What is the best course of treatment for a male patient with abdominal pain, loose watery stools, and increased thirst after eating a burger, who has lab results showing leukopenia, neutrophilia, pyuria, microhematuria, and pus in feces?

Management of Suspected Invasive Bacterial Enterocolitis with Systemic Complications

Immediate Hospitalization and Aggressive Management Required

This patient requires immediate hospital admission for IV antibiotics, aggressive fluid resuscitation, and urgent imaging due to the paradoxical finding of leukopenia with neutrophilia, which indicates severe infection with bone marrow exhaustion—a red flag for neutropenic enterocolitis or overwhelming bacterial sepsis. 1

Critical Recognition of High-Risk Features

The constellation of findings indicates life-threatening invasive bacterial infection requiring immediate intervention:

• Leukopenia with neutrophilia represents bone marrow exhaustion from overwhelming sepsis, not simple gastroenteritis, and carries significant mortality risk 1
• Pus in feces confirms invasive bacterial enterocolitis requiring antibiotic therapy, distinguishing this from viral or non-invasive bacterial diarrhea 1
• Pyuria and microhematuria suggest either concurrent urinary tract infection or systemic inflammatory response syndrome affecting multiple organ systems 1
• Persistent increased thirst despite ORS administration indicates ongoing fluid losses and inadequate rehydration, requiring IV fluid resuscitation 1

Immediate Diagnostic Workup (Do Not Delay Treatment)

Mandatory Imaging

• Abdominal CT scan with IV contrast must be obtained emergently to evaluate for neutropenic enterocolitis, bowel wall thickening (>10mm indicates 60% mortality risk), perforation, or abscess formation 1, 2

Stool Studies (Obtain Before Antibiotics When Possible)

• Bacterial cultures for Salmonella, Shigella, Campylobacter, E. coli (including O157:H7), and Yersinia 1, 3
• C. difficile toxin assay 1
• The presence of 35-40 fecal leukocytes per field with occult blood confirms inflammatory bacterial process 3

Laboratory Monitoring

• Complete blood count with differential to track neutrophil recovery 1
• Comprehensive metabolic panel to assess electrolytes (particularly potassium and sodium) and renal function 3
• Blood cultures if fever or signs of sepsis develop 1

Empirical Antibiotic Therapy (Start Immediately)

Initiate broad-spectrum IV antibiotics immediately without waiting for culture results:

• First-line options: Piperacillin-tazobactam, imipenem-cilastatin, or meropenem 1
• These agents provide coverage for Pseudomonas, Staphylococcus aureus, E. coli, group A Streptococcus, and anaerobes 1
• Continue IV antibiotics until neutrophil count recovers or clinical improvement with resolution of fever and ability to tolerate oral intake 1
• Typical duration is 7-10 days, adjusted based on culture results and susceptibility data 1

Critical Antibiotic Caveat

• Do NOT administer antibiotics if E. coli O157:H7 is confirmed, as this can precipitate hemolytic uremic syndrome 3
• If Salmonella non-typhoidal is confirmed, antibiotics are only indicated for high-risk groups (immunocompromised, signs of systemic dissemination, or severe disease) 3

Aggressive Fluid and Electrolyte Management

• IV fluid resuscitation is mandatory given inadequate response to oral rehydration 1
• Monitor hydration status through skin turgor, mental status, mucous membranes, capillary refill, and vital signs 3
• Correct electrolyte abnormalities, particularly potassium (40-80 mEq/day divided doses if oral intake tolerated) and sodium, guided by laboratory values 1, 3
• Repeat electrolyte tests in 24-48 hours to confirm correction 3

Bowel Rest and Supportive Care

• NPO status (nothing by mouth) with nasogastric decompression may be necessary to reduce mechanical stress on inflamed bowel and prevent complications 1, 2
• Bowel rest serves dual purposes: reducing pain and preventing complications such as perforation or toxic megacolon 2

Pain Management Strategy (Critical Pitfalls to Avoid)

Avoid opioids and antidiarrheal agents, as these can precipitate toxic megacolon, ileus, and mask clinical deterioration in this high-mortality condition (29.5% mortality with positive radiologic findings) 2

• Anticholinergic, antidiarrheal, and opioid agents worsen ileus and prevent recognition of perforation 2
• Acetaminophen (paracetamol) may be used cautiously for mild-to-moderate pain, though this complicates fever monitoring 2
• Nasogastric decompression relieves distension-related pain without masking peritoneal signs 2

Mandatory Surgical Consultation

Obtain immediate surgical consultation for evaluation of potential surgical indications 1:

• Signs of perforation or free intraperitoneal air 1, 2
• Abscess formation 1
• Clinical deterioration despite aggressive medical therapy 1, 2
• Persistent gastrointestinal bleeding after correction of coagulopathy 2
• Bowel wall thickening >10mm on CT (60% mortality risk) 2

Serial Monitoring Requirements

• Serial abdominal examinations are mandatory to detect complications requiring surgical intervention 2
• Clinical signs may be minimal despite catastrophic pathology due to neutropenia, requiring heightened vigilance 2
• Monitor frequency of bowel movements, stool characteristics, temperature, vital signs, and hydration status 3
• Regular reassessment prevents missing toxic dilatation development 2

Adjustment Based on Culture Results

• Narrow antibiotic spectrum based on culture results and susceptibility data when available 1
• If Shigella is confirmed, treat with azithromycin or ciprofloxacin (if susceptible) to reduce duration and fecal shedding 3
• If Campylobacter is suspected based on local resistance patterns, azithromycin 500 mg on day 1, then 250 mg/day for 4 days is preferred over quinolones 3