What are the symptoms of diabetes?

Symptoms of Diabetes

The classic symptoms of diabetes caused by hyperglycemia include polyuria (frequent urination), polydipsia (excessive thirst), unintentional weight loss, and dehydration, though type 2 diabetes often remains asymptomatic for years during its gradual onset. 1

Classic Hyperglycemic Symptoms

The hallmark symptoms directly caused by elevated blood glucose include:

• Polyuria (frequent urination): Excess glucose spills into urine, drawing water with it osmotically, causing increased urination frequency and volume 2
• Polydipsia (excessive thirst): Develops as a compensatory response to fluid loss from frequent urination 2
• Unintentional weight loss: Occurs despite normal or increased appetite due to inability to properly utilize glucose for energy 1, 2
• Dehydration: Results from osmotic diuresis and fluid losses 1
• Blurred vision: Caused by osmotic changes in the lens from hyperglycemia 2
• Fatigue and weakness: Due to cellular energy deficit despite elevated blood glucose 2
• Recurring infections: Hyperglycemia impairs immune function 1

Important Clinical Context by Diabetes Type

Type 1 Diabetes Presentation

• Children typically present with the classic triad of polyuria, polydipsia, and weight loss 1
• Approximately one-third of children present with diabetic ketoacidosis (DKA) at diagnosis 1
• Onset may be more variable in adults and they may not present with classic symptoms 1

Type 2 Diabetes Presentation

• Type 2 diabetes frequently goes undiagnosed for many years because hyperglycemia develops gradually 1
• At earlier stages, hyperglycemia is often not severe enough for individuals to notice classic symptoms 1
• Many patients remain completely asymptomatic during the presymptomatic phase 1
• Despite lack of symptoms, undiagnosed individuals remain at increased risk for macrovascular and microvascular complications 1

Additional Warning Signs in Toddlers

Young children may present with atypical manifestations:

• Behavioral changes: Irritability, unexplained temper tantrums, or unusual drowsiness may indicate hyperglycemia or hypoglycemia 2
• Bedwetting: Previously toilet-trained children may develop new-onset enuresis from polyuria 2
• Decreased activity levels: Child may appear unusually tired or fall asleep at inappropriate times 2

Life-Threatening Emergency Symptoms (DKA/HHS)

Seek immediate emergency care if the following symptoms develop:

• Nausea and vomiting with hyperglycemia 2, 3
• Rapid breathing or unusual breath odor (fruity/acetone smell) 2
• Severe illness appearance with altered mental status 2, 3
• Abdominal pain 3

These symptoms may indicate diabetic ketoacidosis (DKA) or hyperosmolar hyperglycemic state (HHS), both life-threatening emergencies requiring immediate medical intervention 1, 2, 3.

DKA Context

• DKA seldom occurs spontaneously in type 2 diabetes 1
• When DKA occurs in type 2 diabetes, it typically arises with stress of infection (including COVID-19), myocardial infarction, missed insulin doses, illicit drug use (cocaine), or certain medications (glucocorticoids, second-generation antipsychotics, SGLT2 inhibitors) 1
• HHS is more typically associated with type 2 diabetes and presents with severe hyperglycemia, hyperosmolality, and dehydration without significant ketoacidosis 1

Gastrointestinal Symptoms

Diabetes can cause specific GI manifestations:

• Gastroparesis symptoms: Early satiety, postprandial fullness, nausea, and vomiting occur in 5-12% of diabetic patients in the community 3
• Diarrhea: Reported in up to 20% of patients with longstanding diabetes 3
• Constipation: Reported in up to 60% of patients with longstanding diabetes 3
• High blood glucose levels can directly cause nausea, especially with prolonged elevation 3

Critical Clinical Pitfalls

• Do not assume all patients will be symptomatic: Type 2 diabetes has a long presymptomatic phase, making screening essential in at-risk populations 1
• Symptoms alone are poor predictors of disease severity: Even asymptomatic patients face significant complication risks 1
• Rapid glucose changes in either direction can cause symptoms: Both hyperglycemia and hypoglycemia can trigger nausea, fatigue, and other nonspecific symptoms 3
• Never dismiss persistent symptoms: They may indicate poor glycemic control or developing complications requiring immediate intervention 3