Giardiasis

WHAT IS IT?

Giardiasis refers to a condition that is characterized by a GI infection with the parasitic protist Giardia lamblia.

Visual appearance of Giardia lamblia on microscopy (source)
Visual appearance of Giardia lamblia trophozoite on microscopy. Note the “owl’s-eye” appearance seen on the organisms. (source)
WHY IS IT A PROBLEM?

This protists is a parasite that often causes diarrhea in patients.

WHAT MAKES US SUSPECT IT?

Risk factors: camper/hiker

Diarrhea that is foul smelling, watery, and fatty in nature is typical for this condition.

  • Can be associated with bloating/flatus.
HOW DO WE CONFIRM A DIAGNOSIS?

Stool analysis (O&Pcan reveal the presence of trophozoites or cysts in patient feces.

Giardia lamblia cyst seen on microscopy (source)
Giardia lamblia cyst seen on microscopy (source)
HOW DO WE TREAT IT?

Metronidazole is the preferred anti-protozoal medication used to treat infection with this organism.

HOW WELL DO THE PATIENTS DO?

Patients who are treated appropriately will recover fully form this infection.

WAS THERE A WAY TO PREVENT IT?

Avoiding ingestion of contaminated water is an important step in preventing this condition.

WHAT ELSE ARE WE WORRIED ABOUT?

X-linked agammaglobulinemia can present with giardiasis infections due to a lack of IgA

Giardiasis can be characterized as one of the opportunistic infections in patients with AIDS

OTHER HY FACTS?

IgA immunoglobulins help protect against gut infections like this one. Patients with repeat giardiasis are suspicious for IgA deficiency.

FURTHER READING

DynaMed

UpToDate

Page Updated: 06.25.2016