Opportunistic infections associated with immunosuppressed states have been implicated in the pathogenesis of AC. Cryptosporidium parvum was identified in our patient and is associated with 20-57% of AC cases [5]. It causes cholangiopathy via apoptosis of biliary epithelial cells through the Fas/FasL pathway, subsequently causing fibrosis which leads to biliary stricturing [6,7]. The second most implicated pathogen is CMV accounting for 10-20% of cases and is believed to cause vascular injury leading to ischemic cell death and fibrosis. Microsporidium, Mycobacterium Avium Complex, and other opportunistic infections have been inconsistently implicated [7].

The clinical presentation of AC can range from asymptomatic as was seen in our patient to severe right upper quadrant abdominal pain, diarrhea, fevers, jaundice. The degree of abdominal pain has been linked to the degree of papillary stenosis [8,9].

The classic laboratory abnormalities associated with AC are a markedly elevated GGT and ALP, as seen in our patient. Elevations in bilirubin and transaminases have also been reported inconsistently [9]. A study by Daly et al showed that ultrasound is 97% sensitive and 100% specific in diagnosing AC when compared to endoscopic retrograde cholangiopancreatography (ERCP) which is the gold standard [10]. Being cost effective, this is often the first imaging modality used [8,11]. MRCP is now preferred over ERCP if there is no indication of diagnostic or therapeutic procedures [12].

Narcotics such as opioids can provide symptomatic pain relief. The study by Cello et al showed that endoscopic sphincterotomy in AC with papillary stenosis provided sustained improvement in abdominal pain when followed up over a period of at least 9 months [8]. This is likely due to decompression of biliary ducts and bile drainage. The same study showed that sphincterotomy did not lead to a sustained decrease in ALP. For patients not responding to pain management with opioids and sphincterotomy, celiac plexus block has shown to have promising results [13].

A small study with four AC patients treated with ursodiol showed improvement in abdominal pain and a fall in ALP and GGT. However, no follow-up studies have been conducted [14].

Although other agents like paromomycin and azithromycin have been studied, nitazoxanide is the only drug approved by the United States Food and Drug Administration in the treatment of cryptosporidiosis. It is effective in reducing load of parasites in immunocompetent hosts; however, benefit in immunocompromised hosts is uncertain but often considered due to potentially serious complications [15].

Intravenous ganciclovir and foscarnet have not shown benefit in the treatment of CMV cholangitis. Similarly, treatments for other opportunistic pathogens have not shown consistent results [7]. Control of HIV with HAART has shown the most improvement in mortality in AC [4].
Although prior studies showed survival of 7-12 months, recent studies show increased survival to 34 months due to improved access and adherence to HAART [3]. The study by Ko et al found that the presence of opportunistic infections, especially cryptosporidium infection at the time of diagnosis and ALP >1000 was associated with poor outcomes [4]. CD4 count, the severity of cholangiopathy, and sphincterotomy for biliary decompression had no effect on mortality. Progression of sclerosis and cholangiocarcinoma are the complications that have been associated with AC and unfortunately progress despite treatment with HAART.

Our case highlights the important aspects in the etiology, diagnosis, management, and prognosis of AC – a condition associated with high morbidity and mortality. It also calls for more research in distinct aspects of this rarely seen diagnosis in the HAART era.