What is the diagnosis and treatment for a patient with hypokalemia, hyperglycemia, elevated BUN, low albumin, high globulin, and an abnormal albumin to globulin ratio?

Clinical Assessment and Diagnosis

This patient's laboratory findings suggest a chronic disease process, most likely multiple myeloma or another plasma cell dyscrasia, given the markedly elevated globulin (4.8 g/dL), low albumin (3.0 g/dL), and inverted albumin/globulin ratio (0.6). The mild hypokalemia (3.4 mEq/L), slightly low chloride (97 mEq/L), elevated BUN (26 mg/dL), and borderline hyperglycemia (115 mg/dL) are secondary findings that require attention but do not define the primary diagnosis.

Primary Diagnostic Considerations

The constellation of low albumin with markedly elevated globulin creating an inverted A/G ratio is highly suggestive of:

• Multiple myeloma - The most critical diagnosis to rule out given the A/G ratio of 0.6 (normal is 1.0-2.5) 1
• Chronic inflammatory conditions or chronic infections that can elevate globulins
• Liver disease (though typically both albumin and globulin are affected differently)

Required Immediate Workup

The following tests must be obtained urgently to evaluate for plasma cell dyscrasia:

• Serum protein electrophoresis (SPEP) and serum immunofixation electrophoresis (SIFE) to detect M-protein 1
• Serum free light chain (FLC) assay - now standard for screening plasma cell disorders with high sensitivity 1
• 24-hour urine for total protein, urine protein electrophoresis (UPEP), and urine immunofixation electrophoresis (UIFE) 1
• Quantitative immunoglobulin levels (IgG, IgA, IgM) 1
• Complete blood count with differential to assess for anemia and plasma cell burden 1
• Serum calcium - hypercalcemia is common in myeloma 1
• Beta-2 microglobulin and LDH for tumor burden assessment 1
• Serum creatinine to fully assess renal function given the elevated BUN 1

Secondary Laboratory Abnormalities and Management

Hypokalemia (K = 3.4 mEq/L)

Oral potassium supplementation is indicated for this mild hypokalemia, particularly if the patient has cardiac risk factors or is on digitalis. 2

• This borderline low potassium (normal 3.5-5.0 mEq/L) requires treatment, especially given potential cardiac implications 3
• Oral potassium chloride is the preferred route for mild hypokalemia without ECG changes 2, 3
• Typical dosing: 20-40 mEq orally, with repeat potassium measurement 3
• Investigate underlying causes: diuretic use, gastrointestinal losses, or transcellular shifts 3
• In dialysis or chronic kidney disease populations, hypokalemia is associated with malnutrition and increased mortality, making correction important 4

Common pitfall: Do not assume hypokalemia is benign at 3.4 mEq/L - patients with cardiac disease, arrhythmias, or on digitalis are at particular risk and require prompt correction 2

Elevated BUN (26 mg/dL) with Low Albumin

The elevated BUN in the context of low albumin and high globulin raises concern for:

• Renal involvement from plasma cell dyscrasia - myeloma kidney is common 1
• Pre-renal azotemia from dehydration
• Protein catabolism

Key action: Obtain serum creatinine and calculate GFR to assess true renal function 1. The BUN alone is insufficient - the BUN/creatinine ratio helps differentiate pre-renal from intrinsic renal disease 1.

If GFR <60 mL/min/1.73 m², consider nephrology referral, particularly if myeloma is confirmed 1

Hyperglycemia (Glucose 115 mg/dL)

This fasting glucose of 115 mg/dL indicates impaired fasting glucose (prediabetes range 100-125 mg/dL):

• Obtain HbA1c for assessment of chronic glycemic control 1
• Note that HbA1c may be unreliable if significant renal disease is present; consider glycated albumin or continuous glucose monitoring in CKD patients 5
• Screen for diabetic nephropathy if diabetes is confirmed, particularly given the elevated BUN 1

Low Chloride (97 mEq/L)

The slightly low chloride (normal 98-107 mEq/L) is likely secondary to:

• Metabolic alkalosis (check serum bicarbonate/CO2)
• Volume depletion
• Diuretic use if present

This is typically not an independent concern but should be monitored during fluid and electrolyte repletion 1

Treatment Algorithm

Immediate Actions (Within 24-48 Hours):

1. Order complete myeloma workup (SPEP, SIFE, FLC, UPEP, UIFE, quantitative immunoglobulins, beta-2 microglobulin) 1
2. Correct hypokalemia with oral potassium chloride 20-40 mEq 2, 3
3. Obtain serum creatinine and calculate GFR to assess renal function 1
4. Check HbA1c for glycemic assessment 1
5. Obtain serum calcium - critical for myeloma evaluation 1
6. Perform ECG if not recently done, given electrolyte abnormalities 1

Follow-up Based on Results:

If myeloma or plasma cell dyscrasia confirmed:

• Urgent hematology/oncology referral 1
• Bone marrow biopsy with cytogenetics 1
• Skeletal survey or imaging 1
• Aggressive management of renal dysfunction if present 1

If renal dysfunction confirmed (GFR <60):

• Nephrology consultation 1
• Optimize blood pressure control 1
• Consider ACE inhibitor or ARB if proteinuria present 1
• Protein restriction to 0.8 g/kg/day if nephropathy confirmed 1

If diabetes confirmed:

• Initiate glucose control measures 1
• Annual microalbuminuria screening 1
• Optimize cardiovascular risk factors 1

Monitoring:

• Recheck potassium within 1-2 days after supplementation 1
• Recheck BUN, creatinine, and electrolytes every 1-2 days until stable 1
• Monitor albumin levels as marker of nutritional status and disease progression 1, 4

Critical pitfall to avoid: Do not dismiss the inverted albumin/globulin ratio as a benign finding - this requires urgent evaluation for plasma cell dyscrasia, as delayed diagnosis of multiple myeloma significantly impacts morbidity and mortality 1