What is the likely diagnosis and appropriate initial evaluation for a patient with a mildly elevated hematocrit, left upper quadrant pain, microscopic hematuria, high anion‑gap metabolic acidosis, and mildly enlarged axillary lymph nodes?

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Likely Diagnosis and Initial Evaluation

This constellation of findings—mildly elevated hematocrit, left upper quadrant pain, microscopic hematuria, high anion-gap metabolic acidosis, and swollen axillary lymph nodes—suggests a systemic process rather than isolated urologic pathology, with the high anion-gap acidosis being the most concerning feature requiring immediate attention.

Immediate Priority: High Anion-Gap Metabolic Acidosis

  • High anion-gap metabolic acidosis (>12 mEq/L) almost always signifies a serious underlying condition including lactic acidosis, ketoacidosis, toxic ingestions (methanol, ethylene glycol, salicylates), or uremia, and requires urgent evaluation. 1
  • The three primary causes of metabolic acidosis are loss of base, decreased renal excretion of acid, and increased acid production; when the anion gap is elevated, this points toward increased acid production or toxin accumulation. 2
  • Lactic acidosis from decreased oxygen delivery or defective oxygen utilization carries high mortality and must be ruled out emergently. 1

Urgent Laboratory Work-Up for Anion-Gap Acidosis

  • Serum lactate to evaluate for lactic acidosis (tissue hypoperfusion, sepsis, malignancy)
  • Serum ketones (beta-hydroxybutyrate) to assess for diabetic or alcoholic ketoacidosis 1
  • Serum osmolal gap to screen for toxic alcohol ingestion (methanol, ethylene glycol) 1
  • Salicylate level if toxic ingestion suspected 1
  • Blood urea nitrogen (BUN) and creatinine to evaluate for uremic acidosis 1
  • Complete metabolic panel including glucose, electrolytes, albumin 3

Left Upper Quadrant Pain: Differential Diagnosis

The combination of LUQ pain with systemic findings (acidosis, lymphadenopathy) raises concern for:

  • Splenic pathology (infarction, rupture, abscess, lymphoma)
  • Renal pathology (left kidney mass, pyelonephritis, renal infarction)
  • Pancreatic tail pathology (pancreatitis, mass)
  • Gastric pathology (less likely given other systemic findings)

Imaging for LUQ Pain

  • Contrast-enhanced CT of abdomen and pelvis is the preferred initial imaging modality to evaluate LUQ pain with systemic findings, as it can identify splenic, renal, pancreatic, and lymph node pathology simultaneously. 3
  • If renal injury or mass is suspected, multiphasic CT urography (unenhanced, nephrographic, and excretory phases) provides comprehensive evaluation. 3

Microscopic Hematuria Evaluation

  • Confirm true microscopic hematuria with microscopic urinalysis showing ≥3 red blood cells per high-power field on a properly collected specimen; dipstick alone has only 65-99% specificity. 3
  • Examine urinary sediment for dysmorphic RBCs (>80%) and red cell casts, which would indicate glomerular disease and warrant nephrology referral. 3
  • Quantify proteinuria with spot urine protein-to-creatinine ratio; significant proteinuria (>0.5 g/g) suggests renal parenchymal disease. 3, 4

Context-Specific Hematuria Considerations

  • In the setting of systemic illness with acidosis and lymphadenopathy, hematuria may be secondary to underlying malignancy, infection, or glomerular disease rather than isolated urologic pathology. 3
  • Do not attribute hematuria to any concurrent findings without completing appropriate evaluation; multiple pathologies can coexist. 3

Swollen Axillary Lymph Nodes

  • Lymphadenopathy in the context of systemic symptoms (acidosis, hematuria, elevated HCT) raises concern for:
    • Lymphoproliferative disorders (lymphoma, leukemia)
    • Metastatic malignancy
    • Systemic infection
    • Autoimmune/inflammatory conditions

Lymph Node Evaluation

  • Physical examination should document size, consistency, mobility, and distribution of lymphadenopathy
  • Complete blood count with differential to evaluate for hematologic malignancy
  • Imaging (CT chest/abdomen/pelvis) to assess for additional lymphadenopathy and organomegaly
  • Consider lymph node biopsy if lymphadenopathy persists or imaging suggests malignancy

Mildly Elevated Hematocrit

  • Elevated hematocrit can represent:
    • Volume depletion/hemoconcentration (most common)
    • Polycythemia vera (primary)
    • Secondary erythrocytosis (hypoxia, renal cell carcinoma, other tumors)
  • In the context of acidosis and systemic findings, hemoconcentration from volume depletion is most likely, but renal cell carcinoma producing erythropoietin should be considered given the hematuria. 3

Recommended Initial Diagnostic Algorithm

Immediate (Emergency Department/Same-Day)

  1. Arterial or venous blood gas to confirm and characterize metabolic acidosis
  2. Serum lactate, ketones, osmolal gap, salicylate level 1
  3. Complete metabolic panel, BUN, creatinine 1, 3
  4. Complete blood count with differential
  5. Urinalysis with microscopy (confirm hematuria, assess for dysmorphic RBCs, casts, proteinuria) 3
  6. Spot urine protein-to-creatinine ratio 3, 4
  7. Contrast-enhanced CT abdomen/pelvis to evaluate LUQ pain, kidneys, spleen, lymph nodes 3

Urgent (Within 24-48 Hours)

  • Nephrology consultation if dysmorphic RBCs >80%, red cell casts, significant proteinuria, or elevated creatinine 3
  • Hematology/oncology consultation if lymphadenopathy concerning for malignancy or CBC abnormalities
  • Urology referral if imaging reveals renal mass or upper tract pathology 3

Follow-Up Based on Initial Results

  • If acidosis resolves and imaging/labs identify benign cause: standard hematuria work-up with cystoscopy and upper tract imaging per age and risk factors 3
  • If glomerular disease identified: nephrology-directed work-up including complement levels, ANA, ANCA, renal biopsy as indicated 3
  • If malignancy suspected: tissue diagnosis via biopsy of most accessible site

Critical Pitfalls to Avoid

  • Never dismiss high anion-gap acidosis as incidental; it represents serious pathology requiring immediate investigation. 1
  • Do not attribute all findings to a single benign cause (e.g., UTI) without excluding malignancy and systemic disease. 3
  • Do not delay imaging and laboratory evaluation while pursuing outpatient work-up; this presentation warrants urgent/emergent assessment. 3
  • Do not perform isolated hematuria work-up without first addressing the metabolic acidosis and systemic findings. 1, 3

References

1
Research

Anion gap acidosis.

Seminars in nephrology, 1998

3
Guideline

Hematuria Evaluation and Management

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2026

4
Guideline

Hematuria and Proteinuria Evaluation

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2026

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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