mrcpass infectious disease
TRANSCRIPT
A 20 year old man has returned from India, where he was on holiday. He has had a 10 day history of bloody diarrhoea. Which of the following is correct?
A. Shigellosis is a likely diagnosis
B. The finding of cysts in the stools confirms acute amoebic dysentery
C. A negative fluorescent antibody test excludes a diagnosis of acute amoebic dysentery
D. Cholera is a likely diagnosis
E. Giardiasis is a likely diagnosis
Do question later!
Answer: a) shigellosis is a likely diagnosis. Shigella, salmonella, campylobacter and amoebic dysentery are bloody. Cholera and giardia diarrhoea are not usually bloody. Amoebic dysentery occurs when amoeba trophozoites invade the mucosa. Cysts may be caused by ingestion and its presents does not indicate dysentery. A positive fluorescent antibody test points towards amoebic liver abscess more so than dysentery
A 40 year old man presented 14 days after return from a 6-week field trip to Papua New Guinea. He had a six day history of high fevers and rigors. On the day of presentation, he had become vague and confused. He had taken antimalarials as prophylaxis, but ceased when he found that local people did not take them.
His temperature was 40oC, pulse rate 140 bpm, respiratory rate 28 per minute, and blood pressure 100/60 mmHg. He had dry mucous membranes, mild jaundice, pallor, splenomegaly and generalised crackles in both lungs.
Full blood examination revealed:
6.5 g/dLWCC 2.5 x 10^9/LPlatelet 10 x 10^9/Lbilirubin 60 μmol/L(3–20 μmol/L)lactate dehydrogenase 489 U/L (100–225 U/L) creatinine 250 umol/l
What is the likely diagnosis?
A. Leishmaniasis
B. Tick bite fever
C. Endocarditis
D. Falciparum malaria
E. Viral haemorrhagic fever
Do question later!
Answer: d) falciparum malaria. This patient has severe malaria suggested by altered consciousness, focal neurological signs, jaundice, oliguria, severe anaemia, hypoglycaemia, hypotension and acidosis.
Severe malaria requires treatment with intravenous quinine.
P. falciparum rings in erythrocytes
A 25 year old veterinarian presents with a 2 week history of high fevers, night sweats, dry cough, and myalgia. He had no medical history and was taking no regular drug treatment. A travel and occupational history showed that he had lived and worked as a vet in northern India until 6 months ago, when he moved to London.
On examination, the patient had a fever of 38.5°C, a solitary cervical lymph node measuring 1 cm x 0.5 cm in size, and a palpable splenic tip.
Initial investigations showed a CRP of 84 U/l and white cell count of 4.8 x 109/l. Three blood films for malaria parasites were negative. Standard liver function tests showed a raised serum alkaline phosphatase concentration of 520 U/l, a raised (gamma)-glutamyltransferase concentration of 450 U/l, and a raised serum aspartate aminotransferase concentration of 248 U/l); the serum bilirubin concentration was at the upper end of the normal range, at 18 µmol/l. The serum angiotensin converting enzyme concentration was also raised, at 113 U/l.
Which one of the following tests is most likely to yield the diagnosis?
A. Chlamydia serology
B. Mycoplasma serology
C. Brucella serology
D. Legionella serology
E. Paul bunnell test
Do question later!
Answer: c) brucella serology.
The occupation suggests that the patient had worked with animals e.g. cattle. Brucella is transmitted through milk and meat, especially in abbatoirs. The commonest cause is Brucella melitensis. Detection of brucella may require extended culture of 6 weeks and blood agar plates. Detection of Brucella agglutinins (with the Coomb’s test) also helps confirm the diagnosis.
Fever and rigors, followed by possible osteomyelitis, polyarthritis, endocarditis, pneumonia, hepatitis/jaundice, splenic abscess, meningitis/encephalitis, skin changes, orchitis/cervicitis and retinitis.
Past infection causes positive serology and does not necessarily indicate active infection. Tetracycline and gentamicin are treatments of choice (better intracellular penetration).
Brucella melitensis - Gram-negative, aerobic, coccobacillus
A 65 year old man had been on holiday to Arizona in the united states 6 weeks ago. He was brought to hospital with high fever, rigors, malaise, and mild confusion. He had a generalised, non-pruritic maculopapular rash, predominantly on the trunk but also on the extremities, including the palms and soles. There was no history of animal or arthropod exposure, but his house was on the edge of forest.
What is the most likely diagnosis?
A. Falciparum malaria
B. Rickettsial spotted fever
C. Tuberculosis
D. Allergic bronchopulmonary aspergillosis
E. Schistosomiasis
Do question later!
Answer: b) Rickettsial spotted fever. Rocky Mountain or Rickettsial spotted fever (RMSF), classically characterized by fever, myalgias, headache, and a petechial rash, is the most common tick-borne disease in the United States. It is also found in Mexico and South America, southern Africa, and Asia.
Recommended treatment is doxycycline.
Maculopapular rash due to Rickettsial disease
A 62 year old man had been travelling around Asia for 3 months and returned several weeks ago to UK. He has a 7 day history of fever and confusion. His wife mentioned that they had been bitten by mosquitoes but had taken malarial prophylaxis.
On examination, he had generalised upper motor neurone signs and a Glasgow coma score of 10. Computed tomography and magnetic resonance imaging showed multiple non-specific white-matter lesions bilaterally. An electroencephalogram (EEG) demonstrated diffuse slowing in the delta to theta range in both hemispheres, with preserved response to painful stimulation.
Lumbar puncture showed clear cerebrospinal fluid (CSF), with a leukocyte count of 50 × 10^6 cells/L (81% mononuclear), raised protein level of 0.79 g/L (<5); glucose level of 4.3 mmol/L (2.8–4.0) and negative bacterial and fungal cultures. Thick and thin films were negative for malarial parasites.
What is the diagnosis?
A. Plasmodium vivax infection
B. Plasmodium falciparum infection
C. Rickettsial disease
D. HIV seroconversion
E. Japanese encephalitis
Do question later!
Answer: e) Japanese encephalitis.The clinical, epidemiological, radiological, EEG and serological features of this case strongly support a diagnosis of Japanese encephalitis. The Japanese encephalitis flavivirus is the most common cause of encephalitis in Asia. Death occurs in 25% of clinical cases, and permanent neurological deficits occur in up to 50% of survivors.Infection is transmitted from amplifying hosts (primarily waterbirds and pigs) by mosquitoes
A 40 year old man has spent a year in South America working in the computer industry. He develops fevers, night sweats, vomiting and pain in the right upper quadrant. Blood tests reveal a raised white cell count but not eosinophil count. An CT of his abdomen shows a large cyst. Which is the best treatment?
A. Hepatectomy of hepatoma
B. Surgical removal of aspergilloma
C. Albendazole for hydatid cyst
D. Metronidazole for amoebic liver abscess
E. Quadruple therapy for TB
Do question later!
Answer: d) metronidazole for amoebic liver abscess. Amoebiasis caused by Entamoeba histolytica is spread by faeco oral route. It can present months or a year after infection. RUQ and referred pain to the shoulders as well as with systemic symptoms are common presentations.
An 5 year old child presented with a one-day history of lethargy, jaundice, fever, and melaena. Upon admission, blood and CSF cultures were drawn, and antibiotics were administered. TORCH titer results were as follows:
T. Gondii IgG - 0 IU/mL (>12 positive)Rubella IgG - 58.4 IU/mL (>9.9 positive)CMV IgG - 2.7 IU/mL (>1.10 positive)HSV I IgG - 0.25 IU/mL (>1.10 positive)HSV II IgG - 0.70 IU/mL (>1.10 positive)
Which of the following is true regarding the disease?
A. Typically has an incubation period of 7-10 days
B. Causes a rash on the forehead, suboccipital lymphadenopathy and polyarthritis
C. May be complicated by polyarthralgia
D. Is an indication for termination if it occurs in the first two months of pregnancy
E. Can be prevented by vaccination in over 80% of individuals
Do question later!
Answer: a) typically has an incubation period of 7-10 days. Rubella is a togavirus. Its incubation period is 18-21 days. Common features of rubella are rash on the forehead, suboccipital lymphadenopathy, polyarthritis and polyarthralgia. Termination is recommended if infection occurs in the first 16 weeks (4 months) due to the high probability of fetal abnormality (septal defects, cataracts & blindness, deafness, mental retardation).
35 year old man has returned from a field trip in Malaysia. He now has a fever of 39ºC, headache, muscular aches and pains. Examination reveals an erythematous rash on his abdomen and thighs. There was cervical and inguinal lymphadenopathy. Blood tests show:
Hb 14.0 g/dlMCV 80 flWCC 7 x 10^9/lplatelets 120 x 10^9/lurea 7 μmol/lcreatinine 100 μmol/lsodium 142 mmol/lpotassium 4.2 mmol/lbilirubin 16 μmol/lAST 120 U/lALP 1500 U/lalbumin 32 g/lESR 60 mm/hrCRP 180 mg/l
What is the likely illness?
A. Syphilis
B. Chlamydia infection
C. Dengue fever
D. Yellow fever
E. Typhoid fever
Do question later!
Answer: c) dengue fever. Dengue fever is caused by an arthropod borne flavivirus (typically the Aedes mosquito insect). It is present in South East Asia, Africa, Middle East and India. The disease has an incubation period of 7 days. Headaches, retro-orbital pain, musculoskeletal pains and a maculopapular rash can occur. Treatment is conservative with antipyretics and bedrest.
A 30 year old man had a tender painful leg with fevers and a year later, progressively develops a swelling in the left leg. Which organism is likely to be responsible?
A. Loa loa
B. Wuchereria bancrofti
C. Schistosomiasis
D. Leishmaniasis
E. Toxoplasmosis
Do question later!
Answer: b) Wuchereria bancrofti. There is filarial involvement of the lymphatics causing lymphedema or 'elephantiasis'. The organisms are commonly wuchereria bancrofti or brugia malayi. In acute infection, organisms can be detected on a blood film, and filarial serology can be sent. Treatment is with diethylcarbamazepine (DEC) or ivermectin.
Elephantiasis
A 35 year old man was in South East Asia on holiday backpacking alone. He has returned 5 days ago, having been there for a month. His temperature is 38 °C and he has a swollen ankle and elbow joint. He also complains of purulent penile discharge. Which of the following conditions/infections is likely?
A. Reiter's syndrome
B. Chlamydia trachomatis
C. Neisseria gonorrhoeae
D. Staphyloccocus aureus
E. Treponema pallidum
Do question later!
Answer: c) Neisseria gonorrhoeae. This is a typical presentation for gonorrhoeae. There is penile discharge and knee effusions. The discharge and knee aspirate may grow gram negative diplococci. Current recommended treatment is ceftriaxone 125 mg IM single dose. Concurrent treatment for chlamydia should be given for 3-6 weeks, to include oral tetracycline 500 mg 4 times a day or oral doxycycline 100 mg twice a day.
Gram negative diplococci - N. Gonorrhoeae
A 23-year-old man presented to a hospital with a 3 day history of fever, rigors, confusion and malaise. A chest x-ray showed left lower-lobe pneumonia. He works in a factory close to a water tank which acts as a heat exchange for the welding cooling system.
What is the most likely infective organism?
A. Pneumococcus
B. Legionella
C. Mycoplasma
D. Tuberculosis
E. Klebsiella
Do question later!
Answer: b) Legionella. Legionnaire's disease is a severe form of pneumonia caused by the gram negative bacterium Legionella pneumophila. It is an airborne infection with the bacterium sometimes living in air-conditioning systems, whirlpool spas and domestic hot water systems in large buildings.
A 2 year old girl presented with a 12-hour history of fever and poor feeding. The family owned two cats. Her temperature was 39.5°C, and she was irritable, with no localising signs or skin lesions. A full septic screen was performed. Cerebrospinal fluid (CSF) showed a neutrophilic pleocytosis and gram-negative coccobacilli. She was treated with intravenous cefotaxime and gentamicin. Within 24 hours both CSF and blood cultures showed growth of gram-negative bacilli.
What is the likely infective organism?
A. Legionella pneumophilia
B. Haemophilus influenzae
C. Pasteurella multicoda
D. E coli
E. Pseudomonas aeruginosa
Do question later!
Answer: c) Pasteurella multicoda. Pasteurella multocida is an oral commensal of domestic pets known to be an opportunistic human pathogen after traumatic animal contact. The most common infections in humans are skin and pulmonary infections.
Pasteurella meningitis occurs at extremes of age (infants), in the immunocompromised (associated with liver cirrhosis, renal disease and haematological malignancies) and after traumatic head injury.
A 16 year old boy with previous tuberculosis had a 7-day history of progressive cough, wheeze and tachypnoea, despite 4 days of intravenous flucloxacillin and cefotaxime therapy.
Total serum IgE titre was 1600 IU (normal range, 0–180 IU) and the skin prick test was positive for Aspergillus fumigatus.
What should he be treated with?
A. Praziquantel
B. Aciclovir
C. Itraconazole
D. Rifampicin
E. HAART
Do question later!
Answer: c) itraconazole.
Allergic bronchopulmonary aspergillosis (ABPA) is a diagnosis which can be confirmed by significantly elevated serum IgE titre, positive skinprick tests for aspergillus, positive IgG aspergillus precipitins.
Treatment is with antifungals. Steroids may be required in patients with respiratory distress
An 75 year old man presents to hospital unwell with diarrhea. He has a BP of 100/70, heart rate 110 and Temp 38 °C. A diastolic murmur is heard in aortic area. His bloods show: Hb 9.0 g/dlMCV 85 flWCC 13 x 10^9/lplatelets 270 x 10^9/lurea 6 μmol/lcreatinine 80 μmol/lsodium 140 mmol/lpotassium 3.8 mmol/lESR 80 mm/hrCRP 220 mg/l
Which organism is likely to grow in the blood cultures?
A. Streptococcus mitis
B. Staphylococcus aureus
C. Streptococcus bovis
D. Escherichia coli
E. Brucella melitensis
Do question later!
Answer: c) streptococcus bovis. Streptococcus bovis usually enters the bloodstream via the gastrointestinal tract. Nearly all patients with S bovis endocarditis are older than 50 years, and there is also an association with malignancy of the GI tract. Treatment is with penicillin and vancomycin.
A 25 year old secretary comes to the clinic complaining of fevers, crampy abdominal pains and diarrhoea. She has returned from Turkey on a holiday. Whilst there, she visited two spas and spent a long time in jacuzzis. Which of the following organisms might be isolated from stool culture?
A. Vibrio cholerae
B. Cryptosporidium
C. Salmonella
D. Shigella
E. Actinomyces
Do question later!
Answer: b) cryptosporidium. Cryptosporidium is commonly water borne spread. Swimming in hot tubs and pools, lakes, ponds are risk factors. It can also be spread via uncooked food. Treatment is conservative in adults, whilst the drug nitazoxanide is licensed for treatment in children age < 12. Symptoms typically last for 1-2 weeks.
A 35 year old man has lymphopenia on his white cell differential. He complains of headaches. A CT scan of his brain showed a 5 cm ring enhancing lesion in the frontal lobe. Which is the likely infective organism?
A. Cryptosporidia
B. Toxoplasma gondii
C. Aspergillus
D. Cryptococcus neoformans
E. Mycobacterium avium intracellulare
Do question later!
Answer: b) toxoplasma gondii. The lymphopenia suggests HIV infection. Ring enhancing lesions in the brain suggest either cerebral toxoplasmosis or lymphoma.
Ring enhancing lesion in the Basal ganglia
Which of the following is the commonest world wide cause of traveller's diarrhoea?
A. E coli
B. Giardia
C. Shigella
D. Salmonella
E. Campylobacter
Do question later!
Answer: a) E coli. Traveller's diarrhoea is an extremely common occurrence, affecting up to half of travellers to high risk areas such as Africa, Asia and South America. The commonest infective cause world-wide is Escherichia coli. Other bacterial causes include Shigella, Salmonella and Campylobacter, all of which can cause dysentery (diarrhoea with blood).
A 22 year old woman presented with a 1-day history of fever, chills and severe back pain, with no other focal symptoms. On examination, she was febrile with a blood pressure of 75/40 mmHg, and had begun vomiting.
She was treated empirically with intravenous ceftriaxone and flucloxacillin and resuscitated with intravenous fluids. Over several hours, the back pain resolved, and a widespread erythrodermic rash developed, centred mainly on the trunk. Further questioning revealed that the patient had removed a tampon shortly before presentation, as she had just ceased menstruating.
What is the diagnosis?
A. Haemolytic uraemic syndrome
B. E coli sepsis
C. Fungal infection
D. Toxic shock syndrome
E. Meningococcal septicaemia
Do question later!
Answer: d) Toxic shock syndrome. Toxic shock syndrome is due to toxin-1 (TSST-1), a protein secreted by S. aureus or streptococci, was the first of many toxins associated with the syndrome to be identified. Treatment is with penicillin and ceftriaxone.
A 28 year old banker goes on holiday to Brazil. He visits various holiday spots including a cattle ranch. He has headaches and a temperature of 38 ºC. Examination reveals hepatosplenomegaly and spinal tenderness. His blood cultures do not grow any organisms. Which is the likely infective organism?
A. Brucella melitensis
B. Listeria
C. Cryptosporidium
D. Shigella
E. Schistosomiasis
Do question later!
Answer: a) Brucella melitensis. Brucella is spread by contact with cattle, drinking unpasteurized/raw milk. It causes sacroilitis and discitis, and hepatomegaly. Should be treated by doxycycline or rifampicin.
A 40 year old man has been to Malaysia for 6 months. He has an erythematous, serpiginous, pruritic, cutaneous eruption on the medial side of the ankle. What is the diagnosis?
A. Lyme disease
B. Cutaneous larval migrans
C. Leishmaniasis
D. Sarcoidosis
E. Tuberculosis
Do question later!
Answer: b) cutaneous larval migrans. Cutaneous larva migrans is caused by the penetration through intact skin of larval animal hookworms (e.g. Ancylostoma braziliense). Diagnosis is predominantly clinical.
Treatment is often necessary because of intense pruritus, long duration (over a year) and complications, such as impetigo and allergic reactions. Therapy comprises ivermectin, albendazole or thiabendazole.
Cutaneous Larval Migrans
A 25 year old male man has urethral discharge. Gram stain of the discharge sample shows gram negative intracellular diplococci. The patient is treated with cefotaxime as a 500mg single intramuscular dose. A week later, the patient still has urethral discharge. Which of the following organisms is likely to be responsible?
A. Neisseria gonorrhoeae
B. Ureaplasma
C. Chlamydia trachomatis
D. Staphyloccocus aureus
E. Escherichia coli
Do question later!
Answer: c) chlamydia trachomatis. Although the diplococci are likely to be gonorrhoea, this patient has been treated. Recommended treatment options for gonococcal infection are ceftriaxone 250mg single im dose OR cefotaxime (Claforan) 500mg single im dose for gonorrhoea. Persistent discharge suggests another organism, in this case likely chlamydia. Doxycycline would is therefore recommended.
A 34 year old patient has a CD4+ count of 80/mm. He has had a generalised seizure recently. An MRI scan is performed, it shows multiple 1 cm white matter lesions. Which of these diagnoses is likely?
A. Progressive multifocal leukoencephalopathy
B. Demyelination
C. Calcified tubers
D. Behcet's disease
E. Systemic lupus erythematosus
Do question later!
Answer: a) progressive multifocal leukoencephalopathy. PML is caused by the JC virus, and causes white matter lesions in the brain. A CD4+ of 90/mm (<400) is low and suggests HIV infection. Anti-retroviral therapy is the main treatment for PML.
Multifocal areas of demyelination in PML
A 20 year old student travelled to India during his gap year. He is hospitalised due to nausea and rigors. On examination Temp is 39°C and he has a palpable spleen and liver. Which of the following infections is likely?
A. Schistosomiasis
B. Tuberculosis
C. Leishmaniasis
D. Malaria
E. Salmonella infection
Do question later!
Answer: c) leishmaniasis. Visceral leishmaniasis is common in India and in particular HIV positive patients. Patients may report night sweats, weakness, and anorexia. Hepatosplenomegaly is present on examination.
Macrophages with several amastigote forms of Leishmania donovani.
A 23 year old student has just returned from India having been on a holiday. He was bitten by flies whilst he was there. He has been lethargic for two months and has a fever. Clinical examination reveals hepatosplenomegaly. Ultrasound of the abdomen reveals lymphadenopathy. One of the lymph nodes are biopsied (a smear shows amastigotes within a macrophage). What is the diagnosis?
A. Kala azar
B. Babesiosis
C. Schistosomiasis
D. Malaria
E. Amoebiasis
Do question later!
Answer: a) Kala Azar. Leishmaniasis (Kala Azar) is spread by bites from sandflies. Cutaneous lesions can occur at the site of the bite. Visceral leishmaniasis can occur, causing hepatosplenomegaly. The smears can show Donovan bodies (amastigotes of Leishmania donovani).
Three Leishmania amastigotes, each with a clearly visible nucleus
A 35 year old patient has a stiff neck, myalgia and joint pains in the knees, shoulders and elbows. He had felt that his heart beat was irregular. He also developed a rash that came and went on the back over several weeks. Which is the best diagnostic test?
A. Monospot test
B. Herpes virus serology
C. Immunofluorescent antibodies to Borrelia burgdorferi
D. Coxsackie virus serology
E. Serum Anti streptolysin O titres
Do question later!
Answer : c) Immunofluorescent antibodies to Borrelia burgdorferi. This is Lyme disease. It is caused by tick bites spreading Borrelia burgdorgferi. The rash is erythema chronicum migrans. Joint pains and irregular heart beats are common symptoms. Heart block can occur.
Erythema Chronicum Migrans
A middle-aged, obese man had previously been treated for chronic venous insufficiency-related swelling and cellulitis. He had hyperpigmentation and hemosiderin deposition. A further wound swab grew Pseudomonas aeruginosa. Which one of the following antibiotics is recommended?
A. Ciprofloxacin
B. Flucloxacillin
C. Benzylpenicillin
D. Cephalexin
E. Metronidazole
Do question later!
Answer: a) ciprofloxacin. Pseudomonas can cause otitis media, pneumonia (in cystic fibrosis), urinary tract infection and rarely, endocarditis. Gentamicin, ciprofloxacin and meropenem are antibiotics which are effective against pseudomonas infection.
A 38 year old man with previously treated early syphilis and hepatitis C infection presented to a hospital complaining of 3 months of tender right inguinal lymphadenopathy. An excisional biopsy showed the formation of necrotising granuloma indicative of Lymphogranuloma venereum.
What should he be treated with?
A. Benzylpenicillin
B. Erythromycin
C. Clindamycin
D. Gentamicin
E. Doxycycline
Do question later!
Answer: e) doxycycline. Lymphogranuloma venereum is a sexually transmitted disease caused by chlamydia trachomatis. It causes a papule or ulcer that may occur on the penis, urethra or cervix. Proctocolitis may also be present, mimicking inflammatory bowel disease. Regional lymphadenopathy develops in the secondary stage of disease when there may be systemic symptoms.
Confirmation of a diagnosis of LGV requires serological tests or PCR on genitourinary specimens. Prolonged treatment with doxycycline or roxithromycin for 3 weeks is required for affected patients.
Lymphogranuloma venereum
A 45 year old patient presents with meningism. There is no past medical history. CT scan was normal and he had the following CSF results. There were 150 X 10^6/ml white cells (90% lymphocytes) , protein was 6g/l and glucose 2.2 mmol/l. Microscopy revealed no gram positive organisms and no Acid fast bacilli were seen. Which is the best diagnostic test?
A. TB PCR of the cerebrospinal fluid
B. CSF cytology
C. Heaf test
D. Herpes viral serology
E. Blood cultures
Do question later!
Answer: a) TB PCR of the cerebrospinal fluid. TB PCR is rapid. A CSF lymphocytosis low glucose points towards TB meningitis
A 62 year old lady presents with fever and persistent difficulty in speaking. Her signs show a termperature of 39°C. The patient was alert and oriented with respect to time but unable to name objects properly. Dysarthria and occasional word substitution were noted. The patient followed two but not three-step commands.
A provisional diagnosis of an aphasic temporal lobe lesion was made. A CT scan showed a low attenuation lesion involving the medial and posterior aspect of the left temporal lobe and inferior basal ganglia. What is the diagnosis?
A. Polymorpho leukoencephalopathy
B. Cerebral toxoplasmosis
C. Herpes simplex encephalitis
D. Multiple sclerosis
E. Meningococcal meningitis
Do question later!
Answer: c) herpes simplex encephalitis. Herpes simplex viruses (HSV-1 and HSV-2) produce a variety of infections involving mucocutaneous surfaces, the CNS, and occasionally visceral organs. HSV encephalitis is the most common identified cause of acute, sporadic viral encephalitis. Clinically, HSV encephalitis arises as acute onset of fever and focal neurologic, especially temporal lobe signs, as in this case.
A 30 year old lady presents with headache and neck stiffness. Her temperature is 38.5 °C, BP 100/65 and she has a petechial rash in the thigh. CSF examination reveals gram negative diplococci. Which is the best antibiotic therapy?
A. Gentamicin
B. Flucloxacillin
C. Cefuroxime
D. Ciprofloxacin
E. Benzylpenicillin
Do question later!
Answer: e) Benzylpenicillin. The diagnosis is meningococcal meningitis (it would be pneumococcal meningitis if gram positive diplococci were seen). Intravenous ceftriaxone or benzylpenicillin are treatment of choice.
Meningococcal Rash
A patient with HIV takes several different drugs is concerned about changing facial appearance. Which drug is most likely to cause lipodystrophy?
A. Lamivudine (3TC)
B. Zidovudine (AZT)
C. Didanosine (DDI)
D. Nevirapine
E. Saquinavir
Do question later!
Answer: e) Saquinavir.
Protease inhibitors, such as saquinavir, ritonavir and indinavir cause lipodystrophy.Lamivudine is an nucleoside reverse transcriptase inhibitor (NRTI), it commonly causes peripheral neuropathy. AZT (nucleoside reverse transcriptase inhibitor) more commonly causes bone marrow suppression and liver damage. DDI causes pancreatitis. Nevirapine is a non nucleoside reverse transcriptase inhibitor (NNRTI) with stevens johnsons / rash as main side effect.
Facial lipodystrophy
An 18 year old girl was studying for examinations together with a friend who was hospitalised 2 days ago with meningitis. The blood cultures in her friend grew meningococcus group A. Which of the following actions should be taken towards the girl who was in contact with the patient?
A. Immunisation with meningococcus A vaccine
B. Immunisation with meningococcus A and C vaccine
C. Immunisation with meningococcus A and C vaccine, and rifampicin
D. Rifampicin only
E. Full treatment for meningitis A
Do question later!
Answer: c) Immunisation with meningococcus A and C vaccine, and rifampicin. Immunisation is available against strains A and C of this bacteria, however strain B is the most often implicated in meningococcal meningitis. Due to close contact, this girl should be given both available vaccines and also rifampicin. Apart from rifampicin, minocycline and ceftriaxone can also be used for prophylaxis.
A 40 year old diabetic lady presents with a hot swollen left leg. On examination has a temperature of 39°C and her leg is tender to compression. She was treated with intravenous flucloxacillin and benzylpenicillin. However, the erythema has spread even further after 3 days, she is persistently hypotensive with a systolic BP of < 90 mmHg. Which of the following antibiotics should be added?
A. Gentamicin
B. Tazocin
C. Chloramphenicol
D. Clindamycin
E. Amoxycillin
Do question later!
Answer: d) clindamycin. There is suspicion that this lady may have Streptococcus A infection with toxic shock syndrome. Clindamycin has effects of reducing protein synthesis and exotoxin production by the bacteria.
A 22 year old man had been to a Greek island on holiday 2 months ago. He presented with a 2-week history of dry cough, diarrhoea, lethargy, anorexia and fever. He had a past history of cutaneous vasculitis of uncertain aetiology. He was not taking any regular medication.
On examination, the patient’s temperature was 37.5°C, but no other abnormalities were evident. Investigations showed that he had pancytopenia, raised erythrocyte sedimentation rate and hypergammaglobulinaemia.
A second bone marrow biopsy at this time revealed occasional macrophages containing amastigotes. Further history revealed that he had been bitten by sandflies.
What is the diagnosis?
A. Schistosomiasis
B. Cutaneous leishmaniasis
C. Visceral leishmaniasis
D. Malaria
E. Dengue fever
Do question later!
Answer: c) visceral leishmaniasis. The major clinical syndromes caused by the genus Leishmania are cutaneous, mucosal and visceral leishmaniasis. Leishmaniasis is transmitted by Phlebotomus or Lutzomyia sandflies and infects dogs and foxes as well as humans.
Visceral leishmaniasis is caused by Leishmania donovani, L. infantum or L. chagasi.
The incubation period of visceral leishmaniasis is usually 2–8 months. Many infections are subclinical, but the classic presentation is with fever, weight loss, hepatosplenomegaly, pancytopenia and hypergammaglobulinaemia.
The definitive diagnosis depends on demonstrating either amastigotes in tissue or promastigotes in culture. Splenic puncture is the most sensitive means of obtaining a diagnosis, but biopsy of the bone marrow and liver is almost as good.
Pentavalent antimony compounds have been used to treat leishmaniasis for decades, but often have severe side effects, and resistance is developing.Amphotericin can achieve 98% long-term cure in both antimonial-unresponsive and previously untreated patients.
A 30 year old lady presents with headache and neck stiffness. Her temperature is 38.5 °C, BP 100/65 and she has a petechial rash in the thigh. CSF examination reveals gram negative diplococci. Which is the best antibiotic therapy?
A. Gentamicin
B. Flucloxacillin
C. Cefuroxime
D. Ciprofloxacin
E. Benzylpenicillin
Do question later!
Answer: e) Benzylpenicillin. The diagnosis is meningococcal meningitis (it would be pneumococcal meningitis if gram positive diplococci were seen). Intravenous ceftriaxone or benzylpenicillin are treatment of choice
A 45 year old HIV positive man presents with breathlessness. He has a temperature of 38°C. The blood gases show a pH of 7.30, pO2 of 8kPa and pCO2 of 3 kPa. CXR shows bilateral interstitial and alveolar consolidation. Which of the following medications should be used?
A. Quadruple anti TB therapy
B. Amphotericin
C. Co-trimoxazole
D. Gentamicin
E. Teicoplanin
Do question later!
Answer: c) co-trimoxazole. The patient has pneumocystis carinii pneumonia and is hypoxic on the blood gases. IV co-trimoxazole, clindamycin or pentamidine can be used to treat this.
A 25 year old man presented to an emergency department with a 1-day history of fever, headache and myalgia. Two weeks before his presentation, he had returned from a 10-day trip to Costa Rica, where he had injured the sole of his foot on coral. After injuring his foot, he had swum in freshwater rivers. Thick and thin blood films examined at the time for malaria parasites were negative.
What is the likely diagnosis?
A. Amoebiasis
B. Leishmaniasis
C. Schistosomiasis
D. Leptospirosis
E. Brucella abortius
Do question later!
Answer: d) leptospirosis. Leptospira species are endemic in feral and domestic mammals, reptiles and amphibians. Rats and other rodents are the most important sources for human infection. This usually occurs through contact with urine-contaminated soil or water, contact with infected animal tissue, or through rat bites.
Pathogenic leptospiras rapidly invade the bloodstream after penetrating skin or mucous membranes, and multiply in small blood vessel endothelium, resulting in damage and vasculitis in major organs. The mortality rate ranges from 4% to 10%, and adverse indicators are dyspnoea, oliguria, raised white cell count, abnormalities on ECG, and alveolar infiltrates on chest x-ray.
Oral doxycycline is highly efficacious.
A 20 year old man has recently returned from holiday in Spain. He has fever and a sorethroat. Examination reveals palpable lymphadenopathy in the cervical and inguinal areas. Blood tests show:
Hb 11.0 g/dlWCC 12 x 10^9/lplatelets 145 x 10^9/lurea 7 μmol/lcreatinine 80 μmol/lsodium 140 mmol/lpotassium 4.2 mmol/lbilirubin 22 μmol/lAST 90 U/lALP 280 U/lalbumin 32 g/lCRP 110 mg/l
What is likely diagnosis?
A. CMV infection
B. Typhoid fever
C. Infectious mononucleosis
D. Yellow fever
E. Schistosomiasis
Do question later!
Answer: c) infectious mononucleosis. Ebstein Barr virus can cause a pharyngitis, palpable lymphadenopathy, thrombocytopenia and deranged liver function tests. Heterophil antibodies will be positive and there may also be lymphocytosis.
Pharyngitis due to infectious mononucleosis
A 75 year man has severe headaches and photophobia. Examination reveals a temperature of 40°C and neck stiffness. Fundoscopy and CT scan reveal no abnormalities. CSF examination shows Gram positive diplococci. What is the diagnosis?
A. Listeria meningitis
B. TB meningitis
C. Meningococcal meningitis
D. Pneumococcal meningitis
E. Mycoplasma infection
Do question later!
Answer: d) pneumococcal meningitis. The gram positive diplococci points towards pneumococcal meningitis (meningococcus is gram negative). The young and elderly are most at risk. Nerve deafness is likely, paralysis can occur and mortality rate is high among the elderly. Intravenous penicillin or ceftriaxone should be given. Vancomycin and rifampicin can also be used.
Gram positive diplococci
A 35 year old woman presented with a non-healing genital ulcer. She had travelled through Africa 3 years previously.
On examination, An indurated 1.5 cm ulcer was present on the inner aspect of the left labia majoris.
Skin biopsy of the lesion revealed a granuloma surrounding a schistosome egg. Schistosoma haematobium eggs were detected in terminal urine collected between midday and 2 pm.
What should she be treated with?
A. Quinine
B. Benzylpenicillin
C. Tetracycline
D. Flucloxacillin
E. Praziquantel
Do question later!
Answer: e) praziquantel. Schistosomal infestation may persist and present long after leaving an endemic area. Serological tests are the most sensitive method of screening, but are not species-specific. Indirect hemagglutination titres ≥ 64 suggest infection.
Treatment is with praziquantel.
Schistosomal Egg in the urine
A 42 year old man presented 10 days after returning from a 8-week holiday in South-East Asia. He had an eight-day history of malaise, chills, headache, sore throat and generalised rash. He had reported many mosquito bites.
He had fever, a macular rash and generalised lymphadenopathy with mild splenomegaly, but no meningism and no eschar present.
Full blood examination revealed lymphocytosis with numerous atypical lymphocytes and thrombocytopenia. Blood cultures and malaria films were negative. Liver function tests revealed marginally elevated serum transaminase levels. Serological testing revealed past infection with Epstein–Barr virus and cytomegalovirus and was negative for Q fever, dengue, rubella, measles and rickettsial infection.
What is the most likely diagnosis?
A. HIV
B. Dengue fever
C. Syphilis
D. Lyme disease
E. Malaria
Do question later!
Answer: a) HIV. Acute HIV seroconversion may mimic several tropical diseases, including dengue and typhus, as well as infectious mononucleosis.
An 8 year old child develops fevers, myalgia, lethargy and joint pains over 5 days, having been in contact with another child with a similar illness. She has a temperature of 39 ºC. On examination, she has a cheek rash, synovitis of the hand and knee joints, and palpable lymph nodes in the cervical area. Which is a likely diagnosis?
A. Infectious mononucleosis
B. Lyme disease
C. Listeriosis
D. Leptospirosis
E. Parvovirus B19
Do question later!
Answer: e) Parvovirus B19. Parvovirus infection or fifth's disease can cause the 'slapped cheek syndrome'. There is a cheek rash with swollen in the wrist, hands and knees. Diagnosis can be confirmed with an IgM antibody to parvovirus B19.
Slapped Cheek s
A 45 year old pig farmer is admitted to A+E following two generalised seizures. CT scan shows periventricular cystic lesions. There is eosinophilia of 10%. Whic infective organisms is likely?
A. Toxocara canii
B. Ascaris lumbricoides
C. Schistosoma mansoni
D. Yersinia enterolitica
E. Taenia solium
Do question later!
Answer: e) Taenia solium.
Toxocariasis is commonly passed on from dog and cat faeces. Ascariasis is roundworm infection which commonly causes abdominal symptoms.Yersninia is a bacterial infection spread from half cooked meat and unpasteurised milk, causing abdominal symptoms and diarrhoea. Taenia solium is the pork tapeworm which causes the condition cysticercosis described above. Cysts are commonly found in the brain and seizures are common.
Taenia Solium
yndrome
A pregnant 18 year old woman came to the clinic with a low-grade fever,malaise, and headache. She was sent home with a diagnosis of influenza. She again sought treatment 7 days later with a macular rash on her trunk, arms, hands, and feet. Further questioning of the patient when serology results were known revealed that I month previously, she had a painless ulcer on her vagina that healed spontaneously. Which of the following is the most likely diagnosis?
A. Lyme disease
B. Lymphogranumoma venereum
C. Behcet's disease
D. Endocarditis
E. Syphilis
Do question later!
Answer: e) syphilis. The initial lesion of primary syphilis develops at the site of transmission after an incubation period of 10-90 days, with a mean of about 21-28 days, and then heals spontaneously in 3-7 weeks.
T pallidum is sensitive to the penicillins and is easily treatable in the early stages.
Maculopapular rash in secondary syphilis
A 18 year old man was admitted to the emergency room due to fever, headache, vomiting, irritability, and myalgia that had begun 24 hours ago. There was no evidence of previous infection in the upper airways. On examination, the patient was lethargic, disoriented and hypotensive, with petechiae in the legs and upper limbs, and he had conjunctival suffusion.
Cerebrospinal fluid (CSF) was turbid, with 5300 cells/mm3 (97% neutrophils and 3% monocytes)and protein was 0.9 (<0.5).
What is the treatment of choice?
A. Erythromycin
B. Gentamicin
C. Ceftriaxone
D. Metronidazole
E. Hydrocortisone
Do question later!
Answer: c) ceftriaxone. The patient has meningococcal meningitis (suggested by the purpuric rash). Until the organism (Neisseria meningitidis) is isolated and sensitivities tested, the patient should be on a cephalosporin or benzylpenicillin.
Meningococcal Rash
A 32 year old sailor is admitted to hospital with a 3 day history of fever, generalised lymphadenopathy and a macular rash over the trunk and legs. Which of the following diseases may present in this way?
A. Infectious mononucleosis
B. Sarcoidosis
C. Mumps
D. Primary syphillis
E. Familial mediterranean fever
Do question later!
Answer: a) infectious mononucleosis. Infectious mononucleosis may present in this manner, and the rash may be made worse if amoxycillin is given.
Sarcoidosis causes lupus pernio and erythema nodosum but not rashes on the trunk. Also causes hilar lymphadenopathy and lung parenchyma fibrosis, uveitis, arthralgia, cardiomyopathy, cranial nerve palsy and hypercalcaemic nephropathy. Intradermal injection of sarcoid spleen tissue (Kveim test) gives a positive granulomatous response.
Mumps causes parotitis, orchitis, and lymphocytic meningitis.
Secondary syphillis can present with a rash and lymphadenopathy, but primary syphillis does not.
Although systemic amyloidosis may present like this, familial mediterranean fever is a form of polyserositis which presents with features of arthritis. It is found in Ashkenazi Jews and Armenians
20 year old man has recently returned from holiday in Spain. He has fever and a sorethroat. Examination reveals palpable lymphadenopathy in the cervical and inguinal areas. Blood tests show:
Hb 11.0 g/dl
WCC 12 x 10^9/lplatelets 145 x 10^9/lurea 7 μmol/lcreatinine 80 μmol/lsodium 140 mmol/lpotassium 4.2 mmol/lbilirubin 22 μmol/lAST 90 U/lALP 280 U/lalbumin 32 g/lCRP 110 mg/l
What is likely diagnosis?
A. CMV infection
B. Typhoid fever
C. Infectious mononucleosis
D. Yellow fever
E. Schistosomiasis
Do question later!
Answer: c) infectious mononucleosis. Ebstein Barr virus can cause a pharyngitis, palpable lymphadenopathy, thrombocytopenia and deranged liver function tests. Heterophil antibodies will be positive and there may also be lymphocytosis.