History

Fact Explanation
Steatorrhoea Diarrhea is the most common symptom in acute giardiasis. It is more specifically, a steatorrhoea which contains pale, bulky, frothy, foul smelling stools which are floating in the lavatory pan due to fat content. Giardiasis is caused by Giardia intestinalis, a flagellate protozoan which decreases expression of brush-border enzymes namely disaccharidases and lipase. It causes impairment of carbohydrate and lipid digestion resulting osmotic diarrhea. [1,2,3] Travelers to countries where giardiasis is common, People in child care settings, those who are in close contacts with patients, people who swallow contaminated or untreated water,men who have sex with men have a greater risk of becoming infected. [5]
loose or watery stool Sometimes acute giardiasis can be presented as an abrupt onset of explosive, watery diarrhea. [1,2,3]
Abdominal cramps Due to intestinal peristalsis. This is associated with marked abdominal gurgling, distention and passage of foul gas. [1,2,3]
Weight loss Constitutional symptoms such as weight loss,anorexia, fatigue and malaise are common.Weight loss is due to malabsorption. [1,2.3]
Asymptomatic Asymptomatic carriage is very common. Only 20% becomes symptomatic . [1,4]
Recurrent diarrhea Chronic giardiasis may involve 2 or more years of intermittent diarrhea. Chronic infection in children may present as failure to thrive.Urticaria, cholecystitis, and pancreatitis have been reported with Giardia infections. During this chronic phase, lassitude, headache, and myalgia may occur with continued weight loss, anorexia, and malabsorption. [1,2,4]
References
  1. WOLFE,M.S. et al. Giardiasis[online] ,Clin Microbiol Rev.1992 Jan,5,1,93-100. [viewed 23 April 2014]. Available from: http://cmr.asm.org/content/5/1/93.full.pdf
  2. KUCIK,C.J. et al. Common Intestinal Parasites [online],Am Fam Physician. 2004 Mar,1,69(5),1161-1169. [viewed 23 April 2014]. Available from: http://www.aafp.org/afp/2004/0301/p1161.html
  3. VESY,C.J, W.L.PETERSON, Review article: the management of Giardiasis[online] ,Aliment Pharmacol Ther. 1999 Jul,13(7),843-50. [viewed 23 April 2014]. Available from: 10.1046/j.1365-2036.1999.00537.x
  4. ORTEGA, Y.R. et al. Giardia: overview and update[online], Clin Infect Dis. 1997 Sep,25(3),545-9. [viewed 23 April 2014]. Available from: http://dx.doi.org/10.1002/cyto.b.21048
  5. Parasites - Giardia,Centers for Disease Control and Prevention. July 2012.[viewed 24 April 2014]. Available from: http://www.cdc.gov/parasites/giardia/epi.html

Examination

Fact Explanation
Weight loss Rarely,malabsorption causes loss of weight. [1,2]
References
  1. WOLFE,M.S. et al. Giardiasis [online],Clin Microbiol Rev.1992 Jan,5,1,93-100. [viewed 23 April 2014]. Available from: http://cmr.asm.org/content/5/1/93.full.pdf
  2. VESY,C.J, W.L.PETERSON, Review article: the management of Giardiasis [online],Aliment Pharmacol Ther. 1999 Jul,13(7),843-50. [viewed 23 April 2014]. Available from Doi: 10.1046/j.1365-2036.1999.00537.x

Differential Diagnoses

Fact Explanation
Bacterial diarrhoea [1] Usually watery diarrhea and sometimes blood and mucous diarrhea.Dehydration is common.Responds to antibacterial agents.
Amoebic diarrhoea [1,2] Mostly asymptomatic.Symptoms can range from mild diarrhea to severe dysentery with blood and mucus.
Salmonellosis [1] Most people develop diarrhea, fever, vomiting, and abdominal cramps.Dehydration is often severe.
Viral gastroenteritis [1] Most common cause of watery diarrhea.It is associated with abdominal pain,nausea and vomiting.
Crohn's Disease May present as blood and/or mucous diarrhea, fever and weight loss. [1]
Food Poisoning Presents as abdominal cramps, diarrhea, fever and headache. [1]
References
  1. WOLFE,M.S. et al. Giardiasis [online],Clin Microbiol Rev.1992 Jan,5,1,93-100. [viewed 23 April 2014]. Available from: http://cmr.asm.org/content/5/1/93.full.pdf
  2. KUCIK,C.J. et al. Common Intestinal Parasites [online],Am Fam Physician. 2004 Mar,1,69(5),1161-1169. [viewed 23 April 2014]. Available from: http://www.aafp.org/afp/2004/0301/p1161.html

Investigations - for Diagnosis

Fact Explanation
Microscopic examination of stool Visualization of giardia for cysts & trophozoites in saline (trophozoites) & iodine (cysts) smears. 2-3 stool specimens are examined before excluding giardiasis as cyst excretion is irregular. [1]
Entero test (string test) A gelatin capsule containing a nylon string is swallowed while one end of the string is attached to his or her cheek The string is left in place for several hours while the patient is fasting. The mucus from the string is examined microscopically for trophozoites. [1,2]
Enzyme-linked immunosorbent assay (ELISA) This immunological test has a higher specificity and sensitivity (90%). [1,2] The combined tests of microscopy and ELISA together serve as a 'gold standard' for the diagnosis of Giardiasis. [2]
References
  1. WOLFE,M.S. et al. Giardiasis[online],Clin Microbiol Rev.1992 Jan,5,1,93-100. [viewed 23 April 2014]. Available from: http://cmr.asm.org/content/5/1/93.full.pdf
  2. VESY,C.J, W.L.PETERSON, Review article: the management of Giardiasis[online],Aliment Pharmacol Ther. 1999 Jul,13(7),843-50. [viewed 23 April 2014]. Available from Doi: 10.1046/j.1365-2036.1999.00537.x
  3. EL-NAHAS,H.A. et al. Giardia Diagnostic Methods in Human Fecal Samples: A Comparative Study [online],Cytometry B Clin Cytom. 2013 Jan-Feb,84(1),44-9. [viewed 23 April 2014]. Available from: doi: 10.1002/cyto.b.21048.

Investigations - Fitness for Management

Fact Explanation
Blood urea and serum electrolytes Paromomycin can cause ototoxicity and nephrotoxicity.Toxicity should not be a concern in persons with normal kidneys. However, it should be used with caution in those with impaired renal function. Apart from that diarrhea can cause fluid loss and electrolyte imbalance which can lead to renal dysfunction. [1]
References
  1. GARDNER,T.B, HILL, D.R, Treatment of Giardiasis [online],Clin. Microbiol. Rev. January 2001,14,1, 114-128. [viewed 23 April 2014]. Available from: DOI: 10.1128/CMR.14.1.114–128.2001

Management - General Measures

Fact Explanation
Proper personal hygiene Proper personal hygiene has an utmost importance as a Preventive measure. Drinking boiled cool water, Hand washing (before preparing & eating meals & after toilet),washing fruits & vegetables with clean running water,protecting food from flies & other insects,safe disposal of excreta etc. are important. [1]
Community measures Community measures such as provision of purified drinking water, sanitary disposal of excreta,screening of food handlers and health education are paramount preventive strategies. [1]
Nutritional Management Nutritional management of giardiasis consists of foods and supplements that inhibit Giardia growth, replication, and/or attachment to enterocytes; and promote host defense mechanisms against Giardia. These aims can best be achieved by consuming a whole-foods, high fiber,low-fat, low simple-carbohydrate diet. Additionally, ingestion of wheat germ and probiotics can aid in parasite clearance. [2]
References
  1. WOLFE,M.S. et al. Giardiasis [online] ,Clin Microbiol Rev.1992 Jan,5,1,93-100. [viewed 23 April 2014]. Available from: http://cmr.asm.org/content/5/1/93.full.pdf
  2. HAWRELAK,J. Giardiasis: Pathophysiology and Management [online],Altern Med Rev. 2003 May,8(2),129-42. [viewed 23 April 2014]. Available from: http://www.altmedrev.com/publications/8/2/129.pdf

Management - Specific Treatments

Fact Explanation
Nitroimidazole derivatives Metronidazole and Tinidazole are the most commonly used antiprotozoal drugs. Metronidazole utilizes the anaerobic metabolic pathways present in Giardia. 500–750 mg/day for 5–10 days is recommended. The most effective agents for therapy of giardiasis are single doses of tinidazole or ornidazole or 5 to 7 days of metronidazole.[1,2] Combination treatment based on a nitroimidazole with one or two second-line drugs, in a 7–10 day short course, in persistent giardiasis after conventional treatment is also recommended. eg: metronidazole or tinidazole + paromomycin + albendazole. [3] In pregnancy, if treatment is required, paromomycin should be tried in the first trimester and paromomycin or metronidazole should be used in the second and third trimesters. [1]
Management of dehydration Oral Rehydration Solution (ORS) can be used to prevent mild to moderate dehydration.In severe dehydration Intravenous lactated Ringer solution or normal saline should be used. [1,2]
References
  1. GARDNER,T.B, HILL, D.R, Treatment of Giardiasis [online],Clin. Microbiol. Rev. January 2001,14,1, 114-128. [viewed 23 April 2014]. Available from: DOI: 10.1128/CMR.14.1.114–128.2001
  2. VESY,C.J, W.L.PETERSON, Review article: the management of Giardiasis[online],Aliment Pharmacol Ther. 1999 Jul,13(7),843-50. [viewed 23 April 2014]. Available from: 10.1046/j.1365-2036.1999.00537.x
  3. VELEZ,R.L. et al. Short Report: Short Course Combination Therapy for Giardiasis after Nitroimidazole Failure[online],Am. J. Trop. Med. Hyg.83(1), 2010,171–173. [viewed 23 April 2014]. Available from: doi:10.4269/ajtmh.2010.09-0742