Diabetes mellitus its types ,causes newest treatment

Def. :

It’s a clinical syndrome in which there is an error of CHO

metabolism ; due to : insulin deficiency, resistance or both,

ending in : chronic hyperglycemia ± glucosuria,

vasculopathy & neuropathy.

Etiology : ☺ ( 1ry → 95% & 2ry → 5% )

I. Primary : ( includes 3 types : )

a. Type 1 : ( previously called insulin-dependant DM or

juvenile-onset DM ).

b. Type 2 : (previously called non insulin-dependant DM

or adult-onset DM ).

c. MODY : mature onset diabetes in young patient.

- intermediate ( ) type 1 & type 2.

- occurs in young patient.

- ttt by oral anti-diabetic drugs.

N.B. : The old classification of insulin dependant & non-insulin

dependant DM is misleading because many patient é type 2

DM eventually require insulin for control hyperglycemia.

II. Secondary D.M. :

a. Pancreatic causes :

i. Chronic pancreatitis.

ii. Pacreatectomy.

b. Endocrinal :

i. Cushing : cortisone.

ii. Acromegaly : GH.

iii. Thyrotoxicosis.

c. Drugs :

i. Cortisone.

ii. Thiazide.

iii. Contra-ceptive pills.

d. Others :

i. Gestational diabetes.

ii. DIDMOAD syndrome.

Pathogenesis :

Type 1 : 10%.

_ An autoimmune destruction of i pancreatic islet β-cells

leads to insulin deficiency.

_ Genetic predisposition alone does not seem to be

sufficient, perhaps viral infection may play a role.

_ without insulin, these patients are prone to develop

ketoacidosis.

_ Although typically diagnosed before age 30, it can

present at any age due to variability in rate of β-cell

destruction.

Type 2 :

_ It’s characterized by peripheral insulin resistance, so

hyperglycemia develops despite above average level of

insulin.

_ In addition, it may be due to abnormal structure of insulin

or anti-insulin hormones esp. glucagons.

_ Factors that may play a role in pathogenesis include :

genetic predisposition & obesity.

Type 1 Type 2

_ Incidence : 10 % 85%

_ Pathogenesis : Insulin deficiency due to

damage of β-cells.

Insulin resistance.

_ Insulin level : ↓↓ Normal or even ↑↑

_ Age if onset : Younger (usually < 30y). Older (usually > 30y).

_ Body weight : Thin. Obese (usually 80 %).

_ Hereditary : - 30% in identical twins

- usually no family history.

- Near 100%

- strong family history.

_ C / P :

- Severity : Sever. Mild or moderate.

- Ketoacidosis : Common. Rare, need ppt factors.

- Complication : More common. Less common.

_ TTT :

-Oral hypoglycemic : Ineffective. Effective.

- Insulin : Necessary (essential for life ) Usually not required

N.B : In type 2 we may need insulin when B cells fail after years.


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Stages of DM :

I. Pre diabetes : (impaired glucose tolerance)

a. It refers to a group of people who have glucose values

too high to be considered normal but not fit i criteria

for i diagnosis of DM.

b. It’s intermediate category ( ) normal & DM.

c. There is risk factor for future diabetes & CVS diseases.

d. This group includes :

i. +ve family history.

ii. obesity.

iii. ♀ é bad obstetric history → macrosomia.

iv. renal glucosuria.

II. Latent diabetes :

_ Diabetes appear only on exposure to stress &

disappears after removal of stress e.g. : pregnancy.

III. Chemical diabetes :

_ Raised blood glucose é no symptoms.

IV. Clinical diabetes :

a. Uncomplicated :

_ Classic triad of symptoms

_ polyuria : due to osmotic diuresis.

_ polydepsia : due to loss of fluid.

_ polyphagia weight loss : as a result of ↓ insulin

→ no glucose can enter satiety center

→ ↑↑ of satiety center.

b. Complicated :

i. May be I 1st presentation.

ii. Symptoms of complications

N.B. : ● DD of polyuria :

- sever polyuria → DI.

- moderate ~ → DM.

- mild ~ → CRF.

● DD of polyphagia é weight loss :

- Thyrotoxicosis

- DM – Ascaris

Investigations of DM :

I. Blood :

1. Blood sugar tests :

i. Fasting blood glucose :

_ 70 - 110 mg % →normal.

_ > 126 mg % →DM.

_ 110 - 126 mg % →impaired glucose

tolerance.

N.B. : fasting is defined as no caloric intake for at least 8 hours.

ii. 2 h. post-prandial : ( after ingestion of 75 mg

glucose).

_ < 140 mg % → normal.

_ > 200 mg % → DM.

_ 140 - 200 mg % → impaired glucose

tolerance.

iii. Random ( casual ) glucose level :

_ it means glucose level during any time of

day é out regard to last meal.

_ Symptoms of diabetes

blood glucose > 200 mg%. → DM.

2. Oral glucose tolerance test : ( OGTT )

i. Patient should be fasting over night.

ii. Fasting bl. sugar is done.

iii. The patient is fed 75 gm glucose orally.

iv. Take bl. & urine samples every 1/2 h. for 2 h.

v. Diagnosis of diabetes is done acc. To i above

mentioned criteria.

_ Normal curve : 3 criteria :

1) Fasting : 70-110.

2) Reach maximal point in 1h. but still

under 180 mg %.

3) Return to normal within 2 h.

3. Cortisone glucose tolerance test :

i. Dexamethazone 3 mg is given before OGTT.

ii. It will induce hyperglycemia in latent & prediabetic.

II. Urine :

1. Glucosuria : occurs when glucose serum level exceeds

180 mg % ( renal threshold ); but it's not a good

indicator for DM diagnosis.

2. Ketonuria : for diagnosis of diabetic ketoacidosis.

III. Monitoring of ttt : ( to assess ttt efficacy )

1. Plasma glucose monitoring.

2. Glycosylated hemoglobin ( HBA1c )

i. ( HBA1c ) is an indicator of glycemic control.

ii. Normally it's less than 7 % of total HB, & if > 12% →

poor glycemic control in the past 3 months.

iii. It can differentiate ( ) stress induced

hyperglycemia from DM.

IV. Investigations for complication :

1. Plasma lipids.

2. Urine analysis & renal function tests.

3. ECG.

4. Chest X-ray from TB.

V. Investigations for i cause :

_ If 2ry diabetes is suspected < 5 %.

N.B. : New WHO diagnostic criteria :

2 of these 3 criteria :

1- Fasting plasma glucose > 126 mg %.2- Random plasma glucose > 200 mg %.
3- Classic triad of diabetic symptoms
see the pic