Which one of the following congenital infections is most characteristically associated with chorioretinitis?
Correct Answer D:
Congenital toxoplasmosis:
A form of 'salt and pepper' chorioretinitis is also seen in congenital rubella but this is not a common feature.
Chorioretinitis is found in around 75% of patients with congenital toxoplasmosis.
Congenital infections:
The major congenital infections encountered in examinations are rubella, toxoplasmosis and cytomegalovirus.
Cytomegalovirus is the most common congenital infection in the UK. Maternal infection is usually asymptomatic.
Infection with Schistosoma haematobium is most strongly associated with:
Correct Answer E: Schistosomiasis is a risk factor for Squamous cell bladder cancer.
Schistosomiasis:
Schistosomiasis, or bilharzia, is a parasitic flatworm infection. The following types of schistosomiasis are recognized:
Schistosoma haematobium:
This typically presents as a 'swimmer's itch' in patients who have recently returned from Africa. Schistosoma haematobium is a risk factor for squamous cell bladder cancer.
Features:
Management:
Which of the following is least recognized as a cause of a false positive VDRL test?
Correct Answer C:
Syphilis: investigation:
Treponema pallidum is a very sensitive organism and cannot be grown on artificial media. The diagnosis is therefore usually based on clinical features, serology and microscopic examination of infected tissue.
Serological tests can be divided into:
Cardiolipin tests:
Treponemal specific antibody tests:
Causes of false positive cardiolipin tests:
A man develops vomiting and abdominal pain 2 hours after leaving a Chinese restaurant.
What is the most likely causative organism?
Correct Answer D: The obvious clue in this question is the short incubation period - this points to a diagnosis of Staphylococcus aureus or Bacillus cereus. Bacillus cereus infection is often associated with Chinese restaurants due to the link with rice.
There are two recognized types of Bacillus cereus infection. The first type produces a vomiting illness and has an incubation period of 1-6 hours. The second type produces a diarrhoeal illness with an incubation period of 6-14 hours.
Gastroenteritis: Gastroenteritis may either occur whilst at home or whilst travelling abroad (travellers' diarrhoea) Travellers' diarrhoea may be defined as at least 3 loose to watery stools in 24 hours with or without one of more of abdominal cramps, fever, nausea, vomiting or blood in the stool. The most common cause is Escherichia coli.
Another pattern of illness is 'acute food poisoning'. This describes the sudden onset of nausea, vomiting and diarrhoea after the ingestion of a toxin. Acute food poisoning is typically caused by Staphylococcus aureus, Bacillus cereus or Clostridium perfringens.
Stereotypical histories:
Incubation period:
*Vomiting sub-type, the diarrhoeal illness has an incubation period of 6-14 hours.
A 34-year-old man from Venezuela presents with a flu-like illness and periorbital oedema. Generalized lymphadenopathy is noted. A diagnosis of Chagas' disease is confirmed on blood smear.
What is the most appropriate treatment?
Correct Answer A:
Trypanosomiasis:
Two main form of this protozoal disease are recognized:
Two forms of African trypanosomiasis, or sleeping sickness, are seen - Trypanosoma gambiense in West Africa and Trypanosoma rhodesiense in East Africa. Both types are spread by the tsetse fly. 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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