Can Immune Thrombocytopenic Purpura (ITP) cause diarrhea?

Immune Thrombocytopenic Purpura (ITP) and Diarrhea

ITP itself does not directly cause diarrhea as it is primarily a hematologic disorder characterized by low platelet counts, but diarrhea may occur as a side effect of ITP treatments or due to associated conditions. 1

Relationship Between ITP and Gastrointestinal Symptoms

Primary ITP and Diarrhea

• ITP is characterized by destruction of antibody-coated platelets in the reticuloendothelial system, leading to thrombocytopenia 2
• The classic manifestations of ITP include:
  • Petechiae
  • Easy bruising
  • Mucosal bleeding (gums, nose)
  • Blood in urine or stool
  • In severe cases, intracranial hemorrhage 1
• Diarrhea is not listed among the typical clinical manifestations of primary ITP in any of the major guidelines 1

Secondary Causes to Consider

When a patient with ITP presents with diarrhea, consider these possibilities:

1. Treatment-related side effects:

   • Corticosteroids (first-line treatment for ITP) can cause gastrointestinal distress and ulcers 1
   • IVIg may cause diarrhea as a side effect 1

2. Associated autoimmune conditions:

   • ITP can co-occur with inflammatory bowel disease (IBD) as a rare extraintestinal manifestation 3, 4, 5
   • Case reports document patients with both ulcerative colitis and ITP, where colectomy for treatment of UC sometimes resolved the ITP 3, 5

3. Immune checkpoint inhibitor therapy:

   • In patients receiving immunotherapy, immune-related adverse events can include both ITP and colitis/diarrhea 1
   • Diarrhea is reported in up to 54% of patients treated with anti-CTLA-4 antibodies and approximately 19% with anti-PD-1 monotherapy 1

Clinical Approach to ITP Patients with Diarrhea

Evaluation

When an ITP patient presents with diarrhea:

• Rule out gastrointestinal bleeding as a cause of the diarrhea (especially important in thrombocytopenic patients)
• Assess medication side effects, particularly corticosteroids and IVIg 1
• Consider evaluation for inflammatory bowel disease, especially if diarrhea is persistent or contains blood and mucus 3, 4
• In patients on immunotherapy, evaluate for immune-related colitis 1

Management

Management depends on the identified cause:

• For medication-related diarrhea:

  • Consider dose adjustment or alternative ITP treatments
  • Supportive care with antidiarrheal medications if appropriate

• For IBD-associated ITP:

  • Treat the underlying IBD, which may improve both conditions 4
  • In medically refractory cases, colectomy has been reported to resolve both IBD and ITP in some cases 3, 5

• For immune checkpoint inhibitor-related diarrhea/colitis:

  • Follow established guidelines for immune-related adverse events
  • May require holding immunotherapy and initiating corticosteroids 1

Important Clinical Pearls

• The presence of diarrhea in an ITP patient should prompt investigation for secondary causes rather than being attributed to ITP itself
• Diarrhea with blood in an ITP patient requires urgent evaluation to distinguish between gastrointestinal bleeding due to thrombocytopenia versus inflammatory conditions like IBD
• When ITP and diarrhea co-occur, consider the possibility of a shared immune dysregulation mechanism, especially in patients with other autoimmune manifestations 4
• In patients receiving immune checkpoint inhibitors who develop both thrombocytopenia and diarrhea, both conditions may be immune-related adverse events requiring prompt management 1

Remember that while ITP itself does not cause diarrhea, the thorough evaluation of diarrhea in ITP patients is essential to identify treatable causes and prevent complications in these already vulnerable patients.