Block 14 GI Protozoa Helminths N Acute Abdomen

1. In a child with anal itching, a scotch tape test revealed this ovum: What infection is this?

Ascaris lumbricoides

Taenia solium

Enterobius vermicularis

Necator americanus

Ancyclostoma duodenale

The correct answer is Enterobius vermicularis. Enterobius vermicularis, also known as pinworm, is a common cause of anal itching in children. The scotch tape test is a diagnostic test used to identify the eggs of Enterobius vermicularis. The female pinworm lays eggs around the anus, causing itching. The scotch tape test involves applying a piece of clear tape to the perianal area and then examining it under a microscope for the presence of pinworm eggs. This test is simple, non-invasive, and highly specific for Enterobius vermicularis infection.

Explanation

The correct answer is Enterobius vermicularis. Enterobius vermicularis, also known as pinworm, is a common cause of anal itching in children. The scotch tape test is a diagnostic test used to identify the eggs of Enterobius vermicularis. The female pinworm lays eggs around the anus, causing itching. The scotch tape test involves applying a piece of clear tape to the perianal area and then examining it under a microscope for the presence of pinworm eggs. This test is simple, non-invasive, and highly specific for Enterobius vermicularis infection.

2. During an epidemiological survey, a student observed that many school children in a rural community appeared to be lethargic and pale looking. The children spent a lot of time running around on the local beaches and often complained of an intense pruritic and erythematous rash on the feet. Most of them had a low-grade fever with abdominal pain and intermittent diarrhea. Blood examination showed evidence of hypochromic, microcytic anemia and many ova were found in the stool specimens. Which of the following organisms was most probably responsible for the infection?

Ascaris lumbricoides

Ancylostoma duodenale

Enterobius vermicularis

Taenia solium

Strongyloides stercoralis

Trichuris trichiura

The symptoms described in the scenario, including lethargy, pale appearance, pruritic and erythematous rash on the feet, low-grade fever, abdominal pain, and intermittent diarrhea, are consistent with a hookworm infection. Ancylostoma duodenale is a type of hookworm that can cause these symptoms, as well as hypochromic, microcytic anemia, which was also observed in the blood examination. Therefore, Ancylostoma duodenale is the most likely organism responsible for the infection.

Explanation

The symptoms described in the scenario, including lethargy, pale appearance, pruritic and erythematous rash on the feet, low-grade fever, abdominal pain, and intermittent diarrhea, are consistent with a hookworm infection. Ancylostoma duodenale is a type of hookworm that can cause these symptoms, as well as hypochromic, microcytic anemia, which was also observed in the blood examination. Therefore, Ancylostoma duodenale is the most likely organism responsible for the infection.

3. A member of the United Nations mission to Thailand was served 'bolli', a highly seasoned pork delicacy during a diplomatic reception. A few months later, she noticed thin, white, rectangular segments in her stool. There were no other symptoms. She received a single dose of niclosamide, which eliminated the organism. What was the most probable diagnosis?

Echynococcosis

Schistosomiasis

Taeniasis

Trichinosis

Trichuriasis

The most probable diagnosis in this case is Taeniasis. Taeniasis is a parasitic infection caused by the tapeworms of the Taenia genus. Consumption of undercooked or contaminated pork can lead to the transmission of Taenia solium, the pork tapeworm. The presence of thin, white, rectangular segments in the stool is a characteristic symptom of a tapeworm infection. Niclosamide is a medication commonly used to treat tapeworm infections.

Explanation

The most probable diagnosis in this case is Taeniasis. Taeniasis is a parasitic infection caused by the tapeworms of the Taenia genus. Consumption of undercooked or contaminated pork can lead to the transmission of Taenia solium, the pork tapeworm. The presence of thin, white, rectangular segments in the stool is a characteristic symptom of a tapeworm infection. Niclosamide is a medication commonly used to treat tapeworm infections.

4. A visiting physician to the Mayo Clinic, Rochester, MN, was delighted to be surrounded by so many lakes and in the summer would delight in taking his wife and 2 daughters to camp at one of these lakes. He and his family were avid swimmers and they thought that living in MN was just delightful. However, ten days after their last trip the whole family suddenly became sick, with persistent watery, extremely foul smelling diarrhea. There was very little cramping and the physician was still able to go to work. He took fecal samples from all of the family and borrowed a microscope as he thought the family had picked up a parasitic infection and he guessed that he would be able to spot the motile trophozoites. However, after examining samples from all of the family, he found no evidence of anything moving in the fecal samples. In the meantime, the whole family was treated with metronidazole and eventually the diarrhea went away. What is your conclusion from this?

It is unlikely that trophozoites would be found in the feces and he should have looked for cysts

The family members were probably infected with coliform bacteria and not parasites

The samples were too dilute and he should have concentrated them before looking for trophozoites

The physician's assumption that he would be able to spot motile trophozoites in the fecal samples was incorrect. The absence of evidence of anything moving in the samples suggests that trophozoites were not present. Instead, he should have looked for cysts, which are the dormant stage of the parasite that can be found in feces. This would have been a more appropriate method to detect a parasitic infection.

Explanation

The physician's assumption that he would be able to spot motile trophozoites in the fecal samples was incorrect. The absence of evidence of anything moving in the samples suggests that trophozoites were not present. Instead, he should have looked for cysts, which are the dormant stage of the parasite that can be found in feces. This would have been a more appropriate method to detect a parasitic infection.

5. A 31 year old man presents to the ER by ambulance following a collision between the car he was driving and a much larger truck. While he has mild shortness of breath, his main complaint is pain in his upper abdomen with no abdominal wall movement during respiration. You examine his X-ray (above). Your next action after resuscitation, would be to contact the

Radiologist on call.

General surgeon on call.

Inpatient resident team for admission to the respiratory ward.

Cardiologist on call

Based on the information given, the patient is a 31-year-old man who was involved in a car accident and is experiencing pain in his upper abdomen with no abdominal wall movement during respiration. The X-ray image is not provided, but based on the symptoms described, it suggests a possible abdominal injury. In such cases, a general surgeon is the appropriate specialist to contact as they are trained in diagnosing and treating abdominal injuries. The other options, such as a radiologist, cardiologist, or respiratory ward admission, are not as relevant in this scenario.

Explanation

Based on the information given, the patient is a 31-year-old man who was involved in a car accident and is experiencing pain in his upper abdomen with no abdominal wall movement during respiration. The X-ray image is not provided, but based on the symptoms described, it suggests a possible abdominal injury. In such cases, a general surgeon is the appropriate specialist to contact as they are trained in diagnosing and treating abdominal injuries. The other options, such as a radiologist, cardiologist, or respiratory ward admission, are not as relevant in this scenario.

6. A 34 year-old man and his 30 year-old wife went on a camping trip in the Colorado Mountains in September. They cooked over campfires and drank water from cold streams. The following week they noted diarrhea 2-3 times a day. The stools were nonbloody and floated on toilet water showing a greasy film. The diarrhea tended to occur after eating meals that included milk or ice cream. They lost about 20 pounds while the diarrhea lasted for 3 weeks until they sought treatment. What caused the illness?

A parasite in water that results in diarrhea with excretion of acid-fast cysts in stool

A parasite that forms cysts with nuclei that have central karyosomes.

A protozoan that forms flask-shaped ulcers in the colon and can cause liver abscesses.

A flagellated protozoan that is pear-shaped.

The correct answer is a flagellated protozoan that is pear-shaped. This is because the symptoms described, such as diarrhea after consuming milk or ice cream, floating stools with a greasy film, and weight loss, are consistent with Giardiasis, which is caused by the flagellated protozoan Giardia lamblia.

Explanation

The correct answer is a flagellated protozoan that is pear-shaped. This is because the symptoms described, such as diarrhea after consuming milk or ice cream, floating stools with a greasy film, and weight loss, are consistent with Giardiasis, which is caused by the flagellated protozoan Giardia lamblia.

7. A 6-year-old boy who lived on a farm in Louisiana went barefooted at home in the summer. He complained of a red rash on his legs that was itchy. When he started school, the school nurse noticed that he was pale and lethargic. What is a likely helminthic infection in this case?

Enterobius

Schistosoma

Ascaris

Taenia

Ancyclostoma

In this case, a likely helminthic infection is Ancyclostoma. The boy's symptoms of a red rash on his legs, itchiness, paleness, and lethargy are consistent with a hookworm infection, which is caused by Ancyclostoma. Hookworm infections are common in areas with poor sanitation and can be acquired by walking barefoot on contaminated soil, which is likely to occur on a farm.

Explanation

In this case, a likely helminthic infection is Ancyclostoma. The boy's symptoms of a red rash on his legs, itchiness, paleness, and lethargy are consistent with a hookworm infection, which is caused by Ancyclostoma. Hookworm infections are common in areas with poor sanitation and can be acquired by walking barefoot on contaminated soil, which is likely to occur on a farm.

8. A 48-year-old man presents to the ER by ambulance following an acute onset of abdominal pain. He has noticed some left lower quadrant pain over the last week. Temp 99⁰F RR 24 BP 90/60 mmHg. You examine his x-ray:

As the chief resident on call, your next action after resuscitation would be to contact:

The cardiologist on call

The inpatient resident team for admission to the respiratory ward

The general surgeon on call to perform an exploratory laparotomy

The general surgeon on call for placement of a chest tube

Based on the given information, the patient is a 48-year-old man presenting with acute abdominal pain and left lower quadrant pain over the last week. The vital signs show an elevated temperature (990F), increased respiratory rate (24), and low blood pressure (90/60 mmHg). The next action after resuscitation would be to contact the general surgeon on call to perform an exploratory laparotomy. This is because the combination of acute abdominal pain, abnormal vital signs, and the need for surgical intervention suggests a potentially serious intra-abdominal condition that requires immediate evaluation and intervention.

Explanation

Based on the given information, the patient is a 48-year-old man presenting with acute abdominal pain and left lower quadrant pain over the last week. The vital signs show an elevated temperature (990F), increased respiratory rate (24), and low blood pressure (90/60 mmHg). The next action after resuscitation would be to contact the general surgeon on call to perform an exploratory laparotomy. This is because the combination of acute abdominal pain, abnormal vital signs, and the need for surgical intervention suggests a potentially serious intra-abdominal condition that requires immediate evaluation and intervention.

9. A 30-year-old man with AIDS swam in a farmer's pond near a pasture for cows. A week later he complained of watery diarrhea several times a day and, despite eating food normally, lost 6 pounds within a week's time. Which image corresponds to the most likely stool microbe in this case?

A

B

C

D

E

The image that corresponds to the most likely stool microbe in this case is image B. This is because the patient has AIDS, which weakens the immune system, and he swam in a pond near a pasture for cows. This suggests that the most likely cause of his symptoms is an infection with a microbe commonly found in cow feces, such as Escherichia coli (E. coli). Image B shows a gram-negative rod-shaped bacterium, which is consistent with the characteristics of E. coli.

Explanation

The image that corresponds to the most likely stool microbe in this case is image B. This is because the patient has AIDS, which weakens the immune system, and he swam in a pond near a pasture for cows. This suggests that the most likely cause of his symptoms is an infection with a microbe commonly found in cow feces, such as Escherichia coli (E. coli). Image B shows a gram-negative rod-shaped bacterium, which is consistent with the characteristics of E. coli.

10. A 35-year-old petroleum engineer went to work in Ecuador for a year. His work required him to eat and drink local food and water. Six months after arriving, he experienced a bout of dysentery, which resolved slowly while he took antibiotics. A month later, he noticed fever, tiredness, and pain in the right upper quadrant. A liver scan showed an abscess that measured 5X3 cm and was associated with elevated blood levels of liver enzymes. How did this disease develop?

Motile trophozoites from the colon invaded the liver.

Parasitic cysts from the small intestine invaded the liver

Parasitic eggs traveled in intestinal veins to the liver

Bacteria from ulcers in the colon migrated to the liver

A hepatitis virus infected the liver to cause an abscess

The development of the disease in this case is most likely due to motile trophozoites from the colon invading the liver. This is supported by the symptoms of dysentery, which is an infection of the colon, and the presence of a liver abscess. The abscess is likely caused by the trophozoites spreading from the colon to the liver, leading to elevated liver enzymes and symptoms such as fever, tiredness, and pain in the right upper quadrant.

Explanation

The development of the disease in this case is most likely due to motile trophozoites from the colon invading the liver. This is supported by the symptoms of dysentery, which is an infection of the colon, and the presence of a liver abscess. The abscess is likely caused by the trophozoites spreading from the colon to the liver, leading to elevated liver enzymes and symptoms such as fever, tiredness, and pain in the right upper quadrant.

11. A 35 year old man with a history of multiple abdominal surgeries secondary to a past motor vehicle accident, presents to the ER with abdominal pain and distention. X-ray shows:

Large bowel obstruction secondary to constipation

Small bowel obstruction secondary to diverticulitis

Large bowel obstruction secondary to history of splenectomy

Small bowel obstruction secondary to adhesions

Normal bowel pattern

The correct answer is small bowel obstruction secondary to adhesions. Adhesions are bands of scar tissue that can form after abdominal surgery. These adhesions can cause the small bowel to become twisted or blocked, leading to obstruction. Given the patient's history of multiple abdominal surgeries, it is likely that adhesions have formed and are causing the small bowel obstruction. This is supported by the symptoms of abdominal pain and distention. The other options, such as constipation, diverticulitis, and history of splenectomy, do not explain the findings on the X-ray as well as adhesions do.

Explanation

The correct answer is small bowel obstruction secondary to adhesions. Adhesions are bands of scar tissue that can form after abdominal surgery. These adhesions can cause the small bowel to become twisted or blocked, leading to obstruction. Given the patient's history of multiple abdominal surgeries, it is likely that adhesions have formed and are causing the small bowel obstruction. This is supported by the symptoms of abdominal pain and distention. The other options, such as constipation, diverticulitis, and history of splenectomy, do not explain the findings on the X-ray as well as adhesions do.

12. A 42-year-old woman is hospitalized with a shock-like condition. She is hypovolemic and physical exam and laboratory tests reveal multisystem organ failure. She has a moderate fever, a rapid pulse and diaphoresis. She also complains of constant vague upper right quadrant abdominal pain. She is diagnosed with sepsis and given supportive treatment and antibiotics. An abdominal CT scan reveals an enlarged gall bladder but no calculi. Which of the following would be the most likely cause of her gall bladder condition?

Acute acalculus cholecystitis

Carcinoma of the gall bladder

Choledocholithiasis

Chronic cholecystitis

Primary biliary cirrhosis

The most likely cause of the woman's enlarged gall bladder without calculi is acute acalculus cholecystitis. This condition is characterized by inflammation of the gall bladder in the absence of gallstones. The woman's symptoms of fever, rapid pulse, diaphoresis, and upper right quadrant abdominal pain are consistent with acute cholecystitis. The absence of calculi on the CT scan further supports this diagnosis.

Explanation

The most likely cause of the woman's enlarged gall bladder without calculi is acute acalculus cholecystitis. This condition is characterized by inflammation of the gall bladder in the absence of gallstones. The woman's symptoms of fever, rapid pulse, diaphoresis, and upper right quadrant abdominal pain are consistent with acute cholecystitis. The absence of calculi on the CT scan further supports this diagnosis.

13. The definitive diagnosis of parasitic infections is frequently made by the examination of stool samples for 'ova and parasites'. However, some parasites do not produce ova that may be voided in stool and diagnosis may be made by other means such as tissue biopsy or from a blood smear. Which of the following parasites may be found in tissue sections but not in a stool sample?

Trichinella spiralis

Entamoeba histolytica

Giardia lamblia

Necator americanus

Taenia saginata

Trichinella spiralis may be found in tissue sections but not in a stool sample. This is because Trichinella spiralis is a parasite that primarily infects the muscles of its host, particularly the diaphragm and the muscles of the limbs. The larvae of Trichinella spiralis encyst in the muscle tissue, causing inflammation and damage. Therefore, in order to diagnose a Trichinella spiralis infection, a tissue biopsy would be necessary to examine the muscle tissue for the presence of the parasite. Stool samples would not be useful in detecting this parasite as it does not produce ova that can be found in the stool.

Explanation

Trichinella spiralis may be found in tissue sections but not in a stool sample. This is because Trichinella spiralis is a parasite that primarily infects the muscles of its host, particularly the diaphragm and the muscles of the limbs. The larvae of Trichinella spiralis encyst in the muscle tissue, causing inflammation and damage. Therefore, in order to diagnose a Trichinella spiralis infection, a tissue biopsy would be necessary to examine the muscle tissue for the presence of the parasite. Stool samples would not be useful in detecting this parasite as it does not produce ova that can be found in the stool.

14. This 59 year old male suddenly developed severe abdominal pain and was taken to the emergency room. He had a decreased level of consciousness. Vitals: Heart rate 110, Blood pressure 90/60, Temperature 99⁰F The most likely diagnosis is:

Ruptured diverticuli

Volvulus of large intestine

Infarction of splenic artery

Ruptured aortic aneurysm

The sudden onset of severe abdominal pain, decreased level of consciousness, and abnormal vital signs (elevated heart rate, low blood pressure, and high temperature) suggest a medical emergency. These symptoms are consistent with a ruptured aortic aneurysm, which is a life-threatening condition where the wall of the aorta (the main artery that carries blood from the heart to the rest of the body) tears or bursts. This can cause severe internal bleeding and lead to shock and unconsciousness. Immediate medical intervention is necessary to prevent further complications or death.

Explanation

The sudden onset of severe abdominal pain, decreased level of consciousness, and abnormal vital signs (elevated heart rate, low blood pressure, and high temperature) suggest a medical emergency. These symptoms are consistent with a ruptured aortic aneurysm, which is a life-threatening condition where the wall of the aorta (the main artery that carries blood from the heart to the rest of the body) tears or bursts. This can cause severe internal bleeding and lead to shock and unconsciousness. Immediate medical intervention is necessary to prevent further complications or death.

15. Carl presents with watery diarrhea for 10 days after traveling to Mexico. He is subsequently diagnosed with the following organism: On examination of Carl, one would expect to find:

High fever

Severe abdominal pain

Rapid deep breathing

Markedly foul smelling stools

All of the above

Rapid deep breathing, also known as tachypnea, is not typically associated with diarrhea caused by an infectious organism. It is more commonly seen in conditions such as pneumonia, congestive heart failure, or metabolic acidosis. Therefore, it would be unexpected to find rapid deep breathing in Carl's examination findings.

Explanation

Rapid deep breathing, also known as tachypnea, is not typically associated with diarrhea caused by an infectious organism. It is more commonly seen in conditions such as pneumonia, congestive heart failure, or metabolic acidosis. Therefore, it would be unexpected to find rapid deep breathing in Carl's examination findings.

16. A 40-year-old man was seen by his family doctor following complaints of problems with his memory. He also developed migraine-like headaches and signs of progressive psychosis. His other symptoms included nausea, vomiting, dizziness and focal seizures. Physical examination was essentially normal except for decreased visual acuity. A CT scan showed the presence of a brain lesion. CSF anticysticercal antibodies were demonstrated. Which of the following would be the most probable mode of the infection?

The ingestion of undercooked pork

The bite of an infected mosquito

The ingestion of contaminated food

The bite of a sand fly

The ingestion of fish from contaminated water

The most probable mode of infection in this case is the ingestion of contaminated food. This is suggested by the presence of CSF anticysticercal antibodies, which indicates an infection with the parasite Taenia solium. This parasite is commonly transmitted through the ingestion of undercooked pork that contains the larval stage of the parasite. The symptoms described, such as memory problems, headaches, psychosis, and seizures, are consistent with neurocysticercosis, which occurs when the larvae of Taenia solium infect the central nervous system. Therefore, the ingestion of contaminated food is the most likely mode of infection in this case.

Explanation

The most probable mode of infection in this case is the ingestion of contaminated food. This is suggested by the presence of CSF anticysticercal antibodies, which indicates an infection with the parasite Taenia solium. This parasite is commonly transmitted through the ingestion of undercooked pork that contains the larval stage of the parasite. The symptoms described, such as memory problems, headaches, psychosis, and seizures, are consistent with neurocysticercosis, which occurs when the larvae of Taenia solium infect the central nervous system. Therefore, the ingestion of contaminated food is the most likely mode of infection in this case.

17. An elderly man with a recent irreducible swelling in the right groin complains of severe abdominal pain, projectile vomiting and absolute constipation. You did an abdominal X-Ray and it showed massive dilatation of the small intestine. What it the probable diagnosis?

Pyloric stenosis

Intussusceptions

Indirect inguinal hernia

Superior mesenteric artery embolism

Direct inguinal hernia

An indirect inguinal hernia is a condition where there is a protrusion of abdominal contents through the inguinal canal. In this case, the elderly man's symptoms of severe abdominal pain, projectile vomiting, and absolute constipation, along with the massive dilatation of the small intestine seen on the abdominal X-ray, are consistent with the diagnosis of an indirect inguinal hernia. This condition can cause obstruction of the bowel, leading to the symptoms described.

Explanation

An indirect inguinal hernia is a condition where there is a protrusion of abdominal contents through the inguinal canal. In this case, the elderly man's symptoms of severe abdominal pain, projectile vomiting, and absolute constipation, along with the massive dilatation of the small intestine seen on the abdominal X-ray, are consistent with the diagnosis of an indirect inguinal hernia. This condition can cause obstruction of the bowel, leading to the symptoms described.