Endocrinology: Diabetes Mellitus Overview

Diabetes Mellitus Type I

• Clinical Features of Type I Diabetes
  • Acute onset symptoms including:
    • Polydipsia (excessive thirst).
    • Polyuria (excessive urination).
    • Polyphagia (excessive hunger).
    • Significant weight loss.
    • Chronic fatigue.
    • Secondary enuresis (bedwetting after a period of being dry).
    • Development of Ketoacidosis.
• Diagnostic Investigations for Type I Diabetes
  • Next Step: Perform a urine dipstick to check for sugar.
  • Best Step: Measure random glucose. A value equal to or more than $11.1\,mmol/L$ is diagnostic.
  • Additional Screenings:
    • TPO a/b (Thyroid peroxidase antibodies).
    • Tissue transglutaminaze a/b (screening for celiac disease).
• Management of Type I Diabetes
  • Immediate admission to the hospital for the initiation of insulin therapy.
• Follow-up Protocol
  • Glycated haemoglobin (HbA1c) monitoring every $3$ months.
  • Target HbA1c: Equal to or less than $7\%$.
  • Mandatory monitoring for late complications.
• Recommended Vaccinations
  • Pneumococcal vaccine.
  • Influenza vaccine.
  • dTPA (Diphtheria, Tetanus, Pertussis) vaccine.

Diabetes Mellitus Type II

• Clinical Features of Type II Diabetes
  • Often asymptomatic in early stages.
  • Presence of Metabolic syndrome.
  • Dermatological markers: Acanthosis nigricans (darkening of skin folds) and skin tags.
  • Hormonal signs: Hirsutism (excessive hair growth).
  • Infections: Recurrent skin or genital infections.
  • General symptom: Chronic fatigue.
  • Progression to late complications.
• Diagnostic Investigations for Type II Diabetes
  • Next Step: Random blood glucose measurement equal to or greater than $11.1\,mmol/L$.
  • Best Step: Fasting blood glucose (FBG) measurement equal to or greater than $7.0\,mmol/L$. If testing an asymptomatic patient, the fasting glucose test must be repeated.
  • HbA1c Criteria: Equal to or more than $6.5\%$ on two separate occasions.
  • Oral Glucose Tolerance Test (OGTT): Implemented if blood glucose levels are uncertain.

Diagnostic Tests for Type 2 Diabetes

• Fasting Blood Glucose (FBG)
  • Requirements: Patient must be fasting for at least $8$ hours.
  • Usage: Primarily used for diagnosing diabetes; can also detect Impaired Fasting Glucose (IFG).
• Glycated Haemoglobin (HbA1c)
  • Requirements: Non-fasting sample.
  • Standard Procedure: Abnormal values should be repeated in asymptomatic patients and confirmed on a different day, unless two different abnormal tests (e.g., FBG and HbA1c) are available from the same day.
  • Clinical Significance: The threshold of $6.5\%$ ($48\,mmol/mol$) is specifically linked to escalating microvascular disease. HbA1c is a superior predictor of macrovascular disease compared to FBG and $2$-hour post-glucose measurements.
  • Limitations and Accuracy Issues: HbA1c may lack sensitivity or specificity in the following scenarios, requiring FBG or OGTT for diagnosis:
    • Acute-onset glycaemic states (e.g., post-traumatic type 2 diabetes such as pancreatitis).
    • Rapid onset of glycaemia during sepsis or steroid use.
    • Within $4$ months post-partum.
    • Individuals with haemoglobinopathy, haemolysis, or advanced chronic kidney disease.
    • Individuals with iron deficiency (which can cause artificially elevated levels).
    • Individuals who have recently received a blood or iron transfusion.
• Oral Glucose Tolerance Test (OGTT)
  • Requirements: Patient must fast for $8$ hours. A $75\,g$ glucose challenge is administered orally.
  • Samples: Blood is collected as a fasting venous sample and a second sample $2$ hours after the glucose challenge.
  • Capability: The only method capable of detecting Impaired Glucose Tolerance (IGT). It can concurrently detect Impaired Fasting Glucose (IFG).

Management and Follow-up for Type 2 Diabetes

• Management Strategies
  • Primary intervention: Lifestyle modification.
  • Consideration of hypoglycaemic drugs.
• Follow-up Protocol
  • HbA1c every $3$ months with a target of equal to or less than $7\%$.
  • Continuous monitoring for late complications.
• Recommended Vaccinations
  • Pneumococcal.
  • Influenza.
  • dTPA.

Late Complications: Nephropathy

• Monitoring and Screening
  • Perform an albumin/creatinine ratio (ACR) on a spot urine sample annually.
  • Calculate Glomerular Filtration Rate (GFR) annually.
  • Conduct Renal Function Test (RFT) and eGFR yearly.
• Classifications and Treatments
  • Microalbuminuria: Defined as $3$ to $29\,mg/mmol$. Requires the initiation of ACE inhibitors (Angiotensin-Converting Enzyme inhibitors).
  • Macroalbuminuria: Defined as equal to or greater than $30\,mg/mmol$. Requires $24$-hour proteinuria assessment.
• Referral Criteria
  • If eGFR is less than $30\,mL/min$, an urgent referral to a nephrologist is required.

Late Complications: Retinopathy

• Screening Schedule
  • Screening should begin no later than $5$ years after the initial diagnosis.
• Ongoing Assessment Intervals
  • No Retinopathy Present: Repeat screening at least every $2$ years by an optometrist, trained GP, or ophthalmologist.
  • Nonproliferative Retinopathy Identified: Requires an annual eye examination by an optometrist, trained GP, or ophthalmologist.
• Urgent Specialist Referral
  • Proliferative Retinopathy or Macular Oedema: Immediate urgent referral to an ophthalmologist.
  • Vitreous Haemorrhage: Requires same-day evaluation by a specialist.

Diabetes Foot Care and Management

• Neuropathy Screening and Review
  • No Neuropathy: Annual foot assessment is sufficient.
  • Neuropathy Present: Requires a podiatry review every $3$ to $6$ months.