infection PT 1 2016 modif

8/9/2016 MyPastest Back to Filters (/Secure/TestMe/Filter/429893/QA) Question of 153 At what CD4 count should highly active anti-retroviral treatment (HAART) commence in asymptomatic HIV patients? A Below 600/mm3 B Below 400/mm3 C Below 350/mm3 D Below 100/mm3 E Below 50/mm3 Explanation Timing of treatment in human immunodeficiency virus infection A number of cohorts exist, providing important data on the natural history and progression of HIV infection Multiple logistic regression can and has been used to determine the optimal point at which to start HAART, and it appears that the point where the benefit of HAART outweighs the risk is around 350 mm3 5490 Next Question Previous Question Tag Question Feedback End Review Difficulty: Average Peer Responses https://mypastest.pastest.com/Secure/TestMe/Browser/429893 1/2 8/9/2016 MyPastest Session Progress Responses Correct: Responses Incorrect: 152 Responses Total: 153 Responses - % Correct: 1% Blog (https://www.pastest.com/blog) About Pastest (https://www.pastest.com/about-us) Contact Us (https://www.pastest.com/contact-us) Help (https://www.pastest.com/help) © Pastest 2016 https://mypastest.pastest.com/Secure/TestMe/Browser/429893 2/2 8/9/2016 MyPastest Back to Filters (/Secure/TestMe/Filter/429893/QA) Question of 153 A 22-year-old woman returns from a holiday on the Kenyan coast She develops a fever, deteriorates over the next 48 h and becomes unconscious and unrousable She has acute renal failure Which one of the following options is the most appropriate investigation? A Computed tomography (CT) scan, head B Electroencephalograph (EEG) C Erythrocyte sedimentation rate (ESR) D Repeated thick and thin blood smear E C-reactive protein (CRP) Explanation Complications in malaria treatment The patient in the present case has extremely severe falciparum malaria, with cerebral malaria (coma) and renal failure (usually pre-renal) needing renal replacement therapy Patients with full-blown cerebral malaria are at an increased risk of fitting, which may be treated with diazepam Administration of prophylactic anticonvulsants may be associated with an increased mortality Exchange transfusion is recommended for a parasitaemia > 10% with complications (or > 30% if no other complications) Treatment of the malaria is with IV quinine, which increases insulin secretion and the sensitivity of cells to insulin and can cause hypoglycaemia Malaria itself can cause hypoglycaemia too, so blood glucose should be monitored every h 3678 Next Question https://mypastest.pastest.com/Secure/TestMe/Browser/429893 1/2 8/9/2016 MyPastest Previous Question Tag Question Feedback End Review Difficulty: Easy Peer Responses Session Progress Responses Correct: Responses Incorrect: 152 Responses Total: 153 Responses - % Correct: 1% Blog (https://www.pastest.com/blog) About Pastest (https://www.pastest.com/about-us) Contact Us (https://www.pastest.com/contact-us) Help (https://www.pastest.com/help) © Pastest 2016 https://mypastest.pastest.com/Secure/TestMe/Browser/429893 2/2 8/9/2016 MyPastest Back to Filters (/Secure/TestMe/Filter/429893/QA) Question of 153 Which one of the following organisms is the most frequent cause of hospital-acquired infections and is also developing increasing resistance to antimicrobial agents? A Staphylococcus aureus B Streptococcus pneumoniae C Toxoplasma gondii D Pneumocystis jirovecii (formerly called Pneumocystis carinii) E Listeria monocytogenes Explanation Staphylococcus aureus infection Epidemiological studies of Staphylococcus aureus infection, and increasingly these concern meticillin-resistant Staph aureus (MRSA) strains, require typing methods to distinguish between epidemic and endemic strains Staph aureus is part of the normal flora in some individuals; about 25% of people carry the organism permanently, a similar proportion never do, and the rest so intermittently Common carriage sites are the nose, axillae, perineum and toe webs Nasal carriage rates vary from 10% to 40% in normal adults outside a hospital environment, but higher rates are often found in hospital patients, particularly those who have been in hospital for several weeks High carriage rates are also found in those with skin diseases such as eczema, those with insulin-dependent diabetes, patients on chronic haemodialysis or chronic ambulatory peritoneal dialysis, intravenous drug users and human immunodeficiency virus (HIV)-positive patients Some carriers disperse large numbers of staphylococci into the environment on skin squamae https://mypastest.pastest.com/Secure/TestMe/Browser/429893 1/2 8/9/2016 MyPastest The carrier state is highly relevant to the epidemiology of Staph aureus infection as to whether or not this complicates surgery or trauma; the source of Staph aureus in most patients who develop a staphylococcal infection is endogenous 1308 Next Question Previous Question Tag Question Feedback End Review Difficulty: Easy Peer Responses Session Progress Responses Correct: Responses Incorrect: 152 Responses Total: 153 Responses - % Correct: 1% Blog (https://www.pastest.com/blog) About Pastest (https://www.pastest.com/about-us) Contact Us (https://www.pastest.com/contact-us) Help (https://www.pastest.com/help) © Pastest 2016 https://mypastest.pastest.com/Secure/TestMe/Browser/429893 2/2 8/9/2016 MyPastest Back to Filters (/Secure/TestMe/Filter/429893/QA) Question of 153 A 49-year-old woman is referred to you by her GP for suspected chronic fatigue syndrome Which one of the following features would suggest that this was an incorrect diagnosis? A Dysphagia B Frequent headaches C Memory impairment D Recurrent sore throats E Severe myalgia Explanation Chronic fatigue syndrome A diagnosis of chronic fatigue syndrome (CFS) requires the presence of unexplained chronic fatigue for more than six months Although several formal definitions exist, cardinal features of CFS (besides fatigue) include impaired memory or concentration, sore throats, myalgia, arthralgia, headaches, unrefreshing sleep and post-exertion malaise CFS is a diagnosis of exclusion, which requires the absence of any other underlying organic or psychiatric problem Dysphagia Dysphagia might reflect an underlying oesophageal cancer, and should be investigated urgently 1643 Next Question https://mypastest.pastest.com/Secure/TestMe/Browser/429893 1/2 8/9/2016 MyPastest Previous Question Tag Question Feedback End Review Difficulty: Average Peer Responses Session Progress Responses Correct: Responses Incorrect: 152 Responses Total: 153 Responses - % Correct: 1% Blog (https://www.pastest.com/blog) About Pastest (https://www.pastest.com/about-us) Contact Us (https://www.pastest.com/contact-us) Help (https://www.pastest.com/help) © Pastest 2016 https://mypastest.pastest.com/Secure/TestMe/Browser/429893 2/2 8/9/2016 MyPastest Back to Filters (/Secure/TestMe/Filter/429893/QA) Question of 153 A 25-year-old soldier presents to the Emergency Department with a high fever, diarrhoea and vomiting He returned from his recent posting to rural Sierra Leone 10 days ago and has become unwell over the last 24 h On admission he looks unwell and has a temperature of 39 °C He has a pulse rate of 110 bpm Examination is otherwise unremarkable Which one of the following options is the most appropriate next step? A Send samples for FBC, clotting, U&Es, LFTs and a malaria film to the lab B Send the patient direct to an isolation unit C Send samples for a malaria film to the lab D Send samples for FBC, clotting, U&Es, LFTs, a malaria film and blood cultures to the lab E Send the patient home Explanation Malaria/Viral Haemorrhagic Fever Differential The most likely diagnosis in the present case is malaria, in the current climate however the major concern is for viral haemorrhagic fever, in particular a differential of Ebola, and as such guidance has changed from that previously recommended In the past, in someone returning from rural Sierra Leone guidance was send only one sample for malaria (if positive for malaria, can relax and treat for malaria) New guidance dictates that if suspicion of viral haemorrhagic fever, then don't even take a single sample to avoid exposure risk for lab staff, send directly to an isolation unit (Royal Free, Newcastle, Liverpool, Sheffield) - so this would encompass anyone returning from rural West Africa and with a differential of viral haemorrhagic fever and within the 21 day maximum incubation period 624 Next Question https://mypastest.pastest.com/Secure/TestMe/Browser/429893 1/2 8/9/2016 MyPastest Previous Question Tag Question Feedback End Review Difficulty: Difficult Peer Responses Session Progress Responses Correct: Responses Incorrect: 152 Responses Total: 153 Responses - % Correct: 1% Blog (https://www.pastest.com/blog) About Pastest (https://www.pastest.com/about-us) Contact Us (https://www.pastest.com/contact-us) Help (https://www.pastest.com/help) © Pastest 2016 https://mypastest.pastest.com/Secure/TestMe/Browser/429893 2/2 8/10/2016 MyPastest Difficulty: Average Peer Responses Session Progress Responses Correct: Responses Incorrect: 151 Responses Total: 151 Responses - % Correct: 0% Blog (https://www.pastest.com/blog) About Pastest (https://www.pastest.com/about-us) Contact Us (https://www.pastest.com/contact-us) Help (https://www.pastest.com/help) © Pastest 2016 https://mypastest.pastest.com/Secure/TestMe/Browser/429893#Top 2/2 8/10/2016 MyPastest Back to Filters (/Secure/TestMe/Filter/429893/QA) Question 145 of 151 A 29-year-old man is brought to the clinic by his girlfriend He is a long term user of intravenous heroin Over the past few days he has become confused and aggressive and has had a fit Investigations reveal ring lesions on contrast CT scan, his CD4 count is 45/mm3 (normal >500) and an HIV test is positive You suspect he has toxoplasmosis Which one of the following options is the most appropriate therapy for him? A Fansidar B Sulfadiazine and pyrimethamine C Clindamycin D Atovaquone E Azithromycin Explanation Treatment of toxoplasmosis Sulfadiazine and pyrimethamine is seen as combination therapy of choice for patients with toxoplasmosis in the setting of human immunodeficiency virus (HIV) infection Sulfadiazine may, however, be associated with adverse effects (commonly rash) in up to 40% of users Clindamycin may be substituted in these cases Clarithromycin or azithromycin may be additional alternatives but used in combination with pyrimethamine Whilst anti-retroviral therapy may be associated with a decreased viral load and improved CD4 count, there are limited data on discontinuing long-term maintenance therapy against toxoplasmosis, therefore most patients continue permanent therapy at a lower dose 18604 https://mypastest.pastest.com/Secure/TestMe/Browser/429893#Top 1/2 8/10/2016 MyPastest Next Question Previous Question Tag Question Feedback End Review Difficulty: Easy Peer Responses Session Progress Responses Correct: Responses Incorrect: 151 Responses Total: 151 Responses - % Correct: 0% Blog (https://www.pastest.com/blog) About Pastest (https://www.pastest.com/about-us) Contact Us (https://www.pastest.com/contact-us) Help (https://www.pastest.com/help) © Pastest 2016 https://mypastest.pastest.com/Secure/TestMe/Browser/429893#Top 2/2 8/10/2016 MyPastest Back to Filters (/Secure/TestMe/Filter/429893/QA) Question 146 of 151 A previously well 35-year-old man presents in the summer months with a communityacquired pneumonia and mild, watery diarrhoea He has failed to improve after days of amoxicillin given by his GP The temperature is 40°C; the patient is complaining of a headache and seems slightly confused and disorientated but has no clinical evidence of meningitis The peripheral white cell count is on the upper limit of normal and Na+ is 125 mmol/l Two other members of his office are also ill with a similar illness Which one of the following options is the most likely causative organism? A Mycoplasma pneumoniae B Legionella pneumophila C Influenza A virus D Chlamydia pneumoniae E Penicillin-resistant Streptococcus pneumoniae Explanation Legionnaire’s disease Clinical manifestations High fever, altered mental state, hyponatraemia and watery diarrhoea are all typical of legionnaire’s disease (as is the occurrence of a cluster of cases), but can occur to some extent in any pneumonia Differential diagnosis Mycoplasma and Chlamydia not usually cause such a severe pneumonia It is the wrong time of year for influenza The penicillin-resistant pneumococcus is still uncommon in the UK, but is on the increase worldwide 3698 https://mypastest.pastest.com/Secure/TestMe/Browser/429893#Top 1/2 8/10/2016 MyPastest Next Question Previous Question Tag Question Feedback End Review Difficulty: Easy Peer Responses Session Progress Responses Correct: Responses Incorrect: 151 Responses Total: 151 Responses - % Correct: 0% Blog (https://www.pastest.com/blog) About Pastest (https://www.pastest.com/about-us) Contact Us (https://www.pastest.com/contact-us) Help (https://www.pastest.com/help) © Pastest 2016 https://mypastest.pastest.com/Secure/TestMe/Browser/429893#Top 2/2 8/10/2016 MyPastest Back to Filters (/Secure/TestMe/Filter/429893/QA) Question 147 of 151 A 30-year-old man presents with an acute onset of pain and blurred vision of his right eye On examination there is conjunctival injection and dendritic ulceration is seen on his cornea Given the likely diagnosis, which one of the following options is the most important treatment? A Topical steroids B Topical aciclovir C Ampicillin ointment D Topical nystatin E Oral fluconazole Explanation Herpes simplex virus keratitis The likely diagnosis in the present case is herpes simplex virus (HSV) keratitis Topical aciclovir is the drug of choice; topical steroids may make the infection worse and are contraindicated Herpes simplex virus (HSV) can also cause an acute necrotising retinitis, usually seen in immunosuppressed patients such as those with HIV infection, but rarely in immunocompetent people 2692 Next Question Previous Question Tag Question Feedback End Review Difficulty: Easy https://mypastest.pastest.com/Secure/TestMe/Browser/429893#Top 1/2 8/10/2016 MyPastest Peer Responses Session Progress Responses Correct: Responses Incorrect: 151 Responses Total: 151 Responses - % Correct: 0% Blog (https://www.pastest.com/blog) About Pastest (https://www.pastest.com/about-us) Contact Us (https://www.pastest.com/contact-us) Help (https://www.pastest.com/help) © Pastest 2016 https://mypastest.pastest.com/Secure/TestMe/Browser/429893#Top 2/2 8/10/2016 MyPastest Back to Filters (/Secure/TestMe/Filter/429893/QA) Question 148 of 151 An Asian man has intermittent diarrhoea, abdominal bloating and discomfort and complains of the passage of bulky, malodorous stools that are difficult to flush away Which one of the following infections is he most likely to have? A Giardiasis B Amoebiasis C Cryptosporidiosis D Balantidiasis E Blastocystis hominis infection Explanation Giardiasis Clinical manifestations Diarrhoea associated with malabsorption is characteristically seen in giardiasis Underlying pathology The mechanism by which the organism causes malabsorption is not fully understood, but may be due to a loss of brush-border enzyme activity Differential diagnosis Cryptosporidiosis presents with acute watery diarrhoea, fever and malaise that lasts 7– 10 days and is self-limiting Malabsorption does not occur 3575 Next Question https://mypastest.pastest.com/Secure/TestMe/Browser/429893#Top 1/2 8/10/2016 MyPastest Previous Question Tag Question Feedback End Review Difficulty: Average Peer Responses Session Progress Responses Correct: Responses Incorrect: 151 Responses Total: 151 Responses - % Correct: 0% Blog (https://www.pastest.com/blog) About Pastest (https://www.pastest.com/about-us) Contact Us (https://www.pastest.com/contact-us) Help (https://www.pastest.com/help) © Pastest 2016 https://mypastest.pastest.com/Secure/TestMe/Browser/429893#Top 2/2 8/10/2016 MyPastest Back to Filters (/Secure/TestMe/Filter/429893/QA) Question 149 of 151 Which one of the following combination therapies is the most appropriate for the treatment of chronic hepatitis C infection? A Amoxicillin and clavulanic acid B Piperacillin and tazobactam C Isoniazid and pyridoxine D Interferon-α (IFN-α) and ribavirin E Interferon-γ (IFN-γ) and lamivudine Explanation Drug treatment of hepatitis C Mechanism of action Ribavirin is a guanosine analogue with broad anti-viral activity but which may affect the hepatitis C virus (HCV) by inducing a shift toward a TH1-cellular immune response Used orally alone, ribavirin returns the level of serum alanine aminotransferase (ALT) to normal in some individuals but does not substantially change HCV RNA levels However, in combination with interferon (IFN)-α-2b, 1000–1200 mg daily of oral ribavirin improves the sustained virological response rates both for people who have never been treated and those who initially responded to interferon but then relapsed (but not those who never responded) As initial treatment, approximately one-third of patients treated with IFN and ribavirin have a sustained virological response Side-effects Adverse reactions to ribavirin and IFN-α are similar to those with IFN-α alone, but ribavirin causes haemolytic anaemia in many patients Ribavirin is teratogenic; pregnancy must be prevented during and for up to year after https://mypastest.pastest.com/Secure/TestMe/Browser/429893#Top 1/2 8/10/2016 MyPastest administration, whichever sex is being treated 1297 Next Question Previous Question Tag Question Feedback End Review Difficulty: Easy Peer Responses Session Progress Responses Correct: Responses Incorrect: 151 Responses Total: 151 Responses - % Correct: 0% Blog (https://www.pastest.com/blog) About Pastest (https://www.pastest.com/about-us) Contact Us (https://www.pastest.com/contact-us) Help (https://www.pastest.com/help) © Pastest 2016 https://mypastest.pastest.com/Secure/TestMe/Browser/429893#Top 2/2 8/10/2016 MyPastest Back to Filters (/Secure/TestMe/Filter/429893/QA) Question 150 of 151 A 19-year-old man undergoes splenectomy after a horse riding accident He was given the pneumococcal vaccination years previously because of a past history of asthma Which one of the following options is true with respect to prophylaxis against pneumococcal infection? A Penicillin is not indicated B Penicillin prophylaxis 500 mg/day is indicated for at least a 2-year period C Penicillin prophylaxis 1g/day is indicated for a 2-year period D They should be immediately revaccinated against pneumococcus E Pneumococcal vaccination should be repeated every 10 years Explanation Post splenectomy infection High-risk period The greatest risk of infection post splenectomy exists in the first years after removal Guidelines for prevention and management Existing UK guidelines (see the guidelines for the prevention and treatment of infections in patients with an absent or dysfunctional spleen, British Committee for Standards in Haematology) recommend prophylactic antibiotics during this period Some controversy exists however, with French and American guidelines not recommending antibiotic prophylaxis with penicillin due to the development of resistance Pneumococcal vaccination should be repeated every years according to the guidelines because immunity is thought to be less persistent In patients who are penicillin allergic, erythromycin would be the default choice 22456 https://mypastest.pastest.com/Secure/TestMe/Browser/429893#Top 1/2 8/10/2016 MyPastest Next Question Previous Question Tag Question Feedback End Review Difficulty: Difficult Peer Responses Session Progress Responses Correct: Responses Incorrect: 151 Responses Total: 151 Responses - % Correct: 0% Blog (https://www.pastest.com/blog) About Pastest (https://www.pastest.com/about-us) Contact Us (https://www.pastest.com/contact-us) Help (https://www.pastest.com/help) © Pastest 2016 https://mypastest.pastest.com/Secure/TestMe/Browser/429893#Top 2/2 8/10/2016 MyPastest Back to Filters (/Secure/TestMe/Filter/429893/QA) Question 151 of 151 A 25-year-old well woman gives birth at full term to an otherwise well baby with unilateral microphthalmia She recalls a rash during the first trimester of her pregnancy, but cannot remember any other details of the rash Which one of the following options is the most likely causative agent? A Syphilis B Varicella zoster virus (VZV) C Rubella D Cytomegalovirus (CMV) E Parvovirus B19 Explanation Infections and pregnancy Congenital Varicella zoster virus (VZV) infection following primary infection in the mother in the first 20 weeks of pregnancy is associated with about a 2% incidence of fetal abnormality The fetus develops episodes of shingles that affect development of the involved dermatome Congenital syphilis, CMV and rubella tend to cause symmetrical problems Parvovirus B19 is associated with miscarriage and fetal hydrops, but is not clearly associated with any developmental abnormality 3688 End Session Previous Question Tag Question https://mypastest.pastest.com/Secure/TestMe/Browser/429893#Top Feedback End Review 1/2 8/10/2016 MyPastest Difficulty: Difficult Peer Responses Session Progress Responses Correct: Responses Incorrect: 151 Responses Total: 151 Responses - % Correct: 0% Blog (https://www.pastest.com/blog) About Pastest (https://www.pastest.com/about-us) Contact Us (https://www.pastest.com/contact-us) Help (https://www.pastest.com/help) © Pastest 2016 https://mypastest.pastest.com/Secure/TestMe/Browser/429893#Top 2/2 ... 38.4 °C with a BP of 10 0/60 mmHg and a pulse of 10 5/min She has bilateral wheeze on auscultation of the chest Investigations: Hb 13 .1 g/dl WCC 13 .2 × 10 9/l PLT 13 0 × 10 9/l Na+ 13 1 mmol/l K+ 4.5 mmol/l... (https://www.pastest.com/help) © Pastest 2 016 https://mypastest.pastest.com/Secure/TestMe/Browser/429893 2/2 8/9/2 016 MyPastest Back to Filters (/Secure/TestMe/Filter/429893/QA) Question 19 of 15 3 A 17 -year-old girl... (https://www.pastest.com/help) © Pastest 2 016 https://mypastest.pastest.com/Secure/TestMe/Browser/429893 2/2 8/9/2 016 MyPastest Back to Filters (/Secure/TestMe/Filter/429893/QA) Question 11 of 15 3 A patient presents