Blood and tissue parasites — MCQs

A 42-year-old woman comes to the physician because of episodic abdominal pain and fullness for 1 month. She works as an assistant at an animal shelter and helps to feed and bathe the animals. Physical examination shows hepatomegaly. Abdominal ultrasound shows a 4-cm calcified cyst with several daughter cysts in the liver. She undergoes CT-guided percutaneous aspiration under general anesthesia. Several minutes into the procedure, one liver cyst spills, and the patient's oxygen saturation decreases from 95% to 64%. Her pulse is 136/min, and blood pressure is 86/58 mm Hg. Which of the following is the most likely causal organism of this patient's condition?

A 30-year-old forest landscape specialist is brought to the emergency department with hematemesis and confusion. One week ago, she was diagnosed with influenza when she had fevers, severe headaches, myalgias, hip and shoulder pain, and a maculopapular rash. After a day of relative remission, she developed abdominal pain, vomiting, and diarrhea. A single episode of hematemesis occurred prior to admission. Two weeks ago she visited rainforests and caves in western Africa where she had direct contact with animals, including apes. She has no history of serious illnesses or use of medications. She is restless and her temperature is 38.0°C (100.4°F); pulse, 95/min; respirations, 20/min; and supine and upright blood pressure, 130/70 mm Hg and 100/65 mm Hg, respectively. Conjunctival suffusion is seen. Ecchymoses are observed on the lower extremities. She is bleeding from one of her intravenous lines. The peripheral blood smear is negative for organisms. The laboratory studies show the following: Hemoglobin 10 g/dL Leukocyte count 1,000/mm3 Segmented neutrophils 65% Lymphocytes 20% Platelet count 50,000/mm3 Partial thromboplastin time (activated) 60 seconds Prothrombin time 25 seconds Fibrin split products positive Serum Alanine aminotransferase (ALT) 85 U/L Aspartate aminotransferase (AST) 120 U/L γ-Glutamyltransferase (GGT) 83 U/L (N = 5–50 U/L) Creatinine 2 mg/dL Which of the following is the most likely causal pathogen?

A 28-year-old female in the 2nd trimester of pregnancy is diagnosed with primary Toxoplasma gondii infection. Her physician fears that the fetus may be infected in utero. Which of the following are associated with T. gondii infection in neonates?

A 78-year-old woman living in New Jersey is brought to the emergency department in July with a fever for 5 days. Lethargy is present. She has had bloody urine over the last 48 hours but denies any nausea, vomiting, or abdominal pain. She has no history of serious illness and takes no medications. She has not traveled anywhere outside her city for the past several years. She appears ill. The temperature is 40.8℃ (105.4℉), the pulse is 108/min, the respiration rate is 20/min, and the blood pressure is 105/50 mm Hg. The abdominal exam reveals hepatosplenomegaly. Lymphadenopathy is absent. Petechiae are seen on the lower extremities. Laboratory studies show the following: Laboratory test Hemoglobin 8 g/dL Mean corpuscular volume (MCV) 98 µm3 Leukocyte count 4,200/mm3 Segmented neutrophils 32% Lymphocytes 58% Platelet count 108,000/mm3 Bilirubin, total 5.0 mg/dL Direct 0.7 mg/dL Aspartate aminotransferase (AST) 51 U/L Alanine aminotransferase (ALT) 56 U/L Alkaline phosphatase 180 U/L Lactate dehydrogenase (LDH) 640 U/L (N = 140–280 U/L) Haptoglobin 20 mg/dL (N = 30–200 mg/dL) Urine Hemoglobin + Urobilinogen + Protein + A peripheral blood smear is shown (see image). Which of the following is the most likely diagnosis?

A 50-year-old HIV-positive male presents to the ER with a two-day history of fever and hemoptysis. Chest radiograph shows a fibrocavitary lesion in the right middle lobe. Biopsy of the afflicted area demonstrates septate hyphae that branch at acute angles. Which of the following is the most likely causal organism?

A 31-year-old male traveler in Thailand experiences fever, headache, and excessive sweating every 48 hours. Peripheral blood smear shows trophozoites and schizonts indicative of Plasmodia infection. The patient is given chloroquine and primaquine. Primaquine targets which of the following Plasmodia forms:

A 27-year-old female presents to her primary care physician because she is concerned about lighter colored patches on her skin. She recently went sunbathing and noticed that these areas also did not tan. Her doctor explains that she has a fungal infection of the skin that damages melanocytes by producing acids. She is prescribed selenium sulfide and told to follow-up in one month. Which of the following describes the appearance of the most likely infectious organism under microscopy?

A 45-year-old man presents to the emergency department with abdominal distension. The patient states he has had gradually worsening abdominal distension with undulating pain, nausea, and vomiting for the past several months. The patient does not see a physician typically and has no known past medical history. He works as a farmer and interacts with livestock and also breeds dogs. His temperature is 98.7°F (37.1°C), blood pressure is 159/90 mmHg, pulse is 88/min, respirations are 15/min, and oxygen saturation is 99% on room air. Physical exam is notable for mild abdominal distension and discomfort to palpation of the upper abdominal quadrants. Laboratory values are ordered and are notable for a mild eosinophilia. A CT scan of the abdomen demonstrates multiple small eggshell calcifications within the right lobe of the liver. Which of the following is the most likely etiology of this patient's symptoms?

A 26-year-old male with no significant past medical history goes camping with several friends in Virginia. Several days after returning, he begins to experience fevers, headaches, myalgias, and malaise. He also notices a rash on his wrists and ankles (Figure A). Which of following should be initiated for treatment of his condition?

A 41-year-old male with a history of Pneumocystis jirovecii pneumonia is found to have multiple ring-enhancing lesions on brain CT. Which of the following is most likely responsible for this patient's abnormal scan?