2025 – PAGE 331 – INFECTIOUS DISEASES

YERSINIA ENTEROCOLITICA

Ingestion of raw pork or unpasteurized milk resulting in fever and diarrhea should set off alarms about Yersinia enterocolitica. This can also cause PSEUDOAPPENDICITIS, ERYTHEMA NODOSUM, and a REACTIVE ARTHRITIS. It’s a self-limited illness, so there’s no need to treat.

• MNEMONIC: Imagine an angry neighbor with a deep Southern accent saying, “YER SON is a menace. He tossed RED CHITLINS on my yard that had an APPENDIX hangin’ off of it!”
  • KEY: YER SON = your son = Yersinia. Chitterlings are made of pork intestines and are more commonly eaten in the South. If it’s said with a strong Southern accent, it’s pronounced, “CHIT-LINS.” APPENDIX = appendicitis.
• MNEMONIC: (IMAGE) www.pbrlinks.com/YERSINIA1

CLOSTRIDIUM PERFRINGENS

Clostridium perfringens causes a non-bloody diarrhea fairly quickly after ingestion of RAW TURKEY or RAW BEEF. Onset is at about 10 hours or later, with quick onset due to preformed toxins. Very similar to B. cereus food poisoning, it can involve any protein-containing food that is inadequately cooked, left outside or allowed to cool for too long. Treatment is supportive.

• MNEMONIC: Imagine a macho man’s man bragging about his stomach. He says, “You C, I PREFER to eat mystery MEAT out of a carved-out BOWLING BALL that I’ve turned into a bowl.”
  • KEY: PREFER = C. perfringens. MEAT = raw meat, like beef or turkey. BOWLING BALL = 10 = approximate time of onset.

CLOSTRIDIOIDES DIFFICILE (AKA C. DIFF)

For Clostridioides difficile (AKA C. diff), look for diarrhea (> 3 loose bowel movements within 24 hours) that’s associated with mucus and probably BLOOD. They would almost have to give you a history of recent antibiotic use or “a recent illness.” The illness may have required an antibiotic, such as CLINDAMYCIN, a beta lactam, or a cephalosporin. Diagnose by sending multiple stool samples looking for the Clostridioides difficile TOXIN, or a single stool sample looking for a positive nucleic acid amplification test (NAAT or PCR). For treatment, start by discontinuing the antibiotic that caused the C. diff infection. Provide supportive care to address dehydration and electrolyte losses. The agent used to treat the C. diff infection will depend on the severity of the disease and whether this is an initial episode or a recurrence.

• Mild/Moderate Disease (afebrile, diarrhea, possibly some abdominal pain): Use oral metronidazole, vancomycin, or fidaxomicin
• Severe Disease (profuse diarrhea, abdominal pain, abdominal distension, leukocytosis, hypotension): Use oral vancomycin
• First Recurrence: Retreat with the same medication
• Second Recurrence: Use oral vancomycin

PEARLY DIARRHEA REVIEW

• BLOODY DIARRHEA REVIEW: Salmonella, Shigella, Campylobacter, EHEC, EIEC, and possibly Clostridioides difficile.
• TREATMENT FOR ACUTE DIARRHEAS: If you had to take a guess, ceftriaxone would be a good guess for those needing treatment. Macrolides are good second options for the pediatric exam, and trimethoprim-sulfamethoxazole could be a third guess. For Clostridium, use METRONIDAZOLE or VANCOMYCIN.
  • SALMONELLA TYPHI: Rose spots. Ceftriaxone or Cefotaxime.
  • SHIGELLA: Profuse bloody diarrhea. Seizures. Rectal prolapse. Tenesmus. Ceftriaxone/Ciprofloxacin for the sicker patients. For milder cases use oral azithromycin.
  • CAMPYLOBACTER: Crampy pain. Erythromycin.
  • CLOSTRIDIOIDES DIFFICILE: Metronidazole or Vancomycin.