What physical exam and medical history should I focus on for a patient with a suspected infection and recent chemotherapy regimen, including FOLFIRINOX (fluorouracil, irinotecan, oxaliplatin) and G-CSF (Granulocyte-Colony Stimulating Factor) support?

Physical Examination and History for Suspected Infection in Chemotherapy Patients

Critical Physical Examination Components

Focus your physical examination on identifying sources of infection and assessing hemodynamic stability, with particular attention to skin/soft tissue, mucous membranes, catheter sites, and respiratory status. 1

Vital Signs and General Assessment

• Measure complete vital signs including temperature, blood pressure, heart rate, respiratory rate, and oxygen saturation to assess for sepsis or hemodynamic instability 1, 2
• Perform orthostatic vital signs if the patient reports dizziness or appears volume depleted 2
• Assess performance status using ECOG criteria, as this impacts treatment decisions and prognosis 1

Skin and Soft Tissue Examination

• Examine all skin surfaces systematically for ecthyma gangrenosum (painless erythematous papules that progress to painful necrotic lesions within 24 hours, preferentially between umbilicus and knees), which suggests Pseudomonas or other gram-negative infection 1
• Inspect for cellulitis, abscesses, or necrotizing fasciitis, noting any rapidly progressive changes, as neutropenic patients more frequently develop polymicrobial or gram-negative necrotizing infections 1
• Examine perianal area carefully for fissures, abscesses, or cellulitis, which are common infection sources in neutropenic patients 1

Catheter and Line Assessment

• Thoroughly inspect all central venous catheter sites for erythema, warmth, tenderness, or purulent drainage, as catheter-associated infections are common 1
• Palpate along catheter tunnels for tenderness or induration suggesting tunnel infection 1

Mucous Membrane Examination

• Examine oral cavity meticulously for mucositis, ulcerations, thrush, or periodontal infections, as chemotherapy-induced mucosal damage increases infection risk 1
• Assess pharynx and tonsils for erythema, exudates, or ulcerations 1

Respiratory Examination

• Auscultate all lung fields for crackles, wheezes, or decreased breath sounds suggesting pneumonia 1
• Assess for signs of respiratory distress including tachypnea, use of accessory muscles, or hypoxemia 1
• Note any cough characteristics (productive vs. non-productive) 1

Lymph Node Assessment

• Palpate all lymphoid regions (cervical, supraclavicular, axillary, inguinal) for adenopathy 1, 2

Abdominal Examination

• Palpate abdomen for tenderness, organomegaly, or masses, as intra-abdominal infections or typhlitis can occur 1
• Assess for peritoneal signs (rebound, guarding) 1

Neurological Assessment

• Perform focused neurological examination if the patient has headache, altered mental status, or focal symptoms, as CNS infections or complications can occur 1
• Test for nystagmus, slurred speech, and dysmetria if the patient received high-dose cytarabine, as cerebellar toxicity is a concern 1

Essential History Components

Chemotherapy-Specific History

• Document exact chemotherapy regimen received (FOLFIRINOX includes fluorouracil, irinotecan, oxaliplatin) with dates and doses 3
• Determine timing of last chemotherapy cycle relative to symptom onset, as early-onset fever (<10 days) versus late-onset has different implications 1
• Confirm G-CSF administration (timing, primary vs. secondary prophylaxis) as this affects neutrophil recovery patterns 1, 4
• Review cumulative chemotherapy doses and any prior dose modifications 3

Infection Risk Assessment

• Quantify duration and depth of neutropenia (ANC <500/μL, especially <100/μL), as profound neutropenia increases infection risk 1
• Document any prior episodes of febrile neutropenia and causative organisms 1
• Assess for antimicrobial prophylaxis (antibacterial, antifungal, antiviral) currently being used 1

Symptom Characterization

• Characterize fever pattern (onset, duration, maximum temperature, response to antipyretics) 1
• Document associated symptoms: chills, rigors, sweats, cough, dyspnea, diarrhea, dysuria, abdominal pain, headache, skin changes 1
• Assess for bleeding manifestations (petechiae, purpura, mucosal bleeding) suggesting thrombocytopenia 1

Recent Exposures and Procedures

• Document recent procedures (central line placement, dental work, endoscopy, surgery) 1
• Assess recent antibiotic exposures and response to prior antimicrobial therapy 1
• Inquire about sick contacts and environmental exposures 2

Comorbidities and Baseline Function

• Review cardiac history given anthracycline exposure risk and potential for cardiac complications 1
• Document baseline renal function, as high-dose cytarabine requires dose adjustment with renal insufficiency 1
• Assess for diabetes, COPD, or other conditions affecting infection risk 1

Medication Review

• List all current medications including antimicrobials, anticoagulation, immunosuppressants 1
• Document any recent steroid use which may mask inflammatory signs 1

Common Pitfalls to Avoid

• Do not assume absence of localizing symptoms excludes serious infection in neutropenic patients, as inflammatory responses are blunted 1
• Do not overlook subtle skin changes that may represent early ecthyma gangrenosum or necrotizing infection 1
• Do not delay examination of perianal area due to patient discomfort, as this is a critical infection source 1
• Do not forget to assess for ARDS or respiratory deterioration in patients receiving G-CSF during neutrophil recovery 1