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25-Year-Old Man With Abdominal Pain, Nausea, and Fatigue
RESIDENTS’ CLINIC RESIDENTS’ CLINIC
25-Year-Old Man With Abdominal Pain, Nausea, and Fatigue BILAL AIJAZ, MBBS,* AND THOMAS J. BECKMAN, MD†
A
25-year-old man presented to our clinic with a 2month history of abdominal pain, bloating, nausea, and occasional vomiting, including an episode of hematemesis. He described the abdominal pain as dull and crampy, mild to moderate in intensity, and localized to the epigastric region. The abdominal pain was not associated with positional changes, eating, bowel movements, or other factors. The patient also had severe fatigue and daily headaches that were diffuse and worse in the morning. A review of systems was negative for fever, diarrhea, blood per rectum, substantial weight loss, animal exposures, recent travel, head injury, or neck stiffness. His medical and family histories were noncontributory. The patient had been taking ibuprofen, which provided only temporary relief of his headaches. He had previously consulted his primary physician and received a diagnosis of depression. Antidepressant medications were advised but not initiated. The patient presented to our institution for further evaluation. On physical examination, the patient was afebrile. His blood pressure was 122/74 mm Hg, and pulse rate was 74/ min. He appeared fatigued but in no acute distress. Head and neck examination revealed no neck stiffness. Abdominal examination yielded epigastric tenderness, but his abdomen was otherwise soft with normal bowel sounds and no indication of organomegaly or masses. The neurological examination revealed no localizing findings. Results of the remainder of the complete multisystem examination were unremarkable. 1. Which one of the following would be the least appropriate test for evaluating this patient’s symptoms? a. Colonoscopy b. Computed tomography (CT) of the brain c. Serum electrolyte panel and creatinine measurement d. Complete blood cell count e. Esophagogastroduodenoscopy (EGD) *Resident in Internal Medicine, Mayo School of Graduate Medical Education, Mayo Clinic College of Medicine, Rochester, Minn. †Adviser to resident and Consultant in General Internal Medicine, Mayo Clinic College of Medicine, Rochester, Minn. See end of article for correct answers to questions. Individual reprints of this article are not available. Address correspondence to Thomas J. Beckman, MD, Division of General Internal Medicine, Mayo Clinic College of Medicine, 200 First St SW, Rochester, MN 55905 (e-mail: beckman [email protected]). © 2007 Mayo Foundation for Medical Education and Research
Mayo Clin Proc.
•
Colonoscopy would be the least appropriate test because this patient had no lower gastrointestinal symptoms, change in bowel habits, rectal bleeding, or weight loss. Furthermore, screening colonoscopy, or even surveillance colonoscopy in the setting of a family history of adenocarcinoma of the colon, would not be indicated in a patient of this age. Headache, nausea, and vomiting are common symptoms among patients with increased intracranial pressure from conditions such as brain tumor. Moreover, our patient’s nausea and vomiting were worse in the morning, further raising our suspicion of brain tumor. Therefore, CT of the head was warranted to rule out intracranial pathology. Serum electrolyte disturbances, such as hyponatremia and hypokalemia, may cause nausea and vomiting. Conversely, protracted vomiting may cause intravascular volume and serum electrolyte depletion and prerenal azotemia. For these reasons, a serum electrolyte panel and creatinine measurement should be obtained. Our patient reported an episode of hematemesis and was at increased risk of gastrointestinal bleeding due to use of nonsteroidal anti-inflammatory agents. Therefore, his hemoglobin and platelet counts should be assessed with a complete blood cell count. Finally, the patient reported an episode of hematemesis and protracted nausea and vomiting, indications for performing EGD. Noncontrast head CT yielded normal findings. Laboratory studies revealed the following (reference ranges shown parenthetically): serum sodium, 141 mEq/L (135145 mEq/L); potassium, 4.1 mEq/L (3.6-4.8 mEq/L); and creatinine, 1.0 mg/dL (0.8-1.2 mg/dL). A complete blood cell count revealed a hemoglobin level of 15.5 g/dL (13.517.5 g/dL), an elevated white blood cell count of 14.7 × 109/L (3.5-10.5 × 109/L), an absolute neutrophil count of 11.92 × 109/L (1.7-7.0 × 109/L), and a normal platelet count of 303 × 109/L (150-450 × 109/L). Serum liver biochemistry results were within normal limits. Additionally, EGD was performed at that time. 2. Which one of the following conditions should be included in this patient’s differential diagnosis? a. Brain tumor b. Urosepsis c. Cirrhosis d. Giardiasis e. Cholecystitis
March 2007;82(3):359-362
•
www.mayoclinicproceedings.com
For personal use. Mass reproduce only with permission from Mayo Clinic Proceedings.
359
RESIDENTS’ CLINIC
The CT revealed no intracranial lesions. Magnetic resonance imaging is more sensitive than CT for detecting brain tumors, especially those in the posterior fossa, but a mass small enough to be missed on CT is unlikely to cause symptoms of increased intracranial pressure such as headache, nausea, and vomiting. Therefore, brain tumor is an unlikely diagnosis in this patient. Although the patient had nausea and vomiting, his abdominal discomfort was localized to the epigastric area, he denied urinary symptoms, and he had no fever or hemodynamic instability suggestive of urosepsis. Patients with cirrhosis sometimes present with abdominal pain, nausea, and hematemesis, but their symptoms are usually chronic. Additionally, a complete review of systems in this patient failed to identify any risk factors for cirrhosis, and physical examination showed no evidence of chronic liver disease. Furthermore, the patient’s liver biochemistry results, which are usually abnormal in patients with cirrhosis, were normal. Thus, cirrhosis would be an unlikely diagnosis in this patient. Among the diagnoses listed, giardiasis is most likely and should be included in the differential diagnosis. Clinical criteria for the diagnosis of giardiasis are illness duration of 7 or more days and at least 2 of the following symptoms: diarrhea, flatulence, foul-smelling stools, nausea, abdominal cramps, and excessive fatigue.1 Our patient meets the criteria for giardiasis with the clinical features of illness lasting more than 7 days, abdominal cramping, and severe fatigue. Patients with gallstones may be asymptomatic or present with biliary colic, which unlike our patient’s constant mild epigastric pain is typically intermittent, severe, radiating to the back, and worsened by eating. Cholelithiasis and cholecystitis are also more commonly seen in overweight middle-aged women (not thin young men), and the obstructive liver enzymes are usually abnormal, at least during episodes of pain (this patient’s liver biochemistries were normal). Hence, cholecystitis is an unlikely diagnosis for this patient. Esophagogastroduodenoscopy revealed a normal-appearing esophagus, stomach, and duodenum. However, biopsies from the duodenum yielded numerous Giardia organisms. Antimicrobial therapy was initiated. 3. Which one of the following would be the most appropriate medical therapy for this patient? a. Metronidazole orally for 10 days b. Metronidazole orally for 5 days c. Vancomycin orally for 10 days d. Albendazole e. Pantoprazole All patients with symptomatic giardiasis are treated medically. Metronidazole is the recommended initial therapy, but a 10-day course is generally reserved for pa360
Mayo Clin Proc.
•
tients who do not respond to an initial shorter course of therapy. The standard regimen is 250 mg orally 3 times daily for 5 to 7 days and is the treatment of choice for this patient. Remarkably, a 5- to 7-day course of metronidazole is effective in 90% of patients.2 Patients should be counseled on adverse effects including nausea, diarrhea, metallic taste, headache, dizziness, confusion, paresthesia, and dark urine. Oral vancomycin is used to treat Clostridium difficile–induced pseudomembranous colitis or staphylococcal enterocolitis. It has no role in treating parasitic infections. Although albendazole may be used to treat giardiasis, its effectiveness is not as well established as that of metronidazole. Therefore, albendazole is sometimes reserved for patients who cannot tolerate or do not respond to metronidazole. Importantly, medications like pantoprazole that inhibit gastric parietal cell hydrogenpotassium adenosine triphosphatase (ie, proton pump inhibitors) actually increase both the risk of acquiring giardiasis and the severity of the disease by decreasing gastric pH. Therefore, pantoprazole would be contraindicated in this patient. Metronidazole therapy, 250 mg orally 3 times a day for 5 days, was initiated, and the patient was instructed to return for a follow-up appointment in 2 weeks. 4. Which one of the following is the least likely risk factor for giardiasis in this patient? a. Backpacking in the mountains b. Drinking untreated well water c. Chronic anemia d. Homosexual orientation e. Working in a day care center Giardia can cause infection with as few as 10 ingested cysts. Therefore, campers and hikers are at high risk for acquiring giardiasis by drinking water from streams or lakes contaminated with Giardia. Similarly, drinking untreated well water is a risk factor for acquiring giardiasis. Interestingly, water from very deep wells that has been filtered by soil is usually safe. Although anemia is sometimes seen in patients with chronic giardiasis and resulting malabsorption, chronic anemia is not a risk factor for the disease. Homosexuals who engage in oral-anal practices are at risk for acquiring giardiasis,3 but the current patient denied homosexual orientation. Person-to-person transmission, along with water-borne transmission, accounts for most cases of giardiasis. Indeed, individuals exposed to day care or chronic care facilities are at particular risk. Unfortunately, elicitation of a thorough history failed to identify the origin of the patient’s Giardia infection. The patient had many questions about his new diagnosis and was educated regarding the management of giardiasis and ways to prevent spread of the disease.
March 2007;82(3):359-362
•
www.mayoclinicproceedings.com
For personal use. Mass reproduce only with permission from Mayo Clinic Proceedings.
RESIDENTS’ CLINIC
5. In counseling this patient regarding his infectious illness, which one of the following statements would not be appropriate? a. Hand washing will reduce the chance of transmitting Giardia to others b. Boiling and filtering ground water before consumption usually prevents Giardia infection c. Giardia remains viable even in extremely cold water d. If the patient’s symptoms resolve, retesting for Giardia infection is unnecessary e. Giardia infections are usually self-limited and resolve without treatment Giardia is most commonly transmitted person to person (fecal-oral) or by drinking contaminated ground water. Consequently, it is true that careful hand hygiene and treating ground water before consumption will reduce the risk of disease transmission. Day care workers, people who work or reside in chronic care facilities, and food handlers should be especially cognizant of hand washing. People who drink from streams, lakes, or shallow reservoirs should first destroy Giardia cysts by boiling the water or treating it with iodine tablets; filters with pore sizes smaller than 1 µm may be used but are probably less reliable than the other methods. Remarkably, Giardia cysts can survive for long durations even in extremely cold water. Patients with symptomatic giardiasis should always receive medical treatment. When symptoms resolve, retesting is unnecessary. Giardiasis is often not self-limited and may persist as a chronic infection. Indeed, untreated giardiasis is sometimes characterized by symptoms of waxing and waning severity lasting for many months. The patient returned 1 week after completing 5 days of metronidazole therapy, at which time his symptoms had essentially resolved. He was again counseled about ways to avoid acquiring Giardia in the future. DISCUSSION Giardia is a multiflagellated, binucleate, pear-shaped protozoan4,5 initially described in 1681 by Antony van Leeuwenhoek, who identified the organism in stool specimens.3,6 Giardia has a simple life cycle consisting of a cyst form that is responsible for disease transmission and a trophozoite form that causes infection. Giardia attaches to duodenal and jejunal mucosa with a sucking disk.7 The trophozoites then divide by binary fission and complete the disease cycle by shedding cysts into the feces.8 Giardiasis is among the most common gastrointestinal parasitic infections worldwide, occurring in more than 20% of people in developing countries.9 Regions of highest risk are Eurasia, Southeast Asia, Africa, Mexico, and Mayo Clin Proc.
•
South America.10 Giardiasis is also the most commonly diagnosed enteric protozoal infection in the United States.4 Major routes of transmission are person to person (fecal-oral) and consumption of contaminated water.6 Person-to-person transmission occurs in settings of poor hygiene, such as day care centers.11 Water-borne illness usually results from drinking well water or untreated surface water, such as from lakes and streams, which accounts for Giardia as a common cause of infection among hikers and campers. Notably, community outbreaks have been linked to contaminated water supplies.6 The current case was unusual because no risk factors were identified. Giardia infection may be entirely asymptomatic, and the course of symptomatic disease ranges from acute to chronic infection. Symptoms typically occur after a 1- to 2-week incubation period; chronic infection can last for many months.3,6 The most common presenting symptoms, in descending frequency, are diarrhea, malaise, steatorrhea, abdominal cramps, bloating, flatulence, nausea, weight loss, and vomiting.12 Patients with chronic infection often experience major weight loss, malabsorption, and depression.3 Diagnosing giardiasis may be challenging because patients often have no objective evidence of inflammation, such as fever, peripheral leukocytosis, or fecal leukocytes.3 The diagnosis is usually made by examining stool specimens, which may show cysts or trophozoites.8 Diagnostic yield increases with repeated sampling, and therefore examination of 3 separate samples is recommended.7 The diagnosis can also be made with newer tests that use antibodies directed against Giardia antigens, such as enzymelinked immunosorbent assays and direct fluorescence antibody tests. Invasive testing is generally considered a second-line option that is used when stool tests are unrevealing.7 Invasive tests include endoscopic duodenal aspiration and biopsy. Also, EGD may show villous atrophy and plasma cell infiltration of the lamina propria.3 The current case was unusual because the diagnosis of giardiasis was made by EGD, as opposed to the more usual noninvasive methods. The mainstay of treatment of giardiasis is metronidazole, 250 mg orally thrice daily for 5 days, which is effective in 90% of individuals.2 Because of occasional resistance, other treatments sometimes considered include quinacrine, furazolidone, nitroimidazole, paromycin, and albendazole.2 Importantly, patients who experience symptomatic improvement with treatment do not require additional testing to document clearance of infection. However, patients with recurrent symptoms should be retested and alternative diagnoses considered.
March 2007;82(3):359-362
•
www.mayoclinicproceedings.com
For personal use. Mass reproduce only with permission from Mayo Clinic Proceedings.
361
RESIDENTS’ CLINIC
If infection is found, options include re-treatment with a longer course of the same drug, treatment with a new class of drug, or combination therapy.7 In addition to medical therapy, counseling patients regarding methods to prevent disease transmission and recurrent infection is important. REFERENCES 1. Hopkins RS, Juranek DD. Acute giardiasis: an improved clinical case definition for epidemiologic studies. Am J Epidemiol. 1991;133:402-407. 2. Gardner TB, Hill DR. Treatment of giardiasis. Clin Microbiol Rev. 2001;14:114-128. 3. Wolfe MS. Giardiasis. Clin Microbiol Rev. 1992;5:93-100. 4. Lebwohl MD, Deckelbaum RJ, Green PH. Giardiasis. Gastrointest Endosc. 2003;57:906-913.
362
Mayo Clin Proc.
•
5. Ali S, Hill DR. Giardia intestinalis. Curr Opin Infect Dis. 2003;16:453460. 6. Shandera WX. From Leningrad to the day-care center: the ubiquitous Giardia lamblia. West J Med. 1990;153:154-159. 7. Vesy CJ, Peterson WL. Review article: the management of giardiasis. Aliment Pharmacol Ther. 1999;13:843-850. 8. Ortega YR, Adam RD. Giardia: overview and update. Clin Infect Dis. 1997;25:545-549. 9. Curtale F, Nabil M, el Wakeel A, Shamy MY, Behera Survey Team. Anaemia and intestinal parasitic infections among school age children in Behera Governorate, Egypt. J Trop Pediatr. 1998;44:323-328. 10. Wolfe MS. Giardiasis. N Engl J Med. 1978;298:319-321. 11. Overturf GD. Endemic giardiasis in the United States—role of the daycare center [editorial]. Clin Infect Dis. 1994;18:764-765. 12. Brodsky RE, Spencer HC Jr, Schultz MG. Giardiasis in American travelers to the Soviet Union. J Infec Dis. 1974;130:319-323.
Correct answers: 1. a, 2. d, 3. b, 4. c, 5. e
March 2007;82(3):359-362
•
www.mayoclinicproceedings.com
For personal use. Mass reproduce only with permission from Mayo Clinic Proceedings.
25-Year-Old Man With Abdominal Pain, Nausea, and Fatigue BILAL AIJAZ, MBBS,* AND THOMAS J. BECKMAN, MD†
A
25-year-old man presented to our clinic with a 2month history of abdominal pain, bloating, nausea, and occasional vomiting, including an episode of hematemesis. He described the abdominal pain as dull and crampy, mild to moderate in intensity, and localized to the epigastric region. The abdominal pain was not associated with positional changes, eating, bowel movements, or other factors. The patient also had severe fatigue and daily headaches that were diffuse and worse in the morning. A review of systems was negative for fever, diarrhea, blood per rectum, substantial weight loss, animal exposures, recent travel, head injury, or neck stiffness. His medical and family histories were noncontributory. The patient had been taking ibuprofen, which provided only temporary relief of his headaches. He had previously consulted his primary physician and received a diagnosis of depression. Antidepressant medications were advised but not initiated. The patient presented to our institution for further evaluation. On physical examination, the patient was afebrile. His blood pressure was 122/74 mm Hg, and pulse rate was 74/ min. He appeared fatigued but in no acute distress. Head and neck examination revealed no neck stiffness. Abdominal examination yielded epigastric tenderness, but his abdomen was otherwise soft with normal bowel sounds and no indication of organomegaly or masses. The neurological examination revealed no localizing findings. Results of the remainder of the complete multisystem examination were unremarkable. 1. Which one of the following would be the least appropriate test for evaluating this patient’s symptoms? a. Colonoscopy b. Computed tomography (CT) of the brain c. Serum electrolyte panel and creatinine measurement d. Complete blood cell count e. Esophagogastroduodenoscopy (EGD) *Resident in Internal Medicine, Mayo School of Graduate Medical Education, Mayo Clinic College of Medicine, Rochester, Minn. †Adviser to resident and Consultant in General Internal Medicine, Mayo Clinic College of Medicine, Rochester, Minn. See end of article for correct answers to questions. Individual reprints of this article are not available. Address correspondence to Thomas J. Beckman, MD, Division of General Internal Medicine, Mayo Clinic College of Medicine, 200 First St SW, Rochester, MN 55905 (e-mail: beckman [email protected]). © 2007 Mayo Foundation for Medical Education and Research
Mayo Clin Proc.
•
Colonoscopy would be the least appropriate test because this patient had no lower gastrointestinal symptoms, change in bowel habits, rectal bleeding, or weight loss. Furthermore, screening colonoscopy, or even surveillance colonoscopy in the setting of a family history of adenocarcinoma of the colon, would not be indicated in a patient of this age. Headache, nausea, and vomiting are common symptoms among patients with increased intracranial pressure from conditions such as brain tumor. Moreover, our patient’s nausea and vomiting were worse in the morning, further raising our suspicion of brain tumor. Therefore, CT of the head was warranted to rule out intracranial pathology. Serum electrolyte disturbances, such as hyponatremia and hypokalemia, may cause nausea and vomiting. Conversely, protracted vomiting may cause intravascular volume and serum electrolyte depletion and prerenal azotemia. For these reasons, a serum electrolyte panel and creatinine measurement should be obtained. Our patient reported an episode of hematemesis and was at increased risk of gastrointestinal bleeding due to use of nonsteroidal anti-inflammatory agents. Therefore, his hemoglobin and platelet counts should be assessed with a complete blood cell count. Finally, the patient reported an episode of hematemesis and protracted nausea and vomiting, indications for performing EGD. Noncontrast head CT yielded normal findings. Laboratory studies revealed the following (reference ranges shown parenthetically): serum sodium, 141 mEq/L (135145 mEq/L); potassium, 4.1 mEq/L (3.6-4.8 mEq/L); and creatinine, 1.0 mg/dL (0.8-1.2 mg/dL). A complete blood cell count revealed a hemoglobin level of 15.5 g/dL (13.517.5 g/dL), an elevated white blood cell count of 14.7 × 109/L (3.5-10.5 × 109/L), an absolute neutrophil count of 11.92 × 109/L (1.7-7.0 × 109/L), and a normal platelet count of 303 × 109/L (150-450 × 109/L). Serum liver biochemistry results were within normal limits. Additionally, EGD was performed at that time. 2. Which one of the following conditions should be included in this patient’s differential diagnosis? a. Brain tumor b. Urosepsis c. Cirrhosis d. Giardiasis e. Cholecystitis
March 2007;82(3):359-362
•
www.mayoclinicproceedings.com
For personal use. Mass reproduce only with permission from Mayo Clinic Proceedings.
359
RESIDENTS’ CLINIC
The CT revealed no intracranial lesions. Magnetic resonance imaging is more sensitive than CT for detecting brain tumors, especially those in the posterior fossa, but a mass small enough to be missed on CT is unlikely to cause symptoms of increased intracranial pressure such as headache, nausea, and vomiting. Therefore, brain tumor is an unlikely diagnosis in this patient. Although the patient had nausea and vomiting, his abdominal discomfort was localized to the epigastric area, he denied urinary symptoms, and he had no fever or hemodynamic instability suggestive of urosepsis. Patients with cirrhosis sometimes present with abdominal pain, nausea, and hematemesis, but their symptoms are usually chronic. Additionally, a complete review of systems in this patient failed to identify any risk factors for cirrhosis, and physical examination showed no evidence of chronic liver disease. Furthermore, the patient’s liver biochemistry results, which are usually abnormal in patients with cirrhosis, were normal. Thus, cirrhosis would be an unlikely diagnosis in this patient. Among the diagnoses listed, giardiasis is most likely and should be included in the differential diagnosis. Clinical criteria for the diagnosis of giardiasis are illness duration of 7 or more days and at least 2 of the following symptoms: diarrhea, flatulence, foul-smelling stools, nausea, abdominal cramps, and excessive fatigue.1 Our patient meets the criteria for giardiasis with the clinical features of illness lasting more than 7 days, abdominal cramping, and severe fatigue. Patients with gallstones may be asymptomatic or present with biliary colic, which unlike our patient’s constant mild epigastric pain is typically intermittent, severe, radiating to the back, and worsened by eating. Cholelithiasis and cholecystitis are also more commonly seen in overweight middle-aged women (not thin young men), and the obstructive liver enzymes are usually abnormal, at least during episodes of pain (this patient’s liver biochemistries were normal). Hence, cholecystitis is an unlikely diagnosis for this patient. Esophagogastroduodenoscopy revealed a normal-appearing esophagus, stomach, and duodenum. However, biopsies from the duodenum yielded numerous Giardia organisms. Antimicrobial therapy was initiated. 3. Which one of the following would be the most appropriate medical therapy for this patient? a. Metronidazole orally for 10 days b. Metronidazole orally for 5 days c. Vancomycin orally for 10 days d. Albendazole e. Pantoprazole All patients with symptomatic giardiasis are treated medically. Metronidazole is the recommended initial therapy, but a 10-day course is generally reserved for pa360
Mayo Clin Proc.
•
tients who do not respond to an initial shorter course of therapy. The standard regimen is 250 mg orally 3 times daily for 5 to 7 days and is the treatment of choice for this patient. Remarkably, a 5- to 7-day course of metronidazole is effective in 90% of patients.2 Patients should be counseled on adverse effects including nausea, diarrhea, metallic taste, headache, dizziness, confusion, paresthesia, and dark urine. Oral vancomycin is used to treat Clostridium difficile–induced pseudomembranous colitis or staphylococcal enterocolitis. It has no role in treating parasitic infections. Although albendazole may be used to treat giardiasis, its effectiveness is not as well established as that of metronidazole. Therefore, albendazole is sometimes reserved for patients who cannot tolerate or do not respond to metronidazole. Importantly, medications like pantoprazole that inhibit gastric parietal cell hydrogenpotassium adenosine triphosphatase (ie, proton pump inhibitors) actually increase both the risk of acquiring giardiasis and the severity of the disease by decreasing gastric pH. Therefore, pantoprazole would be contraindicated in this patient. Metronidazole therapy, 250 mg orally 3 times a day for 5 days, was initiated, and the patient was instructed to return for a follow-up appointment in 2 weeks. 4. Which one of the following is the least likely risk factor for giardiasis in this patient? a. Backpacking in the mountains b. Drinking untreated well water c. Chronic anemia d. Homosexual orientation e. Working in a day care center Giardia can cause infection with as few as 10 ingested cysts. Therefore, campers and hikers are at high risk for acquiring giardiasis by drinking water from streams or lakes contaminated with Giardia. Similarly, drinking untreated well water is a risk factor for acquiring giardiasis. Interestingly, water from very deep wells that has been filtered by soil is usually safe. Although anemia is sometimes seen in patients with chronic giardiasis and resulting malabsorption, chronic anemia is not a risk factor for the disease. Homosexuals who engage in oral-anal practices are at risk for acquiring giardiasis,3 but the current patient denied homosexual orientation. Person-to-person transmission, along with water-borne transmission, accounts for most cases of giardiasis. Indeed, individuals exposed to day care or chronic care facilities are at particular risk. Unfortunately, elicitation of a thorough history failed to identify the origin of the patient’s Giardia infection. The patient had many questions about his new diagnosis and was educated regarding the management of giardiasis and ways to prevent spread of the disease.
March 2007;82(3):359-362
•
www.mayoclinicproceedings.com
For personal use. Mass reproduce only with permission from Mayo Clinic Proceedings.
RESIDENTS’ CLINIC
5. In counseling this patient regarding his infectious illness, which one of the following statements would not be appropriate? a. Hand washing will reduce the chance of transmitting Giardia to others b. Boiling and filtering ground water before consumption usually prevents Giardia infection c. Giardia remains viable even in extremely cold water d. If the patient’s symptoms resolve, retesting for Giardia infection is unnecessary e. Giardia infections are usually self-limited and resolve without treatment Giardia is most commonly transmitted person to person (fecal-oral) or by drinking contaminated ground water. Consequently, it is true that careful hand hygiene and treating ground water before consumption will reduce the risk of disease transmission. Day care workers, people who work or reside in chronic care facilities, and food handlers should be especially cognizant of hand washing. People who drink from streams, lakes, or shallow reservoirs should first destroy Giardia cysts by boiling the water or treating it with iodine tablets; filters with pore sizes smaller than 1 µm may be used but are probably less reliable than the other methods. Remarkably, Giardia cysts can survive for long durations even in extremely cold water. Patients with symptomatic giardiasis should always receive medical treatment. When symptoms resolve, retesting is unnecessary. Giardiasis is often not self-limited and may persist as a chronic infection. Indeed, untreated giardiasis is sometimes characterized by symptoms of waxing and waning severity lasting for many months. The patient returned 1 week after completing 5 days of metronidazole therapy, at which time his symptoms had essentially resolved. He was again counseled about ways to avoid acquiring Giardia in the future. DISCUSSION Giardia is a multiflagellated, binucleate, pear-shaped protozoan4,5 initially described in 1681 by Antony van Leeuwenhoek, who identified the organism in stool specimens.3,6 Giardia has a simple life cycle consisting of a cyst form that is responsible for disease transmission and a trophozoite form that causes infection. Giardia attaches to duodenal and jejunal mucosa with a sucking disk.7 The trophozoites then divide by binary fission and complete the disease cycle by shedding cysts into the feces.8 Giardiasis is among the most common gastrointestinal parasitic infections worldwide, occurring in more than 20% of people in developing countries.9 Regions of highest risk are Eurasia, Southeast Asia, Africa, Mexico, and Mayo Clin Proc.
•
South America.10 Giardiasis is also the most commonly diagnosed enteric protozoal infection in the United States.4 Major routes of transmission are person to person (fecal-oral) and consumption of contaminated water.6 Person-to-person transmission occurs in settings of poor hygiene, such as day care centers.11 Water-borne illness usually results from drinking well water or untreated surface water, such as from lakes and streams, which accounts for Giardia as a common cause of infection among hikers and campers. Notably, community outbreaks have been linked to contaminated water supplies.6 The current case was unusual because no risk factors were identified. Giardia infection may be entirely asymptomatic, and the course of symptomatic disease ranges from acute to chronic infection. Symptoms typically occur after a 1- to 2-week incubation period; chronic infection can last for many months.3,6 The most common presenting symptoms, in descending frequency, are diarrhea, malaise, steatorrhea, abdominal cramps, bloating, flatulence, nausea, weight loss, and vomiting.12 Patients with chronic infection often experience major weight loss, malabsorption, and depression.3 Diagnosing giardiasis may be challenging because patients often have no objective evidence of inflammation, such as fever, peripheral leukocytosis, or fecal leukocytes.3 The diagnosis is usually made by examining stool specimens, which may show cysts or trophozoites.8 Diagnostic yield increases with repeated sampling, and therefore examination of 3 separate samples is recommended.7 The diagnosis can also be made with newer tests that use antibodies directed against Giardia antigens, such as enzymelinked immunosorbent assays and direct fluorescence antibody tests. Invasive testing is generally considered a second-line option that is used when stool tests are unrevealing.7 Invasive tests include endoscopic duodenal aspiration and biopsy. Also, EGD may show villous atrophy and plasma cell infiltration of the lamina propria.3 The current case was unusual because the diagnosis of giardiasis was made by EGD, as opposed to the more usual noninvasive methods. The mainstay of treatment of giardiasis is metronidazole, 250 mg orally thrice daily for 5 days, which is effective in 90% of individuals.2 Because of occasional resistance, other treatments sometimes considered include quinacrine, furazolidone, nitroimidazole, paromycin, and albendazole.2 Importantly, patients who experience symptomatic improvement with treatment do not require additional testing to document clearance of infection. However, patients with recurrent symptoms should be retested and alternative diagnoses considered.
March 2007;82(3):359-362
•
www.mayoclinicproceedings.com
For personal use. Mass reproduce only with permission from Mayo Clinic Proceedings.
361
RESIDENTS’ CLINIC
If infection is found, options include re-treatment with a longer course of the same drug, treatment with a new class of drug, or combination therapy.7 In addition to medical therapy, counseling patients regarding methods to prevent disease transmission and recurrent infection is important. REFERENCES 1. Hopkins RS, Juranek DD. Acute giardiasis: an improved clinical case definition for epidemiologic studies. Am J Epidemiol. 1991;133:402-407. 2. Gardner TB, Hill DR. Treatment of giardiasis. Clin Microbiol Rev. 2001;14:114-128. 3. Wolfe MS. Giardiasis. Clin Microbiol Rev. 1992;5:93-100. 4. Lebwohl MD, Deckelbaum RJ, Green PH. Giardiasis. Gastrointest Endosc. 2003;57:906-913.
362
Mayo Clin Proc.
•
5. Ali S, Hill DR. Giardia intestinalis. Curr Opin Infect Dis. 2003;16:453460. 6. Shandera WX. From Leningrad to the day-care center: the ubiquitous Giardia lamblia. West J Med. 1990;153:154-159. 7. Vesy CJ, Peterson WL. Review article: the management of giardiasis. Aliment Pharmacol Ther. 1999;13:843-850. 8. Ortega YR, Adam RD. Giardia: overview and update. Clin Infect Dis. 1997;25:545-549. 9. Curtale F, Nabil M, el Wakeel A, Shamy MY, Behera Survey Team. Anaemia and intestinal parasitic infections among school age children in Behera Governorate, Egypt. J Trop Pediatr. 1998;44:323-328. 10. Wolfe MS. Giardiasis. N Engl J Med. 1978;298:319-321. 11. Overturf GD. Endemic giardiasis in the United States—role of the daycare center [editorial]. Clin Infect Dis. 1994;18:764-765. 12. Brodsky RE, Spencer HC Jr, Schultz MG. Giardiasis in American travelers to the Soviet Union. J Infec Dis. 1974;130:319-323.
Correct answers: 1. a, 2. d, 3. b, 4. c, 5. e
March 2007;82(3):359-362
•
www.mayoclinicproceedings.com
For personal use. Mass reproduce only with permission from Mayo Clinic Proceedings.