Introduction

Giardia lamblia (syn. G. duodenalis, G. intestinalis) is a protozoal parasite that is transmitted via the faecal-oral route and through contaminated water. Giardia infection triggers intestinal inflammation, enterocyte apoptosis, intestinal barrier dysfunction, villous shortening and atrophy, disaccharidase deficiency and subsequent malabsorption. These effects manifest as diarrhoea, malabsorption and weight loss in affected patients.¹

Initial Presentation

A 52 year old male truck driver presented with explosive diarrhoea, steatorrhoea, abdominal pain and 5kg weight loss of six weeks duration. He had seen his GP for these symptoms and been diagnosed with giardiasis. His GP prescribed a course of metronidazole, which he took as directed. His symptoms improved while taking the medication, but rapidly worsened once the course was completed. He also experienced severe nausea, vomiting and headaches while taking the drug, which are common side effects of metronidazole.² Due to these adverse effects he was reluctant to return to his GP for further treatment. His diet was high in refined carbohydrates, red meat and processed foods and low in fresh fruit and vegetables. He was not on any medication, but had a history of long term antibiotic therapy to treat chronic sinusitis.

Treatment Plan

Reduce intestinal inflammation while assessing for the presence of Giardia and other gastrointestinal pathogens.

Prescription

• Complete Digestive Stool Analysis (CDSA) & 3 Day Parasitology Test
• Saccharomyces boulardii capsule, 2 capsules twice daily; containing Saccharomyces cerevisiae (boulardii ) 250mg, Vitamin A 900IU, Vitamin D 250IU and zinc 5mg
• Gut repair powder, 2 teaspoons twice daily; containing glutamine 3.5g, slippery elm (Ulmus rubra) powder 500mg, acacia gum (Acacia sp.) 2g, deglycyrrhized licorice (Glycyrrhiza glabra) root 2g and zinc carnosine 75mg (equiv. zinc 16mg)
• Anti-inflammatory diet; Mediterranean style diet with limited red meat, alcohol, gluten, dairy and processed foods

Second Consultation

The results of the CDSA and Parasitology test confirmed the presence of giardiasis, despite taking the prescribed antibiotic. Antibiotic-resistant Giardia is becoming increasingly common worldwide, leading to chronic giardiasis and long-term heath complications.³ 

The test also identified that Lactobacilli  and Bifidobacteria numbers were low while Clostridium difficile was present in large numbers. This opportunistic pathogen is normally repressed by the commensal microbiome. Antibiotic use, particularly when used long term, can disrupt the microbiome and allow Clostridium to gain the upper hand. This can lead to chronic diarrhoea, small intestinal bacterial overgrowth, sepsis or toxic megacolon if left untreated.⁴ The patient’s history of chronic antibiotic use coupled with his current infection and metronidazole use had created the perfect environment for Clostridium to flourish.

Treatment Plan

Treat gastrointestinal infection aggressively with antiparasitic and antimicrobial herbs, while reducing intestinal inflammation and permeability.

Prescription

For 6 weeks, he was prescribed the following:

• Gut antimicrobial capsules, 2 capsules twice daily for the first 4 days per week; containing phellodendron (Phellodendron amurense ) bark 1.6g, andrographis (Andrographis paniculata) whole plant 1g, anise (Pimpinella anisum) oil 125mg and oregano (Origanum vulgare) oil 75mg
• Antiparasite support tablets, 2 capsules twice daily for the first 4 days per week; containing wormwood (Artemisia absinthium) leaf 100mg, stemona (Stemona sessifolia) root 1g, black walnut (Juglans nigra) hull 100mg and clove (Syzygium aromaticum) bud oil 20mg
• Myrrh resin tablets, 3 tablets twice daily for the first 4 days per week; containing myrrh (Commifora myrrha) resin 500mg
• Multi-strain probiotic powder 30 Billion CFU, 1 scoop twice daily for the last 3 days per week; containing Lactobacillus acidophilus 65b, Bifidobacterium infantis 900m, Lactobaccilus delbrueckii ssp. bulgaricus 150m, Lactobacillus plantarum 1.2b, Bifidobacterium breve 900m, Bifidobacterium longum 900m, Lactobacillus helveticus 1.5b, Lactobacillus casei 1.2b, Streptococcus thermophilus 600m, Lactobacillus rhamnosus R1039 9b, Lactobacillus rhamnosus R0011 12b
• Saccharomyces boulardii capsule, 2 capsules twice daily;
• Gut repair powder, 2 teaspoons twice daily;
• Repeat CDSA and 3 Day Parasitology once regime is completed

Third Consultation

At this consultation he had completed the 6-week antimicrobial regime with good compliance. The repeat CDSA and Parasitology found nil Giardia cysts and nil Clostridium. Lactobacilli and Bifidobacterium sp. were still low. He had a vast improvement in his symptoms, with no steatorrhoea or abdominal pain. He was still experiencing episodic diarrhoea, which was no longer explosive. Thorough diet and symptom analysis indicated that the diarrhoea was diet related, with most episodes occurring after large intake of lactose or fructose. As he had not previously had any problems with these foods, this suggested that he was experiencing post-infectious malabsorption syndrome, also known as post-infectious irritable bowel syndrome (IBS). While symptoms of giardiasis usually resolve once the parasite has been treated, up to 30% of affected patients develop long term gastrointestinal symptoms similar to IBS. This is believed to be caused by persistent inflammation in the bowel, leading to increased intestinal permeability and motility. Post-infectious dysbiosis also plays an important role.1

Treatment Plan

Address ongoing dysbiosis and inflammation while supporting digestive function.   

Prescription

• Multi-strain probiotic powder 30 Billion CFU, 1 scoop twice daily;
• Gut repair powder, 2 teaspoons twice daily;
• Liquid herb blend, 5mL three times daily before meals; containing ginger (Zingiber officinale) 10mL, gentian (Gentiana lutea) 10mL, turmeric (Curcuma longa) 40mL and chamomile (Chamomilla recutita) 40mL
• Low FODMAP diet, restricting all foods high in fermentable oligosaccharides, disaccharides, monosaccharides and polyols

Follow Up

After 4 weeks on the low FODMAP diet, he was completely symptom free. Over the next few weeks, high FODMAP foods were reintroduced gradually by class. All were well tolerated except lactose which continued to cause mild diarrhoea.

Treatment plan

Support the re-establishment of a healthy microbiome to prevent the return of Clostridium, and continue to reduce intestinal inflammation and permeability.

Prescription

• Multi-strain probiotic powder 30 Billion CFU, 1 scoop twice daily;
• Gut repair powder, 2 teaspoons twice daily;
• Lactose free anti-inflammatory diet; Mediterranean style diet with limited red meat, alcohol, gluten, dairy and processed foods, and no lactose

Conclusion

While usually acute and short lived, this case demonstrates that the symptoms and consequences of giardiasis can persist even once the initial infection has been treated with aggressive antimicrobial therapy. Long term gut repair work will be needed to restore his gastrointestinal system to full health.

References

1. Halliez MC, Buret AG. Extra-intestinal and long term consequences of Giardia duodenalis infections. WJG. 2013 Dec 21;19(47):8974. DOI 10.3748/wjg.v19.i47.8974
2. eMIMS Online Database. Australia: MIMS Australia; 2019. Metronidazole: [Revised 2018 17 May; Cited 2019 01 October] Available from https://www.emims.com.au/Australia/drug/info/Flagyl/Flagyl?type=full#NameOfTheMedicine
3. Leitsch D. Drug resistance in the microaerophilic parasite Giardia lamblia. Current tropical medicine reports. 2015 Sep 1;2(3):128-35.DOI 10.1007/s40475-015-0051-1
4. Dicks LM, Mikkelsen LS, Brandsborg E, Marcotte H. Clostridium difficile, the difficult “Kloster” fuelled by antibiotics. Current microbiology. 2019 Jun 15;76(6):774-82. DOI: 10.1007/s00284-018-1543-8