Giardiasis differential diagnosis

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Yazan Daaboul, M.D.; Serge Korjian M.D.

Giardiasis must be differentiated from other causes of abdominal pain, bloating, acute or chronic diarrhea, and weight loss, such as other infectious causes of gastroenteritis, including bacterial, viral, fungal, and parasitic pathogens, in addition to non-infectious causes, including acute pancreatitis, appendicitis, bowel obstruction, diverticulitis, drug reaction, hyperthyroidism, inflammatory bowel disease, celiac disease, lactose intolerance, Whipple disease, tropical sprue, and lymphoma.

• Giardiasis must be differentiated from other causes of acute or chronic diarrhea, bloating, abdominal pain, and fever (less common).
• Differential diagnosis of giardiasis includes the following:

• Bacterial infections (e.g. E. coli infection, shigellosis, salmonellosis, C. jejuni infection)
• Viral infections (e.g. norovirus, rotavirus, astrovirus, HIV)
• Fungal infections (e.g. Candida spp.)
• Parasites (E. histolytica, Cryptosporidium spp., Cyclospora)

The following are the non-infectious differential diagnoses of E. coli enteritis:

• Acute pancreatitis
• Adrenal insufficiency and Waterhouse-Friedrichsen syndrome
• Allergy (e.g. insect bite allergy or anaphylaxis)
• Appendicitis
• Bowel obstruction
• Celiac disease
• Diverticulitis
• Drug reaction (e.g. antimicrobial agents, antihypertensive therapy, chemotherapy, anticonvulsants)
• Endometriosis
• Familial Mediterranean fever
• Gastrointestinal perforation
• Hyperthyroidism
• Ileus
• Inflammatory bowel disease (Crohn’s disease or ulcerative colitis)
• Intussusception
• Ischemic colitis
• Ketoacidosis
• Lactose intolerance
• Lymphoma
• Mesenteric ischemia
• Necrotizing enterocolitis
• Ogilvie syndrome
• Peritonitis
• Pneumonia
• Poisoning and toxicity (e.g. carbon monoxide poisoning, organophosphate poisoning, digitoxin toxicity)
• Ruptured abdominal aortic aneurysm
• Spider bite
• Tropical sprue
• Volvulus
• Urinary tract infection
• Whipple disease

To view a comprehensive list of abdominal pain differential diagnoses, click here.
To view a comprehensive list of diarrhea differential diagnoses, click here.

Giardiasis must be differentiated from other diseases that may cause chronic diarrhea, weight loss, and abdominal pain especially in immunocompromised patients.