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Diabetes Mellitus

Overview

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Types / Classification

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Diagnostic Criteria

OGTT methodology: 75 g anhydrous glucose dissolved in water; 2-hour sample drawn. Endorsed by WHO, IDF, and ADA with identical cutoffs.

Special Populations

• GDM: Screened at 24–28 weeks gestation; uses either a one-step (75 g OGTT, ADA) or two-step (50 g challenge then 100 g OGTT, ACOG) approach with separate thresholds.
• Children: Same glucose criteria; T1DM more common but T2DM rising with childhood obesity.

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Management

General Targets (ADA Standards of Care)

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Type 1 DM

1. Insulin is mandatory — no alternative
   • Basal-bolus regimen: Long-acting insulin (glargine, detemir, degludec) + rapid-acting insulin (aspart, lispro, glulisine) at meals
   • Continuous Subcutaneous Insulin Infusion (CSII) / insulin pump: preferred in many patients
2. Continuous Glucose Monitoring (CGM): standard of care; reduces HbA1c and hypoglycemia
3. Closed-loop systems ("artificial pancreas"): automated insulin delivery; increasingly available
4. Carbohydrate counting and flexible dosing
5. Sick-day rules: never stop insulin; monitor ketones

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Type 2 DM

Step-wise pharmacotherapy:

1. Lifestyle modification first: weight loss (≥5–10% body weight), dietary changes (low glycemic index, caloric restriction), ≥150 min/week moderate aerobic activity
2. Metformin: First-line pharmacotherapy (unless contraindicated — eGFR < 30, contrast dye, hepatic failure); reduces hepatic glucose production; weight-neutral; low hypoglycemia risk
3. Add-on agents (chosen by comorbidity profile):

1. Insulin initiation in T2DM: Start with basal insulin (10 units or 0.1–0.2 U/kg/day); titrate by 2 units every 3 days to fasting glucose target

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Gestational DM

• First-line: Medical nutrition therapy (MNT) + exercise; target fasting < 5.3 mmol/L, 1-h post-meal < 7.8 mmol/L
• Pharmacotherapy if targets not met: Insulin preferred (safe, well-studied); metformin accepted but crosses placenta
• Post-delivery: retest at 6–12 weeks with 75 g OGTT; annual screening thereafter

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Monitoring & Screening

• Self-monitoring of blood glucose (SMBG) or CGM: individualized frequency
• HbA1c: every 3 months until at goal, then every 6 months
• Annual: lipid panel, urine albumin-to-creatinine ratio, eGFR, dilated eye exam, foot exam
• Screening asymptomatic adults: age ≥ 35 (or younger if overweight + risk factors) every 3 years — FPG, HbA1c, or OGTT

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Complications to Monitor & Prevent

• ACE inhibitors/ARBs: first-line for diabetic nephropathy with albuminuria
• Statin therapy: indicated in most adults with DM aged > 40 or with CV risk factors
• Aspirin: for secondary prevention in established ASCVD

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Pancreatitis

Types

1. Acute Pancreatitis

• Interstitial Edematous Pancreatitis: most common; diffuse or focal pancreatic enlargement with enhancement on CT
• Necrotizing Pancreatitis: non-perfusion of pancreatic parenchyma ± peripancreatic necrosis on CECT; ~5–10% of cases; highest mortality

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2. Chronic Pancreatitis

• End-stage: exocrine insufficiency (steatorrhea, malabsorption) + endocrine insufficiency (pancreatogenic/type 3c diabetes)
• Hallmark on imaging: pancreatic calcifications, ductal dilation, parenchymal atrophy

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3. Special Subtypes

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Causes / Etiology

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Diagnosis

1. Typical abdominal pain — epigastric, often radiating to the back, constant, severe
2. Serum lipase and/or amylase ≥ 3× upper limit of normal
3. Confirmatory cross-sectional imaging (CT/MRI with characteristic findings)

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Laboratory Findings

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Imaging

CT Abdomen with IV Contrast (CECT)

• Gold standard for staging severity and detecting necrosis
• Best performed 48–72 hours after symptom onset (necrosis may not be visible initially)
• CT Severity Index (Balthazar Score): grades A–E based on pancreatic inflammation + necrosis percentage

CT Findings — Necrotizing Pancreatitis

Other Imaging Modalities

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Severity Scoring Systems

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Management

Acute Pancreatitis

1. Initial Resuscitation (First 12–24 Hours)

• IV fluid resuscitation: Lactated Ringer's preferred over normal saline (reduces SIRS, acidosis); 250–500 mL/hr initially; titrate to urine output > 0.5 mL/kg/hr, HR < 100, MAP 65–85 mmHg
• Monitor closely: BUN, creatinine, hematocrit, urine output

2. Pain Management

• IV opioids (morphine, hydromorphone, fentanyl) — effective and safe; old concerns about morphine causing sphincter of Oddi spasm are not clinically significant
• NSAIDs (ketorolac) as adjunct

3. Nutrition

• Mild pancreatitis: Oral feeding tolerated as soon as patient can eat (low-fat, soft diet); no need for bowel rest
• Severe/moderately severe: Enteral nutrition (nasojejunal or nasogastric) preferred over parenteral — maintains gut barrier, reduces infectious complications; start within 24–72 hours
• TPN only if enteral route not feasible

4. Antibiotics

• Not routinely indicated for sterile pancreatitis
• Reserve for proven/suspected infected necrosis — guided by FNA culture or clinical deterioration with fever + rising CRP; use carbapenems (imipenem, meropenem) or fluoroquinolones + metronidazole (penetrate pancreatic tissue)

5. Cause-Specific Interventions

6. Management of Complications

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Chronic Pancreatitis

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Asthma

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Definition

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Pathophysiology

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Triggers / Risk Factors

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Clinical Features

• Wheeze (expiratory > inspiratory)
• Dyspnea / chest tightness
• Cough (especially nocturnal; may be the only symptom — cough-variant asthma)

• Expiratory wheeze on auscultation
• Prolonged expiratory phase
• Use of accessory muscles (severe)
• Silent chest = very severe obstruction (no airflow to generate wheeze — ominous sign)
• Pulsus paradoxus > 10 mmHg (severe)

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Diagnosis

Diagnostic Criteria (GINA 2023)

1. Characteristic symptom pattern (variable wheeze, dyspnea, cough, chest tightness)
2. Objective evidence of variable expiratory airflow limitation (confirmatory pulmonary function testing)

Spirometry — Key Tests

Note: Normal spirometry does not exclude asthma — testing during a symptomatic period or bronchoprovocation challenge (methacholine, mannitol) may be needed.

Bronchial Provocation Testing

• Used when spirometry is normal but asthma is suspected
• Methacholine challenge: PC₂₀ < 8 mg/mL = airway hyperresponsiveness (positive)
• Useful to rule out asthma (high sensitivity — negative test makes asthma unlikely)

Additional Investigations

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Classification

By Symptom Control (GINA)

By Severity (Based on Treatment Required to Achieve Control)

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Management

GINA Stepwise Approach (Adults & Adolescents ≥ 12 years)

GINA 2019+ Update: ICS-containing reliever (budesonide-formoterol) preferred over SABA alone at all steps — reduces exacerbation risk even in mild asthma.

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Drug Classes

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Biologic Therapies (Step 5 — Severe Asthma)

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Acute Exacerbation Management

Severity Assessment

Treatment Protocol

1. Oxygen: Titrate to SpO₂ 93–95% (avoid hyperoxia)
2. SABA: Salbutamol 2.5–5 mg nebulized every 20 minutes × 3 (or MDI 4–8 puffs), then reassess
3. Ipratropium bromide: Add 0.5 mg nebulized in moderate–severe attacks (reduces hospitalizations)
4. Systemic corticosteroids: Prednisolone 40–50 mg oral (or IV methylprednisolone 1 mg/kg) — start early; course 5–7 days
5. Magnesium sulfate IV: 2 g IV over 20 minutes for severe/life-threatening attacks not responding to initial treatment
6. Heliox: Consider in severe refractory obstruction (reduces turbulent airflow)
7. Intubation & mechanical ventilation: Last resort; use permissive hypercapnia strategy

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Non-Pharmacological Management

• Allergen avoidance: HDMA covers, pet removal, cockroach control
• Smoking cessation: Reduces ICS effectiveness; accelerates decline
• Allergen immunotherapy (AIT): Subcutaneous or sublingual; reduces sensitization and exacerbations in allergic asthma
• Breathing exercises: Buteyko, physiotherapy — reduce reliever use, improve quality of life
• Weight loss: Significant benefit in obese patients (reduces airway inflammation, improves control)
• Asthma action plan: Written self-management plan for every patient — recognizing worsening, when to increase treatment, when to seek emergency care
• Vaccination: Annual influenza; pneumococcal for severe/oral steroid-dependent asthma

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Monitoring

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