You are the GI fellow consulted to see a 17 year old white male with a chief complaint of diarrhea & bright red blood per rectum (BRBPR).
The patient was in his usual state of health until he experienced sudden-onset diffuse, crampy abdominal pain and diarrhea roughly 36 hours ago. He experienced 3-5 episodes of loose, bloody stools at home before seeking emergency care, and had several additional episodes of bloody diarrhea in the emergency department before being transferred to the ICU for monitoring, IV hydration and empiric antibiotic therapy with metronidazole (Flagyl). His abdominal pain is intermittent, 8/10 in severity, does not radiate, and is somewhat relieved during defecation but is worst before and after he moves his bowels; it is not related to time of day or food intake.
Three days prior to admission, the patient underwent surgical extraction of his wisdom teeth without complication, and completed 3 days of antibiotic therapy with amoxicillin.
Review of Systems:
- Positive for: general malaise, abdominal pain, diarrhea, BRBPR, dizziness upon standing, anorexia.
- Negative for: nausea, vomiting, fever, chills, weight loss, rashes, foul smelling/malodorous stools, recent travel outside the area, sick contacts, changes in diet, contact with recently-hospitalized persons or persons living in a nursing home or rehab environment.
Medical History: None.
Surgical History: Wisdom tooth extraction, 3 days prior to admission.
Family History: No siblings. Mother & father are middle-aged & in good general health. One uncle with colon cancer (>50 years), father’s uncle has a history of Crohn’s disease.
Social History: The patient is a high school junior and works as a lifeguard every summer. He frequents various pools, and part of his responsibilities include cleaning restrooms. The patient admits to an episode of recreational swimming in a freshwater lake at a nearby state park 2 weeks prior to admission. He denies the use of tobacco, alcohol, and illicit drugs.
Physical Exam: The patient is tall and thin, but well-developed. Vital signs are stable and have been within normal limits since admission.
- HEENT: pupils are equal & reactive to light, extraocular movements are intact, the sclerae are anicteric and there is no jaundice; neck full range of motion, no masses, no lymphadenopathy.
- Cardiovascular: bradycardia is noted, rate 52, normal rhythm; extremities are warm and capillary refill is <2 seconds.
- Respiratory: symmetric chest wall rise & fall; lungs are clear to auscultation bilaterally.
- Abdominal: normal to inspection, symmetric, non-distended; bowel sounds are somewhat increased, and there is tenderness to palpation most prominent in the right & left lower quadrants; no rebound tenderness or guarding.
- Skin/extremities: no rash, edema, clubbing, or cyanosis.
Significant Labs & Studies: An EKG performed in the emergency department shows sinus bradycardia. Hemoglobin – 14.8 (down from 16.3 at admission), WBCs 12.7 (86% PMNs; down from 14.2 at admission), Complete metabolic panel & urinalysis are within normal limits, CT imaging from admission is included below.
The decision to continue IV Flagyl is made & the patient continues to do well overnight, with only one additional episode of BRBPR. He is transferred to the general medical floor, and scheduled for flexible sigmoidoscopy with sedation for the following day. Stool studies eventually reveal many WBCs, a mix of enteric organisms, a negative PCR for C. difficile, and cultures are negative for E. coli O157:H7, Salmonella spp., Shigella spp., Yersinia spp.; ova & parasite screening is also nondiagnostic.
Sigmoidoscopy reveals, beginning at around the splenic flexure and worsening proximally, an inflamed and friable colon without distinctive/pathognomonic features (a representative picture is included below); the rectosigmoid colon is spared. Biopsies are taken, but the pathology report is pending.
What is the most likely diagnosis?
- A) Food poisoning
- B) Microscopic colitis
- C) Crohn’s disease
- D) Ulcerative colitis
- E) Infectious colitis
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