What additional assessments are recommended for an elderly female patient with stomach pain, recurrent Urinary Tract Infections (UTIs), pruritic rash, and prediabetes?

Assessment of Stomach Pain in Elderly Female with Recurrent UTIs, Pruritic Rash, and Prediabetes

Given this patient's recurrent UTIs and prediabetes, the stomach pain warrants evaluation for metformin-associated lactic acidosis if she is on metformin, alongside imaging to assess for complicated UTI with upper tract involvement or anatomic abnormalities.

Immediate Priority: Rule Out Metformin-Associated Lactic Acidosis

• If the patient is taking metformin for prediabetes, metformin-associated lactic acidosis must be considered immediately, as it presents with nonspecific symptoms including abdominal pain, malaise, and respiratory distress 1
• Check serum lactate level (>5 mmol/L suggests lactic acidosis), arterial blood gas for anion gap acidosis, and metformin plasma level (typically >5 mcg/mL in toxicity) 1
• Assess renal function with eGFR, as elderly patients are at higher risk for metformin accumulation due to age-related decline in renal function, and recurrent UTIs may have compromised kidney function 1
• The combination of elderly age, recurrent UTIs (suggesting possible renal impairment), and abdominal pain creates a high-risk scenario for this life-threatening complication 1

Imaging for Complicated UTI Assessment

• CT urography (CTU) is the primary imaging modality recommended for this patient with recurrent UTIs to evaluate for anatomic abnormalities, obstruction, calculi, or upper tract complications that could explain both the recurrent infections and abdominal pain 2
• Plain abdominal radiograph should be obtained as a minimum screening tool in diabetic/prediabetic patients presenting with abdominal pain and UTI symptoms to identify complications such as emphysematous pyelonephritis or calculi 3
• Ultrasound of kidneys and bladder can serve as an initial screening tool to detect hydronephrosis, postvoid residual volume, and renal stones, though it is less sensitive than CT 4, 2
• The recurrent nature of UTIs indicates this is likely a complicated UTI scenario requiring imaging workup, as the American College of Radiology recommends imaging for patients with frequent reinfections or relapses 2

Laboratory Evaluation

• Obtain urinalysis and urine culture with susceptibility testing to document active infection and guide antibiotic therapy 5
• Check complete metabolic panel including liver function tests, as hepatic impairment can predispose to lactic acidosis and may be relevant to abdominal pain 1
• Measure serum glucose and hemoglobin A1c to assess diabetes control, as poor glycemic control increases UTI risk and complications 3
• Check complete blood count to evaluate for anemia (which could be related to vitamin B12 deficiency from metformin) and leukocytosis (suggesting infection or inflammation) 1
• Assess vitamin B12 levels if on metformin, as deficiency occurs in approximately 7% of patients and requires monitoring 1

Specific History Elements to Elicit

• Determine exact location, character, onset, and radiation of abdominal pain, as location guides differential diagnosis 6
• Ask about constitutional symptoms (fever, chills, malaise, myalgias) that could indicate systemic infection or lactic acidosis 1, 3
• Document timing of UTI episodes, treatments received, and whether infections recur within 2 weeks of treatment (suggesting relapse versus reinfection) 2
• Inquire about dysuria, frequency, urgency, hematuria, and flank pain to distinguish lower versus upper tract involvement 5
• Assess for symptoms of incomplete bladder emptying, which predisposes to recurrent UTIs 4

Physical Examination Focus

• Perform suprapubic examination for tenderness suggesting cystitis 5
• Check for costovertebral angle tenderness bilaterally to assess for pyelonephritis or upper tract involvement 3
• Examine for signs of volume depletion (hypotension, tachycardia) which increases lactic acidosis risk 1
• Assess respiratory rate and pattern, as tachypnea may indicate metabolic acidosis 1
• Perform abdominal examination noting any distension, guarding, rebound, or disproportionate tenderness relative to examination findings (which suggests unusual causes) 7

Critical Pitfalls to Avoid

• Do not dismiss abdominal pain as simple gastritis in an elderly patient on metformin with recurrent UTIs—this combination demands evaluation for serious complications 1, 3
• Elderly patients may present with atypical symptoms and blunted inflammatory responses, making diagnosis more challenging 6
• The pruritic rash may be unrelated, but consider whether it represents a drug reaction or systemic process contributing to the clinical picture 7
• Recurrent UTIs in elderly females with anatomic abnormalities can lead to upper tract complications including intrarenal abscess, which requires CT imaging for detection 3