Endocrinology Flashcards
What is C-Peptide and what is it a good marker for?
C-Peptide is a peptide chain cleaved off from pro-insulin. Used for measuring endogenous insulin. Reduced and eventually disappears in T1DM
How does Ketoacidosis occur?
High rates of b-oxidation of fats occur in the liver due to low glucose utilisation. The low insulin/anti-insulin ratio + increased fatty acids leads to increased ketogenesis
What is the pathophysiology of T1DM
Destruction of b-cell of islets of Langerhans leading to absolute insulin deficiency
What is the pathophysiology of T2DM
Impaired insulin secretion and insulin resistance. Typically progresses from preliminary phase of impaired glucose tolerance or impaired fasting glucose
What are the risk factors for T1DM
- Other autoimmune diseases
2. hereditary - HLA DR3/DR4
What are the risk factors for T2DM
- Old age
- Family history
- Obesity/metabolic syndrome
- Alcohol excess
What are some secondary causes of DM
PEGGD:
- Pancreatic Disease
- Endocrine - cushing’s, acromegaly
- Genetic - wolfram’s, wilson’s, haemochromatosis
- Gestational diabetes
- Drugs - thiazides, corticosteroids, atypical antipsychotics
What is the presentation for both types of DM
Polyuria, polydipsia, lethargy, infections
What is the diff presentation seen in T1DM
Weight loss, dehydration, ketonuria, pear drop breath, hyperventilation
What are the eye complications of DM
Glaucoma, cataracts, retinopathy, CNIII or VI palsy.
How do you diagnose DM
- Symptoms AND one raised venous glucose test (fasting or random)
- Two raised venous glucose tests
- HbA1c >/= 6.5% but less than this does not exclude DM
Glucose tests:
- Fasting glucose >/= 7mmol/L
- Random glucose >/= 11.1mmol/L
- OGTT >/= 11.1mmol/L
What are the conditions where HbA1c may not be used for diagnosis?
Anaemia, haemoglobinopathies, suspected gestational diabetes, children (HbF), CKD
What is the OGTT criteria for impaired glucose tolerance?
Random plasma glucose 7.8 - 11.0mmol/L
What is the fasting plasma glucose criteria for impaired fasting glucose?
Fasting plasma glucose 6.1-6.9mmol/L
Other investigations for DM?
Bedside - BP (may have HTN), Urine dip (for proteins)
Bloods - FBC, U&Es, LFTs, Lipids
Fundoscopy
Regular podiatry checkups
What are the common insulin regimens for T1DM and what are the benefits for each one
BD biphasic regimen - twice daily pre-mixed insulins. Useful for those with regular lifestyle.
Basal-Bolus regimen - intermediate/long acting at bedtime + short acting insulin to cover meal times. Useful for those with unpredictable mealtimes/lifestyle
Insulin pump therapy - adjustable basal infusion rate of insulin. Patient can then activate/programme boluses. Useful for patients with unpredictable lives, recurrent hypos, delayed meals.
Complications of insulin?
Hypoglycaemia, weight gain, insulin resistance, injection site complications: painful lesions, abscesses, lipohypertrophy.
Causes of hypoglycaemia?
EXPLAIN:
- EXogenous drugs: insulin, oral hypoglycaemics, alcohol, aspirin poisoning, b-blockers.
- Pituitary insufficiency
- Liver Disease/failure
- Addison’s disease
- Islet cell tumours: insulinomas
- Non-pancreatic neoplasms (eg: fibrosarcomas)
How can patients with hypoglycaemia present?
- Adrenergic symptoms: sweating, tremor, palpitations, pallor
- CNS: headache, confusion slurring of speech, change of behaviour
- Coma
What is the management of severe hypoglycaemia
- If conscious -> 15-20g short acting carbohydrate/glucose. Glucogel can also be used if conscious but uncooperative
- If unconscious with IV access -> 200ml 10%glucose in 15mins (bolus)
- If unconscious but no IV access -> Glucagon 1mg IM.
What lifestyle advice can you give patients with T2DM?
Control diet, regular exercise, smoking cessation, attend patient programmes: DESMOND, XPERT
What are the HbA1c targets for adults with T2DM?
- If managed by lifestyle or on one drug not associated with hypo - 6.5%
- if managed by drugs associated with hypo - 7.0%
- If HbA1c >/= 7.5% need to reinforce about lifestyle or intensify drug treatment
What are the side effects of Metformin?
GI disturbances - diarrhoea, abdo pain, nausea, vomiting.
Lactic acidosis
What are the contraindications of Metformin?
hepatic and renal failure, elderly
