The differential diagnosis at this point is very broad and difficult to organize. It is helpful to recognize that Mr. G appears to be suffering from the syndrome of delirium and to use the framework for delirium to organize your thinking (see Chapter 11, Delirium and Dementia). It is also reasonable to consider Mr. G’s underlying chronic medical problems as important clinical clues and initially focus on the serious complications of these conditions; in other words, initially focus on diseases for which he has a high pretest probability:
Table 12-10 lists the differential diagnosis.
Mr. G could have any, or a combination, of these conditions. His critical high blood sugar makes a complication of diabetes the leading hypothesis; all of the other diagnoses are “must not miss” hypotheses.
When Mr. G arrives in the emergency department, he is barely responsive but able to move all 4 extremities. His BP is 85/50 mm Hg; pulse, 120 bpm; RR, 24 breaths per minute; temperature, 37.2°C. His lungs are clear, and cardiac exam shows an S4 with no S3 or murmurs. His abdomen is nontender, and there is no peripheral edema. He has no foot ulcers. Initial laboratory tests include the following:
Sodium, 140 mEq/L; K, 4.9 mEq/L; Cl, 110 mEq/L; HCO3, 20 mEq/L; BUN, 99 mg/dL; creatinine, 4.3 mg/dL; glucose, 1246 mg/dL.
Arterial blood gases: pH 7.40; PO2, 88 mm Hg; PCO2, 35 mm Hg.
WBC is 8400/mcL, with 75% polymorphonuclear neutrophils, 3% bands, 18% lymphocytes, and 4% monocytes.
Albumin, 4.4 g/dL; total bilirubin, 0.3 mg/dL; alkaline phosphatase, 175 units/L; AST (SGOT), 40 units/L; ALT (SGPT), 56 units/L; INR, 1.1.
Serum ketones, negative
Urinalysis: 2+ protein, 4+ glucose, no ketones, 3–5 WBC/hpf, occasional bacteria
Is the clinical information sufficient to make a diagnosis? If not, what other information do you need?
Patients who have HHS are usually older type 2 diabetics with the gradual onset of polydipsia, polyuria, and lethargy. They become extremely dehydrated, with reduction in urinary output, and have very high serum glucose levels, accompanied by alterations in mental status.