Nokea
Microscopy of a sputum smear from a pneumonia patient revealed Gram-positive diplococci with pointed ends surrounded by a capsule. What is the causative agent?
- A. Streptococcus pneumoniae
- B. Klebsiella pneumoniae
- C. Neisseria meningitidis
- D. Staphylococcus aureus
Correct Answer: A
Rationale: The correct answer is A: Streptococcus pneumoniae.
1. Gram-positive diplococci with pointed ends: characteristic morphology of Streptococcus pneumoniae.
2. Surrounded by a capsule: S. pneumoniae is encapsulated, important for virulence.
3. Klebsiella pneumoniae (B) is a Gram-negative rod, Neisseria meningitidis (C) is a Gram-negative diplococcus, and Staphylococcus aureus (D) is a Gram-positive cocci in clusters, not diplococci.
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Your patient is a 22-year-old man. The patient reports that two weeks after unprotected sexual contact, a small ulcer appeared on its penis. The local inguinal lymph nodes are enlarged. Dark field microscopic examination of the ulcer secretions was performed. The test reveals presence of motile, curved spirochete. The most common causative agent of the disease is:
- A. Chlamydia trachoma's
- B. Treponema pallidum
- C. Neisseria gonorrhoeae
- D. Herpes simplex virus, type 2
Correct Answer: B
Rationale: The correct answer is B: Treponema pallidum. The scenario describes symptoms of primary syphilis, which is caused by Treponema pallidum. The presence of a painless ulcer (chancre) and enlarged inguinal lymph nodes are characteristic of syphilis. Dark field microscopic examination showing motile, curved spirochetes is highly specific for Treponema pallidum.
Incorrect explanations:
A: Chlamydia trachomatis typically causes urethritis or cervicitis, not painless ulcers.
C: Neisseria gonorrhoeae causes gonorrhea, which presents with purulent discharge, not painless ulcers.
D: Herpes simplex virus type 2 causes genital herpes, leading to painful ulcers and vesicles, not painless ulcers seen in syphilis.
The primary stage of syphilis is usually manifested as:
- A. Diffuse maculopapular rush
- B. Purulent exudation from the urethra
- C. Syphilitic granulomas (gummas)
- D. Non-tender chancre (ulcus durum)
Correct Answer: D
Rationale: The correct answer is D: Non-tender chancre (ulcus durum). In the primary stage of syphilis, an individual typically develops a painless ulcer known as a chancre at the site of infection. This ulcer is usually firm, round, and clean with well-defined borders. It is important to note that it is non-tender, which distinguishes it from other skin conditions. This characteristic helps healthcare providers differentiate syphilis from other sexually transmitted infections.
Explanation for other choices:
A: Diffuse maculopapular rash - This is more commonly associated with secondary syphilis.
B: Purulent exudation from the urethra - This is not a typical presentation of primary syphilis.
C: Syphilitic granulomas (gummas) - Gummas typically develop in the tertiary stage of syphilis, not in the primary stage.
On the 8th day since the patient was inoculated with antitetanic serum because of dirty wound of his foot he has developed rising temperature up to 380% , pains in the joints, rash and itch. The blood tests revealed leukopenia and thrombocytopenia. Allergic reaction of what type has developed in this case?
- A. Anaphylactic
- B. Cytotoxic
- C. Delayed type of hypersensitivity
- D. Immunocomplex
Correct Answer: D
Rationale: The correct answer is D: Immunocomplex. In this case, the patient's symptoms of fever, joint pains, rash, and itch along with leukopenia and thrombocytopenia indicate a serum sickness reaction. This is a type III hypersensitivity reaction where antigen-antibody complexes deposit in tissues, leading to inflammation and tissue damage. The symptoms typically occur 1-2 weeks after exposure to the antigen. Anaphylactic reaction (choice A) is immediate and involves IgE antibodies. Cytotoxic reaction (choice B) involves destruction of cells by antibodies. Delayed hypersensitivity (choice C) usually takes 48-72 hours to develop and involves T-cells. Therefore, the correct answer is D as it aligns with the symptoms and timeline of a type III hypersensitivity reaction.
Which of the following bacteria is known for causing pneumonia?
- A. Streptococcus pneumoniae
- B. Mycobacterium tuberculosis
- C. Escherichia coli
- D. Pseudomonas aeruginosa
Correct Answer: A
Rationale: The correct answer is A: Streptococcus pneumoniae. This bacteria is known for causing pneumonia due to its ability to infect the lungs and cause inflammation leading to pneumonia symptoms. It is a common cause of community-acquired pneumonia. Mycobacterium tuberculosis (B) causes tuberculosis, not pneumonia. Escherichia coli (C) is associated with urinary tract infections and gastrointestinal infections, not pneumonia. Pseudomonas aeruginosa (D) is known to cause infections in immunocompromised individuals but is not a common cause of pneumonia.
The drug most often used in fighting protozoan infections of the reproductive system is:
- A. ampicillin
- B. tetracycline
- C. ciprofloxacin
- D. metronidazole
Correct Answer: D
Rationale: The correct answer is D: metronidazole. Metronidazole is specifically effective against protozoan infections due to its ability to target and disrupt the DNA of the parasites. It is commonly used to treat infections such as trichomoniasis and giardiasis that affect the reproductive system. Ampicillin (A) and tetracycline (B) are antibiotics that target bacteria, not protozoa. Ciprofloxacin (C) is also an antibiotic that is effective against certain bacterial infections but not protozoan infections. Therefore, metronidazole is the most appropriate choice for fighting protozoan infections of the reproductive system.