Type 1 diabetes Flashcards
What defines diabetes?
Elevated blood glucose above a diagnostic threshold
What body fat distribution increases CVD risk?
Apple-shaped fat distribution
What is the underlying cause of Type 1 Diabetes Mellitus (T1DM)?
Autoimmune destruction of pancreatic beta-cells leading to absolute insulin deficiency
What are the two types of T1DM?
Type 1A (immune-mediated)
Type 1B (idiopathic)
What is latent autoimmune diabetes in adults (LADA)?
A slow-progressing form of Type 1A diabetes diagnosed in later life
What is the main genetic risk factor for T1DM?
High-risk HLA genotypes
= DR3-DQ2 and DR4-DQ8
Name three environmental risk factors for T1DM
(1) Viral infections (eg, Coxsackie B4)
(2) Early cow’s milk exposure
(3) Vitamin D deficiency
What type of hypersensitivity reaction is involved in T1DM pathophysiology?
Type IV (cell-mediated) hypersensitivity
What is the classic triad of symptoms in T1DM presentation?
Polyuria, polydipsia, and weight loss
What is the primary investigation for diagnosing T1DM?
Serum glucose levels
(fasting ≥7.0 mmol/L or random ≥11.1 mmol/L with symptoms)
Why is HbA1c not used for diagnosing T1DM?
It does not accurately reflect rapid-onset hyperglycemia
Name three autoantibodies associated with T1DM
- GAD (glutamic acid decarboxylase),
- IA2 (islet antigen-2)
- ZnT8 (zinc transporter-8)
GAD, ICA, IAA
What is the preferred insulin regimen for T1DM?
Basal-bolus regimen
(long-acting basal + short-acting bolus with meals)
What should patients do to prevent lipohypertrophy?
Rotate insulin injection sites
Name two methods of insulin delivery apart from multiple daily injections (MDI
- Continuous subcutaneous insulin infusion (CSII/pump)
- Fixed-dose insulin regimens
What structured education programs are available for T1DM patients?
DAFNE (Dose Adjustment for Normal Eating)
BERTE
What should be included in an annual review for a T1DM patient?
- Weight
- Blood pressure
- HbA1c
- Renal function
- Lipids
- Retinal screening
- Foot risk assessment
How is hypoglycemia managed?
15-20g rapidly absorbed carbohydrate
What is islet transplantation, and who is it for?
Injection of cadaveric pancreatic islets into the liver, used for severe hypoglycemia or uncontrolled diabetes
What is a life-threatening complication of type 1 diabetes mellitus characterised by hyperglycemia, ketonemia, and metabolic acidosis?
Diabetic ketoacidosis (DKA)
What neuropathy pattern is common in T1DM?
Sensory polyneuropathy in a stocking distribution
What autoimmune condition is commonly associated with T1DM?
Hyperthyroidism
= patients should be screened with TSH and free T4
How long do long-acting insulin analogies such as Lantus tend to last in the body?
18-24 hours
How long can a person with type 1 diabetes live on average without insulin?
8 months
A 5 year old child is brought to the GP for bedwetting at night for the last few months. He has previously been dry by day by the age of 3 and dry by night by the age of 4. His older brother had a similar problem when he was that age.
He does not complain of pain on passing urine, but his mother reports that he is going to the toilet more often. He complains of feeling tired and has lost some weight. His bowel habits are regular and his parents describe him as a generally happy child and he enjoys going to school. He has had some abdominal pain recently.
Given the most likely diagnosis, what is the most appropriate medical management?
Subcutaneous insulin
An 8-year-old girl presents with one day of vomiting and abdominal pain, and a two-week history of increased thirst, frequent urination, and recent weight loss. She is otherwise healthy, and her sister has a thyroid condition.
The girl is alert with a soft, nontender abdomen. Urine dip shows:
Glucose +++ and ketones ++
Random blood sugar is 33.2. She was diagnosed with diabetes and admitted for an insulin infusion, later discharged with an insulin pen. Over the next two weeks, her blood glucose is well controlled with one unit of insulin daily. What reason best explains this patient’s current insulin requirements? and why?
Residual function of remaining beta cells
= This patient with very low insulin requirements after a recent diagnosis of type 1 diabetes mellitus (polydipsia, polyuria, weight loss, raised random blood glucose) presenting in moderate DKA (vomiting, ketonuria) is experiencing a honeymoon period. The ‘honeymoon period’ in T1DM describes a time when the disease has been identified and is being treated with exogenous insulin, but there is still some residual insulin production as not all beta-pancreatic cells have been destroyed. As a result, the patient’s insulin requirements may be very low
A 15-year-old girl is brought to A&E unconscious after a seizure. Her friends said she had been acting strangely and said her stomach hurt that morning. She was sweaty in class, and then fainted and started jerking for a few minutes. She has a background in type 1 diabetes mellitus.
On examination, the girl is not responsive to pain. Her respiratory rate is 16, her heart rate is 100 and her blood pressure is 98/54. Her pupils are 3 mm in diameter, equal and reactive to light.
What is the most appropriate definitive management at this stage in the emergency department?
2ml/kg IV 10% dextrose
A 19-year-old girl is seen in the GP, complaining of a dark rash in her axillae and around her neck. The rash has been present for several months. She also complains of tiredness, lethargy, increased thirst and frequent passage of urine, which is more during the nights recently. She denies dysuria and haematuria. She attained menarche at the age of 12 years, with regular periods since then.
On examination, her body mass index (BMI) is 36 and all other vital signs are within the normal range. Abdominal examination is unremarkable. Which test would most likely establish a diagnosis?
Fasting blood glucose
How is the diagnosis of type 1 diabetes mellitus made?
- Raised blood glucose measurements (random BM > 11.0 mmol/L)
- Other markers like raised HbA1c, urine ketones and raised fasting glucose (>7.0 mmol/L)
What is the ideal target HbA1c for most people with type 1 diabetes?
48mmol/ mol
Which cells are targeted by the immune system in type 1 diabetes mellitus?
Pancreatic beta cells
What is the ‘honeymoon period’ in type 1 diabetes mellitus?
Immediately after diagnosis, insulin requirements may be very low if the pancreas is still able to produce a significant amount of insulin
Why does type 1 diabetes mellitus cause diabetic ketoacidosis?
Lack of insulin causes starvation state
An 18-year-old male presents to his GP with a history of tiredness, polydipsia and polyuria.
Which investigation results would on its own be sufficient to diagnose diabetes mellitus in this patient?
(1) Random blood glucose ≥ 11.1mmol/l
(2) Fasting plasma glucose ≥ 7mmol/l
(3) 2-hour glucose tolerance ≥ 11.1mmol/l
(4) HbA1C ≥ 48mmol/mol (6.5%)
A 17-year-old boy presents to his GP with fatigue, weight loss and polyuria. Following relevant investigations, the GP diagnoses type 1 diabetes. The patient is otherwise stable and blood ketones are not present.
What is the most appropriate next management step?
Basal-bolus Insulin
In managing Type 1 Diabetes in a hospital setting, the total daily insulin requirement is split into long-acting and short-acting insulin regimens
How much is given to long-acting and short-acting?
Three-fifths given as short-acting for meal coverages
Two-fifths given as long-acting for basal insulin
What is first-line treatment in type 1 diabetes?
Basal-bolus Insulin 2x
= Twice-daily basal insulin detemir, insulin aspart bolus with meals
May prefer an insulin pump is they’re good patients
A 25-year-old woman attends a follow-up appointment with the diabetic specialist nurse following a recent hospital admission for diabetic ketoacidosis. She is counselled on blood glucose monitoring.
Currently, she is self-monitoring her capillary blood glucose and is considering a continuous glucose monitoring device. If she chooses not to have continuously, she asks the nurse how often she needs to self-monitor glucose monitor.
What are the minimum recommended times of day to routinely self-monitor her capillary blood glucose levels?
Before each meal and before bed
A 32-year-old female presents with a 2-month history of fatigue and nocturia. On further questioning, she also admits to increased thirst. She does not have dysuria or urgency, denies the possibility of pregnancy and has otherwise been well. Her brother was recently diagnosed with diabetes, although she is not sure which type. She has looked at the symptoms online and is worried about a possible diabetes diagnosis; she wants to know how she can distinguish between the types of diabetes.
Her body mass index (BMI) is 29 kg/m².
What tests would be best in differentiating these diagnoses?
C-peptide levels (low or undetectable C-peptide level) and diabetes-specific autoantibodies
What is the difference between Fixed-Rate Insulin Infusion (FRII) and Subcutaneous (SC) Insulin and when is each used?
(1) FRII (Fixed-Rate Insulin Infusion)
= Given intravenously (IV), used in emergencies like diabetic ketoacidosis (DKA) to rapidly lower blood glucose and ketones
(2) Subcutaneous (SC) Insulin
= Given under the skin, used for long-term diabetes management after stabilisation from DKA or for routine insulin therapy
(3) FRII is used in hospitals for acute conditions, while SC insulin is used after stabilisation for ongoing diabetes control eg, type 1 and type 2 diabetes
(4) Basal bolus is used in SC
When HbA1c levels are elevated in individuals with type 1 diabetes. What is the correct next step?
Increase the patient’s insulin doses
In type 1 diabetics, blood glucose targets
? mmol/l on waking
? mmol/l before meals at other times of the day
? mmol/l bedtime blood glucose
(A) 5-7
(B) 4-7
(C) 6-10
Risk of type 1 diabetes being passed to child
5%-8%
A patient with type 1 diabetes describes vomiting after large meals.
What underlying neurological process is most likely to have occurred?
Autonomic neuropathy
= The patient has gastroparesis which is caused by an autonomic nerve
dysfunction
