Diabetes Mellitus- Notes for PLAB 1

Need to quickly review Diabetes – Diagnosis, Medication mnemonics, Pre-op management of diabetes and more? Have a quick read below:

Hypoglycaemia

• Blood glucose <4mmol/L or <72mg/dL
• Important Cause- Alcohol

Dx- Whipple’s Triad

1. Low plasma glucose (usually <4)
2. Manifestations (sweating, confusion, tachycardia, hypotension, altered mentation)
3. If blood glucose is corrected- rapid resolution of symptoms occur

Rx

Conscious/ Drowsy

• 200mL Fruit Juice
• Oral Glucose Gel

Unconscious/Cannot Swallow

• IV Glucose / 1mg Glucagon IM/SC (2 Tubes)

Seizures

• Glucagon

Alcoholic

• IV Glucose

Unconscious + Alcohol

• Set IV line then IV Glucose (cannot use Oral and Glucagon)

Preparations of IV Glucose

D10

• 10 minutes- 150mL
• 15 minutes- 200mL
• Every 1-2 minutes- 50mL until patient conscious or 250mL given (5 times)

D20

• 10 minutes- 75mL
• 15 minutes- 100mL

Insulinoma

• Diagnosis by C-peptide Test

Hyperosmolar Hyperglycaemic State

• High Glucose + High Serum Osmolality but Without DKA

Rx

• IVF 0.9% NS and Electrolyte Correction

Diabetic Ketoacidosis

• Glucose >11 + Abdominal pain + Vomiting + Kussmaul breathing + Dehydration

Dx

• Glucose>11 + Ketonuria ++/Ketonemia + ABG- pH < 7.3 + HCO3<15

Rx

0.9% NaCl initially > Insulin pump at 0.1unit/kg/hour > ABG or VBG> KCL 40mmol/L > D5/D10 when Glucose<12 > Don't use HCO3 (cerebral oedema)

• 1 ltr IV fluid 0.9% over 1 hour (if systolic BP >90)

or

• 1 ltr IV fluid 0.9% over 10-15 minutes (if systolic BP <90)

DKA or Sepsis

• Baby with Severe dehydration (dry mucous membranes, sunken eyes and fontanelles, reduced skin turgor) + Hyponatremia + Hypokalemia

Rx

• IV Fluids (0.9% NaCl + KCl)

Diabetes Mellitus

Diagnosis

• 1 Abnormal Value + Symptoms

Or

• 2 Abnormal values Without Symptoms

Abnormal values (FBG and not RBS, Preferred over HbA1c because cheaper)

• FBS >_ 7 mmol/L (126 mg/dL)
• HbA1c >_ 48 mmol/L (>6.5%) (Normal- 42, Target in DM= <48)

Pre-Diabetes (Impaired Glucose Tolerance)

Fasting- 5.5-6.9
2 hour Post-Prandial/ OGTT- 7.8-11 (140-200)
HbA1c- 42-47

• Tiredness is not a symptom of DM alone
• In Asymptomatic People with 1 abnormal value> repeat test in 2 weeks to confirm the diagnosis

Gestational DM/ Acromegaly

• OGTT is DxOC

Variants

MODY (Maturity Onset Diabetes of Young)

• DM <25 Y/O + FHx (2 generations) + Mild Hyperglycaemia
• Rx- Refer to Endocrinology for Genetic Counselling + Lifestyle modifications
• Sulphonylureas before Insulin
• Rx- Refer to Endocrinologist

LADA- Late Autoimmune Diabetes of Adults (30-50 YO)

• DM1 Variant with Slow Progression + Autoimmune Disease

DM1 vs DM2

• GAD Antibodies (Glutamic Acid Decarboxylase)

Diabetes Treatment

• Target- <_ 48 (<6.5)
• Newly Diagnosed
• First- Lifestyle Modifications
• Still HbA1c>48? – Start 1 OHA (usually metformin)
• Still High HbA1c?
• <58- Lifestyle modifications
• >58- LIFESTYLE MODIFICATIONS > Add another OHA

Diabetes Medications

• Impaired KFT- Insulin/ Gliptins (DDP4)
• C/I- With Bad Kidneys, avoid MS (Metformin, Sulfonylurea)
• Biguanides- Metformin (<30 eGFR, reduce dose if <45)
• Sulphonylureas (risk of Hypoglycaemia)

Weight

• Increase (SPR)- Sulphonylureas (e.g., Glibenclamide), Glitazones (Pioglitazone), Repaglinide
• Decreases- Biguanides (Metformin)
• No effect- DDP4 (Gliptins)

Kidneys

• Good- Insulin, Gliptins (DDP4)
• Bad- Metformin, Sulphonylureas (With Bad Kidneys, avoid MS (Metformin, Sulfonylurea)
• SGLT-2 inhibitors (Gliflozin)- contraindicated if GFR<60

Heart failure

• Gliptins (DDP 4 inhibitors- also in Pancreatitis) and Glitazones (also in Bladder Cancer)
• Preferred- SGLT2 Inhibitors (Dapagliflozin)
• SGLT-2 inhibitors- contraindicated if GFR<60

Mnemonics

• With bad kidneys (GFR <30), do not use MS (Metformin, Sulphonylureas)
• The heart has 4 chambers, so with Heart Failure (and Pancreatitis), do not use DDP4 inhibitors (Gliptins)
• The Pie (Pioglitazone) comes with the die (Risk of bladder cancer). Pioglitazone is also contraindicated in Heart Failure
• Hypoglycaemic that cause weight gain are SPR- Sulphonylureas, Pioglitazone, Repaglinide
• The rest cause weight loss except DDP4 inhibitors (Gliptins) which have no effect on the weight
• SPR without the P (SR) have the risk of hypoglycaemia: Sulphonylureas and Repaglinide

Euglycemic DKA

• Occurs in SGLT-2 (Gliflozin)- All features of DKA but Blood Glucose is not elevated (<11), Ix- Capillary Ketones>Urinary Ketones, ABG, Rx- IV Fluids

Autonomic Neuropathy

• Both Sympathetic and Parasympathetic branches (ANS)
• Causes- Diabetes, Alcohol, Aging
• Features- Sweating, Incontinence, Diarrhoea or Constipation, Impotence, Postural hypotension
• Suspect it in DM patients with Persistent Diarrhoea
• Metformin (Biguanide) can cause Diarrhoea as well
• Stop DAMN drugs in any patients with Diarrhoea or Vomiting

Pre-Op Mx for Diabetes

T2DM (on OHAs)

• Minor Surgery- Continue
• Major Surgery (1 meal skip)- Continue
• Longer Surgery (>1 meal skip)/ Uncontrolled DM- Switch to Insulin
• Emergency Surgery- R/O DKA
• Omit- Sulphonylureas (cause hypoglycaemia)
• Longer surgery- Consider omitting Metformin
• Safe to Use- Rest all

T1DM (on Insulin)

• Minor Surgery- Omit Dose (morning if AM surgery, lunchtime if PM surgery)
• Major- Switch to VRIII (Variable Rate Intravenous Insulin Infusion Ratio)
• Before Sx- 80% of total once daily in VRIII (long-acting) + Continue Other Insulin
• Intra-op- 80% of total once daily in VRIII (long-acting) + Stop Other Insulin
• Target during Sx- 6-10 (max 12)
• KCl + Glucose + NaCl also given
• Emergency- Switch to VRIII
• For Major Sx- In all cases, restart the previous regimen when per mouth diet is re-established + Check Blood glucose 4 hourly

Read our other guides for PLAB 1

• PSVT vs Afib- ECG
• ECG Basics
• CXR Basics

Ultra Short Notes you can download

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