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Question 1
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A 55-year-old rancher presents to the ER with his spouse. He is experiencing a high fever and excessive sweating. During the examination, multiple black blisters are observed, which are producing a malodorous discharge. What is the typical microorganism linked to this ailment?
Your Answer: Clostridium perfringens
Explanation:Gas gangrene is a severe bacterial infection that can lead to muscle necrosis, sepsis, gas production, and ultimately, death. The infection can occur in two ways: through traumatic or surgical inoculation of a wound with bacteria, or spontaneously, which is often observed in immunocompromised patients. While there are multiple causes of gas gangrene, clostridium perfringens, a type of clostridia species, is frequently implicated. The condition typically begins with pain and progresses to systemic symptoms such as fever and dehydration. Skin changes, including blisters that can burst and produce a foul-smelling discharge, are also common. Movement may produce a crackling sound known as crepitus.
Clostridia: Gram-Positive Anaerobic Bacilli
Clostridia are a group of gram-positive, obligate anaerobic bacilli. There are several species of Clostridia, each with their own unique features and pathologies. C. perfringens produces α-toxin, a lecithinase, which can cause gas gangrene and haemolysis. Symptoms of gas gangrene include tender, oedematous skin with haemorrhagic blebs and bullae, and crepitus may be present on palpation. C. botulinum is typically found in canned foods and honey and can cause flaccid paralysis by preventing the release of acetylcholine. C. difficile is known for causing pseudomembranous colitis, which is often seen after the use of broad-spectrum antibiotics. This species produces both an exotoxin and a cytotoxin. Finally, C. tetani produces an exotoxin called tetanospasmin, which prevents the release of glycine from Renshaw cells in the spinal cord, leading to spastic paralysis.
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This question is part of the following fields:
- Infectious Diseases
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Question 2
Incorrect
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Which of the following vaccines utilizes an inactive form of the virus or organism?
Your Answer: Oral polio
Correct Answer: Influenza (intramuscular)
Explanation:Types of Vaccines and Their Characteristics
Vaccines are essential in preventing the spread of infectious diseases. However, it is crucial to understand the different types of vaccines and their characteristics to ensure their safety and effectiveness. Live attenuated vaccines, such as BCG, MMR, and oral polio, may pose a risk to immunocompromised patients. In contrast, inactivated preparations, including rabies and hepatitis A, are safe for everyone. Toxoid vaccines, such as tetanus, diphtheria, and pertussis, use inactivated toxins to generate an immune response. Subunit and conjugate vaccines, such as pneumococcus, haemophilus, meningococcus, hepatitis B, and human papillomavirus, use only part of the pathogen or link bacterial polysaccharide outer coats to proteins to make them more immunogenic. Influenza vaccines come in different types, including whole inactivated virus, split virion, and sub-unit. Cholera vaccine contains inactivated strains of Vibrio cholerae and recombinant B-subunit of the cholera toxin. Hepatitis B vaccine contains HBsAg adsorbed onto aluminium hydroxide adjuvant and is prepared from yeast cells using recombinant DNA technology. Understanding the different types of vaccines and their characteristics is crucial in making informed decisions about vaccination.
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This question is part of the following fields:
- Infectious Diseases
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Question 3
Incorrect
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A 6-year-old girl is brought to her general practitioner by her mother, with a 3-day history of fever up to 37.8 °C. She had no history of lesions on the buccal mucosa but developed a maculopapular rash across the face and trunk. A few days before the appearance of the rash, she complained of some eye pain, sore throat and general body aches. On physical examination, she has a discrete rose-pink maculopapular rash on the face, neck and trunk, low-grade fever and enlarged posterior auricular and suboccipital lymph nodes.
What is the most likely diagnosis?Your Answer: Meningitis
Correct Answer: Rubella
Explanation:Distinguishing Between Viral Diseases: Rubella, Mumps, Meningitis, Scarlet Fever, and Erythema Infectiosum
Rubella, also known as German measles, is a typically mild viral disease that often goes unnoticed, with almost half of those infected showing no symptoms. However, it can have severe consequences for pregnant women, especially in the early stages of pregnancy. Symptoms include eye pain, sore throat, low-grade fever, and a rose-pink rash that starts on the face and spreads to the trunk and extremities within 24 hours.
Mumps is another viral disease caused by rubulavirus. It typically presents with low-grade fever, malaise, headache, and myalgia, followed by painful swelling of the salivary glands and tender cervical lymphadenopathy. Mumps is highly contagious and has become less common in developing countries due to vaccination.
Meningitis is a serious condition characterized by inflammation of the meninges. Symptoms include fever, headache, and neck stiffness, and it requires urgent medical attention.
Scarlet fever is caused by group A β-hemolytic streptococci and presents with exudative pharyngitis, fever, and a bright red rash. It typically evolves from a tonsillar/pharyngeal focus and is uncommon without buccal lesions.
Erythema infectiosum, also known as fifth disease, is a mild childhood illness caused by parvovirus B19. It presents with a bright red rash on the cheeks and may have atypical rashes in adults.
It is important to distinguish between these viral diseases to ensure proper treatment and prevent complications.
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This question is part of the following fields:
- Infectious Diseases
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Question 4
Incorrect
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A previously healthy 27-year-old man presents with abdominal discomfort and shortness of breath. He has been experiencing a dry cough for the past two weeks. He works as a full-time accountant, does not smoke, and drinks approximately 15 units of alcohol per week. He recently went on a trip to Amsterdam with some friends. He has also noticed a widespread skin rash with pink rings and pale centers. Upon admission, his blood work shows low sodium levels, normal potassium levels, elevated urea levels, and high creatinine levels. His chest x-ray reveals diffuse reticular infiltrates and a small pleural effusion on the right side. What is the most likely organism responsible for his symptoms?
Your Answer: Pneumocystis jiroveci
Correct Answer: Mycoplasma pneumoniae
Explanation:Typical presentation of mycoplasma pneumonia includes flu-like symptoms that progressively worsen and a dry cough. During examination, the patient may exhibit erythema multiforme, indicating the presence of the infection. This type of pneumonia is commonly acquired within the community. Although Streptococcus pneumoniae is also a possible cause, it is not the focus of this particular case.
Mycoplasma pneumoniae: A Cause of Atypical Pneumonia
Mycoplasma pneumoniae is a type of bacteria that causes atypical pneumonia, which is more common in younger patients. This disease is associated with various complications such as erythema multiforme and cold autoimmune haemolytic anaemia. Epidemics of Mycoplasma pneumoniae typically occur every four years. It is important to recognize atypical pneumonia because it may not respond to penicillins or cephalosporins due to the bacteria lacking a peptidoglycan cell wall.
The disease usually has a gradual onset and is preceded by flu-like symptoms, followed by a dry cough. X-rays may show bilateral consolidation. Complications may include cold agglutinins, erythema multiforme, erythema nodosum, meningoencephalitis, Guillain-Barre syndrome, bullous myringitis, pericarditis/myocarditis, and gastrointestinal and renal problems.
Diagnosis is generally made through Mycoplasma serology and a positive cold agglutination test. Management involves the use of doxycycline or a macrolide such as erythromycin or clarithromycin.
In comparison to Legionella pneumonia, which is caused by a different type of bacteria, Mycoplasma pneumoniae has a more gradual onset and is associated with different complications. It is important to differentiate between the two types of pneumonia to ensure appropriate treatment.
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This question is part of the following fields:
- Infectious Diseases
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Question 5
Incorrect
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A 50-year-old woman started treatment for tuberculosis infection 3 months ago and now complains of a burning sensation at the base of her feet. Which medication could be responsible for this new symptom?
Your Answer: Ethambutol
Correct Answer: Isoniazid
Explanation:Isoniazid treatment may lead to a deficiency of vitamin B6, which can result in peripheral neuropathy. This is a well-known side effect of TB medications that is often tested in medical school exams. The patient’s symptoms suggest the possibility of peripheral neuropathy caused by a lack of vitamin B6 due to Isoniazid therapy. Typically, pyridoxine hydrochloride is prescribed concurrently with Isoniazid to prevent peripheral neuropathy.
The Importance of Vitamin B6 in the Body
Vitamin B6 is a type of water-soluble vitamin that belongs to the B complex group. Once it enters the body, it is converted into pyridoxal phosphate (PLP), which acts as a cofactor for various reactions such as transamination, deamination, and decarboxylation. These reactions are essential for the proper functioning of the body.
One of the primary causes of vitamin B6 deficiency is isoniazid therapy, which is a medication used to treat tuberculosis. When the body lacks vitamin B6, it can lead to peripheral neuropathy, which is a condition that affects the nerves outside the brain and spinal cord. It can also cause sideroblastic anemia, which is a type of anemia that affects the production of red blood cells.
Overall, vitamin B6 plays a crucial role in the body, and its deficiency can have severe consequences. It is essential to ensure that the body receives an adequate amount of this vitamin through a balanced diet or supplements.
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This question is part of the following fields:
- Infectious Diseases
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Question 6
Incorrect
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You want to screen a 60-year-old patient for hepatitis B. What is the most appropriate test to conduct?
Your Answer: Hepatitis B viral load
Correct Answer: HBsAg
Explanation:If the result of the anti-HBs test is positive, it means that the person is immune to hepatitis B either through vaccination or previous infection. On the other hand, a positive HBsAg test indicates that the person is currently infected with hepatitis B, either in its acute or chronic form.
Interpreting hepatitis B serology is an important skill that is still tested in medical exams. It is crucial to keep in mind a few key points. The surface antigen (HBsAg) is the first marker to appear and triggers the production of anti-HBs. If HBsAg is present for more than six months, it indicates chronic disease, while its presence for one to six months implies acute disease. Anti-HBs indicates immunity, either through exposure or immunization, and is negative in chronic disease. Anti-HBc indicates previous or current infection, with IgM anti-HBc appearing during acute or recent hepatitis B infection and persisting IgG anti-HBc. HbeAg is a marker of infectivity and HBV replication.
To illustrate, if someone has been previously immunized, their anti-HBs will be positive, while all other markers will be negative. If they had hepatitis B more than six months ago but are not a carrier, their anti-HBc will be positive, and HBsAg will be negative. However, if they are now a carrier, both anti-HBc and HBsAg will be positive. If HBsAg is present, it indicates an ongoing infection, either acute or chronic if present for more than six months. On the other hand, anti-HBc indicates that the person has caught the virus, and it will be negative if they have been immunized.
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This question is part of the following fields:
- Infectious Diseases
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Question 7
Incorrect
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A 32-year-old male patient visits the sexual health clinic complaining of a recent genital lesion. The patient reports experiencing severe pain and first noticed the lesion one week ago. He admits to engaging in unprotected sexual activity with multiple partners within the past three months. Upon examination, a deep ulcer with a ragged border is observed on the penis shaft, accompanied by tenderness and inguinal lymphadenopathy. What is the probable diagnosis?
Your Answer: Gonorrhoea
Correct Answer: Chancroid
Explanation:The man’s ulcer appears to be caused by chancroid, which is known for causing deep and painful genital ulcers accompanied by inguinal lymphadenopathy. Gonorrhoea is an unlikely diagnosis as it typically presents with penile discharge and no ulceration. Herpes simplex can also cause painful genital ulcers, but they are usually multiple and superficial, and inguinal lymphadenopathy is not as common as with chancroid. Lymphogranuloma venereum causes painless ulceration that heals quickly, while primary syphilis causes a painless ulcer called a chancre.
Understanding Chancroid: A Painful Tropical Disease
Chancroid is a disease that is commonly found in tropical regions and is caused by a bacterium called Haemophilus ducreyi. This disease is characterized by the development of painful genital ulcers that are often accompanied by painful swelling of the lymph nodes in the groin area. The ulcers themselves are typically easy to identify, as they have a distinct border that is ragged and undermined.
Chancroid is a disease that can be quite painful and uncomfortable for those who are affected by it.
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This question is part of the following fields:
- Infectious Diseases
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Question 8
Incorrect
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When visiting a 60-year-old patient at home to do a wound dressing, the District Nurse wants to confirm if the patient has received complete tetanus vaccination. What is the number of tetanus vaccine doses required for life-long protection?
Your Answer: 2
Correct Answer: 5
Explanation:Tetanus Vaccination and Management of Wounds
The tetanus vaccine is a purified toxin that is given as part of a combined vaccine. In the UK, it is given as part of the routine immunisation schedule at 2, 3, and 4 months, 3-5 years, and 13-18 years, providing a total of 5 doses for long-term protection against tetanus.
When managing wounds, the first step is to classify them as clean, tetanus-prone, or high-risk tetanus-prone. Clean wounds are less than 6 hours old and have negligible tissue damage, while tetanus-prone wounds include puncture-type injuries acquired in a contaminated environment or wounds containing foreign bodies. High-risk tetanus-prone wounds include wounds or burns with systemic sepsis, certain animal bites and scratches, heavy contamination with material likely to contain tetanus spores, wounds or burns with extensive devitalised tissue, and wounds or burns that require surgical intervention.
If the patient has had a full course of tetanus vaccines with the last dose less than 10 years ago, no vaccine or tetanus immunoglobulin is required regardless of the wound severity. If the patient has had a full course of tetanus vaccines with the last dose more than 10 years ago, a reinforcing dose of vaccine is required for tetanus-prone wounds, and a reinforcing dose of vaccine plus tetanus immunoglobulin is required for high-risk wounds. If the vaccination history is incomplete or unknown, a reinforcing dose of vaccine is required regardless of the wound severity, and a reinforcing dose of vaccine plus tetanus immunoglobulin is required for tetanus-prone and high-risk wounds.
Overall, proper vaccination and wound management are crucial in preventing tetanus infection.
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This question is part of the following fields:
- Infectious Diseases
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Question 9
Incorrect
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A 25-year-old woman presents to the Genitourinary Medicine Clinic with a 1-week history of a change in her vaginal discharge. She says it has a thin and white consistency with a fishy odour. There is no history of abdominal pain or urinary symptoms. She is sexually active with one regular partner and takes the combined oral contraceptive pill regularly.
On examination, her observations are within normal limits. Her abdomen is soft and nontender. Bimanual examination is unremarkable, with no adnexal tenderness elicited.
Microscopic examination reveals the presence of clue cells.
What is the most likely diagnosis?
Select the SINGLE likely diagnosis from the list below.
Select ONE option only.Your Answer: Trichomoniasis
Correct Answer: Bacterial vaginosis
Explanation:Sexually Transmitted Infections: Differentiating Bacterial Vaginosis from Other Common STIs
Bacterial vaginosis is a non-sexually transmitted infection caused by an overgrowth of Gardnerella vaginalis. It is characterized by a fishy-smelling vaginal discharge and a raised vaginal pH due to reduced lactobacilli. Clue cells on microscopy aid in diagnosis.
Chlamydia is the most contagious sexually transmitted infection, but the absence of clue cells makes it an unlikely diagnosis. Gonorrhoea, the second most common STI, presents with urethral or vaginal discharge and dysuria, but does not involve clue cells.
Syphilis, caused by Treponema pallidum, has three stages of infection, but the primary and secondary stages involve symptoms not present in this patient. Trichomoniasis, caused by Trichomonas vaginalis, presents with an offensive discharge, raised vaginal pH, and a strawberry cervix, but the presence of clue cells makes it an unlikely diagnosis.
It is important to differentiate between these common STIs and bacterial vaginosis to ensure appropriate treatment and prevent further complications.
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This question is part of the following fields:
- Infectious Diseases
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Question 10
Incorrect
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A 25-year-old patient visits their doctor with suspected tonsillitis recurrence. They report having had tonsillitis three times in the past year and currently have a fever and cough. During the examination, the doctor notes tender cervical lymphadenopathy and exudative tonsils. The patient is prescribed phenoxymethylpenicillin. On day 5 of treatment, blood tests are taken and reveal the following results:
Hb 150 g/L Male: (135-180) Female: (115 - 160)
Platelets 390 * 109/L (150 - 400)
WBC 10.2 * 109/L (4.0 - 11.0)
Neuts 0.8 * 109/L (2.0 - 7.0)
Lymphs 9.2 * 109/L (1.0 - 3.5)
Mono 0.2 * 109/L (0.2 - 0.8)
Eosin 0.0 * 109/L (0.0 - 0.4)
What could be the possible reasons for the abnormalities in these blood results?Your Answer: Tonsillitis unresponsive to treatment
Correct Answer: Underlying diagnosis of glandular fever
Explanation:The presence of lymphocytosis and neutropenia in a person who has been treated for recurrent tonsillitis may indicate an underlying condition. Glandular fever, caused by the Epstein-Barr virus, is a common cause of recurrent tonsillitis in young people and can result in an increase in activated T and B lymphocytes, leading to lymphocytosis. The virus may also cause neutropenia, although the exact cause is not fully understood. A peritonsillar abscess, tonsillitis unresponsive to treatment, and treatment with phenoxymethylpenicillin are unlikely to cause significant abnormalities in the full blood count. While lymphoma may explain the lymphocytosis, it would not account for the neutropenia and is less likely than an underlying glandular fever infection.
Understanding Neutropaenia: Causes and Severity
Neutropaenia is a medical condition characterized by low neutrophil counts, which is below 1.5 * 109. A normal neutrophil count ranges from 2.0 to 7.5 * 109. It is crucial to recognize this condition as it increases the risk of severe infections. Neutropaenia can be classified into three categories based on its severity: mild (1.0 – 1.5 * 109), moderate (0.5 – 1.0 * 109), and severe (< 0.5 * 109). There are several causes of neutropaenia, including viral infections such as HIV, Epstein-Barr virus, and hepatitis. Certain drugs like cytotoxics, carbimazole, and clozapine can also cause neutropaenia. Benign ethnic neutropaenia is common in people of black African and Afro-Caribbean ethnicity, but it requires no treatment. Haematological malignancies like myelodysplastic malignancies and aplastic anemia, as well as rheumatological conditions like systemic lupus erythematosus and rheumatoid arthritis, can also cause neutropaenia. Severe sepsis and haemodialysis are other potential causes of neutropaenia. In summary, neutropaenia is a medical condition that can increase the risk of severe infections. It is important to recognize its severity and underlying causes to provide appropriate treatment and management.
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This question is part of the following fields:
- Infectious Diseases
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Question 11
Incorrect
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A 45-year-old man presents to his General Practitioner with a 7-day history of flu-like symptoms, including spiking fevers, headache, rigors, vomiting and diarrhoea.
On examination, he looks unwell, is febrile and jaundiced. His abdomen is soft, with mild, generalised tenderness and hepatosplenomegaly. He returned from Nigeria six months ago after a 8-week stay with a charity mission. He had all the appropriate travel vaccinations and took mefloquine prophylaxis.
What is the most likely diagnosis?Your Answer: Hepatitis A
Correct Answer: Malaria
Explanation:Travel-Related Illnesses: Symptoms, Diagnosis, and Treatment
Malaria, Yellow Fever, Enteric Fever, Hepatitis A, and Schistosomiasis are some of the common travel-related illnesses that can affect people visiting certain parts of the world.
Malaria is a potentially life-threatening illness caused by a parasite transmitted by mosquitoes. Symptoms include headache, cough, fatigue, fever with rigors, nausea, vomiting, and diarrhea. Diagnosis is made through thick and thin blood films, and treatment should be guided by an infectious disease specialist.
Yellow fever is an insect-borne tropical disease with symptoms that may include a flu-like illness, jaundice, and abnormal bleeding. It has a short incubation period of 3-6 days and is transmitted by mosquitoes. Vaccination is recommended for travelers to high-risk areas.
Enteric fever is caused by salmonella typhoid or paratyphoid and is transmitted orally via contaminated food or drink. Symptoms include severe flu-like symptoms, especially diarrhea and fever. Diagnosis is made through blood cultures, and treatment is with antibiotics.
Hepatitis A is a viral infection transmitted via contaminated food or water. Symptoms include a flu-like illness, jaundice, and tender hepatomegaly. Diagnosis is made through blood tests, and treatment is supportive.
Schistosomiasis is a parasitic infection spread by flatworms that live in freshwater. Symptoms can include fever, rash, abdominal pain, and diarrhea. Chronic infection may present as rectal bleeding, hematuria, anemia, or cystitis. Diagnosis is made through blood and stool tests, and treatment is with antiparasitic medication.
In conclusion, travelers to certain parts of the world should be aware of the risk of these illnesses and take appropriate precautions, including vaccination, prophylaxis, and avoiding contaminated food and water. If symptoms develop, prompt medical attention should be sought.
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This question is part of the following fields:
- Infectious Diseases
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Question 12
Incorrect
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A 25-year-old student presents to the Emergency Department with confusion and recurring fevers. He describes a flu-like illness in recent days, with myalgia and rigours every two days. He has previously been well, other than an episode of suspected malaria on a gap year in Brazil three years ago, which was felt to be successfully treated. He has not been abroad since.
On examination, he has splenomegaly, scleral icterus and a temperature of 39.1°C.
Investigations reveal the following:
Investigation Result Normal value
Haemoglobin (Hb) 95 g/l 135–175 g/l
White Cell Count (WCC) 14 × 109/l 4.0–11.0 × 109/l
Platelets (PLT) 100 × 109 150–450× 109/l
Blood film Awaited
Which of the following is the most likely causative organism?Your Answer: Dengue virus
Correct Answer: Plasmodium vivax
Explanation:Differential Diagnosis for a Patient with Fluctuating Pyrexia: Malaria vs. Other Causes
The patient in question is experiencing fluctuating rigours of malaria, despite not having been in a malaria-affected zone for two years. This suggests a recurrence of pre-existing malaria, with the most likely subtype being P. vivax due to its ability to lie dormant in the liver for extended periods. While dengue fever is a possibility, the history of fluctuating pyrexia is more indicative of malaria, which also causes anaemia and thrombocytopenia. P. falciparum is a reasonable differential, but less likely given the patient’s travel history. P. malariae is rare and typically presents with fevers recurring every three days, making it less likely. Yellow fever is also unlikely due to the patient’s travel timeline and lack of jaundice. Overall, malaria is the most likely cause of the patient’s symptoms.
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This question is part of the following fields:
- Infectious Diseases
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Question 13
Incorrect
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A 28-year-old woman is seeking screening for sexually transmitted infections due to starting a new relationship. What is the most frequently diagnosed sexually transmitted infection in the UK?
Your Answer: Genital herpes
Correct Answer: Chlamydia
Explanation:Chlamydia is a common sexually transmitted infection caused by Chlamydia trachomatis. It is prevalent in the UK, with approximately 1 in 10 young women affected. The incubation period is around 7-21 days, but many cases are asymptomatic. Symptoms in women include cervicitis, discharge, and bleeding, while men may experience urethral discharge and dysuria. Complications can include epididymitis, pelvic inflammatory disease, and infertility.
Traditional cell culture is no longer widely used for diagnosis, with nuclear acid amplification tests (NAATs) being the preferred method. Testing can be done using urine, vulvovaginal swab, or cervical swab. Screening is recommended for sexually active individuals aged 15-24 years, and opportunistic testing is common.
Doxycycline is the first-line treatment for Chlamydia, with azithromycin as an alternative if doxycycline is contraindicated or not tolerated. Pregnant women may be treated with azithromycin, erythromycin, or amoxicillin. Patients diagnosed with Chlamydia should be offered partner notification services, with all contacts since the onset of symptoms or within the last six months being notified and offered treatment.
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This question is part of the following fields:
- Infectious Diseases
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Question 14
Incorrect
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A 50-year-old man with a persistent chest infection visits the clinic for evaluation. Despite two rounds of antibiotics, there has been no significant improvement. The medical team decides to conduct a chest x-ray and screening blood tests. When analyzing the blood tests, which of the following markers is typically not elevated in response to an acute infection?
Your Answer: Ferritin
Correct Answer: Albumin
Explanation:A decrease in albumin levels is frequently observed after an acute phase response.
Acute phase proteins are a group of proteins that are produced by the liver in response to inflammation or infection. These proteins are involved in various physiological processes such as immune response, blood clotting, and iron metabolism. Examples of acute phase proteins include CRP, procalcitonin, ferritin, fibrinogen, alpha-1 antitrypsin, caeruloplasmin, serum amyloid A, serum amyloid P component, haptoglobin, and complement.
During the acute phase response, the liver decreases the production of other proteins known as negative acute phase proteins. These proteins include albumin, transthyretin, transferrin, retinol binding protein, and cortisol binding protein. The levels of acute phase proteins, particularly CRP, are commonly measured in acutely unwell patients. Elevated levels of CRP are indicative of inflammation or infection, and levels greater than 150 at 48 hours post-surgery suggest the development of complications.
It is important to note that while acute phase proteins play a significant role in humans, some of these proteins, such as serum amyloid P component, have a more significant role in other mammals like mice. Overall, the production of acute phase proteins is a crucial part of the body’s response to inflammation or infection, and monitoring their levels can aid in the diagnosis and management of various medical conditions.
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This question is part of the following fields:
- Infectious Diseases
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Question 15
Incorrect
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You are working in a GP surgery and you meet a 25-year-old newly qualified healthcare assistant who has come in to see you as she would like to know more about the BCG vaccination and whether she needs to have it. You advise her that she will need the BCG as she is at risk of occupational exposure. She would also like to know more about who needs to have the BCG vaccination.
Who needs a BCG vaccination assuming they have not had one before?Your Answer: A 36-year-old woman who has started to work as a secretary in a GP practice
Correct Answer: A 22-year-old man who has started work as a prison officer
Explanation:Children born in areas with a high prevalence of tuberculosis (TB) or with parents/grandparents from such areas, as well as individuals under the age of 35 at high risk of occupational exposure to TB, are administered the BCG vaccine. However, there is no evidence to support the effectiveness of the BCG vaccine for individuals over the age of 35, and therefore it is not administered to them.
The BCG Vaccine: Who Should Get It and How It’s Administered
The Bacille Calmette-Guérin (BCG) vaccine is a vaccine that provides limited protection against tuberculosis (TB). In the UK, it is given to high-risk infants and certain groups of people who are at risk of contracting TB. The vaccine contains live attenuated Mycobacterium bovis and also offers limited protection against leprosy.
The Greenbook provides guidelines on who should receive the BCG vaccine. It is recommended for all infants living in areas of the UK where the annual incidence of TB is 40/100,000 or greater, as well as infants with a parent or grandparent who was born in a country with a high incidence of TB. The vaccine is also recommended for previously unvaccinated tuberculin-negative contacts of cases of respiratory TB, new entrants under 16 years of age who were born in or have lived for a prolonged period in a high-risk country, healthcare workers, prison staff, staff of care homes for the elderly, and those who work with homeless people.
Before receiving the BCG vaccine, any person being considered must first be given a tuberculin skin test, except for children under 6 years old who have had no contact with tuberculosis. The vaccine is given intradermally, normally to the lateral aspect of the left upper arm. It can be given at the same time as other live vaccines, but if not administered simultaneously, there should be a 4-week interval.
There are some contraindications for the BCG vaccine, including previous BCG vaccination, a past history of tuberculosis, HIV, pregnancy, and a positive tuberculin test (Heaf or Mantoux). It is not given to anyone over the age of 35, as there is no evidence that it works for people of this age group.
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This question is part of the following fields:
- Infectious Diseases
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Question 16
Incorrect
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A 28-year-old female visited her doctor complaining of a 3-week history of excessive malodorous vaginal discharge. Microscopy revealed the presence of clue cells, and she was diagnosed with Gardnerella vaginalis-induced bacterial vaginosis.
What would be the appropriate treatment option?Your Answer: Co-amoxiclav
Correct Answer: Metronidazole
Explanation:Common Antibiotics and Antifungals: Uses and Dosages
Metronidazole, Azithromycin, Co-amoxiclav, Fluconazole, and Nystatin are common antibiotics and antifungals used to treat various infections. Metronidazole is recommended for bacterial vaginosis and can be taken orally or applied topically. Azithromycin is used for Chlamydia, gonorrhea, and chancroid. Co-amoxiclav is a broad-spectrum antibiotic used for respiratory and urinary tract infections, among others. Fluconazole is an oral antifungal used for severe oral and vaginal candidiasis. Nystatin is an antifungal used for oral candidiasis. Dosages and treatment durations vary depending on the specific infection being treated.
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This question is part of the following fields:
- Infectious Diseases
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Question 17
Incorrect
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A 29-year-old man who has recently arrived in the UK from Uganda visits the clinic with complaints of exhaustion and purple skin lesions all over his body. During the examination, you observe multiple raised purple lesions on his trunk and arms. Additionally, you notice some smaller purple lesions in his mouth. He has recently initiated acyclovir treatment for herpes zoster infection. What is the probable diagnosis?
Your Answer: Haemangioma
Correct Answer: Kaposi's sarcoma
Explanation:The presence of raised purple lesions is a typical indication of Kaposi’s sarcoma, which may suggest that the patient has an underlying HIV infection. Given the high prevalence of HIV in Uganda and the recent occurrence of herpes zoster, it is possible that the patient’s immune system is compromised. Dermatofibromas, which are typically small and firm, would not be found in the mouth, while psoriasis is characterized by red, scaly lesions that do not appear on mucosal surfaces. A drug reaction is an unlikely explanation for the patient’s symptoms. Although a haemangioma can present as a purple raised lesion, it is uncommon to find them in the mouth, and Kaposi’s sarcoma is a more likely diagnosis in this case.
Kaposi’s Sarcoma in HIV Patients
Kaposi’s sarcoma is a type of cancer that is commonly seen in patients with HIV. It is caused by the human herpes virus 8 (HHV-8) and is characterized by the appearance of purple papules or plaques on the skin or mucosa. These lesions may later ulcerate, causing discomfort and pain. In some cases, respiratory involvement may occur, leading to massive haemoptysis and pleural effusion.
Treatment for Kaposi’s sarcoma typically involves a combination of radiotherapy and resection. This can help to reduce the size of the lesions and prevent further spread of the cancer. However, it is important to note that Kaposi’s sarcoma can be a serious and potentially life-threatening condition, particularly in patients with HIV. As such, it is important for individuals with HIV to be regularly screened for this condition and to seek prompt medical attention if any symptoms are present.
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This question is part of the following fields:
- Infectious Diseases
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Question 18
Incorrect
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A 29-year-old individual visits the GP complaining of explosive diarrhoea and vomiting that started 24 hours ago. Upon further inquiry, the patient denies any presence of blood in their stool and has not traveled abroad recently. The patient mentions consuming rice that was kept warm in a rice cooker for multiple days. What is the probable causative agent responsible for the patient's symptoms?
Your Answer: Campylobacter jejuni
Correct Answer: Bacillus cereus
Explanation:It is probable that this young man is suffering from toxigenic food poisoning caused by Bacillus cereus, which is known to occur after consuming reheated rice. The spores of Bacillus cereus germinate in cooked rice and produce toxins if the cooked product is not adequately chilled. While S. aureus can also cause toxigenic food poisoning, the specific history of this case makes it less likely to be the underlying organism. Norwalk virus, on the other hand, can cause severe diarrhea and vomiting, but it is not associated with any particular food item. Bacterial food poisoning caused by Campylobacter and Shigella typically involves a longer history of bloody diarrhea.
Gastroenteritis can occur either at home or while traveling, known as travelers’ diarrhea. This condition is characterized by at least three loose to watery stools in 24 hours, accompanied by abdominal cramps, fever, nausea, vomiting, or blood in the stool. The most common cause of travelers’ diarrhea is Escherichia coli. Acute food poisoning is another pattern of illness that results in sudden onset of nausea, vomiting, and diarrhea after ingesting a toxin. Staphylococcus aureus, Bacillus cereus, or Clostridium perfringens are typically responsible for acute food poisoning.
There are several types of infections that can cause gastroenteritis, each with its own typical presentation. Escherichia coli is common among travelers and causes watery stools, abdominal cramps, and nausea. Giardiasis results in prolonged, non-bloody diarrhea, while cholera causes profuse, watery diarrhea and severe dehydration leading to weight loss. Shigella causes bloody diarrhea, vomiting, and abdominal pain, while Staphylococcus aureus results in severe vomiting with a short incubation period. Campylobacter typically starts with a flu-like prodrome and progresses to crampy abdominal pains, fever, and diarrhea, which may be bloody and mimic appendicitis. Bacillus cereus can cause two types of illness, vomiting within six hours, typically due to rice, or diarrheal illness occurring after six hours. Amoebiasis has a gradual onset of bloody diarrhea, abdominal pain, and tenderness that may last for several weeks.
The incubation period for gastroenteritis varies depending on the type of infection. Staphylococcus aureus and Bacillus cereus have an incubation period of 1-6 hours, while Salmonella and Escherichia coli have an incubation period of 12-48 hours. Shigella and Campylobacter have an incubation period of 48-72 hours, while Giardiasis and Amoebiasis have an incubation period of more than seven days.
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This question is part of the following fields:
- Infectious Diseases
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Question 19
Correct
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A 35-year-old HIV positive man comes to your travel clinic seeking advice on vaccinations for his upcoming trip. He is currently on antiretroviral therapy and his most recent CD4 count is 180 cells/mm³. He has no other medical conditions and is feeling well.
Which vaccines should be avoided in this individual?Your Answer: Tuberculosis (BCG)
Explanation:Patients who are HIV positive should not receive live attenuated vaccines like BCG. Additionally, immunocompromised individuals should avoid other live attenuated vaccines such as yellow fever, oral polio, intranasal influenza, varicella, and measles, mumps, and rubella (MMR). This information is sourced from uptodate.
Types of Vaccines and Their Characteristics
Vaccines are essential in preventing the spread of infectious diseases. However, it is crucial to understand the different types of vaccines and their characteristics to ensure their safety and effectiveness. Live attenuated vaccines, such as BCG, MMR, and oral polio, may pose a risk to immunocompromised patients. In contrast, inactivated preparations, including rabies and hepatitis A, are safe for everyone. Toxoid vaccines, such as tetanus, diphtheria, and pertussis, use inactivated toxins to generate an immune response. Subunit and conjugate vaccines, such as pneumococcus, haemophilus, meningococcus, hepatitis B, and human papillomavirus, use only part of the pathogen or link bacterial polysaccharide outer coats to proteins to make them more immunogenic. Influenza vaccines come in different types, including whole inactivated virus, split virion, and sub-unit. Cholera vaccine contains inactivated strains of Vibrio cholerae and recombinant B-subunit of the cholera toxin. Hepatitis B vaccine contains HBsAg adsorbed onto aluminium hydroxide adjuvant and is prepared from yeast cells using recombinant DNA technology. Understanding the different types of vaccines and their characteristics is crucial in making informed decisions about vaccination.
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This question is part of the following fields:
- Infectious Diseases
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Question 20
Incorrect
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A 3-day-old infant delivered via caesarean section at 38 weeks gestation presents with limb hypoplasia, rudimentary digits, and microcephaly. What is the probable prenatal infection that the baby was exposed to?
Your Answer: Cytomegalovirus
Correct Answer: Varicella zoster virus
Explanation:During pregnancy, if a woman shows signs of primary infection with varicella zoster, it is considered a classical indication. The risk to the fetus is highest before 20 weeks of gestation and can lead to skin scarring, limb underdevelopment, microcephaly, and eye defects. If there is any uncertainty about a pregnant woman’s history of chickenpox, she should be tested for varicella antibodies and given varicella zoster immunoglobulins if she is not immune. Cytomegalovirus infection during pregnancy can result in cerebral calcification, microcephaly, and sensorineural deafness. HIV does not pose any physical risk to the developing fetus, but there is a risk of perinatal transmission. Rubella infections during pregnancy are linked to deafness, congenital cataracts, and cardiac complications.
Chickenpox exposure in pregnancy can pose risks to both the mother and fetus, including fetal varicella syndrome. Post-exposure prophylaxis (PEP) with varicella-zoster immunoglobulin (VZIG) or antivirals should be given to non-immune pregnant women, with timing dependent on gestational age. If a pregnant woman develops chickenpox, specialist advice should be sought and oral aciclovir may be given if she is ≥ 20 weeks and presents within 24 hours of onset of the rash.
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This question is part of the following fields:
- Infectious Diseases
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Question 21
Incorrect
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A 28-year-old female is admitted to the Medical Admissions Unit with symptoms of neck stiffness, photophobia, and fever. No rash is present, and her GCS is 15. Upon lumbar puncture, her CSF shows increased opening pressure and turbidity, with a raised white cell count and low glucose. Ceftriaxone is initiated, but what additional treatment is necessary to enhance outcomes?
Your Answer: Vancomycin
Correct Answer: Dexamethasone
Explanation:The patient’s presentation and CSF results strongly suggest bacterial meningitis, for which appropriate antibiotic therapy has been initiated. To improve neurological outcomes and reduce the risk of sequelae such as deafness, dexamethasone is the recommended additional treatment. However, it should be noted that dexamethasone is contraindicated in cases of septic shock or meningococcal septicaemia. Antivirals such as aciclovir are not indicated in bacterial meningitis, while fluconazole, an anti-fungal, is also not appropriate. Prednisolone has no role in the treatment of meningitis.
The investigation and management of suspected bacterial meningitis are intertwined due to the potential negative impact of delayed antibiotic treatment. Patients should be urgently transferred to the hospital, and an ABC approach should be taken initially. A lumbar puncture should be delayed in certain circumstances, and IV antibiotics should be given as a priority if there is any doubt. The bloods and CSF should be tested for various parameters, and prophylaxis should be offered to households and close contacts of patients affected with meningococcal meningitis.
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This question is part of the following fields:
- Infectious Diseases
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Question 22
Incorrect
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You are asked to review an elderly nursing home resident who has generalised inflammation of his oropharynx and is finding it difficult to eat. His past history of note includes the use of a steroid inhaler for chronic obstructive pulmonary disease (COPD). On examination, there are areas of erythema and a number of white plaques accompanied by some white, curd-like material.
Which diagnosis best fits this clinical picture?Your Answer: Hairy leukoplakia
Correct Answer: Oropharyngeal candidiasis
Explanation:Differential Diagnosis of Oral Lesions: Candidiasis, HIV Infection, Hairy Leukoplakia, Darier’s Disease, and Leukoedema
Oral lesions can present in various forms and have different underlying causes. In the case of an elderly man with long-term use of a steroid inhaler for COPD, poor oral hygiene, and possibly poorly fitting prosthetics, the most likely diagnosis is oropharyngeal candidiasis. This yeast-like fungal infection can be treated with antifungal medication, applied to the oral mucosa and any removable oral prostheses, and soaking the latter in an antifungal denture-soaking solution.
HIV infection can also cause oral lesions, primarily in patients with advanced disease. Candidiasis is a common opportunistic infection in these patients, but hairy leukoplakia, associated with Epstein-Barr virus, can also occur. Hairy leukoplakia presents as painless white lesions on the tongue or buccal mucosa, with a characteristic hairy appearance that cannot be scraped off.
Darier’s disease is a rare genetic disorder that causes greasy hyperkeratotic papules in seborrhoeic regions, nail abnormalities, and mucous membrane changes. Mucosal lesions are found in approximately 15% of patients, appearing as white papules with a central depression, most commonly in the mouth.
Leukoedema is a benign condition characterized by a blue, grey, or white appearance of the oral mucosa, with wrinkled, streaky lesions, mostly found on the inside of the cheeks. It is more common and pronounced in smokers.
In summary, the differential diagnosis of oral lesions includes candidiasis, HIV infection, hairy leukoplakia, Darier’s disease, and leukoedema. A thorough examination and consideration of the patient’s medical history can help determine the underlying cause and appropriate treatment.
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This question is part of the following fields:
- Infectious Diseases
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Question 23
Incorrect
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A 35-year-old woman presents with a 7-day history of mucopurulent anal discharge, bloody stool and pain during defecation. She denies any recent travel and has not experienced any vomiting episodes.
Which of the following is the most probable diagnosis?
Your Answer: Salmonella infection
Correct Answer: Gonorrhoea
Explanation:Sexually Transmitted Infections: Differential Diagnosis
Sexually transmitted infections (STIs) are a common cause of morbidity worldwide. When evaluating a patient with symptoms suggestive of an STI, it is important to consider a broad differential diagnosis. Here are some common STIs and their clinical presentations:
Gonorrhoea: This is a purulent infection of the mucous membranes caused by Neisseria gonorrhoeae. In men, symptoms include urethritis, acute epididymitis, and rectal infection. A diagnosis can be made by identifying typical Gram-negative intracellular diplococci after a Gram stain.
Crohn’s disease: This is an inflammatory bowel disease that presents with prolonged diarrhea, abdominal pain, anorexia, and weight loss. It is not consistent with a typical STI presentation.
Candidiasis: This is a fungal infection caused by yeasts from the genus Candida. It is associated with balanitis, presenting with penile pruritus and whitish patches on the penis.
Salmonella infection: This is often transmitted orally via contaminated food or beverages. Symptoms include a severe non-specific febrile illness, which can be confused with typhoid fever. There is nothing in this clinical scenario to suggest Salmonella infection.
Chancroid: This is a bacterial STI caused by Haemophilus ducreyi. It is characterised by painful necrotising genital ulcers and inguinal lymphadenopathy.
In summary, a thorough differential diagnosis is important when evaluating patients with symptoms suggestive of an STI.
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This question is part of the following fields:
- Infectious Diseases
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Question 24
Incorrect
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A 26-year-old man came to the clinic complaining of fevers, sore throat, and cervical lymphadenopathy that had been going on for 8 days. A positive monospot test was obtained. What is the most appropriate management plan?
Your Answer: Aciclovir
Correct Answer: Reassurance
Explanation:Infectious mononucleosis caused by the Epstein bar virus (EBV) is usually a self-limiting condition that lasts for approximately 2 weeks in individuals with a healthy immune system. Treatment options such as aciclovir, penicillin V, clarithromycin, and valganciclovir are not effective for treating EBV.
Understanding Infectious Mononucleosis
Infectious mononucleosis, also known as glandular fever, is a viral infection caused by the Epstein-Barr virus (EBV) in 90% of cases. It is most commonly seen in adolescents and young adults. The classic triad of symptoms includes sore throat, pyrexia, and lymphadenopathy, which are present in around 98% of patients. Other symptoms include malaise, anorexia, headache, palatal petechiae, splenomegaly, hepatitis, lymphocytosis, haemolytic anaemia, and a maculopapular rash. The symptoms typically resolve after 2-4 weeks.
The diagnosis of infectious mononucleosis is confirmed through a heterophil antibody test (Monospot test) in the second week of the illness. Management is supportive and includes rest, drinking plenty of fluids, avoiding alcohol, and taking simple analgesia for any aches or pains. It is recommended to avoid playing contact sports for 4 weeks after having glandular fever to reduce the risk of splenic rupture.
Interestingly, there is a correlation between EBV and socioeconomic groups. Lower socioeconomic groups have high rates of EBV seropositivity, having frequently acquired EBV in early childhood when the primary infection is often subclinical. However, higher socioeconomic groups show a higher incidence of infectious mononucleosis, as acquiring EBV in adolescence or early adulthood results in symptomatic disease.
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This question is part of the following fields:
- Infectious Diseases
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Question 25
Incorrect
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A 25-year-old man visits his General Practitioner with a complaint of a sore throat that has been bothering him for the past three weeks. He reports feeling significantly fatigued, which is affecting his academic performance. On examination, he appears healthy and has tender cervical lymphadenopathy; his tonsils are enlarged but no exudate is present, and he has tender splenomegaly.
Which of the following investigation findings is most likely to be associated with this condition?
Select the SINGLE most appropriate result from the list below.Your Answer: Raised antistreptolysin titres
Correct Answer: Raised liver transaminases (aspartate transaminase and alanine aminotransferase)
Explanation:The patient has raised liver transaminases, thrombocytosis, neutrophilia, raised antistreptolysin titres, and a reduced estimated glomerular filtration rate (eGFR). The most probable diagnosis is glandular fever/infectious mononucleosis caused by the Epstein-Barr virus (EBV). This infection is common in adolescents and presents with a prolonged sore throat, lethargy, and flu-like symptoms. Splenomegaly or hepatosplenomegaly, along with lymphadenopathy, are often observed. Liver function tests, especially the transaminases, are commonly elevated during active infection. Thrombocytopenia is commonly associated with glandular fever due to splenic involvement. Neutrophilia is less likely in this case than lymphocytosis, which is common with glandular fever. Antistreptolysin titres rise after a streptococcal infection, but glandular fever is a more likely diagnosis than streptococcal infection. Reduced eGFR associated with a sore throat should raise suspicion of dehydration or glomerulonephritis caused by a streptococcal infection, but neither of these diagnoses is as likely as glandular fever. The diagnostic investigation of choice for glandular fever is the Monospot test, which tests for heterophile antibodies to EBV.
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This question is part of the following fields:
- Infectious Diseases
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Question 26
Incorrect
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A 26-year-old man presents to the GUM clinic with penile discharge and dysuria for the past 5 days. Urethral swabs are taken and microscopy reveals the presence of diplococci. Sensitivities are not yet available, and he is diagnosed with gonorrhoea. What is the recommended initial treatment?
Your Answer: Oral azithromycin
Correct Answer: IM ceftriaxone
Explanation:Gonorrhoea is best treated with intramuscular ceftriaxone, and it is crucial to notify and treat sexual partners. All patients with gonorrhoea should undergo a test of cure after 2 weeks.
Understanding Gonorrhoea: Causes, Symptoms, Microbiology, and Management
Gonorrhoea is a sexually transmitted infection caused by the Gram-negative diplococcus Neisseria gonorrhoeae. It can occur on any mucous membrane surface, including the genitourinary tract, rectum, and pharynx. The incubation period of gonorrhoea is typically 2-5 days. Symptoms in males include urethral discharge and dysuria, while females may experience cervicitis leading to vaginal discharge. Rectal and pharyngeal infections are usually asymptomatic.
Immunisation against gonorrhoea is not possible, and reinfection is common due to antigen variation of type IV pili and Opa proteins. Local complications may develop, including urethral strictures, epididymitis, and salpingitis, which can lead to infertility. Disseminated infection may also occur, with gonococcal infection being the most common cause of septic arthritis in young adults.
Management of gonorrhoea involves the use of antibiotics. Ciprofloxacin used to be the treatment of choice, but there is now increased resistance to it. Cephalosporins are now more widely used, with a single dose of IM ceftriaxone 1g being the new first-line treatment. If ceftriaxone is refused, oral cefixime 400mg + oral azithromycin 2g should be used. Disseminated gonococcal infection (DGI) and gonococcal arthritis may also occur, with symptoms including tenosynovitis, migratory polyarthritis, and dermatitis. Later complications include septic arthritis, endocarditis, and perihepatitis.
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This question is part of the following fields:
- Infectious Diseases
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Question 27
Incorrect
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A 26-year-old male patient complains of painful ulcers on his penis shaft and dysuria for the past three days. He has never experienced such symptoms before. The clinical diagnosis suggests primary genital herpes. What is the best course of action for managing this condition?
Your Answer: Topical valaciclovir
Correct Answer: Oral aciclovir
Explanation:Even if the presentation is delayed for up to 5 days, primary genital herpes infections require oral antiviral therapy.
Understanding Herpes Simplex Virus
Herpes simplex virus (HSV) is a common viral infection that affects humans. There are two strains of the virus, HSV-1 and HSV-2, which were previously thought to cause oral and genital herpes, respectively. However, there is now considerable overlap between the two strains. The primary infection may present with severe gingivostomatitis, while cold sores and painful genital ulceration are common features.
Management of HSV includes oral aciclovir for gingivostomatitis and genital herpes, and topical aciclovir for cold sores, although the evidence base for the latter is modest. Patients with frequent exacerbations may benefit from longer-term aciclovir. In pregnant women, a primary attack of herpes during pregnancy at greater than 28 weeks gestation may require elective caesarean section at term. Women with recurrent herpes who are pregnant should be treated with suppressive therapy and advised that the risk of transmission to their baby is low.
The cytopathic effect of HSV can be seen in Pap smears, which show multinucleated giant cells representing infection by the virus. The 3 M’s – multinucleation, margination of the chromatin, and molding of the nuclei – are characteristic features of HSV infection. Understanding the features and management of HSV is important for effective treatment and prevention of transmission.
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This question is part of the following fields:
- Infectious Diseases
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Question 28
Correct
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A 32-year-old man has recently returned from a backpacking trip in Southeast Asia. While there, he consumed food from various street vendors. He complained of abdominal discomfort, bloating and loose stools. Analysis of three stool samples showed cysts in two of them. The patient was treated with metronidazole and showed improvement.
What is the probable medical condition in this scenario?Your Answer: Giardiasis
Explanation:Giardiasis: A Protozoal Parasite Causing Diarrhoeal Illness
Giardiasis is a diarrhoeal disease caused by the flagellate protozoan Giardia intestinalis (previously known as G. lamblia). It is prevalent in areas with poor sanitation and can cause asymptomatic colonisation or acute or chronic diarrhoeal illness. Travellers to highly endemic areas are at high risk of infection. Ingestion of as few as ten Giardia cysts can cause infection. Diarrhoea is the most common symptom of acute Giardia infection, occurring in 90% of symptomatic subjects. The traditional basis of diagnosis is identification of G. intestinalis trophozoites or cysts in the stool of infected patients via stool ova and parasite examination. Standard treatment consists of antibiotic therapy, and metronidazole is the most commonly prescribed antibiotic for this condition. Giardia infection may occur more commonly in families with X-linked agammaglobulinaemia and in sexually active men who have sex with men (MSM).
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This question is part of the following fields:
- Infectious Diseases
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Question 29
Incorrect
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A 74-year-old woman is being evaluated after taking oral flucloxacillin for cellulitis in her right lower limb. The local protocol recommends using oral clindamycin as the next line of treatment. What is the most crucial side effect of clindamycin that she should be cautioned about?
Your Answer: Sore throat, bruising or lethargy
Correct Answer: Diarrhoea
Explanation:The use of clindamycin as a treatment is strongly linked to an increased likelihood of contracting C. difficile.
Clostridioides difficile is a type of bacteria that is commonly found in hospitals. It is a Gram positive rod that produces an exotoxin which can cause damage to the intestines, leading to a condition called pseudomembranous colitis. This bacteria usually develops when the normal gut flora is suppressed by broad-spectrum antibiotics, with second and third generation cephalosporins being the leading cause of C. difficile. Other risk factors include proton pump inhibitors. Symptoms of C. difficile include diarrhea, abdominal pain, and a raised white blood cell count. The severity of the infection can be determined using the Public Health England severity scale, which ranges from mild to life-threatening.
To diagnose C. difficile, a stool sample is tested for the presence of C. difficile toxin (CDT). Treatment for a first episode of C. difficile infection typically involves oral vancomycin for 10 days, with fidaxomicin or a combination of oral vancomycin and IV metronidazole being used as second and third-line therapies. Recurrent infections occur in around 20% of patients, increasing to 50% after their second episode. In such cases, oral fidaxomicin is recommended within 12 weeks of symptom resolution, while oral vancomycin or fidaxomicin can be used after 12 weeks. For life-threatening C. difficile infections, oral vancomycin and IV metronidazole are used, and surgery may be considered with specialist advice. Other therapies, such as bezlotoxumab and fecal microbiota transplant, may also be considered for preventing recurrences in certain cases.
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This question is part of the following fields:
- Infectious Diseases
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Question 30
Incorrect
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A 42-year-old male complains of difficulty breathing after experiencing flu-like symptoms for a week. He has a dry cough and no chest discomfort. A chest x-ray reveals bilateral consolidation, and he has red rashes on his limbs and torso. Which test is most likely to provide a definitive diagnosis?
Your Answer: Blood culture
Correct Answer: Serology for Mycoplasma
Explanation:A diagnosis of Mycoplasma can be made based on symptoms such as flu-like symptoms, bilateral consolidation, and erythema multiforme. The most suitable diagnostic test for this condition is Mycoplasma serology.
Mycoplasma pneumoniae: A Cause of Atypical Pneumonia
Mycoplasma pneumoniae is a type of bacteria that causes atypical pneumonia, which is more common in younger patients. This disease is associated with various complications such as erythema multiforme and cold autoimmune haemolytic anaemia. Epidemics of Mycoplasma pneumoniae typically occur every four years. It is important to recognize atypical pneumonia because it may not respond to penicillins or cephalosporins due to the bacteria lacking a peptidoglycan cell wall.
The disease usually has a gradual onset and is preceded by flu-like symptoms, followed by a dry cough. X-rays may show bilateral consolidation. Complications may include cold agglutinins, erythema multiforme, erythema nodosum, meningoencephalitis, Guillain-Barre syndrome, bullous myringitis, pericarditis/myocarditis, and gastrointestinal and renal problems.
Diagnosis is generally made through Mycoplasma serology and a positive cold agglutination test. Management involves the use of doxycycline or a macrolide such as erythromycin or clarithromycin.
In comparison to Legionella pneumonia, which is caused by a different type of bacteria, Mycoplasma pneumoniae has a more gradual onset and is associated with different complications. It is important to differentiate between the two types of pneumonia to ensure appropriate treatment.
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This question is part of the following fields:
- Infectious Diseases
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