Makindo Medical Notes.com

Related Subjects: Type 1 DM |Type 2 DM |Diabetes in Pregnancy |HbA1c |Diabetic Ketoacidosis (DKA) Adults |Hyperglycaemic Hyperosmolar State (HHS) |Diabetic Nephropathy |Diabetic Retinopathy |Diabetic Neuropathy |Diabetic Amyotrophy |Maturity Onset Diabetes of the Young (MODY) |Diabetes: Complications

Type 1 diabetes is due to autoimmune destruction of insulin-producing cells (ß cells) in the pancreas, leading to marked insulin deficiency and resultant hyperglycaemia. Type 1 diabetics need Insulin or else they will succumb to diabetic ketoacidosis.

About

• Autoimmune (beta cells) islet cell destruction leads to loss of Insulin
• Endogenous Insulin production is 16-24 u per day
• Insulin allows glucose and potassium to enter into cells
• Lack of Insulin causes hyperglycaemia and ketosis and DKA
• This must be replaced by exogenous insulin

Aetiology

• Autoimmune islet cell destruction and associations with HLA D3 and HLA D4
• Type 1 diabetes is a cell-mediated autoimmune disease against pancreatic beta cells
• Most evidence suggests a T cell-mediated disorder
• C-peptide can be assayed as a marker of endogenous insulin secretion
• Raised Glutamic acid decarboxylase (GAD) is seen in Type 1 Diabetes
• Another possible autoantigen is Insulinoma-associated protein 2 (IA-2)
• GAD is useful in identifying late presenting Type 1s -"LADA" latent autoimmune diabetes of the adult

Clinical

• Polyuria, Polydipsia, weight loss, Blurred vision
• Superficial infections, Oral/Genital balanitis/vulvitis
• Diabetic ketoacidosis - Ketone breath, Kussmaul's respiration

Later complications

• Ophthalmological
  • Cataract x2-5 population
  • Non-Proliferative Retinopathy
  • Proliferative Retinopathy: more advanced stage where the retina is deprived of oxygen and new, fragile blood vessels can begin to grow in the retina. The new blood vessels may leak blood thus clouding vision. May lead to retinal detachment.
  • Macular oedema: is swelling in an area of the retina called the macula responsible for our colour vision and fine detail vision. Leads to loss of acuity and partial vision loss or blindness. Usually seen in those with signs of diabetic retinopathy.
  • Rubeosis of the Iris
  • Glaucoma: damage to optic nerve. Incidence x 2
• Renal /Nephropathy
  • Proteinuria
  • End stage renal failure
  • Type IV Renal tubular acidosis
• Neurological
  • Distal symmetrical polyneuropathy
  • Polyradiculopathy
  • Mononeuropathy
  • Autonomic neuropathy
  • Diabetic amytrophy
• Gastrointestinal
  • Gastroparesis
  • Fatty liver
  • Diarrhoea
  • Constipation
• Genitourinary
  • Cystopathy
  • Erectile dysfunction
  • Female sexual dysfunction
  • Genital/Vaginal candida
• Cardiovascular
  • Ischaemic heart disease
  • Heart failure (Often HFpEF)
  • Peripheral vascular disease
  • Stroke
• Lower limb
  • Deformity - hammer toe, claw toe
  • Charcot joint
  • Ulceration
  • Peripheral vascular disease
  • Amputation
• Dermatology
  • Cellulitis
  • Furunculosis
  • Folliculitis
  • Ulcers
  • Necrobiosis
  • Acanthosis Nigricans
  • Digital Sclerosis: Stiffening of the finger joints. Thick,waxy, tight skin on the back of hands, toes, and fingers
  • Eruptive Xanthomatosis
  • Fungal infections: itchy red rashes often surrounded by tiny blisters and scales. Warm, moist folds on the skin. Intertrigo, athlete's foot, ringworm, and vaginal infections
• Dental
  • Gum disease
  • Periodontal disease
  • Candida
• Psychological
  • Depression, Anxiety, Anger
  • Behavioural changes
• Treatment
  • Hypoglycaemia with Insulin and Sulphonylureas
  • Side effects - Metformin and GI disturbance

International definitions

• Normal Fasting sugar < 6.1 mmol [110 mg/dl] and 2 hr < 7.8 mmol/l [140 mg/dl]
• Diabetes: Fasting Blood sugar > 7.0 mmol [126 mg/dl]
• Impaired Glucose tolerance OGTT 2 hr Glucose > 7.8-11 mmol/l [140-199 mg/dl]
• Diabetes : Random > 11.1 mmol/l [200 mg/dl] + symptoms (if not repeat another day)

Investigations

• Islet cell antibodies (ICA) 80%
• Glutamic acid decarboxylase antibodies(GAD) 90%
• Insulin autoantibodies (IAA)
• FBC, U&E to look for renal disease
• Lipids - screen for and treat dyslipdemias
• ECG - evidence of IHD or LVH
• CXR to assess heart size
• Retinal photography to document eye disease

Management - all need Insulin

• See the separate topic on Diabetic ketoacidosis
• Weight loss, dietary advice, risk factor assessment, smoking cessation, exercise
• Insulin is given in several different methods all trying to mimic the normal physiological Insulin response
• Normal requirements are 16-24 units per day
• There is often a honeymoon period after a few weeks in which Insulin requirements drop

Regimens

• Insulin is given subcutaneously usually in varying sites to avoid local complications
• Mixed Intermediate/soluble Insulin given bd
• Basal/Bolus where 50-60% of the Insulin is given as a long-acting basal dose and then a dose of soluble short-acting is given with meals.
• For those who fail these methods with an HbA1C above 7.5 then an Insulin pump may help
• If possible Type 1 diabetic who are well can be maintained on their normal basal-bolus doses. If they are ill and unable to take oral intake and sugar control is poor then either an increase in Insulin can be given with IV fluids or if control still remains poor then a sliding scale should be instituted for the acute event. Insulin should never be stopped. Perioperatively a sliding scale regimen is used. There should be a local policy to which you should adhere.