Type 1 diabetes

What it is, symptoms and effects

From: MedlinePlus Genetics, National Library of Medicine

Type 1 diabetes is a disorder characterized by abnormally high levels of blood glucose, also called blood sugar. In this form of diabetes, specialized cells in the pancreas called beta cells stop producing insulin. Insulin controls how much glucose (a type of sugar) is passed from the blood into cells for conversion to energy. Lack of insulin results in the inability to use glucose for energy or to control the amount of glucose in the blood.

Type 1 diabetes can occur at any age, from early childhood to late adulthood. The first signs and symptoms of the disorder are caused by high blood glucose and may include frequent urination (polyuria), excessive thirst (polydipsia), fatigue, blurred vision, tingling or loss of feeling in the hands and feet, and weight loss. These symptoms may recur during the course of the disorder if blood glucose is not well controlled by insulin replacement therapy. Improper control can also cause blood glucose levels to become too low (hypoglycemia). This may occur when the body's needs change, such as during exercise or if eating is delayed. Hypoglycemia can cause headache, dizziness, hunger, shaking, sweating, weakness, and agitation.

Uncontrolled type 1 diabetes can lead to a life-threatening complication called diabetic ketoacidosis. Without insulin, cells cannot take in glucose. A lack of glucose in cells prompts the liver to try to compensate by releasing more glucose into the blood, and blood glucose can become extremely high. The cells, unable to use the glucose in the blood for energy, respond by using fats instead. Breaking down fats to obtain energy produces waste products called ketones, which can build up to toxic levels in people with type 1 diabetes, resulting in diabetic ketoacidosis. Affected individuals may begin breathing rapidly; develop a fruity odor in the breath; and experience nausea, vomiting, facial flushing, stomach pain, and dryness of the mouth (xerostomia). In severe cases, diabetic ketoacidosis can lead to coma and death.

Over many years, the chronic high blood glucose associated with diabetes may cause damage to blood vessels and nerves, leading to complications affecting many organs and tissues. The retina, which is the light-sensitive tissue at the back of the eye, can be damaged (diabetic retinopathy), leading to vision loss and eventual blindness. Kidney damage (diabetic nephropathy) may also occur and can lead to kidney failure and end-stage renal disease (ESRD). Pain, tingling, and loss of normal sensation (diabetic neuropathy) often occur, especially in the feet. Impaired circulation and absence of the normal sensations that prompt reaction to injury can result in permanent damage to the feet; in severe cases, the damage can lead to amputation. People with type 1 diabetes are also at increased risk of heart attacks, strokes, and problems with urinary and sexual function.

Inheritance

From: MedlinePlus Genetics, National Library of Medicine

Pattern unknown

Understanding terms used in the source

These definitions explain medical words used above. A definition is not evidence that another condition is present, and it does not predict how a symptom will develop. Ask the clinician which terms apply to the actual examination or test result.

Diabetic ketoacidosis

A type of diabetic metabolic abnormality with an accumulation of ketone bodies.

Blurred vision

Lack of sharpness of vision resulting in the inability to see fine detail.

Retinopathy

Any noninflammatory disease of the retina. This nonspecific term is retained here because of its wide use in the literature, but if possible new annotations should indicate the precise type of retinal abnormality.

Agitation

A state of excessive motor activity that is associated with mental distress or a feeling of substantial unease or inner tension. Distinguished from restlessness by the increased level of emotional distress and negative intensity of the experience. Agitation has a significant level of physical activity that is typically threatening to the self or others.

Blindness

Blindness is the condition of lacking visual perception defined as a profound reduction in visual perception. On the 6m visual acuity scale, blindness is defined as less than 3/60. On the 20ft visual acuity scale, blindness is defined as less than 20/400. On the decimal visual acuity scale, blindness is defined as less than 0.05. Blindness is typically characterized by a visual field of no greater than 10 degrees in radius around central fixation.

When it may begin

From: MedlinePlus Genetics, National Library of Medicine

Type 1 diabetes can occur at any age, from early childhood to late adulthood.

Inheritance in the source

From: MedlinePlus Genetics, National Library of Medicine

Pattern unknown

Which doctor should you see?

The suggested department for discussing Type 1 diabetes is Diabetology, with a endocrinologist / diabetologist as the relevant type of clinician. General physician / Family Medicine; paediatrician for children. Referral depends on symptoms.

Additional services that may be relevant, depending on the findings, include: Clinical Genetics.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• What type of glucose problem has been confirmed?
• What are the individual monitoring and follow-up goals?
• If treatment can cause low glucose, what response plan should be taught?

Treatment discussions and follow-up

Where the source describes treatments, these are an overview of possible care, not a prescription for an individual. Ask which option applies to the confirmed diagnosis, what benefit is expected, what adverse effects to watch for and how progress will be assessed. Availability, approvals and local practice can differ from the country described in the source.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.