Recurrent abdominal pain in a 16-year-old girl.

A 16-year-old girl was admitted with acute onset of abdominal pain associated with vomiting. There was no abdominal distension, fever, jaundice or gastrointestinal bleeding. She had two similar episodes in the preceding 6 months. On examination, there was mild tenderness in the epigastrium. Her blood sugar, renal parameters, results of liver function tests and serum amylase were normal. The blood samples collected for analysis are shown in Figure 1. Upper gastrointestinal endoscopy was unremarkable.

Figure 1

Blood sample collected for analysis

What is your diagnosis?

Diagnosis: Acute Pancreatitis

Figure 1 shows a creamy supernatant on standing, suggesting high lipid content. Serum triglyceride level was 1640 mg/dL, which was persistently elevated after the acute episode. Serum lipase was also elevated (480 U/L). Ultrasound and contrast-enhanced CT scan of the abdomen showed an edematous pancreas with peri-pancreatic fluid collection consistent with acute pancreatitis. Recurrent acute pancreatitis due to hypertriglyceridemia was considered. She was managed conservatively during the acute episode and was advised dietary fat restriction and fibrates for prevention of recurrence. She was symptom free at 10 months of follow-up.

DISCUSSION

Recurrent acute pancreatitis remains a great diagnostic challenge for every treating clinician. It is characterized by repeated episodes of pancreatitis that usually resolve between the attacks. Metabolic disorders like hypercalcemia and hypertriglyceridemia are rare causes of recurrent pancreatitis. The exact mechanism of hypertriglyceridemia-induced pancreatitis remains unclear. Chylomicrons are triglyceride-rich large lipoprotein particles that impair the blood flow in capillary beds of the pancreas. This results in ischemia and disruption of the acini, exposing them to pancreatic lipase. Free fatty acids thus released produce toxic injury to the capillary endothelium and pancreatic acinar cells.1 The activation of trypsinogen due to the acidosis produced by fatty acids is also responsible for initiation of pancreatitis.2

The clinical course of hyperlipidemic pancreatitis does not differ from that of other types of acute pancreatitis. It consists of a toxic phase with distant-organ dysfunction of varying severity and a late phase with local and regional complications.3 The diagnosis of acute pancreatitis is often missed in the setting of hypertriglyceridemia as it can cause spuriously normal amylase levels. Determination of serum lipase level may be useful in such situations for diagnosis of suspected pancreatitis. The presence of lactescent plasma gives a bedside clue to hypertriglyceridemia.

The treatment of hypertriglyceridemia-induced pancreatitis in the acute phase is similar to that of pancreatitis of other causes. However, plasmapheresis can accelerate the removal of the precipitating lipoproteins in the acute setting.4–6 It also causes an alteration in the cytokine and anti-cytokine levels resulting from pancreatic inflammation. Yet another effective modality is the use of intravenous insulin and heparin. Lipoprotein lipase activity is enhanced, resulting in degradation of the chylomicrons with reduction of triglyceride levels.7 Also, the combination of insulin and heparin improves the microcirculation and causes inhibition of neutrophil activity. Dietary fat restriction is required for prevention of further episodes of acute pancreatitis. Fish oil containing omega-3 fatty-acids can decrease the endogenous production of triglyceride-rich lipoproteins. Drug treatment with fibrates is considered if there is persistence of hyperlipidemia on a fat-reduced diet.