John is a 17-year-old high school student brought by his mother to the ER in a confused state. He was dehydrated and breathing deeply and rapidly. His mother mentioned that few hours earlier, he complained of nausea and stomach pain. He is known to have type 1 diabetes mellitus for approximately 10 years and is on insulin therapy. She stated that her son had not been adherent to his treatment lately and he often ate chocolate and sweets. He has also been struggling with his studies as well. John had a similar condition twice over the past 2 years.

On examination:

• Weight: 89 kg, Height: 184 cm, BMI: 26.3
• BP: 140/86 mmHg, Heart Rate: 92/min, Temperature: 37.6 ⁰C, Respiratory Rate: 26/min, O₂ SAT: 96%
• Patient seems anxious and disoriented to place and time. He has dry skin, tongue, and mucous membranes, sunken eyes. Warm skin. Fruity smell of his breath with rapid deep (Kussmaul type) breathing.

What is the suspected diagnosis based on John's symptoms considering his type 1 diabetes?  

John's laboratory investigation showed:

• Urinalysis:
  • Color: colorless/clear, pH: 5.0, Specific gravity: 1038, Osmolarity : 1251 mOsm/kg; Glucose: +++, Ketones: ++, Albumin: +, Nitrates: trace, WBCs: 12-14/HPF, RBCs: 0/HPF, Urate crystals: +, Yeast: +
• Blood analysis:
  • CBC:
    • RBCs: 5.2 x 10¹²/L, Hemoglobin: 154 g/L, Hematocrit: 0.44
    • MCV: 75 fL, MCH: 31pg, RDW: 15.9%, Reticulocytes: 1.8%, ESR: 22 mm/hour
    • WBC: 12 x 10⁹/L, (Neutrophils: 8.2 x 10⁹/L, Lymphocytes: 1.0 x 10⁹/L, Basophils: 0.08 x 10⁹/L, Eosinophils: 0.32 x 10⁹/L, Monocytes: 0.5 x 10⁹/L)
    • Platelet counts: 428 x 10⁹/L
  • Na: 125 mmol/L, K: 5.8 mmol/L, Cl: 96 mmol/L
  • Glucose: 27 mmol/L, HbA1C: 9.3%, BUN: 10.2 mmol/L Creatinine: 146 µmol/L, Uric acid: 475 mmol/L
  • Triglycerides: 2.9 mmol/L, Cholesterol: 5.8 mmol/L, HDL: 0.9 mmol/L, LDL: 3.8 mmol/L
  • Bilirubin: 11 mmol/L, Albumin: 42 g / L,
  • B-Hydroxybutyrate: 3.8 mmol/L
• Arterial blood gas:
  • pH: 7.257
  • O₂ SAT: 96%
  • p_a O₂(Arterial): 10.8 kPa = 92 mmHg
  • p_a CO₂ (Arterial): 4.34 kPa = 32 mmHg
  • HCO3: 13.0 mmol/L

What is HbA_1c and why is it an important lab test?

John's laboratory investigation showed:

• Urinalysis:
  • Color: colorless/clear, pH: 5.0, Specific gravity: 1038, Osmolarity : 1251 mOsm/kg; Glucose: +++, Ketones: ++, Albumin: +, Nitrates: trace, WBCs: 12-14/HPF, RBCs: 0/HPF, Urate crystals: +, Yeast: +
• Blood analysis:
  • CBC:
    • RBCs: 5.2 x 10¹²/L, Hemoglobin: 154 g/L, Hematocrit: 0.44
    • MCV: 75 fL, MCH: 31pg, RDW: 15.9%, Reticulocytes: 1.8%, ESR: 22 mm/hour
    • WBC: 12 x 10⁹/L, (Neutrophils: 8.2 x 10⁹/L, Lymphocytes: 1.0 x 10⁹/L, Basophils: 0.08 x 10⁹/L, Eosinophils: 0.32 x 10⁹/L, Monocytes: 0.5 x 10⁹/L)
    • Platelet counts: 428 x 10⁹/L
  • Na: 125 mmol/L, K: 5.8 mmol/L, Cl: 96 mmol/L
  • Glucose: 27 mmol/L, HbA1C: 9.3%, BUN: 10.2 mmol/L Creatinine: 146 µmol/L, Uric acid: 475 mmol/L
  • Triglycerides: 2.9 mmol/L, Cholesterol: 5.8 mmol/L, HDL: 0.9 mmol/L, LDL: 3.8 mmol/L
  • Bilirubin: 11 mmol/L, Albumin: 42 g / L,
  • B-Hydroxybutyrate: 3.8 mmol/L
• Arterial blood gas:
  • pH: 7.257
  • O₂ SAT: 96%
  • p_a O₂(Arterial): 10.8 kPa = 92 mmHg
  • p_a CO₂ (Arterial): 4.34 kPa = 32 mmHg
  • HCO3: 13.0 mmol/L

Select all the laboratory values that are elevated (select all the apply)

How do you interpret the following blood gas analysis results?

• Arterial blood gas:
  • pH: 7.257
  • O₂ SAT: 96%
  • p_a O₂(Arterial): 10.8 kPa = 92 mmHg
  • p_a CO₂ (Arterial): 4.34 kPa = 32 mmHg
  • HCO3: 13.0 mmol/L

Johns was given iv insulin and fluid replacement therapy.

The following table shows John's control laboratory results after treatment:

	Before treatment	8 hours after treatment
Na (mmol/L)	125	132
K (mmol/L)	5.8	3.4
Cl (mmol/L)	96	103
HCO3 (mmol/L)	13	22
BUN (mmol/L)	10.2	6.0
Creatinine (mmol/L)	146	65
Glucose (mmol/L)	27	8.2
Urine: ketone	+++	++
Osmolality (mOsm/L)	1251	310
pH	7.27	7.32
pCO2 (mmHg)	32	35
Hemoglobin (g/L)	154	140

What is the main cause of significant reduction of serum potassium level following treatment?