Differentiating Diabetes mellitus type 2 from other diseases

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1];Associate Editor(s)-in-Chief: Seyedmahdi Pahlavani, M.D. [2]

Overview

Type 2 diabetes mellitus must be differentiated from other disorders that may present with polyuria, polydipsia, weight loss or weight gain. Such disorders may include other forms of diabetes mellitus (e.g. type 1 DM, MODY), other endocrine disorders (e.g. hypothyroidism, cushings syndrome, wolfram syndrome, alstrom syndrome) or drug-related disorders.

Differentiating Diabetes Mellitus Type 2 from other Diseases

Type 2 DM must be differentiated from other forms of diabetes mellitus as well as other endocrine disorders based on the symptoms and laboratory findings. The following table shows the appropriate history and symptoms, and laboratory findings that may distinguish type 2 DM from other diseases:

Disease	History and symptoms					Laboratory findings								Additional findings
	Polyuria	Polydipsia	Polyphagia	Weight loss	Weight gain	Serum glucose	Urinary Glucose	Urine PH	Serum Sodium	Urinary Glucose	24 hrs cortisol level	C-peptide level	Serum glucagon
Type 1 Diabetes mellitus	+	+	+	+	-	↑	↑	Normal	Normal	N/↑	Normal	↓	Normal	Auto antibodies present (Anti GAD-65 and anti insulin anti bodies)
Type 2 Diabetes mellitus	+	+	+	+	-	↑	↑	Normal	Normal	↑	Normal	Normal	↑	Acanthosis nigricans
MODY	+	+	+	-	+	↑	↑	Normal	Normal	↑	Normal	Normal	N	-
Psychogenic polydipsia	+	+	-	-	-	Normal	Normal	Normal	↓	Normal	Normal	Normal	Normal	-
Diabetes insipidus	+	+	-	-	-	Normal	Normal	Normal	↑	Normal	Normal	Normal	Normal	-
Transient hyperglycemia	-	-	-	-	-	↑	↑	Normal	Normal	↑	Normal	Normal	N/↑	In hospitalized patients especially in ICU and CCU
Steroid therapy	+	-	-	-	+	↑	↑	Normal	Normal	↑	↑	N/↑	N/↑	Acanthosis nigricans,
RTA 1	-	-	-	+	-	Normal	Normal	↑	Normal	↑	Normal	Normal	Normal	Hypokalemia, nephrolithiasis
Glucagonoma	-	-	-	-	-	↑	Normal	Normal	Normal	-	Normal	Normal	↑	Necrolytic migratory erythema
Cushing syndrome	-	-	-	-	+	↑	-	Normal	↓	N/↑	↑	Normal	Normal	Moon face, obesity, buffalo hump, easy bruisibility