Purpose: We evaluate the accuracy of diagnostic markers in identifying acute cholecystitis in critically ill patients with a non-biliary admitting diagnosis. We hypothesize that the “classic” markers of acute cholecystitis including Right Upper Quadrant (RUQ) pain, elevated WBC and gallbladder wall thickening on ultrasound, have low-diagnostic yield in the Intensive Care Unit (ICU) patient population.
Methods: The study included all consecutive patients (n=62) who received a Percutaneous Cholecystostomy (PC) while admitted to the Medical (MICU) or Surgical (SICU) Intensive Care Unit during a 5-year period. The predictive value of each marker for diagnosing acute cholecystitis was evaluated.
Results: Forty-two patients had acute cholecystitis suspected upon PC placement: 8 patients had purulent or white bile, 34 patients had stones present in the cystic duct or non-visualization of the cystic duct with contrast injection. Our results confirm low sensitivities of RUQ pain (38%), elevated WBC (67%) and gallbladder wall thickening (50%) for diagnosing acute cholecystitis in the critically ill patient population. Hepatobiliary (HIDA) scans (positive predictive value 93%) were the most sensitive marker.
An ultrasound showing gallbladder wall thickening (15/20=75%) was the most common reason for PC placement in patients who did not have findings of acute cholecystitis.
Conclusion: We confirm our hypothesis that the classic markers used to diagnose acute cholecystitis are not reliable in the critically ill patient population. We propose a combination of biochemical and radiological criteria should be used to avoid missing a diagnosis of acute cholecystitis in these vulnerable patients.
Acute Cholecystitis - AC
Percutaneous Cholecystostomy - PC
White Blood Cell Count - WBC
Body Mass Index - BMI
Computed tomography - CT
Intensive Care Unit - ICU
Length of Stay - LOS
Acute Cholecystitis (AC) affects an estimated 20 million patients annually in the United States [1,2]. The standard of care for treatment is latively straight forward, often times ambulatory Laparoscopic Cholecystectomy (LC). However, in critically ill patients the risk of general anesthesia and a surgical cholecystectomy is often prohibitive. Instead, placement of Percutaneous Cholecystostomy (PC) is preferable [3-10].
Percutaneous Cholecystostomies can serve as either a definitive procedure or bridging therapy until the patient is clinically stable for a surgical cholecystectomy [11-18]. During the course of an ICU stay, patients can develop classic signs and symptoms that are attributed to acute cholecystitis standard clinical, laboratory and radiological markers used to diagnose acute cholecystitis are by default and perhaps incorrectly, used to justify PC placement in this unique patient population.
The purpose of our study was to establish evidence-based criteria for placement of PC in critically ill patients with a non-biliary diagnosis on admission. Our goal was to evaluate diagnostic markers for acute cholecystitis and the need for a PC in ICU patients, as opposed to defining criteria for PC placement in patients who were critically ill from their gallbladder disease. Our hypothesis was that the “classic” markers of acute cholecystitis including right upper quadrant pain, elevated WBC and ultrasound findings of gallbladder wall thickening have low-diagnostic yield in the intensive care unit patient population. We further postulated that relying on classic markers results in an over-diagnosis of acute cholecystitis and unnecessary PC placement. By establishing evidence-based criteria for placement of percutaneous cholecystostomy tubes we hope to prevent unnecessary testing and procedures.
|Patient Characteristics||Value||Number of patients (N = 62)||Percentage of patients|
|Age||62.3 ± 18.0||-||-|
|BMI||30.3 ± 12.0||-||-|
|Hospital LOS (days)||26.3 ± 19.4||-||-|
|ICU LOS (days)||18.8 ± 16.9||-||-|
|30-day Mortality||Alive at 30 days||39||63.0%|
|Dead at 30 days||23||37.0%|
|Days between admission and C-tube placement||13.5 ± 15.4||-||-|
|Days until to C-tube removal||70.1 ± 64.4||-||-|
|Diagnostic Markers||Number of patients (N=62)||Positive predictive value||Negative predictive value|
|Laboratory Markers (on Admission)|
|Ultrasound: GB wall thickening||39||50%||21%|
|Ultrasound: Pericholecystic fluid||25||32%||58%|
|Ultrasound: Sonographic Murphy’s sign||11||13%||95%|
|Hepatobiliary (HIDA) Scan||19||93%||68%|
|Diagnostic Markers||Number of patients (N=19)||%|
|Laboratory Markers (on Admission)|
|Ultrasound: GB wall thickening||11||58%|
|Ultrasound: Pericholecystic fluid||4||21%|
|Ultrasound: Sonographic Murphy’s sign||2||11%|
|Species||Number of Positive Cultures (N=20)||Percentage|
Patients presenting with acute cholecystitis have established algorithms for diagnosis and treatment [15-19]. However, development of biliary disease in critically ill patients may present atypically and therefore require a modified management approach. We retrospectively reviewed 62 critically ill patients who underwent PC placement at our institution and evaluated the clinical, radiological and diagnostic markers used to arrive at the diagnosis of acute cholecystitis. Our hypothesis was that the standard markers used to diagnose acute cholecystitis in non-critically ill patients were not diagnostic of this disease process in the critically ill patient population. To our knowledge, this is the first study specifically looking at predictive value of diagnostic markers for acute cholecystitis in intensive care unit patients without a primary biliary diagnosis.
The Tokyo Guidelines were an attempt to establish evidence-based criteria for the diagnosis of acute cholecystitis based on the presence of clinical symptoms, signs of systemic infection, and positive radiographic findings on ultrasound, Computed Tomography (CT) or Hepatobiliary (HIDA) scan. The defined clinical symptoms of AC include right upper quadrant pain, or tenderness and a positive Murphy’s sign (cessation of inspiration with deep palpation in the right upper quadrant) . Objective markers included an elevated White Blood Cell (WBC) count, fever or an elevated C-Reactive Protein (CRP) as well as imaging findings of AC. Characteristic findings on ultrasound or CT include gallbladder wall thickening and the presence of peri-cholecystic fluid or gallstones. An alternative diagnostic test is the Hepatobiliary scan. Hepatobiliary (HIDA) in which an ejection fraction <35% or non-visualization of the cystic duct and gallbladder after a defined time period is considered diagnostic of acute cholecystitis. while Hepatobiliary (HIDA) scans have a positive predictive value and negative predictive value of >90%, severe comorbidities, especially hepatic disease, can frequently cause false positives, rendering the test less sensitive in critically ill patients . Additionally, Hepatobiliary (HIDA) scans are not bedside procedures and therefore may be impractical to administer to critically ill patients, particularly if they are ventilator-dependent and cannot be transported safely from the intensive care unit setting for imaging [21,22].
In our study, patients largely underwent RUQ ultrasounds followed by Hepatobiliary (HIDA) scans to confirm acute cholecystitis. CT scans were not included within the study because they were rarely performed in our studied patient population (n=3). Therefore positive predictive value and negative predictive value of CT scans cannot be commented on based on our available data. In our study Hepatobiliary (HIDA) scans were the most sensitive marker (positive predictive value 93%) for diagnosing acute cholecystitis. However, in the group of 20 patients who did not have acute cholecystitis suspected on PC placement, 5/19 (26.3%) did have positive Hepatobiliary (HIDA) scans. This suggests Hepatobiliary (HIDA) scan, while sensitive for predicting acute cholecystitis in ICU patients with a non-biliary diagnosis are not the most specific test for this patient population. Additionally, one patient was found to have acute cholecystitis suspected on PC placement despite a normal Hepatobiliary (HIDA) scan. Conversely, jaundice, while having a very low positive predictive value (2%), had the highest negative predictive value (95%) of any diagnostic test for acute cholecystitis in our study population.
Our findings show no single test accurately confirms acute cholecystitis in the studied patient population. Hepatobiliary (HIDA) scans had the highest positive predictive value of our tested diagnostic markers but also resulted in some false positive results. However, given the high morbidity and mortality associated with untreated acute cholecystitis or an emergent cholecystectomy, acceptance of some false positives may be necessary to avoid the risk of missing this disease process in critically ill patients. Emergent cholecystectomies in the critically ill patient population is associated with mortality as high as 14-19% .
Multiple studies have established the use of PC as a safe alternative therapy for acute cholecystitis. The reported recurrence of acute cholecystitis after PC varies widely in the literature with anywhere from 14%-61% of patients failing to experience a complete resolution of their symptoms [9-12]. Initial clinical improvement and resolution of symptoms is often reported to be quite high, with up to 80-90% of patients reporting an improvement of their symptoms within the first 2-5 days [11,12]. Rates of interval laparoscopic cholecystectomy after PC placement range from 30-80%, with most studies reporting between 30-60% of patients initially treated with PC subsequently requiring either an emergent or elective cholecystectomy [23-25]. Conversion rates to open cholecystectomy have been reported as high as 32% [24,25]. A study by Bickel and associates comparing the rate of conversion to open cholecystectomy after early (within 2 days of symptom onset) and late (3-6 days post symptom onset) PC placement found that the early PC group had a significantly lower conversion rate (8.3%) compared to the delayed PC placement group (33.3%) .
Ours was the first study to establish evidence-based criteria for the placement of percutaneous cholecystostomy in critically ill patients without a primary biliary disease. An inherent limitation exists in the specific nature of our inclusion criteria which reduces the potential study population size. Additionally, as we have no institutional algorithm in place for diagnosing acute cholecystitis, we were restricted to using conditional criteria such as positive cultures and cystic duct visualization during cholecystostomy tube placement. This limits the conclusions that can be drawn regarding the utility of individual diagnostic markers in identifying acute cholecystitis. Further research that includes a larger study population and uniform use of diagnostic markers is needed to determine if there is an optimal combination of diagnostic testing that can be used to confirm the diagnosis of acute cholecystitis and to determine which ICU patients would truly benefit from a percutaneous cholecystostomy. Additional limitations of this study include our inability to capture complications that might have been addressed at outside hospitals. Although we tracked records for patients at least 90-days after their admission for PC placement, we also cannot reliably confirm if patients underwent subsequent cholecystectomy in a large number of cases where patients if performed at an outside facility or if the surgical cholecystectomy was not mentioned in subsequent visits. Additionally, the retrospective nature of study results in incomplete data acquisition for some patients.
Hepatobiliary (HIDA) scans are the most sensitive test for confirming acute cholecystitis in critically ill patients. However, the Hepatobiliary(HIDA) has a low sensitivity for this patient population. Our current clinical recommendation is that a combination of biochemical criteria, as well as an ultrasound and Hepatobiliary (HIDA) scan be used to confirm acute cholecystitis in the ICU patient population. The risk of percutaneous cholecystostomy is negligibly low in comparison to the very high risk of a missed diagnosis of acute cholecystitis. As such, focus should be on avoiding a missed diagnosis and the potentially devastating sequelae of acute cholecystitis.
Disclosure of Potential Conflicts of Interest: All authors declare no conflict of interest.
Ethical approval: This article does not contain any studies with human participants or animals performed by any of the authors.
Citation: Shaheen AW, Weinstein MS, Beekley A, Marks JA, Eisenbrey JR, et al. (2017) Evaluating Diagnostic Markers to Predict Acute Cholecystitis in Critically Ill Patients Prior to Placement of a Percutaneous Cholecystostomy. J Emerg Med Trauma Surg Care 4: 018.
Copyright: © 2017 Aisha W Shaheen, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.