Giardiasis management

Definition

Giardiasis is an infestation of the upper small intestine caused by the flagellated protozoan Giardia lamblia (Giardia intestinalis). The organism produces cytopathic effects that lead to malabsorption and diarrhoea. It is more common in immunocompromised individuals and is usually acquired through ingestion of contaminated water.

Clinical presentation

• Crampy abdominal pain

• Chronic diarrhoea

• Steatorrhoea

• Weight loss

Investigations

• Evidence of Giardia intestinalis trophozoites or cysts on serial stool examination from three samples

• Serological evidence of Giardia intestinalis antigen or antibody

• Evidence of Giardia intestinalis in duodenal aspirates or biopsy specimens

Pharmacological treatment

Metronidazole

• Dose: 400–800 mg

• Route: Oral (PO)

• Frequency: Every 8 hours

• Duration: 5 days

OR

Tinidazole

• Dose: 2 g

• Route: Oral (PO)

• Frequency: Once daily

• Duration: 3 days