**Author details**

As **Table 3**, the initial step in the evaluation of chronic diarrhoea is to send stool off for assessment of stool osmotic gap. This allows the differentiation of chronic watery diarrhoea into secretory (faecal osmotic gap <50 mOsm per kg) and osmotic (faecal osmotic gap >125 mOsm per kg). Watery diarrhoea is likely osmotic because the symptoms caused by malabsorption and

Physical examination is important and provide important clue into the diagnosis of chronic diarrhoea [45]. Recent weight loss and lymphadenopathy could result from chronic infection or malignancy. Eye finding such as episcleritis or exophthalmia suggests that the diarrhoea is caused by inflammatory bowel disease (IBD) and hyperthyroidism, respectively. The signs that are directly attributed to giardiasis are limited; in fact, there are no specific signs that direct the clinician to suspect giardiasis. However, signs such as anaemia (iron deficiency anaemia), nail pallor, glossitis and koilonychias suggest that there is malabsorption of iron,

Stool microscopy is an important initial test to identify *giardia* trophozoite, blood and faecal leukocyte. Faecal pH test can be done quickly in most centre along with faecal electrolyse to help distinguish secretory diarrhoea from osmotic diarrhoea. A complete blood count, albumin level, erythrocyte sedimentation rate, liver function testing, thyroid-stimulating hormone level and electrolyte levels are important and help exclude other diagnosis such as hyperthyroidism, inflammatory bowel disease, chronic pancreatitis as well as chronic hepatitis [45]. **Figure 2** shows the diagnosis algorithm in managing patients with chronic diarrhoea [45].

*Giardia* is one of the most common water-borne diseases in Thailand and in the world. The finding is particularly more in the area with poor sanitation and unsafe water. In Thailand, the parasites are found in lake and canal but also in water supplies, swimming pool and well. *Giardia* can be transmitted through food and person-person contact. *Giardia* infection usually will be cleared within a few weeks; however, patients might still have intestinal symptoms

The mechanisms of malabsorption in giardiasis are still obscured. The mechanism such as epithelial dysfunction, villi malformation and immunological disordered has been postulated to be an important cause of malabsorption and maldigestion in giardiasis. It is important to recognise symptoms of chronic giardiasis because this may lead to long-term disability.

Infection with *Giardia* duodenalis may remain asymptomatic or cause acute or chronic diarrhoea. In addition to the intestinal presentation, patient may also develop extra-intestinal complication such as impairment of cognitive function, muscular complications and nutritional

and cause such as *giardia*, especially in region such as Thailand, should be identified.

maldigestion.

34 Current Topics in Giardiasis

**5.2. Physical examinations**

**5.3. Laboratory diagnosis**

**6. Conclusion**

even after the infection is cleared.

Amornnivit Kanokwanvimol

Address all correspondence to: godsmack186@gmail.com

Thammasat University Hospital, Bangkok, Thailand
