A 43-year-old uninsured man with a history of heavy alcohol abuse was admitted to the hospital with 6 months of malaise, nausea, abdominal distension, and pain. More recently he was experiencing dizziness, weakness, excessive urinary volume, and a nonproductive cough. Approximately four months before presentation he had been diagnosed with diabetes mellitus, but was unable to comply with recommended medications because of the cost.
Assessment
The patient was tachycardic, with a pulse of 132 beats per minute. His other vital signs were unremarkable. Physical examination was notable for dry mucous membranes, Kussmaul breathing, distension of the abdomen with a palpable liver edge, caput medusa stigmata, and bilateral trace lower extremity edema.
Laboratory investigations revealed blood glucose of 457 mg/dL, hemoglobin A1c of 9.8%, arterial pH of 7.314, serum bicarbonate of 7.5 mEq/L, positive urine ketones, and an anion gap of 29 mmol/L. β-Hydroxybutyrate was elevated to 104.7 mg/dL (reference range [RR] 0.0-3.0 mg/dL). Liver function tests were notable for a bilirubin of 2.2 mg/dL, a direct bilirubin of 1.3 mg/dL (RR 0.0-0.2 mg/dL), an elevated alkaline phosphatase to 175 U/L (RR 39-117 U/L), and a mildly elevated aspartate aminotransferase of 42 U/L (normal range 12-39 U/L). The lipase was within normal limits. Amylase, obtained 2 months later, was low at 11 U/L. A hematologic panel demonstrated a mild normocytic anemia, with a hemoglobin of 12.7 g/dL, and a mean corpuscular volume of 100 fL.
An ultrasound scan of his abdomen demonstrated hepatosplenomegaly and steatosis. An initial computed tomography (CT) scan demonstrated large intra-abdominal gas collection surrounding the pancreas, distal stomach, and duodenum (Figure). His CT scan demonstrated features consistent with severe acute necrotizing pancreatitis. He was admitted to the hospital because of concern for diabetic ketoacidosis and necrotizing pancreatitis.
Diagnosis
A drainage of the pancreatic collection was consistent with abscess and revealed frank pus with multiorganism growth including Citrobacter freundii, Lactobacillus species, and Klebsiella pneumoniae. Two peripancreatic drains were placed (one internal, one external) after aggressive irrigation of the cavity was performed. He was treated with intravenous electrolyte and fluid repletion, as well as vancomycin and meropenem.
Given that he initially presented with diabetic ketoacidosis with an elevated anion gap, he was thought to have ketosis-prone type 2 diabetes. We later proposed that the diabetes was actually the underdiagnosed type 3c diabetes mellitus after further investigation found an insulin antibody to be negative at <0.4 U/mL (RR 0.0-0.4 U/mL), islet cell antibody to be negative, a glutamic acid decarboxylase antibody above normal at 11.5 U/mL (RR 0.0-0.4 U/mL) (which 19 days later was noted to be normal at <5.0 m/mL), and a normal c-peptide and pancreatic polypeptide. Further testing revealed a low pancreatic fecal elastase of 18 μg/g (RR >201 μg/g) and an elevated γ-glutamyltransferase of 130 U/L (RR 9-64 U/L). Of note, his fat-soluble vitamins (A, D, E, and K) were all low or low normal.
This case is notable for both the rare diagnosis of acute necrotizing pancreatitis complicated by infected pancreatic necrosis and the under-recognized type 3c diabetes.
Severe acute necrotizing pancreatitis (formerly known as emphysematous pancreatitis) is a rare condition, with the two main causes being gas-producing bacterial infections and pancreatic fistulas with the gastric tract. This is a severe complication of pancreatitis and is diagnosed by the imaging findings of gas in the retroperitoneal space. Once diagnosed, management should include antibiotics and percutaneous drainage of fluid. Surgical debridement may be necessary. In this case the cause was thought to be gas-producing C. freundii.
The World Health Organization and the American Diabetes Association define type 3c as pancreatogenic, pancreoprive, or a pancreatic diabetes mellitus due to multiple conditions including acute, relapsing, and chronic pancreatitis, hemochromatosis, cystic fibrosis, fibrocalculous pancreatopathy, pancreatic trauma, pancreatectomy, pancreatic agenesis, and pancreatic cancer. Many patients with type 3c are misdiagnosed with type 2 diabetes. This is thought to be due to poor awareness of the condition. Ewald and Bretzel proposed the first set of diagnostic criteria for type 3c diebetes.5 Their criteria include the presence of exocrine pancreatic insufficiency, pathologic pancreatic imaging, and the absence of type 1 diabetes autoimmune antibodies. Their proposed minor criteria include impaired β-cell function, lack of excessive insulin resistance, impaired incretin secretion (GLP-1, pancreatic polypeptide), and low serum levels of lipid-soluble vitamins. Other studies diagnosed type 3c if fecal elastase 1 levels were <200 ug/g and imaging supported the diagnosis with pathologic findings.
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-Melissa Noble, MD, Emily Moreno, MSPH, MA, Morteza Khodaee, MD, MPH
This article originally appeared in the August 2016 issue of The American Journal of Medicine.
