Classifying and Treating an initial Clostridium difficile Infection

There are no accepted guidelines for defining the severity of C. diff. Below I share a few found in the literature.

The following table is from: https://gi.org/guideline/diagnosis-and-management-of-c-difficile-associated-diarrhea-and-colitis/

C. Diff. Infection severity scoring system and summary of recommended treatments
Severity	Criteria	Treatment	Comment
Mild-to-moderate disease	Diarrhea plus any additional signs or symptoms not meeting severe or complicated criteria	Metronidazole 500mg orally three times a day for 10 days. If unable to take metronidazole, vancomycin 125 mg orally four times a day for 10 days	If no improvement in 5–7 days, consider change to vancomycin at standard dose (vancomycin 125mg four times a day for 10 days)
Severe disease	Serum albumin <3g/dl plus ONE of the following: WBC ≥15,000 cells/mm³, Abdominal tenderness	Vancomycin 125 mg orally four times a day for 10 days
Severe and complicated disease	Any of the following attributable to CDI: Admission to intensive care unit for CDI Hypotension with or without required use of vasopressors Fever ≥38.5 °C Ileus or significant abdominal distention Mental status changes WBC ≥35,000 cells/mm³ or <2,000 cells/mm³ Serum lactate levels >2.2 mmol/l End-organ failure (mechanical ventilation, renal failure, etc.)	Vancomycin 500 mg orally four times a day and metronidazole 500 mg IV every 8 h, and vancomycin per rectum (vancomycin 500 mg in 500 ml saline as enema) four times a day	Surgical consultation suggested
Recurrent CDI	Recurrent CDI within 8 weeks of completion of therapy	Repeat metronidazole or vancomycin pulse regimen	Consider FMT after 3 recurrences

CDI, Clostridium difficile infection; FMT, fecal microbiota transplant; IV, intravenous; WBC, white blood cell.

Table from Gastroenterology. 2009 May;136(6):1899-912

Classification and Treatment of Initial *C difficile* Infection
Severity	Clinical manifestations	Treatment
Carrier	No discernible clinical symptoms or signs	No treatment is indicated
Mild to moderate	Mild diarrhea < 12 stools/day Afebrile Mild-to-moderate abdominal discomfort or tenderness. Nausea with rare or absent vomiting. With or with hospitalization Not in intensive care unit Dehydration Leukocytosis <20,000 BUN or creatinine above baseline	Discontinuation of predisposing antibiotics Hydration Monitor clinical status Isolation Consider probiotics Oral metronidazole 500 mg 3 times daily or intravenous metronidazole 500 mg 3 times daily if not tolerating oral intake Oral vancomycin 125 mg 4 times daily if intolerant of metronidazole
Severe	Severe or bloody diarrhea > 12 stools/day Pseudomembranous colitis Severe abdominal pain Nausea or vomiting Ileus Temperature >38.9°C Age > 60 years In the intensive care unit Leukocytosis > 20,000 Albumin < 2.5mg/dL Renal failure	As above plus: Oral vancomycin 125 mg 4 times daily Consider addition of intravenous metronidazole 500 mg 3 times daily
Fulminant	Toxic megacolon Peritonitis Albumin < 2.5mg/dL Renal failure Respiratory distress Hemodynamic instability	As above plus: Surgical consultation Oral vancomycin 125 mg 3 times daily and intravenous metronidazole 500 mg 3 times daily Consider IVIG