What is the diagnosis for a patient with hyperglycemia, polydipsia, polyuria, infected leg, weight loss, and vision changes on Gliclazide?

Diagnosis: Type 1 Diabetes Mellitus with Infected Diabetic Foot Ulcer

This 28-year-old female presents with classic Type 1 diabetes mellitus (T1DM) manifesting as hyperglycemia with polyuria, polydipsia, weight loss, and blurred vision, complicated by an infected right leg wound—a presentation requiring immediate insulin therapy and aggressive wound management. 1

Primary Diagnosis: Type 1 Diabetes Mellitus

The clinical presentation strongly indicates new-onset T1DM rather than Type 2 diabetes based on several key features:

• Age and body habitus: 28 years old with BMI 17.24 (underweight), inconsistent with typical Type 2 diabetes presentation 1
• Classic triad: Polyuria, polydipsia, and significant weight loss indicate absolute insulin deficiency 1
• Acute symptom onset: Rapid development of symptoms suggests autoimmune β-cell destruction 1
• Inadequate response to oral agent: Currently on Gliclazide (a sulfonylurea) which is inappropriate for T1DM and explains poor glycemic control 2

The patient requires immediate transition from Gliclazide to insulin therapy as sulfonylureas are ineffective in absolute insulin deficiency and may delay appropriate treatment. 2

Secondary Diagnosis: Infected Diabetic Foot Ulcer

The infected right leg represents a diabetic foot infection requiring urgent classification and treatment:

Infection Severity Assessment

Based on clinical presentation, classify the infection severity 3:

• Mild infection: If only purulence/erythema present with cellulitis <2 cm, limited to skin/subcutaneous tissue, patient systemically well 3
• Moderate infection: If cellulitis extends >2 cm, lymphangitic streaking present, or involves deeper structures (fascia, muscle, tendon, bone) but patient metabolically stable 3
• Severe infection: If systemic toxicity present (fever, tachycardia, confusion, vomiting, severe hyperglycemia, acidosis) 3

Given the severe hyperglycemia and metabolic instability, this likely represents at minimum a moderate-to-severe infection. 3

Critical Evaluation Steps

Immediately assess 3:

• Vital signs: Temperature, heart rate, blood pressure to detect systemic toxicity 3
• Metabolic status: Check for diabetic ketoacidosis (DKA) given T1DM presentation—measure serum bicarbonate, ketones, arterial pH 3
• Wound characteristics: Debride and probe wound to determine depth, presence of purulence, involvement of bone (probe-to-bone test positive suggests osteomyelitis) 3
• Vascular assessment: Palpate dorsalis pedis and posterior tibial pulses; absent pulses indicate critical ischemia requiring urgent vascular consultation 3
• Laboratory markers: Elevated C-reactive protein >2 SD above normal, leukocytosis, severe hyperglycemia suggest serious infection 3

Management Priorities

Immediate Actions (First 24-48 Hours)

1. Hospitalization is mandatory given severe hyperglycemia, metabolic instability, and infected wound 3

2. Rule out hyperglycemic crisis 3:

• Check blood gas for acidosis (pH <7.3 suggests DKA)
• Measure serum/urine ketones
• Assess serum osmolality (>320 mOsm/kg suggests hyperosmolar state)
• Monitor for altered mental status, Kussmaul respirations

3. Metabolic stabilization 3:

• Aggressive IV fluid resuscitation for volume depletion from osmotic diuresis 3
• Correct electrolyte abnormalities, particularly hypokalemia (insulin drives potassium intracellularly) 2
• Initiate IV insulin infusion if DKA present; transition to subcutaneous basal-bolus regimen once stable 2
• Monitor blood glucose hourly initially, then every 2-4 hours 2

4. Infection management 3:

• Do NOT delay antibiotics for culture results in moderate-severe infection 3
• Obtain wound cultures via deep tissue biopsy or curettage after debridement (not superficial swab) 3
• Empiric broad-spectrum IV antibiotics covering Staphylococcus aureus (including MRSA if risk factors present), β-hemolytic streptococci, and gram-negative organisms 3
• Surgical debridement of necrotic tissue within 24-48 hours if present 3
• Plain radiographs (two views) to assess for osteomyelitis, gas in soft tissues 3

Common Pitfalls to Avoid

• Never continue sulfonylureas in suspected T1DM—this delays appropriate insulin therapy and worsens outcomes 2
• Never treat hyperglycemia before adequate fluid resuscitation—rapid glucose correction without volume repletion risks hypovolemic shock 2
• Never prescribe antibiotics for uninfected ulcers—but this wound is clearly infected based on clinical description 3
• Never assume adequate perfusion without pulse examination—ischemia dramatically worsens infection prognosis and may necessitate urgent revascularization 3

Hyperglycemia and Infection Relationship

Severe hyperglycemia directly impairs immune function, creating a vicious cycle 4:

• Decreased polymorphonuclear leukocyte chemotaxis and phagocytosis 4
• Impaired wound healing 3
• Increased infection-related mortality 4

Tight glycemic control (80-110 mg/dL in ICU setting) reduces infection complications and mortality, though targets may be liberalized to 140-180 mg/dL in non-ICU settings to reduce hypoglycemia risk 4

Long-term Diabetes Management

Once acute crisis resolved 1:

• Confirm T1DM diagnosis with autoantibodies (GAD, IA-2, ZnT8) and C-peptide level
• Initiate basal-bolus insulin regimen or insulin pump therapy
• Diabetes education on carbohydrate counting, insulin dosing, hypoglycemia recognition
• Screen for other autoimmune conditions (thyroid disease, celiac disease)
• Establish multidisciplinary foot care to prevent recurrent ulceration