Chiang Mai Med J 2007;46(2):45-53.
Original article
CT FINDINGS OF ACUTE PANCREATITIS IN MAHARAJ NAKORN CHIANG MAI HOSPITAL Anchalee Wongnai, M.D., Wittanee Na-Chiang Mai, M.D. Department of Radiology, Faculty of Medicine, Chiang Mai University
Purpose To retrospectively review etiologies, CT findings, complications and correlation between the CT severity index (CTSI) and length of hospital stay (LOS) in the patients with acute pancreatitis in Maharaj Nakorn Chiang Mai Hospital. Materials and methods Ninety one patients with a diagnosis of acute pancreatitis were recruited from the Maharaj Nakorn Chiang Mai Hospital database from October 2003 to June 2005. The etiologies of acute pancreatitis were collected from medical records. Fifty patients underwent CT scans in the hospital. The CT findings were analyzed. All patients were grouped into mild, moderate and severe pancreatitis using the currently accepted CTSI, developed by Bathazar et al. Correlation between CTSI and LOS was calculated by ANOVA and Sheffe methods using the SPSS program. Result The most common etiology of acute pancreatitis was alcohol ingestion, which presented in 30 patients (60%). By using the currently accepted CTSI, we graded the severity of acute pancreatitis as mild in 30 (60%), moderate in 16 (32%) and severe in 4 (8%) of the 50 patients. The most common extrapancreatic abnormality was pleural effusion; which accounted for 29 (58%) of the 50 patients. Complications of pancreatitis were as follows; pancreatic abscess in 6 patients (12%), infected pancreatic necrosis in 2 (4%), pancreatic pseudocyst in 4 (8%), venous thrombosis in 8 (16%) and splenic infarction in 1 patient (2%). When comparing LOS between groups, there was a significant difference in LOS between the mild and moderate pancreatitis groups (p=0.04) and between the mild and severe pancreatitis groups (p=0.001), but there was no significant difference in LOS between the moderate and severe pancreatitis groups (p=0.078). Conclusion The most common etiology of acute pancreatitis in Maharaj Nakorn Chiang Mai Hospital is alcohol ingestion. Most of the patients with acute pancreatitis are in the mild group. The most common complication is venous thrombosis. The grading of pancreatitis could be graded in mild and severe acute pancreatitis groups, which correlated well with patient outcome. Chiang Mai Medical J 2007;46(2):45-53. Keywords: acute pancreatitis, CT severity index, complication of pancreatitis, grading of pancreatitis Address requests for reprints: Anchalee Wongnai, M.D., Department of Radiology, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand. E-mail:
[email protected] Received 14 September 2006, and in revised form 7 February 2007
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Diagnosis of acute pancreatitis can be made on the basis of clinical history, physical examination and laboratory findings. In some circumstances the diagnosis is difficult. Recently CT scanning has become the modality of choice in diagnosing acute pancreatitis and searching for complications. (1) Contrast-enhanced computed tomography is the most important imaging modality for the diagnosis and staging of severe acute pancreatitis, due to its excellent capacity in demonstrating early inflammatory changes as well as complications, in particular pancreatic necrosis. CT examinations during the initial work-up is valuable in staging disease severity and assessing the need for possible intervention. CT plays an important role in differentiating edematous and necrotizing forms of acute pancreatitis, since clinical assessment alone can result in an underestimation of the severity of the disease.(2) In Maharaj Nakorn Chiang Mai Hospital, the prevalence of acute pancreatitis among patients is quite high, and the clinicians often request CT scans to diagnose and evaluate patients suspected of having this disease. However the imaging finding, CTSI and complications were not reported from our hospital. Steps were there fore taken to commission a study that would be conducted by us. We were interested in researching the etiology, CT findings, complications of acute pancreatitis and correlation between the CTSI and LOS in patients with acute pancreatitis. Materials and methods Patients We performed a retrospective review of 91 consecutive patients, who were admitted to Maharaj Nakorn Chiang Mai Hospital with a primary diagnosis of acute pancreatitis during October 2003 to June 2005. Of these
Wongnai A, Na-Chiang Mai W.
91 patients, fifty (35 male and 15 female; mean age 40.7 years; range 17-96 years) were included in this study. Forty one patients, whose CT scans and medical record were unavailable, were excluded. CT Technique All examinations were performed on an MDCT scanner (Toshiba Aquilion 16). Preand post contrast images were obtained. The post contrast scan was performed in the portovenous phase, 60-70 seconds after intravenous contrast administration of 100 mL of ionic or non-ionic contrast media 350 mg/mL, collimation, 2x16 mm. Reconstruction thickness was 7 mm and reconstruction interval, 7 mm; and helical scanning was performed during a single breath-hold period. Image analysis Soft copies of all contrast-enhanced CT scans were retrospectively reviewed on E-film workstations by two observers, who were unaware of presenting signs and symptoms of the patient outcomes. The findings of each case were analyzed and the patients were then grouped by using the CT severity index developed by Balthazar et al (Table 1).(1,3,4) The severity of pancreatitis was categorized as mild (score, 0-3 points), moderate (4-6 points), or severe (7-10 points). Complications of acute pancreatitis were assessed under the following: pseudocyst, infected pancreatic necrosis, pancreatic abscess, venous thrombosis, splenic infarction, pseudoaneurysm and pancreatic fistula in each group of pancreatitis patients. Extrapancreatic abnormalities such as pericardial effusion, pleural effusion, THAD and fatty liver were also assessed.
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patients (4%). There were 3 patients in this study who had no other risk factor of acute pancreatitis, but they had taken medication. No cause of acute pancreatitis was detected in 2 patients.
Statistical analysis Statistical analyses were performed by using commercially available software (SPSS 13). Etiologies and complications of acute pancreatitis were calculated by using frequency (valid percent), and correlation between the CTSI and LOS was calculated by using ANOVA and Sheffe statistical analysis. Results Etiology The most common etiology of acute pancreatitis in Maharaj Nakorn Chiang Mai Hospital was alcohol ingestion, which accounted for 30 (60%) patients; most of them being men (28 men, 2 women). The second most common cause was either gallstone or CBD stone in 9 patients (18%). The remaining etiologies of acute pancreatitis in this study were trauma in 4 patients (8%), drugs in 3 (6%) post ERCP in 1 patient (2%), post surgery in 1 patient (2%) and idiopathic in 2
CT findings of acute pancreatitis Of the 50 patients in this study, a total of 58 CT scans were obtained at either single examinations or consecutive follow-up studies. All soft copies of the CT scans were analyzed. Of the 50 patients, 2 had a normal CT scan, 2 had glandular enlargement alone, 33 had pancreatic gland and peripancreatic gland abnormality and 13 had pancreatic necrosis. The progression of pancreatic necrosis was observed in one patient. On the initial CT scan, there was 50% necrosis of the pancreas (white arrow). CTSI=10 (Severe acute pancreatitis)
Pericardial effusion was found in 2 patients, who also had bilateral pleural effusion. In this study, fatty liver was found in 14 (28%) patients. Ten patients had alcoholic pancreati-
tis. The remaining four patients had no history of alcohol ingestion, but one had underlying cirrhosis. One patient in this study developed THAD during the course of acute pancreatitis, which appeared as a wedge shaped hyperattenuation lesion involved in the lateral segment of the left lobe, and anterior segment of the right lobe. Complications of acute pancreatitis The complications of acute pancreatitis in this study were infected pancreatic necrosis, pancreatic abscess, pancreatic pseudocyst,
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venous thrombosis and splenic infarction, as shown in Table 3. Neither pseudoaneurysm nor pancreatic fistula was found. The most common complication was venous thrombosis. Most of the common thrombosed vessels were splenic vein. One patient in the moderate pancreatitis group developed infected pancreatic necrosis (Fig. 2). All patients with severe pancreatitis developed complications (Table 3). In this study, we found only one patient with splenic infarct, who was in the severe group of pancreatitis.
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Correlation between LOS and CTSI Of the 50 patients, 46 (90%) recovered from their illness and four died in the hospital. The LOS was the only indicator of patient outcome. In this study, we calculated the correlation of CTSI and LOS in 48 patients. Two patients were excluded due to unavailable data on duration of hospital stay. The LOS ranged from 3 to 76 days (mean, 15.92 days). The mean LOS was 10.21 days in the mild group, 20.62 days in the moderate group and 37 days in the severe group.
Figure 2. A 73-year-old man with underlying diabetes mellitus, presented with a history of 2 days abdominal pain. A post contrast CT scan (A and B) shows marked necrosis involving more than 30% of the pancreas with multiple gas bubbles (small arrow) in an area of fluid collection compatible with infected pancreatic necrosis. Air bubbles in the abdominal aorta are also noted (large arrow).
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There was a significant difference in LOS between the mild and moderate groups (p=0.04) and mild and severe pancreatitis groups (p=0.001), but no significant difference between the moderate and severe pancreatitis groups (p=0.078) (Table 4). Discussion Etiology of acute pancreatitis In this study, alcohol ingestion was the most common etiology of acute pancreatitis and a far more common cause than stone. This was in contrast to the current literature, which states that the most common cause of acute pancreatitis is stone, a reported by J Darto Casas et al.(5) CT findings of acute pancreatitis The prevalence of normal CT scans in acute pancreatitis varies among series by between 14% to 28%, but the exact prevalence is unknown because surgical and pathological correlation is lacking and most patients with clinically mild pancreatitis do not undergo
Wongnai A, Na-Chiang Mai W.
CT imaging.(6) In this study, there were 2 patients with clinical diagnosis of acute pancreatitis, but the CT scans were normal, and two patients showed progression of mild (CT severity index = 3) to severe pancreatitis during admission. Progression from mild to severe acute pancreatitis can occur, but it is a rare Phenomenon.(5) Most pancreatic necrosis cases develop early in the course of severe pancreatitis and they are usually well established 96 hours after the onset of clinical symptoms. The overall accuracy of dynamic CT in the detection of pancreatic necrosis is 80 to 90%. (1,6) The percentage of patients with necrosis in this study (24%) was slightly higher than the prevalence (5%-20%) described in the literature.(7-9) These patients were found in both moderate and severe pancreatitis groups. There was one patient in our series who developed late pancreatic necrosis. The development of late necrosis is interesting, important and difficult to explain. It occurs only in patients with peripancreatic fluid
CT findings of acute pancreatitis
collection (CTSI >3), and was detected at the first follow up of this study between the 1st and 2nd week of hospitalization. A follow-up CT is recommended after 7-10 days if the initial scan shows a CTSI score of 3-10. Extrapancreatic abnormalities in acute pancreatitis The effusion is widely cited to occur in 3%17% of cases with a preference for the left side. The exact etiology for pleural effusion in acute pancreatitis is not clear, but it may be related to a lymphatic spread of fluid across the diaphragm. Based on our patient population, pleural effusion occurring in 58% was more common than that classically described. This study found no left side predominance. Most of the effusions were bilateral. The tendency for bilaterality was similar to that reported by Simmons M Z et al.(10) Complications of pancreatitis In this study, most of the complications were seen in patients with high CTSI (>3 score), especially in the severe pancreatitis group. This finding correlated with the report by Balthazar et al.(3) Our incidence of infected pancreatic necrosis was also similar to that report. There were 3 (6%) patients with infected pancreatitic necrosis in this study, which amounted to 37.5% of the patients with this condition. Pancreatic abscess occurs with an incidence of up to 3% in the literature. It is a late complication after necrotizing pancreatitis. Based on our patient population, pancreatic abscess occurring in 10% was slightly more common than that described in the literature. It clearly indicates in the literature,(3) that the likelihood of an abscess developing is highest in patients with associated necrosis and fluid collections and slightly lower if only
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necrosis is present. In this study, the incidence of pancreatic pseudocyst (6%) was similar to that in the literature,(7) in which pancreatic pseudocyst arises in about 6% of patients following an attack of acute pancreatitis. Pseudocysts are most often peripancreatic in location, but they have been found throughout the abdomen, as well as within the mediastinum and pelvis.(6) Naturally, the vessels near the pancreas are at the greatest risk of developed pseudoaneurysm. Our results showed that although there were no cases of pseudoaneurysm formation, other vascular abnormalities were more frequently present than those previously estimated. Splenic vein thrombosis was detected in 8 patients (16%) and splenic infarction in 1 patient (2%), which correlated with the report of Mortelé, Koenraad J et al.(11) CT severity index (CTSI) and length of hospital stay (LOS) A significant difference in the LOS between mild and moderate pancreatitis groups (p=0.004) and mild and severe pancreatitis groups (p=0.001) was observed, and it correlated with the result reported by Koenraad J M, et al.(11) According to this finding, the grading of pancreatitis could be graded as mild (CTSI 0-3) and severe (CTSI 4-10) acute pancreatitis, which correlated well with the patient outcome. Conclusion The most common etiology of acute pancreatitis in Maharaj Nakorn Chiang Mai Hospital is alcohol ingestion. When using the currently accepted CTSI grade in this study, most of the patients with acute pancreatitis were in the mild group. Complications of pancreatitis were often found in the severe pancreatitis group, and the most common
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complication was venous thrombosis. The grading of pancreatitis could be graded in mild (CTSI 0-3) and severe (CTSI 4-10) acute pancreatitis groups, which correlated well with the patient outcome. Acknowledgements We would like to express our sincere gratitude to Assistenat Professor Suwalee Pojchamarnwiputh, teaching staff member in the Department of Radiology, for her suggestions and assistance in word processing. We are also grateful to Mr. Winyan Suksang for providing some of the statistical data used in this study. Finally, we would like to acknowledge the technichians in the Department of Radiology for providing some of the imaging information. References 1. Balthazar EJ. Acute pancreatitis: assessment of severity with clinical and CT evaluation. Radiology 2002;223:603-13. 2. Merkle EM, Gorich J. Imaging of acute pancreatitis. European Radiology 2002;12:1979-92. 3. Balthazar EJ, Robinson DL, Megibow AJ, Ranson JH. Acute pancreatitis: value of CT in establishing
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prognosis. Radiology 1990;174:331-6. 4. Balthazar EJ, Ranson JH, Naidich DP, Megibow AJ, Caccavale R, Cooper MM. Acute pancreatitis: prognostic value of CT. Radiology 1985;156:76772. 5. Casas JD, Diaz R, Valderas G, Antonio M, Patricia C. Prognostic value of CT in the early assessment of patient with acute pancreatitis. AJR 2004;182: 569-74. 6. Balthazar EJ, Freeny PC, Vansonnenberg E. Imaging and intervention in acute pancreatitis. Radiology 1994;193:297-306. 7. Beger HG, Rau B, Mayer J, Pralle U. Natural course of acute pancreatitis. World J Surg. 1997;21:130-5. 8. London NJ, Leese T, Lavelle JM, Rapid-bolus contrast-enhanced dynamic computed tomography in acute pancreatitis: a prospective study. Br J Surg 1991;78:1452-6. 9. Yassa N, Agostini J, Ralls P. Accuracy of CT in estimating extent of pancreatic necrosis. Clin Imaging 1997;21:407-10. 10. Simmons MZ, Miller JA, Zurlo JV, Charles DJ. Pleural effusion associated with acute pancreatitis: incidence and appearance based on computed tomography. Emergency Radiology 1997;4:287-9. 11. Mortele KJ, Mergo PJ, Taylor HM, Ernst MD, Ros PR. Splenic and Perisplenic Involvement in Acute Pancreatitis: Determination of Prevalence and Morphologic Helical CT Features J Comput Assist Tomogr 2001;25:50-4.
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ลักษณะภาพเอกซเรย์คอมพิวเตอร์ในผู้ป่วยตับอ่อนอักเสบเฉียบพลัน ในโรงพยาบาลมหาราชนครเชียงใหม่ อัญชลี วงค์ใน, พ.บ., วิทธนี ณ เชียงใหม่, พ.บ. ภาควิชารังสีวทิ ยา คณะแพทยศาสตร์ มหาวิทยาลัยเชียงใหม่ บทคัดย่อ วัตถุประสงค์ เพื่อศึกษาถึงสาเหตุ ลักษณะทางเอกซเรย์คอมพิวเตอร์ ภาวะแทรกซ้อน และ ความสัมพันธ์ระหว่าง CT severity index และระยะเวลาการนอนโรงพยาบาล ในผูป้ ว่ ยตับอ่อนอักเสบ เฉียบพลันในโรงพยาบาลมหาราชนครเชียงใหม่ วิธกี ารวิจยั เป็นการศึกษาแบบย้อนหลังถึงลักษณะทางเอกซเรย์คอมพิวเตอร์ในผูป้ ว่ ยตับอ่อนอักเสบ เฉียบพลันจำนวน 91 ราย ในโรงพยาบาลมหาราชนครเชียงใหม่ ตัง้ แต่เดือนตุลาคม พ.ศ. 2546 ถึง เดือนมิถนุ ายน พ.ศ. 2548 มีผปู้ ว่ ยจำนวน 50 ราย ทีไ่ ด้รบั การทำเอกซเรย์คอมพิวเตอร์ในโรงพยาบาล มหาราชนครเชียงใหม่ ลักษณะทางเอกซเรย์คอมพิวเตอร์ได้ถกู นำมาวิเคราะห์ และแบ่งกลุม่ ความ รุนแรง โดยวิธีการให้คะแนนที่เป็นที่ยอมรับในปัจจุบัน (CT severity index) ที่ถูกพัฒนาขึ้นโดย Bathazar et al ความสัมพันธ์ระหว่าง CT severity index และระยะเวลาการนอนโรงพยาบาลถูกนำ มาวิเคราะห์โดยวิธี ANOVA และ Sheffe โดยโปรแกรม SPSS ผลการศึกษา สาเหตุทพ่ี บบ่อยทีส่ ดุ ของภาวะตับอ่อนอักเสบเฉียบพลันในโรงพยาบาลมหาราชนคร เชียงใหม่ คือ การดืม่ แอลกอฮอล์พบร้อยละ 30 ในการศึกษาครัง้ นีแ้ บ่งความรุนแรงของภาวะตับอ่อน อักเสบเฉียบพลันออกเป็น 3 ระดับ คือ รุนแรงน้อยพบ 30 ราย รุนแรงปานกลาง 16 ราย และ รุนแรงมาก 4 ราย ความผิดปกตินอกตับอ่อนทีพ่ บมากทีส่ ดุ คือ น้ำในช่องเยือ่ หุม้ ปอดซึง่ พบในผูป้ ว่ ย ทัง้ หมด 29 ราย ภาวะแทรกซ้อนของตับอ่อนอักเสบทีพ่ บในการศึกษานีค้ อื ; ฝีทต่ี บั อ่อน 6 ราย ภาวะ เนือ้ ตายติดเชือ้ 2 ราย ภาวะถุงน้ำทีต่ บั อ่อนและรอบๆ ตับอ่อน 4 ราย หลอดเลือดดำอุดตัน 8 ราย และม้าม ขาดเลือด 1 ราย จากการศึกษานีพ้ บว่ามีความแตกต่างอย่างมีนยั สำคัญในเรือ่ งของระยะเวลา นอนโรงพยาบาลระหว่างกลุ่มผู้ป่วยที่มีความรุนแรงของโรคน้อยและปานกลาง (p=0.004) และ ระหว่างกลุ่มที่มีความรุนแรงน้อยและรุนแรงมาก (p=0.001) แต่ไม่พบความแตกต่างในกลุ่มที่มี ความรุนแรงของโรคปานกลางและรุนแรงมาก (p=0.078) สรุปผลการศึกษา สาเหตุที่พบบ่อยที่สุดของภาวะตับอ่อนอักเสบในโรงพยาบาลมหาราชนครเชียงใหม่ คือ การดืม่ แอลกอฮอล์ และผูป้ ว่ ยส่วนใหญ่อยูใ่ นกลุม่ ทีม่ คี วามรุนแรงน้อย ภาวะแทรกซ้อน ที่พบบ่อยที่สุดคือหลอดเลือดดำอุดตัน ถ้าพิจารณาถึงความสัมพันธ์ระหว่างระยะเวลาในการนอน โรงพยาบาลและระดับความรุนแรงของโรค พบว่าภาวะตับอ่อนอักเสบเฉียบพลันสามารถทีจ่ ะแบ่ง ได้เป็น รุนแรงน้อยและรุนแรงมาก ซึ่งพบว่ามีความสัมพันธ์กับการให้การรักษาผู้ป่วยมากกว่า เชียงใหม่เวชสาร 2550;46(2):45-53. คำสำคัญ: ตับอ่อนอักเสบเฉียบพลัน ภาวะแทรกซ้อนของตับอ่อนอักเสบ ความรุนแรงของ ตับอ่อนอักเสบ
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