A 30-year-old man comes for review. He lives with a woman who has recently being diagnosed with having tuberculosis. The man was born in the UK, has no past medical history of note and is currently asymptomatic.
His records show that he had the BCG vaccination as a child.
What is the most appropriate test to check for latent tuberculosis?
Correct Answer B: The two main tests used for screening in the UK are the Mantoux (skin) test and the interferon gamma (blood) test. Whilst the use of the interferon-gamma test is increasing it is still reserved for specific situations, none of which apply in this case. Please see the NICE guidelines for more details.
The Heaf test is no longer used in the UK.
Tuberculosis: screening:
The Mantoux test is the main technique used to screen for latent tuberculosis. In recent years the interferon gamma blood test has also been introduced. It is used in a number of specific situations such as:
Mantoux test:
False negative tests may be caused by:
Heaf test:
The Heaf test was previously used in the UK but has been since been discontinued. It involved injection of PPD equivalent to 100,000 units per ml to the skin over the flexor surface of the left forearm. It was then read 3-10 days later.
A 37-year-old sewer worker presents to the Emergency Department with flu-like symptoms and pyrexia for the past 3 days. Since this morning he has started to develop a headache and signs of meningism are found on examination. Blood tests show:
What is the antibiotic treatment of choice?
Correct Answer D: Leptospirosis - give penicillin or doxycycline.
This patient has leptospirosis. The treatment of choice is benzylpenicillin. A lumbar puncture should ideally be done first to confirm meningeal involvement.
Leptospirosis:
Also known as Weil's disease*, leptospirosis is commonly seen in questions referring to sewage workers, farmers, vets or people who work in abattoir. It is caused by the spirochaete Leptospira interrogans (serogroup L icterohaemorrhagiae), classically being spread by contact with infected rat urine. Weil's disease should always be considered in high-risk patients with hepatorenal failure.
Features:
Management:
*The term Weil's disease is sometimes reserved for the most severe 10% of cases that are associated with jaundice.
Which one of the following organisms causes lymphogranuloma venereum?
Correct Answer D:
STI: ulcers: Genital herpes is most often caused by the herpes simplex virus (HSV) type 2 (cold sores are usually due to HSV type 1). Primary attacks are often severe and associated with fever whilst subsequent attacks are generally less severe and localized to one site.
Syphilis is a sexually transmitted infection caused by the spirochete Treponema pallidum. Infection is characterized by primary, secondary and tertiary stages. A painless ulcer (chancre) is seen in the primary stage.
The incubation period= 9-90 days.
Chancroid is a tropical disease caused by Haemophilus ducreyi. It causes painful genital ulcers associated with inguinal lymph node enlargement.
Lymphogranuloma venereum is caused by Chlamydia trachomatis. Typically infection comprises of three stages:
Other causes of genital ulcers:
*Previously called Calymmatobacterium granulomatis.
A 74-year-old female presents with headache and neck stiffness to the Emergency Department. Following a lumbar puncture the patient was started on IV ceftriaxone. CSF culture grows Listeria monocytogenes.
What is the most appropriate treatment?
Correct Answer B: The current BNF suggests treatment with amoxicillin/ampicillin + gentamicin. Treatment should be for at least 10- 14 days.
Listeria:
Listeria monocytogenes is a Gram positive bacillus which has the unusual ability to multiply at low temperatures. It is typically spread via contaminated food, typically un-pasteurized dairy products. Infection is particularly dangerous to the unborn child where it can lead to miscarriage.
Features - can present in a variety of ways:
Suspected Listeria infection should be investigated by taking blood cultures. CSF may reveal a pleocytosis, with 'tumbling motility' on wet mounts.
Which one of the following organisms causes West African sleeping sickness?
Correct Answer B:
Trypanosomiasis: Two main form of this protozoal disease are recognized:
Two forms of African trypanosomiasis, or sleeping sickness, are seen:
Trypanosoma rhodesiense tends to follow a more acute course. Clinical features include:
American trypanosomiasis, or Chagas' disease, is caused by the protozoan Trypanosoma cruzi. The vast majority of patients (95%) are asymptomatic in the acute phase although a chagoma (an erythematous nodule at site of infection) and periorbital oedema are sometimes seen. Chronic Chagas' disease mainly affects the heart and gastrointestinal tract:
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