the common bile duct (CBD) with proximal dilatation (18 patients). Significant strictures involving the juxta-ampullary pancreatic duct were identified in six of 12 patients. Twenty-one of the 26 patients had associated infections which included: Cryptosporidium (CS), Mycobacterium avium intracellulare (MAI), cytomegalovirus (CMV), Microsporidium (MSP), and Isospora (ISP). Three patients were operated upon for acute acalculous cholecystitis. In each instance, organisms were identified in both the bile duct and the inflamed gallbladder.

AIDS-related cholangiopathy. Critical analysis of a prospective series of 26 patients

Several types of biliary tract abnormality of undetermined origin have been described among AIDS patients. The aims of this study are: (1) to evaluate whether biliary tree involvement is in fact one or several homogeneous morphological entities, (2) to specify the role of CMV or Cryptosporidium sp. infection, and (3) to evaluate the possible efficacy of treatment. Since ultrasound had revealed abnormality in the biliary tree, 26 consecutive AIDS patients underwent cholangiography. Cholangiograms enabled us to distinguish between two types of biliary tract involvement: (1) gradual and regular stenosis of the terminal portion of the common bile duct associated with dilation but without irregularity of the intrahepatic biliary ducts was present in 27% of our cases, and (2) distal stenosis of the extrahepatic biliary ducts combined with diffuse irregularity of the caliber of the intrahepatic bile ducts was present in 73% of our cases. Concomitant infection by CMV or Cryptosporidium sp. was significantly more frequent when intrahepatic duct irregularities were present (94%) than when absent (14%, P < 0.001). Anti-CMV treatment and sphincterotomy were unsuccessful in treating anomalies of the intrahepatic biliary tract. Conversely, sphincterotomy caused rapid and lasting disappearance of pain in all our patients. In conclusion, biliary tract involvement in AIDS patients is of two types. CMV infection and infection by Cryptosporidium sp. are most frequent when the large intrahepatic ducts are implicated.

Squamous metaplasia of extrahepatic biliary system in an AIDS patient with cryptosporidia and cholangitis

AIDS-related cholangiopathy is an increasingly recognized syndrome associated with significant morbidity and mortality. The mechanism of cholangiopathy is unknown but is assumed to be related to infectious pathogens such as CMV and cryptosporidia. The case of a Haitian with HIV and long-standing intestinal cryptosporidiosis who presented with cholangitis and protuberant intrabiliary filling defects is reported. Histopathological examination of biliary biopsies revealed previously unreported extensive squamous metaplasia of the bile duct epithelium, and the histogenesis of this condition is discussed. Chronic cryptosporidial infestation may be directly pathogenic resulting in squamous metaplasia that mimics biliary malignancy.

A survey of cytomegalovirus (CMV) DNA in primary sclerosing cholangitis (PSC) liver tissues using a sensitive polymerase chain reaction (PCR) based assay

Reactivation of cytomegalovirus (CMV) has been implicated as a possible etiological agent in primary sclerosing cholangitis (PSC) partly because of the ability of CMV infection to cause hepatobiliary damage, and further because of the recent recognition of a PSC-like syndrome in AIDS patients, many of whom have hepatobiliary infection with CMV. Direct evidence of CMV infection in PSC has come from a study detecting CMV DNA in 7/7 PSC livers, but only 5/20 controls. We have developed an assay for CMV-DNA by amplification of the immediate early region of CMV using the polymerase chain reaction, followed by Southern blotting and 32P oligoprobing of the amplification product. This system has an average sensitivity of at least 25 copies of CMV-DNA per 5000 formalin-fixed paraffin-embedded cells. 37 PSC and 19 control samples of formalin-fixed paraffin-embedded hepatobiliary tissues were studied. Amplification for the beta-globin in each sample was used as an amplification control, and fetal lung with known CMV infection as the CMV-positive control. 37/37 PSC tissues amplified for beta-globin, and one of these was positive for CMV-DNA. All 19 controls amplified for beta-globin, with none being positive for CMV. The lack of CMV-DNA in 35/36 PSC samples at a level of 25 copies per 5000 cells, we believe, rules out any significant CMV reactivation in these tissues, and suggests that CMV replication and re-activation is not responsible for the progression of PSC.

Coccidian infections in AIDS. Toxoplasmosis, cryptosporidiosis, and isosporiasis

Cryptosporidium sp. and Isospora belli are coccidian protozoan parasites that were long recognized as pathogens for many animal species. The medical community became acquainted with these organisms with the advent of AIDS. Both parasites are associated with persistent, debilitating enteritis and, in the case of Cryptosporidium, biliary tract involvement in patients with AIDS. For the immunocompetent host, infection with these two pathogens usually results in self-limited diarrhea. Cryptosporidiosis appears to occur more often than isosporiasis, but the true prevalence of both infections for various populations of humans is unknown. Clinically, cryptosporidiosis is indistinguishable from isosporiasis. Diagnosis is based on finding the acid-fast (red staining oocyst in stained fecal specimens). There is no known effective therapy for cryptosporidiosis, whereas patients with isosporiasis respond promptly to treatment with trimethoprim-sulfamethoxazole. Patients with AIDS and isosporiasis have a high relapse rate after achieving complete remission and therefore need to be maintained on suppressive therapy. Much more needs to be learned about these two fascinating, "newly recognized" parasites.

Cryptosporidiosis in the acquired immunodeficiency syndrome: a study of 15 autopsy cases

The pathologic changes associated with human cryptosporidiosis have not been well characterized. In this report, 15 cases of cryptosporidiosis in acquired immunodeficiency syndrome patients are described. Organisms were found in autopsy tissue specimens in 13 cases, and only in antemortem stool samples in two. Gastrointestinal/hepatobiliary distribution of organisms was as follows: small intestine (13 cases), extrahepatic bile ducts (eight), intrahepatic bile ducts (seven), large intestine (six), pancreas (five), stomach (three), and esophagus (one). At all sites, infection was usually associated with nonspecific reactive epithelial changes, architectural abnormalities such as villous flattening in the small intestine, and interstitial edema with mixed inflammatory cell infiltrates. Presence of organisms and associated mucosal injury were patchy and of variable severity in the intestine. In the biliary tract, injury was commonly diffuse and severe. Pancreatic duct injury was generally mild and often limited to hyperplastic squamous metaplasia. In late-stage acquired immunodeficiency syndrome patients with cryptosporidiosis, widespread infection in the gastrointestinal and biliary systems by this coccidian was more common and severe than previously suggested. Although the mechanisms have yet to be determined, infection usually is accompanied by pathologic changes that may be causally related to pathophysiologic abnormalities, such as diarrhea and malabsorption, and may account for other clinical manifestations of pancreatitis, cholangitis, and obstructive cholestasis.

Acute cholecystitis: radiological management

Acute cholecystitis is a common condition which may be difficult to diagnose with confidence on clinical grounds alone. A large number of techniques are now available for imaging the gall bladder but, in practice, ultrasonography and cholescintigraphy are of greatest value. The former is cheap, readily available and features such as the presence of gall stones, gall bladder wall inflammation and a positive sonographic Murphy sign strongly suggest the diagnosis of acute cholecystitis. In addition to its diagnostic uses, ultrasonographically guided percutaneous cholecystostomy provides an alternative and sometimes life-saving form of treatment in those patients who are unfit for surgery. Cholescintigraphy is a highly accurate, non-invasive method for assessing patency of the cystic duct but is not always available in the emergency situation and takes longer to perform than an ultrasound examination. Acute cholecystitis, however, has many manifestations and may be calculous or acalculous, be associated with a patent or obstructed cystic duct, and may be complicated or uncomplicated. Imagining modalities other than those mentioned above may be useful in certain circumstances and this chapter aims to present the advantages and disadvantages of each technique in order to provide guidance for the clinician caring for a patient with suspected acute cholecystitis.

The management of HIV-related illness in the emergency department

As the AIDS epidemic progresses, the number of ED patients with HIV-related illness will continue to increase. As reviewed in this article, much of the existing clinical research in HIV-related illness has an impact on the diagnostic and management issues that arise in the ED. Many of the patterns of disease, subtleties of diagnosis, and therapies unique to AIDS patients have already been greatly elucidated. However, as the recognition of this disease goes into only its second decade, many questions remain. Further studies are needed, for example, to improve physician assessment of HIV risk, to further identify discriminators of PCP and bacteremia, and to optimize strategies for disposition and outpatient management. In the future, in the areas of research and clinical care, emergency medicine will play an increasing important role in the front-line attack on this modern epidemic.

Cryptosporidiosis

Before 1982, only eight case reports of human cryptosporidiosis and fewer than 30 papers on Cryptosporidium spp. appeared in the biomedical literature. At that time, cryptosporidiosis was thought to be an infrequent infection in animals and rarely an opportunistic infection in humans. The concept of Cryptosporidium spp. as pathogens has changed dramatically within the past 8 years because of improved diagnostic techniques, increased awareness within the biomedical community, and the development of basic research programs in numerous laboratories. Presently, greater than 1,000 publications including over 400 case reports in the biomedical literature address Cryptosporidium spp. and cryptosporidiosis. Cryptosporidium parvum is now thought to be one of the three most common enteropathogens causing diarrheal illness in humans worldwide, especially in developing countries. It is likely that cryptosporidiosis was previously included in the 25 to 35% of diarrheal illness with unknown etiology. Because of the severity and length of diarrheal illness and because no effective therapy has been identified, cryptosporidiosis is one of the most ominous infections associated with AIDS. The role of C. parvum as an enteropathogen is well established; documentation of its role as a cause of hepatobiliary and respiratory diseases is now appearing in the literature. Our present understanding of the natural history, epidemiology, biology, and immunology of Cryptosporidium spp. as well as the clinical features, pathogenicity, and treatment of cryptosporidiosis are reviewed here.

Hepatobiliary cryptosporidiosis and cytomegalovirus infection mimicking metastatic cancer to the liver

A cholestatic syndrome caused by sclerosing cholangitis and papillary stenosis has been described in patients with the acquired immunodeficiency syndrome and hepatobiliary cryptosporidiosis and cytomegalovirus infection. The case of a 41-year-old homosexual man with the acquired immunodeficiency syndrome who presented with abdominal pain, diarrhea, fever, and cholestasis is reported. A percutaneous transhepatic cholangiogram showed that the extrahepatic and right-sided intrahepatic ducts were normal. Computerized tomography of the abdomen showed multiple hypodense lesions in the liver. Guided needle biopsies of several of these lesions showed severe confluent necrotizing pericholangitis with cytomegalovirus-infected cells. Numerous cryptosporidia were seen attached to biliary epithelium. The unique histopathologic and radiographic features of this case should be added to the spectrum of hepatobiliary manifestations of the acquired immunodeficiency syndrome.

Cryptosporidiosis and AIDS

Cryptosporidiosis in patients with AIDS presents as a chronic enteritis, with biliary complications in about 10% of sufferers. The disease is persistent and progressively fatal. Due to the widespread prevalence of the parasite in the community and amongst domesticated animals, persons with AIDS are constantly at risk. Treatment is extremely difficult in view of the apparent lack of a specific anticryptosporidial drug. Methods of immunomodulation are worth considering, but the main recourse may have to be a prolonged regimen of rehydration and parenteral nutrition. However, if T helper cell function improves, the disease may go into remission or the parasite could be eliminated. Vaccination of those at risk is not feasible at present.

Empyema of the gallbladder in a patient with AIDS-related complex

A case of staphylococcus aureus empyema of the gallbladder in a patient with AIDS-related complex is presented. The case is remarkable for the indolence of the clinical presentation and the magnitude of gallbladder dilatation noted at computed tomographic (CT) examination. Empyema of the gallbladder may constitute an unusual manifestation of bacterial disease in patients with AIDS or AIDS-related complex and cholelithiasis.