Type 1 Diabetes Flashcards
What is type 1 diabetes?
A metabolic disorder characterised by hyperglycaemia due to absolute insulin deficiency
Briefly describe the pathophysiology of type 1 diabetes
Due to destruction of pancreatic beta cells mostly by immune-mediated mechanisms
What are the risk factors for type 1 diabetes?
- Geographic region
- Genetic predisposition
- Infectious agents
- Dietary factors
What infectious agents are linked to type 1 diabetes?
Coxsackie B virus and enterovirus.
What are the signs of type 1 diabetes?
- Tachypnoea
What are the symptoms of type 1 diabetes?
- Polyuria
- Polydypsia
- Unexplained weight loss
- Blurred vision
- Nausea and vomiting
- Abdominal pain
- Lethargy
What age group is most commonly diagnosed with type 1 diabetes?
Usually presents in childhood or adolescence→ typical age 5 to 15 years.
What investigations should be ordered for type 1 diabetes?
- Random plasma glucose
- Fasting plasma glucose
- 2-hour plasma glucose
- Plasma or urine ketones
- HbA1c
Why investigate random plasma glucose?
Confirms diagnosis in the presence of symptoms of polyuria, polydipsia and unexplained weight loss.
≥11 mmol/L.
Why investigate using fasting plasma glucose?
≥6.9 mmol/L.
Why investigate using 2-hour plasma glucose?
≥11 mmol/L.
Why investigate using plasma or urine ketones?
In the presence of hyperglycaemia suggest type 1 diabetes also assess for diabetic ketoacidosis.
Medium or high quantity.
Why investigate using HbA1c?
Reflects degree of hyperglycaemia over the preceding 3 months.
≥48 mmol/mol (≥6.5%).
Which definitive test can be used to differentiate between type 1 or type 2 diabetes? And why?
C-peptide is a byproduct formed when pro-insulin is processed to insulin. Therefore, its levels reflect insulin production. Half life of C-peptide is 3 to 4 times longer than that of insulin.
Low or undetectable C-peptide level indicates absence of insulin secretion from pancreatic beta cells.
Briefly describre the treatment for type 1 diabetes
Patient education is essential. Monitoring and treatment is relatively complex. The condition is life-long and requires the patient to fully understand and engage with their condition. It involves the following components:
- Subcutaneous insulin regimes
- Monitoring dietary carbohydrate intake
- Monitoring blood sugar levels on waking, at each meal and before bed
- Monitoring for and managing complications, both short and long term
Briefly describe the basis of the insulin regime
Insulin is usually prescribed as a combination of a background, long acting insulin given once a day and a short acting insulin injected 30 minutes before intake of carbohydrate (i.e. at meals). Insulin regimes are initiated by a diabetic specialist.
What is the target HbA1c? And why is this important?
HbA1c level of 48 mmol/mol (6.5%) or lower to minimise the risk of long-term vascular complications
How often should HbA1c be measured?
Every 3-6 months
What are the complications of type 1 diabetes?
- Diabetic Ketoacidosis (DKA)
- Hypoglycaemia
- Retinopathy
- Diabetic kidney disease
- Peripheral or autonomic neuropathy
- Cardiovascular disease
What differentials should be considered in type 1 diabetes?
- Type 2 diabetes
How does type 1 diabetes and type 2 diabetes differ?
Differentiating signs and symptoms:
- Typically, signs of insulin resistance (such as acanthosis nigricans) should be sought and in their absence clinical suspicion of type 1 diabetes is greater
- Signs of more marked insulin deficiency (for example, glycaemic lability as well as susceptibility to ketosis) raise suspicion of type 1 diabetes
- Older age and slow onset, obesity, a strong family history, absence of ketoacidosis, and initial response to oral anti-hyperglycaemic drugs are typical of type 2 diabetes.
Differentiating investigations:
- C-peptide present and autoantibodies absent
What are the short-term complications of type 1 diabetes?
Hyperglycaemia (including DKA) and hypoglycaemia.
Briefly describe hypoglycaemia, how it presents and how it is treated
Hypoglycaemia is a low blood sugar level. Most patients are aware of when they are hypoglycaemic by their symptoms, however some patients can be unaware until severely hypoglycaemic. Typical symptoms are tremor, sweating, irritability, dizziness and pallor. More severe hypoglycaemia will lead to reduced consciousness, coma and death unless treated.
Hypoglycaemia needs to be treated with a combination of rapid acting glucose such as lucozade and slower acting carbohydrates such as biscuits and toast for when the rapid acting glucose is used up. Options for treating severe hypoglycaemia are IV dextrose and intramuscular glucagon.
Why do long term complications occur in type 1 diabetes?
Chronic exposure to hyperglycaemia causes damage to the endothelial cells of blood vessels. This leads to leaky, malfunctioning vessels that are unable to regenerate. High levels of sugar in the blood also causes suppression of the immune system, and provides an optimal environment for infectious organisms to thrive.
What are the macrovascular complications of type 1 diabetes?
Development of atherosclerosis, which increases the risk of cardiovascular diseases (CVDs), such as myocardial infarction, heart failure, stroke and peripheral arterial disease (for example intermittent claudication).
What are the microvascular complications of type 1 diabetes?
Nephropathy
- Diabetic kidney disease is caused by damage to small blood vessels in the kidneys.
- Particularly glomerulosclerosis.
Retinopathy
- Diabetic retinopathy is caused by small blood vessel damage to the retina, leading to progressive loss of vision and possible blindness.
Neuropathy
- Diabetes causes nerve damage through different mechanisms, including direct damage by the hyperglycemia and decreased blood flow to nerves by damaging small blood vessels.
What are the infection related complications of type 1 diabetes?
Urinary Tract Infections, pneumonia, skin and soft tissue infections (particularly in the feet) and fungal infections (particularly oral and vaginal candidiasis).
How should cardiovascular risk be managed in type 1 diabetes?
Assess the following cardiovascular risk factors annually:
- Lifestyle (including smoking status)
- Waist circumference
- Blood glucose control
- BP
- Albuminuria
- Full lipid profile
- Family history of CVD
Should aspirin be offered for prevention of CVD in type 1 diabetes?
Do not routinely offer aspirin for the primary prevention of CVD. Decisions about antiplatelet treatment will usually be made by, or in consultation with, secondary care.
What is the threshold BP for starting anti-hypertensives if no albuminuria or features of the metabolic syndrome are present?
The threshold for starting antihypertensive treatment in an adult with type 1 diabetes is blood pressure greater than or equal to 135/85 mmHg.
What is the first line treatment for hypertension in type 1 diabetes?
Offer an angiotensin-converting enzyme (ACE) inhibitor, provided there are no contraindications.
If an ACE inhibitor is not tolerated, offer an angiotensin-II receptor antagonist (AIIRA) if appropriate.
Briefly describe the use of lipid modification therapy in type 1 diabetes
Do not use a risk assessment tool to assess cardiovascular disease (CVD) risk in people with type 1 diabetes.
For people with type 1 diabetes who do not have established CVD offer statin treatment with atorvastatin 20 mg for the primary prevention of CVD if the person:
- Is older than 40 years of age;
- Has had diabetes for more than 10 years;
- Has established nephropathy;
- Has other CVD risk factors (such as obesity and hypertension).
For people with type 1 diabetes who have established CVD advise statin treatment with atorvastatin 80 mg for the secondary prevention of CVD.
At every diabetic review appointment, what parameters should be assessed?
- HbA1c
- Height, weight, waist circumference and BMI
- Assess for depression, anxiety, and eating disorders
- Check smoking status
- Monitor for neuropathy and associated complications
- Including erectile dysfunction, neuropathic pain, autonomic neuropathy and gastroparesis
In a patient with type 1 diabetes, what complications should be assessed yearly?
- Check injection sites and address any injection site problems
- Assess for cardiovascular risk factors, including smoking status, waist circumference, blood glucose control, blood pressure, full lipid profile, and family history of cardiovascular disease
- Ensure the person is screened for eye disease, kidney disease, and foot problems
- Ensure the person is screened for thyroid disease
Briefly describe the monitoring for diabetic eye complications in type 1 diabetes
On diagnosis, immediately refer adults with type 1 diabetes to the local eye screening service.
Depending on the findings, follow structured eye screening by one of the following:
- Referral to an ophthalmologist
- Earlier review
- Routine annual review
How often is NHS diabetic eye screening?
Annually.
Briefly describe the monitoring for diabetic kidney disease in type 1 diabetes
All adults with type 1 diabetes (with or without detected nephropathy) should receive annual screening for diabetic nephropathy.
Ask the person to bring in the first urine sample of the day (‘early morning urine’) once a year
- Send the urine specimen for estimation of the albumin:creatinine ratio (ACR)
Check serum creatinine at the same time to calculate estimated glomerular filtration rate (eGFR)
What should be offered to men with type 1 diabetes and erectile dysfunction?
Offer men the opportunity to discuss erectile dysfunction as part of their regular review.
Offer a phosphodiesterase-5 (PDE-5) inhibitor (sildenafil, vardenafil, or tadalafil) to men with type 1 diabetes with isolated erectile dysfunction.
Briefly describe the monitoring for diabetic foot complications in type 1 diabetes
People with type 1 diabetes should have their feet checked by a primary healthcare professional at diagnosis and at least once a year thereafter, or sooner if any foot problems arise. They should also be advised to check their own feet on a daily basis.
Briefly describe what is assessed in a diabetic foot exam
To examine the feet of a person with diabetes, remove their shoes, socks, bandages, and dressings (as appropriate) and examine both feet for evidence of the following risk factors:
- Neuropathy
- Limb ischaemia
- Ulceration
- Callus formation
- Infection and/or inflammation
- Deformity
- Gangrene
- Charcot arthropathy
Briefly describe the use of Flash Glucose Monitoring
This uses a sensor on the skin that measures the glucose level of interstitial fluid. There is a lag of 5 minutes behind blood glucose. This sensor records the glucose readings at short intervals so you get a really good impression of what the glucose levels are doing over time. The user needs to use a “reader” to swipe over the sensor and it is the reader that shows the blood sugar readings. Sensors need replacing every 2 weeks for the FreeStyle Libre system. It is quite expensive and NHS funding is only available in certain areas at the time of writing.
The 5 minute delay also means it is necessary to do capillary blood glucose checks if hypoglycaemia is suspected.
Why is it important that type 1 diabetic patients change their injection site regularly?
Injecting into the same spot can cause a condition called “lipodystrophy”, where the subcutaneous fat hardens and patients do not absorb insulin properly from further injections into this spot. For this reason patients should cycle their injection sites.
