clostridioides%20difficile%20infection
CLOSTRIDIOIDES DIFFICILE INFECTION
Treatment Guideline Chart
Clostridioides (formerly Clostridium) difficile infection is commonly associated with antibiotic treatment and is one of the most common nosocomial infections.
Symptoms usually start on days 2-3 of antibiotic treatment, but may also occur up to 8-12 weeks after discontinuation of antibiotics.
Discontinuation of antibiotics may be the only measure needed for patients with only mild diarrhea, no fever, no abdominal pain nor a high WBC count.
Cessation of antibiotics allows for reconstitution of the normal colonic microflora and markedly reduces risk of recurrence.

Clostridioides%20difficile%20infection Diagnosis

Laboratory Tests

  • Submitted stool specimens which are formed should not be used for laboratory testing  
    • There should be no recent initiation of enteral feeding or laxative use in the past 2 days 
  • When restrictions on sample submission are not implemented, multistep testing is recommended over single-step nucleic acid amplification tests (NAATs)   
  • Patients who are unable to produce stool specimens (eg those with ileus or toxic megacolon) may submit perirectal swabs for polymerase chain reaction testing 

Enzyme-Linked Immunoassay for Toxin 

  • Most common test used to detect C difficile toxins A and B
  • Has moderate specificity, rapid turnaround time (TAT), and is inexpensive but is not used alone due to its low sensitivity
    • Results are available within 2-6 hours
  • The test may need to be repeated in patients who initially had negative test results, but in whom C difficile infection is highly suspected

Glutamate Dehydrogenase (GDH)

  • Detects C difficile common antigen but does not differentiate between toxigenic and non-toxigenic strains 
  • Used as a screening tool for C difficile infection detection with good sensitivity but low specificity, has a rapid TAT, and is widely available and inexpensive

Nucleic Acid Amplification Tests (NAATs)

  • Detects C difficile toxin genes by identifying toxigenic organisms in the stool  
  • May be used alone or as part of a multistep testing when toxin and GDH tests are indeterminate 
    • False positives are of concern in single-step testing
  • Has high sensitivity but low to moderate specificity

Stool Cytotoxin Assay

  • Gold standard for the diagnosis of C difficile-mediated infection
  • Highly sensitive and specific
  • Disadvantages: Expensive, results only available after 24-48 hours, requires a tissue culture facility

Stool Culture

  • Not helpful in diagnosis because the test is not specific for pathogenic toxin-producing strains of C difficile
  • May be used for epidemiological typing and strain characterization

Other Laboratory Tests

White Blood Cell (WBC) Count

  • May show leukocytosis 

Blood Chemistry 

  • Eg serum creatinine, albumin, electrolytes 
  • May show electrolyte imbalance and evidence of dehydration
  • Serum lactate may serve as indicator of disease severity before performing surgical treatment

Stool Exam

  • Grossly bloody stools are rare, but occult blood may be present in severe colitis

Imaging

Endoscopy

  • Indications
    • If there is a delay or difficulty in lab tests for C difficile 
    • When lab exams for C difficile are negative but suspicion of the infection remains high 
    • When there is a need for rapid diagnosis, ie fulminant disease
    • In a patient who cannot produce stool because of ileus
    • As part of testing for other colonic diseases
  • The pseudomembranous finding on bowel mucosa or on examination of a biopsy sample is pathognomonic of C difficile colitis
  • Findings may be normal in mild disease or may show only nonspecific colitis in moderate cases
  • Sigmoidoscopy alone may not detect abnormalities when lesions are confined to the right colon
  • Colonoscopy and sigmoidoscopy may be contraindicated in patients with fulminant colitis because of the risk of perforation

Computed Tomography (CT) Scan

  • Not useful in confirming the diagnosis of early or mild colitis
  • May be used as a confirmatory procedure for suspected C difficile infection when thickening of colonic mucosa is seen
  • Can quickly diagnose fulminant disease
    • Abdominal and pelvic CT scan may be done in patients with complicated infection, ie abdominal distension with signs and symptoms of ileus or toxic megacolon
  • In cases involving the right colon, it may reveal bowel wall edema and inflammation

Classification

Stages of C difficile Infection

Non-severe Infection  

  • Diarrhea with mild abdominal pain and cramping 
  • Dehydration and electrolyte imbalance with mild to moderate infection 
  • Systemic inflammatory response symptoms (eg fever, fatigue)
  • WBC count <15,000/μL and serum creatinine <1.5 mg/dL

Severe Infection 

  • Diarrhea with increased abdominal pain and cramping including systemic inflammatory response symptoms 
  • Hypoalbuminemia <2.5 g/dL, WBC count ≥15,000/μL or serum creatinine >1.5 mg/dL and not caused by pre-existing comorbidities 

Fulminant Infection  

  • Hypotension or shock due to C difficile infection or 
  • Clinical and radiographic evidence of ileus not due to another disease process or toxic megacolon or 
  • Peritonitis on exam, radiographic finding of free air in abdomen and/or 
  • Colonic perforation 

Recurrent Infection 

  • C difficile infection meeting the above diagnostic criteria after initial resolution of symptoms following treatment completion and occurring within 8 weeks of prior episode or after new use of systemic antibiotic
  • 10-30% of patients with C difficile infection will experience a recurrent infection
  • Recurrences are not usually due to development of antibiotic-resistant organisms
    • Usually due to germination of persistent spores in the colon after treatment or reinfection because of reingestion of the pathogen 
  • Risk factors for recurrence include advanced age, severe infection or disease, immunocompromised state and concomitant use of other antibiotics for another infection

Multiply Recurrent Infection 

  • ≥2 recurrences of C difficile infection occurring after the initial episode with each episode meeting the above diagnostic criteria
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