Other Forms of Diabetes (not Type 1 or 2)

Question 1

Describe features of Maturity-onset diabetes of the young (MODY)

Answer 1

• Commonest type of monogenic diabetes (~1% diabetes)
• Diagnosed <25y
• Autosomal dominant
• Non-insulin dependent
• Single gene defect altering beta cell function
• Tend to be non-obese

Question 2

What is MODY caused by?

Answer 2

Monogenic mutation

Question 3

Which patients might be MODY?

Answer 3

• Parent affected with diabetes
• Absence of islet autoantibodies
• Evidence of non-insulin dependence?
• Good control on low dose insulin
• No ketosis
• Measurable C-peptide
• Sensitive to sulphonylurea

Question 4

Which type of diabetes is C peptide negative within 5 years in?

Answer 4

In Type 1 diabetes (due to complete autoimmune beta cell destruction)

Question 5

Which type of diabetes does C peptide persist?

Answer 5

Type 2 and MODY

Question 6

When is Permanent Neonatal Diabetes usually diagnosed?

Answer 6

Diagnosed <6 months

Question 7

What are signs of Permanent Neonatal Diabetes?

Answer 7

Small babies, epilepsy, muscle weakness

Question 8

Where is the mutation in Permanent Neonatal Diabetes?

Answer 8

Mutations encode Kir6.2 and SUR1 subunits of the beta cell ATP sensitive potassium channel

Question 9

Describe features of maternally inherited diabetes and deafness (MIDD)

Answer 9

• Mutation in mitochondrial DNA
• Loss of beta cell mass
• Similar presentation to Type 2
• Wide phenotype

Question 10

What is lipodystrophy?

Answer 10

• Selective loss of adipose tissue
• Associated with insulin resistance, dyslipidaemia, hepatatic steatosis, hyperandrogenism, PCOS

Question 11

What can you treat chronic pancreatitis with?

Answer 11

Caused by alcohol
Stop alcohol, treat with insulin

Question 12

What diseases of the exocrine pancreas use insulin to treat it?

Answer 12

Pancreatic Neoplasia
Cystic Fibrosis

Question 13

What does insulin improve in CF?

Answer 13

• Body weight
• Reduces infections
• Lung function
• Improves quality of life, and ?survival

Question 14

How does acromegaly cause diabetes?

Answer 14

• Excessive secretion of growth hormone
• Similar to Type 2
• Insulin resistance rises, impairing insulin action in liver and peripheral tissues

Question 15

How does Cushings syndrome cause diabetes?

Answer 15

• Increased insulin resistance, reduced glucose uptake into peripheral tissues
• Hepatic glucose production increased through stimulation of gluconeogenesis via increased substrates (proteolysis and lipolysis)

Question 16

What are Pheochromocytomas?

Answer 16

Tumours that secrete adrenaline or noradrenaline

Question 17

What do Pheochromocytomas cause?

Answer 17

• Increased gluconeogenesis
  
  • Excess glucose
• Decreased glucose uptake

Question 18

Which type of drug increases insulin resistance?

Answer 18

Glucocorticoids