What is Diabetes Mellitus? Flashcards by Peter Savage

What is diabetes mellitus?

A group of metabolic diseases of multiple aetiologies characterised by hyperglycaemia together with disturbances of carbohydrate, fat and protein metabolism resulting from defects in insulin secretion, insulin action, or both

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What are the symptoms of hyperglycaemia?

Polydipsia
Polyuria
Blurred vision
Weight loss
Infections

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What are the metabolic decompensations of hyperglycaemia?

DKA

HHS

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What are the long term complications of hyperglycaemia?

Microvascular:
- Retinopathy
- Neuropathy
- Nephropathy
Macrovascular:
Stroke, MI, PVD

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What fasting venous plasma [Glucose] level is considered high?

> 7mmol/L

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What random venous [Glucose] plasma level is considered high?

> 11.1mmol/L

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What tests are used to measure blood glucose?

Fasted/Random plasma glucose
Glucose tolerance test
Diagnostic HbA1C

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What is considered a high HbA1c?

> 48mmol/L

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What is considered a high GTT?

> 11.1mmol/L

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What is measured for a GTT?

2hrs after 75g CHO

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What is intermediate hyperglycaemia?

Impaired fasting glucose 6.1-7mmol/L
Impaired GTT >7.8/<11mmol/L
HbA1c 42-47mmol/mol

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What is the purpose of diabetes diagnostic criteria?

Identifies groups with significantly increased risks of mortality and microvascular complications

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Intermediate hyperglycaemia identifies what?

Groups at higher risk of future diabetes and adverse outcomes

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What is normoglycaemia?

Glucose levels associated with low risk of developing diabetes and cardiovascular disease

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How is diabetes diagnosed?

ONE lab glucose WITH symptoms

TWO lab glucose/HbA1c WITHOUT symptoms

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What does HbA1c tell us?

Indication of blood glucose levels over last 8-12 weeks

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When can HbA1c not be used for diagnosis?

Young people
Current/recent pregnancy
Short duration of symptoms
High risk DM acutely ill
On medication which causes rapid glucose rise
Acute pancreatic damage/surgery
Renal failure
HIV infection

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Which drugs cause a rapid rise in glucose? When can they be used?

Corticosteroids
Antipsychotics
Long term (>2months)

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What is the breakdown of types of diabetes?

90% type 2
10% type 1
1% other

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When does insulin dominate?

In the absorptive state

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Which cells secrete insulin?

beta cells

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Which cells secrete glucagon?

alpha cells

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Insulin inhibits what?

Glycogenolysis and gluconeogenesis in the liver

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What is the cause of T1DM?

Postive autoantibodies (anti GAD)

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Incidence of diabetes is highest in which age group?

10-19y/os

What is the concordance in T1DM in monozygotic twins?

30-50%

What is the concordance in T1DM if the father has T1DM?

6% risk

What is the concordance in T1DM if the mother has T1DM?

1% risk

What is the concordance in T1DM if the sibling has T1DM?

8% risk

What is the concordance in T1DM if the non-identical twin has T1DM?

10%

What is the concordance in T1DM if both parents have T1DM?

30%

Development of T1DM requires what?

Genetic disposition PLUS: Trigger Autoimmunity

What effect does insulin have on adipose tissue?

Reduced lipolysis

What effect does insulin have on the liver?

Reduced glucose production

What effect does insulin have on muscle?

Increased glucose uptake

What is the effect of insulin deficiency on the liver?

Raised glucose production

What is the effect of insulin deficiency on adipose tissue?

Increased lipolysis

What is the effect of insulin deficiency on muscle?

Reduced glucose uptake

Which counter-regulatory hormones are raised in insufficient insulin intake?

Glucagon Cortisol Catecholamines Growth hormones

How does hyperglycaemia lead to impaired renal function?

High osmotic load (glucosuria) leading to loss of water and electrolytes --> consistent dehydration

Increased lipolysis has what negative effect in diabetes?

Increases FFA levels to the liver, increasing gluconeogenesis Increased ketogenesis

What is the clinical presentation of T1DM?

``` Thirst Tiredness Polyuria/nocturia Weight loss Blurred vision Abdominal pain SHORT DURATION ```

How does T1DM present on examination?

Ketones on breath Dehydration May have increased RR/HR, H↓TN Low grade infections

What is the concordance in T2DM if an identical twin has T2DM?

90-100%

What is the concordance in T2DM if one parent has T2DM?

15%

What is the concordance in T2DM if both parents has T2DM?

75%

What is the concordance in T2DM if a sibling has T2DM?

10%

What is the concordance in T2DM if one non-identical twin has T2DM?

10%

What are insulin levels like in T2DM?

Initially high, progressively decrease

How do symptoms present in T2DM?

``` OFTEN SYMPTOMLESS Thirst Tiredness Polyuria / nocturia Sometimes weight loss Blurred vision Symptoms of complications ```

Which signs typically present in T2DM?

NOT KETOTIC Usually overweight Low grade infections Micro/macrovascular complications

What are the screening factors for asymptomatic patients in T2DM?

``` Any TWO of: Overweight FH >30 if Maori/asian >40 if European Previous Hx gestational DM High birth weight baby Inactive lifestyle Previously high [Glc] ```

Which recognised genetic syndrome causes diabetes?

MODY | Maturity Onset Diabetes in the Young

What is MODY?

Autosomal dominant single gene cause of beta-cell dysfunction

How many diabetes patient have MODY/

Which types of mutations occur in MODY?

Glucokinase mutations | Transcription factor mutations

How does glucokinase diabetes present?

Onset at birth Stable hyperglycaemia Diet treatment Complications rare

What cause transcription factor mutations?

HNF-1alpha HNF-1beta HNF-4alpha

How does transcription factor diabetes present?

``` Adolescence/young adult onset Progressive hyperglycaemia 1/3 diet 1/3 OHA 1/3 insulin Complications frequent ```

What is the role of glucokinase?

Gluc --> G-6-P

What causes secondary diabetes mellitus?

Drug induced Pancreatic destruction Genetic syndromes - DIDMOAD Endocrine disorders

What are the most common causes of pancreatic damage?

Haemochromatosis Cystic fibrosis Chronic pancreatitis Pancreatectomy

Which endocrine disorders can cause secondary diabetes mellitus?

Cushings syndrome Acromegaly Pheochromocytoma

What is gestational diabetes?

Increasing insulin resistance in pregnancy | Developing in 2nd/3rd trimester

Gestational diabetes is more common in who?

FH of T2DM | Overweight and inactive

Which neonatal problems are associated with gestational diabetes?

Macrosomia Respiratory distress Neonatal hypoglycaemia

Mothers suffering gestational diabetes are at increased risk of what?

T2DM later in life