What is the diagnosis for symptoms including right upper quadrant discomfort, right lower quadrant discomfort, intermittent right flank pain, fullness in bladder, and cloudy urine?

Diagnostic Approach to Right-Sided Abdominal Pain with Urinary Symptoms

This symptom constellation most likely represents a urinary tract infection (UTI), potentially complicated by pyelonephritis or urolithiasis, and requires immediate urinalysis with urine culture followed by CT imaging if initial workup is equivocal or suggests upper tract involvement. 1, 2

Initial Diagnostic Steps

Obtain urinalysis and urine culture immediately as the first diagnostic test, since cloudy urine with bladder fullness strongly suggests UTI, and pyuria is the principal biomarker of urinary tract infection. 2, 3, 4 The combination of right flank pain (suggesting upper tract involvement) with lower urinary tract symptoms (bladder fullness, cloudy urine) indicates potential pyelonephritis or complicated UTI. 2, 3

Key Clinical Features to Document

• Fever and systemic symptoms: Presence of fever with flank pain indicates pyelonephritis rather than simple cystitis, which typically presents without fever. 3
• Dysuria, frequency, and urgency: These are the most diagnostic symptoms of UTI, though their absence does not rule out infection, particularly in complicated cases. 3, 4
• Hematuria: Check for gross or microscopic hematuria, as this may indicate urolithiasis or upper tract infection. 1
• Duration of symptoms: Symptoms present for at least 6 weeks would suggest chronic infection or interstitial cystitis/bladder pain syndrome. 1, 5

Imaging Algorithm Based on Initial Findings

If Urinalysis Shows Pyuria/Bacteriuria

Proceed directly to CT abdomen and pelvis without contrast if urolithiasis is the primary concern, as this is the gold standard for detecting stones with high sensitivity and can identify complications such as hydronephrosis. 1 The ACR rates noncontrast CT as usually appropriate (rating 9/9) for acute flank pain with suspected stone disease. 1

Alternatively, obtain CT abdomen and pelvis with IV contrast if the clinical picture suggests complicated UTI, pyelonephritis with abscess formation, or if the differential includes right lower quadrant pathology (appendicitis, diverticulitis). 1, 6 CT with contrast has 95% sensitivity for detecting appendicitis and can identify alternative diagnoses including infectious enterocolitis, right colonic diverticulitis, and genitourinary pathology. 1

If Right Upper Quadrant Pain Predominates

Obtain right upper quadrant ultrasound first if biliary pathology is suspected, as the ACR rates this 9/9 (usually appropriate) for RUQ pain evaluation. 1, 7, 8 Ultrasound has 96% accuracy for detecting gallstones and can assess for cholecystitis. 1, 8

However, the combination of RUQ, RLQ, and flank pain makes biliary disease less likely as the primary diagnosis, since biliary colic typically presents with postprandial RUQ pain alone, not diffuse right-sided pain with urinary symptoms. 7

Critical Diagnostic Pitfalls

• Do not dismiss pyuria as insignificant: Even with negative standard urine culture (≥10⁵ CFU/mL), pyuria indicates urinary tract inflammation and may represent chronic UTI with lower bacterial counts that are clinically significant. 4, 5 In symptomatic women, bacterial growth as low as 10² CFU/mL can reflect true infection. 4

• Do not assume simple cystitis with flank pain: Right flank pain indicates upper tract involvement (pyelonephritis or urolithiasis) and requires imaging evaluation, not just empiric antibiotics. 1, 3, 6 Patients with urinary obstruction, diabetes, or immunocompromise are more likely to develop complicated infection or abscess. 6

• Nitrites are more specific than other dipstick components: Positive nitrites strongly suggest UTI, but negative nitrites do not rule out infection, particularly in patients with high pretest probability based on symptoms. 4

• Bacteriuria is more specific than pyuria: Pyuria alone is commonly found without infection, particularly in patients with lower urinary tract symptoms like incontinence, but bacteriuria is more specific for true UTI. 4

Recommended Diagnostic Sequence

1. Urinalysis with microscopy and urine culture (first-line test) 2, 3, 4
2. If pyuria/bacteriuria present with flank pain: CT abdomen/pelvis without contrast (for stones) or with contrast (for complicated UTI/pyelonephritis) 1, 6
3. If imaging shows hydronephrosis or obstruction: Urgent urology consultation for possible percutaneous nephrostomy or intervention 6
4. If initial workup negative but symptoms persist: Consider CT with contrast to evaluate for appendicitis, diverticulitis, or other non-urinary pathology 1

Treatment Implications

Do not delay imaging in patients with flank pain and systemic symptoms, as pyonephrosis (infected obstructed kidney) requires urgent drainage and can lead to sepsis. 6 CT is the study of choice for diagnostic evaluation in patients who do not respond promptly to treatment or have complicated clinical pictures. 6

If pyelonephritis is confirmed, ensure adequate tissue-penetrating antibiotics are used, as agents effective for cystitis (like nitrofurantoin) may not achieve adequate tissue levels for upper tract infection. 3