1. Prepared by Seena Tabibi, MD and reviewed by Mark Marzinke, PhD.

An adult with a past medical history of hypertension, significant alcohol consumption, smoking, and marijuana use presents with chest pain, dyspnea, and abdominal pain. The symptoms started a few days ago.

Vitals:

• Blood Pressure 126/63 mm Hg
• Temperature 35.5 °C
• Heart Rate 83 beats/minute
• Oxygen saturation 99%

Physical Examination: Within normal limits.

Chest X-ray: Within normal limits.

Labs:Troponin I: <0.04 ng/mL (Reference: <0.04 ng/mL)

Urinalysis:

• Specific gravity: 1.002 (Reference: 1.005-1.030)
• Blood: Negative
• Leukocyte esterase: Negative
• White Blood Cells: 1-2/hpf
• Red Blood Cells: 0-1/hpf
• Protein: None
• Casts: None

Urine Toxicology: Negative (Reference: Negative)

Complete Blood Count:

• White Blood Cells 11.28 K/cu mm (Reference: 4.5-11.0 K/cu mm)
• Hemoglobin 14.6 g/dL (Reference: 13.0-17.0 g/dL)
• Platelets 344 K/cu mm (Reference: 150-450 K/cu mm)

Serum Chemistries:

• Na⁺ 113 mmol/L (Reference: 136-148 mmol/L)
• Cl^- <60 mmol/L (Reference: 96-106 mmol/L)
• K⁺ 6 mmol/L (Reference: 3.6-5.2 mmol/L)
• HCO3^- 33 mEq/L (Reference: 22-28 mEq/L)
• Ca²⁺6 mg/dL (Reference: 8.5-10.5 mg/dL)
• Glucose 87 mg/dL (Reference: 60-100 mg/dL)
• Albumin: 2.5 g/dL (Reference: 3.4-5.4 g/dL)
• AST 152 U/L (Reference: 8-33 U/L)
• ALT 73 U/L (Reference: 7-35 U/L)
• ALP 44 U/L (Reference: 44-147 U/L)
• BUN 24 mg/dL (Reference: 6-24 mg/dL)
• Creatinine 1.1 mg/dL (Reference: 0.74- 1.35 mg/dL)
• Triglycerides 117 mg/dL (Reference: <150 mg/dL)

Whole Blood Testing:

• Na⁺ 114 mmol/L (Reference: 136-149 mmol/L)
• Cl^- 61 mmol/L (Reference: 98-107 mmol/L)
• K⁺ 2 mmol/L (Reference: 3.5-5.0 mmol/L)
• Glucose 80 mg/dL (Reference: 60-100 mg/dL)

Urine Chemistry Testing:

• Urine Osmolality: 80 mOsmol/kg H2O (Reference: 50-1200 mOsmol/kgH2O)
• Urine Sodium: <20 mmol/L (Ref:  <20 mmol/L-214 mmol/L; random)

Question: What is the most likely explanation for the laboratory results?