What is the best course of action for a female patient with chest pain at the costochondral junction of ribs 4-5-6, lower back pain, left thigh pain, and dysuria, with no history of trauma or fall, and no symptoms of difficulty breathing, cough, radiation of pain, tingling, numbness, or weakness?

Diagnostic Approach to Multi-System Presentation

This patient requires urgent evaluation for urinary tract infection as the primary diagnosis, with the chest wall pain most consistent with costochondritis, but cardiac causes must be excluded first given the multi-system presentation. 1

Immediate Priority: Exclude Life-Threatening Cardiac Causes

The costochondral junction pain at ribs 4-5-6 requires cardiac evaluation before assuming a benign musculoskeletal etiology, particularly in a female patient where atypical presentations are common. 1

Critical Red Flags Assessment

• Perform focused cardiovascular examination to identify acute coronary syndrome, which may present with diaphoresis, tachycardia, tachypnea, hypotension, crackles, S3, or mitral regurgitation murmur 1
• Obtain ECG within 10 minutes to identify STEMI, pericarditis patterns, or signs of pulmonary embolism 2
• Measure cardiac troponin as soon as possible to exclude myocardial injury 2
• Obtain chest radiograph to evaluate for pneumothorax, pneumonia, pleural effusion, or other pulmonary pathology 1, 2

Features Suggesting Benign Musculoskeletal Origin

The presentation has several reassuring features that make cardiac ischemia less likely:

• Pain localized to a very limited area (costochondral junction) is unlikely related to myocardial ischemia 1
• Absence of dyspnea, diaphoresis, or radiation makes acute coronary syndrome less probable 1
• Gradual onset and positional nature (alleviated by rest) suggests musculoskeletal etiology 1

However, 7% of patients with reproducible chest wall tenderness still have acute coronary syndrome, so palpable tenderness alone cannot exclude cardiac pathology. 2

Primary Diagnosis: Urinary Tract Infection

The dysuria with discomfort on urination is most consistent with uncomplicated cystitis and should be the primary focus of treatment. 3, 4

Diagnostic Workup for Dysuria

• Perform urinalysis (both dipstick and microscopic examination) in this patient, as pyuria is usually present with UTI and its absence suggests another condition 5, 6
• Obtain urine culture to guide appropriate antibiotic use, especially important given the multi-system presentation 4
• The absence of urgency and hematuria does not exclude UTI, as uncomplicated cystitis is usually manifested by dysuria with or without frequency/urgency 5

Key Diagnostic Considerations

• In women, urinary tract infection is the most frequent cause of dysuria 3
• Coliform organisms, notably Escherichia coli, are the most common pathogens 3
• The absence of vaginal discharge makes cervicitis less likely, increasing the probability of UTI 4

Secondary Diagnosis: Costochondritis

If cardiac workup is negative, the costochondral junction pain at ribs 4-5-6 is consistent with costochondritis. 1, 2

Diagnostic Features

• Tenderness of costochondral joints on palpation is characteristic 2
• Pain localized to costochondral junction without trauma, bruising, swelling, or deformity supports this diagnosis 1
• Chest radiography has limited sensitivity for costochondral abnormalities but may be useful to exclude other pathology 1

Treatment Approach

• Treat with anti-inflammatory medications if cardiac testing is negative 2
• Provide reassurance about the benign nature of the condition 2

Lower Back and Thigh Pain Assessment

The lower right back pain and left posterior thigh pain require evaluation for musculoskeletal causes versus referred pain from other systems.

Reassuring Features

• Absence of radiation, tingling, numbness, or lower extremity weakness makes radiculopathy or spinal cord pathology unlikely 7
• Gradual onset and relief with rest suggest mechanical/musculoskeletal origin 1
• No history of trauma or fall reduces concern for fracture 1

Clinical Approach

• These symptoms are likely musculoskeletal in nature given the absence of neurological deficits 7
• Consider myofascial pain or muscle strain as potential etiologies 1
• If symptoms persist or worsen, consider imaging to exclude other pathology 1

Management Algorithm

1. Immediate cardiac evaluation: ECG, troponin, chest radiograph to exclude life-threatening causes 1, 2

2. If cardiac workup negative:

   • Diagnose costochondritis and treat with NSAIDs 2
   • Obtain urinalysis and urine culture for dysuria 4, 5
   • Initiate empiric antibiotic therapy for uncomplicated cystitis with short-course antimicrobial regimen 5

3. For back and thigh pain:

   • Treat conservatively with rest, NSAIDs, and activity modification 1
   • Reassess if symptoms persist or neurological signs develop 7

Critical Pitfalls to Avoid

• Do not assume reproducible chest wall tenderness excludes serious cardiac pathology, as 7% of such patients have acute coronary syndrome 2
• Do not rely on nitroglycerin response as a diagnostic criterion, as relief does not confirm or exclude myocardial ischemia 1, 2
• Do not treat dysuria empirically without urinalysis in patients with multi-system complaints, as this may miss alternative diagnoses 4
• Do not dismiss the multi-system presentation as purely musculoskeletal without objective testing to exclude serious pathology 1, 7