Endocrine Disorders Flashcards
1. Overview of the endocrine system 2. Classification of endocrine disorders and their manifestations 3. Epidemiology and pathophysiology of the main types of diabetes mellitus 4. Diagnostic criteria of diabetes mellitus 5. Treatment goals for diabetes 6. Strategies and mediations used to manage the main types of diabetes mellitus 7. Impact of diabetes mellitus and its management on oral health and dental care
What is the endocrine system made up of
- Hypothalamus
- Pituitary gland
- Pineal gland
- Thyroid and parathyroid gland
- Thymus
- Pancreas
- Adrenal glands
- Ovary/Testes
- Placenta
What is the role of the endocrine system
It coordinates the function of organs through chemical messengers (hormones) in the blood stream
What are hormones
- peptides, steroids or amino acids
- produced by endocrine glands and released in the bloodstream
- they bond selectively to receptors on target cells
- they influence the function of target tissues
When do endocrine disorders manifest
When there is overproduction or underproduction of hormones; there could be primary gland dysfunction, secondary dysfunction or receptor dysfunction
How is diabetes insipidus different to diabetes mellitus
This is not related to glucose homeostasis - there is abnormality in antidiuretic hormone
What are the different forms of diabetes mellitus
- Type 1 = lack of insulin
- Type 2 = insulin resistance
- MODY = maturity onset diabetes of the young (autosomal dominent)
- Drug induced = steroids and immunotherapy (causes hyperglaecimia)
- Cystic fibrosis
Briefly outline how glucose homeostasis is achieved in a healthy person
Rise in blood glucose after food causes the pancreas to release insulin. This stimulates glycogen formation in the liver and glucose uptake by tissue cells. Blood glucose is now normalised
Fall in blood glucose causes the pancreas to release glucagon. This stimulates glycogen breakdown into glucose. Blood glucose is normalised
What are the clinical features at presentation of diabetes
- osmotic symptoms; polyuria, polydipsia, nocturia, weight loss
- recurrent infections e.g. candidiasis because the high blood sugar makes you more prone to bacterial and viral infections
- lethargy
- visual blurring due to increased lens viscosity
- diabetic emergencies;
1. Type I Diabetic ketoacidosis
2. Type II Hyperosmolar hyperglycaemic syndrome
What are the clinical features of diabetic ketoacidosis
Type I
- osmotic symptoms
- weight loss
- abdominal pain
- confusion
- sweet smelling breath due to high ketones
What are the clinical features of hyperosmolar hyperglycaemic syndrome
- osmotic symptoms
- dry mouth
- confusion
- hallucinations
- reduced consciousness
- coma
What complications can occur with long-term poorly controlled diabetes mellitus
- Vascular complications
- Problems affecting nerves
- Increased risk of infections and poor healing
What vascular complications can occur with poorly controlled diabetes mellitus
- Microvascular
- retinopathy: causing blindness
- nephropathy: leading cause of CKD
- neuropathy: impaired sensations to lower limbs - Macrovascular atherosclerosis leading to
- angina pectoris and myocardial infarction
- TIAs and cerebrovascular accidents
- peripheral vascular disease leading to acute limb ischaemia, gangrene, amputation
What neural complications can occur with poorly controlled diabetes mellitus
- Symmetric polyneuropathy
- Autonomic neuropathy
- Mononeuropathy
What is symmetric polyneuropathy
Affects the distal feet and hands
- causes paraesthesia, dysesthesia or painless loss of sense of touch, vibration, proprioception or temperature
- lower extremities; foot ulceration and infection
What is involved with autonomic neuropathy
- Gastroparesis
- Erectile dysfunction
- Orthostatic hypotension
- Neuropathic bladder
- Impaired salivary production causing dry mouth
What is mononeuropathy
Causes diplopia (when one of the cranial nerves is affected) ptosis when they affect the 3rd cranial nerve or motor palsies when they affect the 4th or 6th cranial nerves
- causes finger weakness and numbness (median nerve)
- causes foot drop (peroneal nerve) prone to nerve compression disorders such as carpel tunnel
Why does poorly controlled diabetes mellitus cause an increased risk of infection and poorer healing
Because hyperglycaemia has an adverse effect on granulocytes and T-cell function
- making patients prone to fungal and bacterial infection
- candidiasis and bacterial foot infections
What is the diagnostic criteria for diabetes
Diabetic symptoms + one of the criterion below
- random blood glucose >= 11.1 mmol/L
- fasting blood glucose >7.0 mmol/L
- oral glucose tolerance test; 2hr glucose >= 11.1 mmol/L after taking a 75g glucose load
- HbA1c >= 48 mmol/mol
If asymptomatic then another positive test result is needed on a separate day within the diabetic range
What does glycosylated Hb (HbA1c) show
This is a surrogate marker of the average glucose levels over the past 3 months
- if greater than 48mmol/mol = DM
- if between 42-47 = pre-diabetic range
When can the HbA1c value not be used to assess whether patients are diabetic and what can be used instead
If there is a haemoglopinopathy present (sikle cell disease or thalasemia; fructosamine can be used instead
What are the treatments for diabetes
- control hyperglycaemia to alleviate symptoms
- prevention of complications
- avoid hypoglycaemic episodes
- if on metformin/diet then HbA1c <48mmol/mol
- otherwise HbA1c <53mmol/mol
- address other cardiovascular risk factors
Why is continuous monitoring not as good as using a finger prick test
Because this measures interstitial glucose (not capillary) and so it is not as accurate
Describe what a diebetic patient should aim to eat
- less saturated fat and cholesterol
- reduced amounts of carbohydrates: should eat whole grain sources with higher fiber content
- caloric intake should be balanced with physical activity
- should eat at regular intervals
What oral drugs can be given for diabetic patients to control their blood glucose levels
- Metformin
- Gliclazide
- Pioglitazone
- Acarbose
- Repaglinide
- Sitagliptin
- Dapagliflozin
How does metformin work
It is a biguanide which reduces target tissue resistance
How does gliclazide work
It is a sulphonylurea which stimulates insulin release from the pancreas
How does pioglitazone work
This is a thiozolinedione which alleviates insulin resistance and stimulates the pancreas to release insulin; this is not commonly used because it causes fluid retention and heart failure
How does acarbose work
It is an alpha-glucosidae inhibitor which delays intestinal breakdown of oligosaccharises to glucose
How does repalinide work
It is a meglitinide which stimulates insulin release but is quicker acting than sulphonylyreas
How does sitagliptin work
It is a DDP-4 inhibitor which stimulates insulin production through GLP-1 pathway
How does dapagliflozin work
It is an SGLT-2 inhibitor which excretes glucose through urine
What are non-insulin injectables
These are GLP-1 analogues which promote weight loss and improve glycaemic control
- these can be daily or weekly injections and are derived from gilla monster saliva
Where can insulin be injected
- upper outer arm
- abdomen
- buttocks
- upper outer thighs
What are the dental aspects of diabetes mellitus
- Chronic/aggressive periodontitis
- Severe dentoalveolar abcesses with facial space involvement
- Dry mouth; secondary to dehydration and decreased salivary flow
- Oral lichenoid reaction
- Oral candidiasis, angular chelitis
What precautions must be taken when treating a diabetic patient
- Dental treatment may impact normal food intake pattern so could interfere with diabetic control
- The patient should be told to eat a normal breakfast and to take their medications
- There is a risk of orthostatic hypotension as a result of autonomic neuropathy so patients should be raised slowly to the upright position in the dental chair
- Steroids should be avoided as they worsen glycaemic control (make liver less responsive to insulin)
- Routine antibiotics should be taken for emergency surgery
