Plasma Lactescence in Acute Pancreatitis
A 54-year-old man with history of diabetes mellitus and acute necrotizing pancreatitis was admitted with acute abdominal pain. A computed tomography scan of the abdomen revealed findings consistent with acute pancreatitis. Initial laboratory analysis was unremarkable except for HbA1c 11.1%, lipase of 2195 U/L, and amylase of 234 U/L. Interestingly, the laboratory reported that the patient’s plasma was grossly lactescent. Subsequent analysis of his lipid profile revealed markedly elevated serum triglycerides (TG) at 5533 mg/dL (normal value, 0-150 mg/dL). Emergent plasmapheresis was initiated. After 2 session of plasmapheresis, serum TG dropped to 266 mg/dL, with resolution of serum lactescence and pancreatitis.
Severe hypertriglyceridemia characterized by plasma TG levels of >1000 mg/dL is the third most common cause of acute pancreatitis after alcohol and gall stones. The risk of developing acute pancreatitis is 5% with TG >1000 mg/dL and increases proportionately with further increase in TG levels.1 Metabolism of TG by pancreatic lipase leads to excess production of free fatty acids, which are toxic to the pancreas.
Patients typically present with the classic symptoms of acute pancreatitis. On physical examination there can be signs of hyperchylomicronemia like eruptive xanthoma and lipemia retinalis. Elevated TG can lead to plasma lactesence, which is a milky white discoloration of plasma. The laboratory can sometimes detect this milky white discoloration after centrifugation of the blood sample for chemistry, as was seen in our case (Figure).
Triglycerides should be routinely checked in cases of acute pancreatitis. Presences of pseudohyponatremia and normal amylase level in the evidence of acute pancreatitis can give a clue to the diagnosis. After conventional treatment of pancreatitis is initiated, patients with a serum TG level >1000 mg/dL, lipase >3 times normal, and those with severe pancreatitis should be considered for therapeutic plasma exchange. Although no randomized trials have demonstrated a benefit of plasma exchange, case series have reported resolution of pancreatitis and normalization of TG levels after 1 or 2 sessions of plasma exchange.2 Apart from genetic causes, a search for a secondary cause of hypertriglyceridemia like diabetes, alcoholism, obesity, and hypothyroidism should be done. Secondary prophylaxis with a low-fat diet and fenofibrates should be initiated once patients are stable.
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-Sumit Kumar, MD
This article originally appeared in the November 2016 issue of The American Journal of Medicine.