Diagnostic Assessment — Gastrointestinal - Giardiasis
Example 1 of 1 · fictitious patient (Veteran CH)
Diagnostic Assessment
Gastrointestinal - Giardiasis
No Statement of Principles applies to this condition (non-SOP claim).
ADF History
Veteran CH, date of birth 12 August 1983, Australian Army, Cook, later Corporal, enlisted 03 February 2003, medically discharged 14 April 2016. Operational service: Iraq, 15 October 2005 to 20 May 2006 (warlike); Afghanistan, 01 May 2010 to 20 December 2010 (warlike).
Occupational History
As an army cook the veteran prepared and served food for up to 150 personnel in garrison kitchens, field kitchens and forward patrol bases, washed produce and equipment, handled raw food, managed water supplies for the kitchen and was rostered to field sanitation duties, including the cleaning and burning out of latrines. In forward locations he also took part in patrols and convoy duties.
Field catering and sanitation duties carry a high risk of exposure to enteric pathogens through contaminated water, food, ice and faecal material. Forward operating bases in Afghanistan relied on local wells and surface water, had crowded accommodation, shared ablutions and pit latrines, and had limited laboratory diagnosis and a restricted range of antiparasitic medicines.
History
Veteran CH, an army cook in the Australian Army, developed giardiasis on 14 September 2010 while on warlike service at a forward patrol base in Afghanistan, after drinking inadequately treated well water and ingesting river water on patrol, during an outbreak in crowded accommodation with poor sanitation. The infection was incompletely treated and worsened to chronic giardiasis with malabsorption and weight loss in November 2010, and was confirmed on duodenal biopsy in February 2011.
Timeline
- 15 Feb 2009 — A medical officer at the garrison health centre diagnosed gastro-oesophageal reflux disease, attributed to irregular meals and shift work in field kitchens, and commenced esomeprazole 40 mg daily. He continued it without a break, including throughout his 2010 deployment. "GORD, esomeprazole 40 mg daily"
- 26 Aug 2010 — On warlike service in Afghanistan, during a three-day patrol from a forward patrol base, a resupply of bottled water failed. The patrol drank water from a village well treated only with chlorine tablets, and the veteran slipped during a river crossing and swallowed river water. The patrol report recorded the water resupply failure, and the health record noted three other patrol members with diarrhoea in the following fortnight. "well water, chlorine tablets only"
- 16 Sep 2010 — He presented to the role 1 facility with two days of foul-smelling watery diarrhoea, abdominal cramps, bloating, flatulence and sulphurous belching, without blood. Twelve personnel at the patrol base had similar symptoms. A stool antigen test at the role 2 facility on 18 Sep 2010 was positive for Giardia duodenalis. He was given metronidazole 2 g daily for three days, as tinidazole was unavailable. "foul diarrhoea, bloating, Giardia antigen"
- 30 Sep 2010 — His symptoms improved partially. He returned to kitchen duties at the patrol base, where water for washing produce and equipment still came from the local well, and resumed his rostered latrine burn-out duties. A repeat stool test was planned but could not be processed at his location. "partial improvement, repeat stool unavailable"
- 25 Nov 2010 — He re-presented with persistent and worsening diarrhoea, pale greasy stools, abdominal distension and fatigue, with weight loss of 9 kg since September (from 82 kg to 73 kg). Dairy products worsened the symptoms. A stool antigen test was again positive. Metronidazole was repeated for seven days but symptoms persisted until he returned to Australia in December 2010. "steatorrhoea, 9 kg weight loss"
- 10 Feb 2011 — A gastroenterologist found Giardia trophozoites on duodenal biopsy with partial villous blunting, and a stool PCR was positive. Serum IgA was undetectable, consistent with selective IgA deficiency, and coeliac serology was performed on an IgG basis and was negative. He was treated with tinidazole and then albendazole, and stool PCR was negative on 20 Apr 2011. "duodenal Giardia, IgA deficiency"
- 12 Jul 2011 — He had persisting post-infectious lactose intolerance and irritable bowel symptoms, with bloating and loose stools after dairy and fatty food. His weight had recovered to 79 kg. A dietitian commenced a low-lactose, low-FODMAP diet. He was medically discharged on 14 Apr 2016 for other conditions. "post-giardial lactose intolerance"
Symptoms
At onset the veteran had foul-smelling watery diarrhoea, abdominal cramps, bloating, flatulence, sulphurous belching and nausea. After onset the diarrhoea persisted and from November 2010 became pale and greasy, with abdominal distension, fatigue, intolerance of dairy products and weight loss of 9 kg.
He now reports bloating, urgency and loose stools after dairy and fatty food, and avoids lactose. He has intermittent abdominal discomfort consistent with post-infectious irritable bowel syndrome.
Imaging
No imaging is required to establish this diagnosis.
Onset Date
The most likely date of onset of this condition is 14 Sep 2010.
At that date the veteran was on warlike service in Afghanistan as the cook at a forward patrol base, living in crowded accommodation with shared ablutions and pit latrines during an outbreak of diarrhoeal illness.
This date is appropriate because the routine health review of 30 Aug 2010 recorded no gastrointestinal symptoms, and he first presented on 16 Sep 2010 with diarrhoea of two days' duration, confirmed as giardiasis on 18 Sep 2010. The interval of 19 days after the water exposure of 26 Aug 2010 is within the usual incubation period of giardiasis. It falls within continuous full-time service.
For the causes that rely on exposure, the 25 days before onset run from 20 Aug 2010 to 14 Sep 2010. The drinking of chlorine-treated well water and ingestion of river water on 26 Aug 2010, the consumption of produce washed in well water and locally supplied ice, the crowded accommodation, the latrine duties and the contact with dogs and livestock all fall within that window. He took esomeprazole daily throughout it, and his selective IgA deficiency, a lifelong state, was present at the time.
For the worsening causes, the documented clinical worsening is on 25 Nov 2010, with steatorrhoea and weight loss of 9 kg, confirmed on duodenal biopsy on 10 Feb 2011. The 25 days before it run from 31 Oct 2010 to 25 Nov 2010, during which he continued to work with well water at the patrol base. The inadequate treatment was given from 18 to 20 Sep 2010.
1. What is the formal diagnosis of the condition claimed above?
The formal diagnosis is Giardiasis (ICD-10-AM A07.1), progressing to chronic giardiasis with malabsorption and post-infectious lactose intolerance. No Statement of Principles has been determined for giardiasis.
Giardiasis is an infection of the small intestine by the protozoan parasite Giardia duodenalis (also called Giardia lamblia or intestinalis). Infection follows ingestion of cysts in contaminated water or food or by faecal-oral contact; as few as ten cysts can cause infection, and cysts resist the chlorine concentrations used in routine water treatment. After an incubation period of about 1 to 3 weeks the trophozoites attach to the duodenal lining, causing diarrhoea, cramps, bloating, flatulence and nausea. Incomplete treatment, reinfection and impaired mucosal immunity lead to chronic infection with malabsorption, weight loss and lactose intolerance.
The infection was acquired on warlike service in Afghanistan. It began on 14 September 2010, was confirmed by stool antigen testing on 18 September 2010, worsened to chronic giardiasis with malabsorption by 25 November 2010 and was confirmed on duodenal biopsy on 10 February 2011.
2. For each diagnosis identified, please also provide the following dates:
When did the veteran first experience symptoms attributable to this condition?
14 September 2010.
When did the veteran first present to a health / medical provider for this condition?
16 September 2010.
When was the condition confirmed / formally diagnosed?
18 September 2010.
When did the veteran first present to you (or your practice) for this condition?
14 October 2025.
3. How was this diagnosis confirmed? i.e. what were the key symptoms and signs, investigation results, specialist opinions?
The diagnosis was confirmed by a positive Giardia duodenalis stool antigen test at the role 2 facility on 18 September 2010, repeated on 25 November 2010, and by duodenal biopsy on 10 February 2011, which showed Giardia trophozoites with partial villous blunting, supported by a positive stool PCR.
The clinical picture was consistent: foul-smelling diarrhoea, cramps, bloating and sulphurous belching beginning 19 days after drinking inadequately treated water, during an outbreak at the patrol base. The later steatorrhoea, weight loss and lactose intolerance are characteristic of chronic giardiasis. A gastroenterologist confirmed the diagnosis, and clearance was confirmed by a negative stool PCR on 20 April 2011.
4. What do you consider to be the cause(s) of the condition in this veteran? Give consideration to constitutional and common risk factors, pre-existing injuries or diseases, and occupational or lifestyle risks, as well as direct causative mechanisms.
No Statement of Principles has been determined by the Repatriation Medical Authority for giardiasis. The claim is therefore decided on the sound medical-scientific evidence of what causes and worsens the condition, without the limits a Statement of Principles would impose, and the causes below are those well recognised in the medical literature.
Legislation: the clinical onset of this condition was on 14 September 2010, after 1 July 2004, during continuous full-time service on warlike service in Afghanistan, where the infection was acquired and worsened. This is a Military Rehabilitation and Compensation Act 2004 (MRCA) claim. Each cause must be related to the person's service. Under the beneficial approach required by the legislation, the absence of documentation does not mean that an event or exposure did not occur: lack of evidence is not evidence of lack.
Recognised causes on the medical-scientific evidence (no Statement of Principles)
Causative factors
Cause 1: drinking untreated or inadequately treated water from a well, river, lake, stream or other surface source in an area where Giardia is endemic, within the 25 days before the clinical onset of giardiasis; — MET
- On 26 August 2010, on warlike service in Afghanistan, the veteran's patrol drank water from a village well treated only with chlorine tablets after a resupply of bottled water failed. Giardia cysts survive routine chlorination, and giardiasis is highly endemic in rural Afghanistan. This was 19 days before onset, within the 25 days from 20 August 2010 to 14 September 2010.
Cause 2: consuming food, drink or ice prepared or washed with contaminated water, or uncooked produce, in an area where Giardia is endemic, within the 25 days before the clinical onset of giardiasis; — MET
- As the patrol base cook he washed salad vegetables and fruit in water drawn from the local well, tasted food during preparation and drank beverages made with ice from a local supplier, throughout the 25 days before onset. The contamination of the patrol base water supply was confirmed by the outbreak that followed.
Cause 3: swimming in, wading through or being immersed in surface water and swallowing water, in an area where Giardia is endemic, within the 25 days before the clinical onset of giardiasis; — MET
- On 26 August 2010 he slipped during a river crossing on patrol in Afghanistan and swallowed river water downstream of villages and grazing livestock. This was within the 25 days before onset.
Cause 4: living in crowded accommodation with shared ablution and toilet facilities and inadequate sanitation, during an outbreak of giardiasis or diarrhoeal illness, for at least 1 week within the 25 days before the clinical onset of giardiasis; — MET
- Throughout the 25 days before onset he lived at a forward patrol base in Afghanistan with about 60 personnel in tents, sharing pit latrines and limited hand-washing water. Twelve personnel developed similar diarrhoeal illness in September 2010, and person-to-person spread of Giardia is common in such conditions.
Cause 5: having occupational contact with human faecal material, including the cleaning, emptying or burning out of latrines, within the 25 days before the clinical onset of giardiasis; — MET
- He was rostered to burn out and clean the patrol base latrines several times a week in August and September 2010, with only basic gloves and limited water for washing, within the 25 days before onset.
Cause 6: having close contact with dogs, livestock or other animals, or their faeces, in an area where Giardia is endemic, within the 25 days before the clinical onset of giardiasis; — MET
- Stray dogs lived at the patrol base and were fed kitchen scraps, and patrols moved through compounds with goats, sheep and cattle, within the 25 days before onset. Dogs and livestock carry Giardia assemblages that infect humans.
Cause 7: taking a proton pump inhibitor or having reduced gastric acid secretion at the time of exposure to Giardia before the clinical onset of giardiasis; — MET
- The veteran took esomeprazole 40 mg daily from 15 February 2009, prescribed in service for reflux, throughout the deployment and at the time of the exposure of 26 August 2010. Gastric acid normally destroys a proportion of ingested cysts, and acid suppression lowers the infective dose.
Cause 8: having selective immunoglobulin A deficiency, hypogammaglobulinaemia or another immune deficiency at the time of exposure to Giardia before the clinical onset of giardiasis; — MET
- Serum IgA was undetectable on 10 February 2011, confirming selective IgA deficiency, a lifelong state that was present at the time of exposure in August 2010. Secretory IgA is the main defence against Giardia attachment to the intestinal lining, and IgA deficiency predisposes to symptomatic and chronic giardiasis.
Worsening factors
Worsening 1: being re-exposed to Giardia through contaminated water, food or faecal-oral contact within the 25 days before the clinical worsening of giardiasis; — MET
- From 31 October to 25 November 2010 the veteran continued to work in the patrol base kitchen in Afghanistan, where produce and equipment were washed in well water, and to clean latrines, during continuing cases of diarrhoea among personnel. These re-exposures fell within the 25 days before the worsening on 25 November 2010.
Worsening 2: receiving an incomplete or ineffective course of antiparasitic treatment for giardiasis before the clinical worsening of giardiasis; — MET
- On 18 September 2010 he received only three days of metronidazole because tinidazole, the preferred single-dose treatment, was unavailable in theatre, and no test of cure could be performed. The infection persisted and progressed to chronic giardiasis with malabsorption by 25 November 2010.
Worsening 3: taking a proton pump inhibitor at the time of the clinical worsening of giardiasis; — MET
- Esomeprazole 40 mg daily continued throughout the deployment and was being taken at the time of the worsening on 25 November 2010.
Worsening 4: having selective immunoglobulin A deficiency, hypogammaglobulinaemia or another immune deficiency at the time of the clinical worsening of giardiasis; — MET
- His selective IgA deficiency, confirmed on 10 February 2011, was present at the worsening on 25 November 2010 and impaired clearance of the infection.
Worsening 5: inability to obtain appropriate clinical management for giardiasis. — MET
- On warlike service in Afghanistan the veteran could not obtain tinidazole, a stool test of cure or gastroenterology review, and he could not be removed from the contaminated water supply at the patrol base. The infection persisted for three months and progressed to chronic giardiasis with malabsorption and weight loss of 9 kg. Under Brew v Repatriation Commission (1999) this is an inability to obtain appropriate clinical management.
The % contribution of the causes is 100% and significant.
Sequelae
The chronic giardiasis has resulted in post-infectious lactose intolerance and post-infectious irritable bowel syndrome, which are sequelae of the service-acquired infection and should be considered for acceptance.
Unintended Consequence
Not applicable on the present evidence. The worsening followed incomplete treatment because the appropriate medicine was unavailable, rather than an adverse effect of treatment given.
Inability to Attain Appropriate Medical Management
MET. On warlike service in Afghanistan the veteran received only a three-day course of metronidazole because tinidazole was unavailable, no stool test of cure could be processed at his location, gastroenterology review was not available and he continued to work with the contaminated well water supply. The infection persisted and worsened to chronic giardiasis with steatorrhoea and weight loss of 9 kg by 25 November 2010, and was cleared only after specialist treatment in Australia in 2011. Applying the objective and subjective tests in Brew v Repatriation Commission (Full Federal Court, 10 September 1999, Merkel J), operational constraints that prevent appropriate diagnosis and treatment amount to an inability to obtain appropriate clinical management.
5. Please provide a Health Summary and a medication / prescribing history.
See attached report.
References
- 15 Feb 2009, Outpatient health record, Medical Officer, Garrison health centre
- 26 Aug 2010, Patrol report and outpatient health record, Afghanistan
- 30 Aug 2010, Outpatient health record, Medical Officer, Afghanistan
- 16 Sep 2010, Outpatient health record, Medical Officer, Role 1 facility, Afghanistan
- 18 Sep 2010, Stool antigen result, Role 2 facility laboratory, Afghanistan
- 25 Nov 2010, Outpatient health record, Medical Officer, Afghanistan
- 10 Feb 2011, Gastroscopy, duodenal biopsy and immunoglobulin results, Gastroenterologist
- 20 Apr 2011, Stool PCR result, Pathology laboratory
- 12 Jul 2011, Dietetic assessment, Dietitian
