Question 161#

A 33-year-old man presents 6 weeks after visiting North Africa on business. He describes feeling lethargic, abdominal pain and having episodic fever. A blood screen is sent which reveals the following:

• Hb 15.9 g/dl
• WBC 7.1 *10⁹/l
• Platelets 343 *10⁹/l
• Bilirubin 53 μmol/l
• ALP 169 u/l
• ALT 364 u/l
• Hepatitis A IgM Negative
• HBsAg Negative

What is the most likely diagnosis? 

A. Infectious mononucleosis

Correct Answer E: The incubation period and negative HBsAg points to a diagnosis of Hepatitis E.

Hepatitis E:

Overview: 

• RNA virus
• Spread by the faecal-oral route, incubation period = 3-8 weeks
• Common in Central and South-East Asia, North and West Africa, and in Mexico
• Causes a similar disease to hepatitis A, but carries a significant mortality (about 20%) during pregnancy
• Does not cause chronic disease
• A vaccine is currently in development*, but is not yet in widespread use

*New England Journal of Medicine 356:895, 2007

Question 162#

What is the most appropriate antibiotic to use in cholera?

A. Erythromycin

Correct Answer C: 

Cholera:

Overview:

• Caused by Vibro cholerae - Gram negative bacteria

Features: 

• Profuse 'rice water' diarrhoea
• Dehydration
• Hypoglycaemia 

Management: 

• Oral rehydration therapy
• Antibiotics: doxycycline, ciprofloxacin

Question 163#

A 17-year-old man attends the local sexual health clinic. He has developed a large, keratinized genital wart on the shaft of his penis. This has been present for around three months but he has been too embarrassed to present before now.

What is the most appropriate initial management?

A. Topical acyclovir

Correct Answer B: 

Genital wart treatment:

• Multiple, non-keratinized warts: topical podophyllum
• Solitary, keratinized warts: cryotherapy

As the wart is keratinized cryotherapy should be used initially.

Genital warts:

Genital warts (also known as condylomata accuminata) are a common cause of attendance at genitourinary clinics. They are caused by the many varieties of the human papilloma virus HPV, especially types 6 & 11. It is now well established that HPV (primarily types 16,18 & 33) predisposes to cervical cancer.

Features:

• Small (2 - 5 mm) fleshy protuberances which are slightly pigmented
• May bleed or itch

Management: 

• Topical podophyllum or cryotherapy are commonly used as first-line treatments depending on the location and type of lesion. Multiple, non-keratinized warts are generally best treated with topical agents whereas solitary, keratinized warts respond better to cryotherapy
• Imiquimod is a topical cream which is generally used second line
• Genital warts are often resistant to treatment and recurrence is common although the majority of anogenital infections with HPV clear without intervention within 1-2 years

Question 164#

A 24-year-old man is admitted to the Emergency Department with breathing difficulties and confusion three weeks after returning from a holiday in Cambodia. His partner says he has had 'the flu' for the past two weeks. A blood film is positive for malarial parasites and a chest x-ray and arterial blood gases suggest acute respiratory distress syndrome. A diagnosis of severe falciparum malaria is suspected.

What is the treatment of choice?

A. Intravenous artesunate

Correct Answer A: Severe falciparum malaria - intravenous artesunate.

Malaria: Falciparum:

Feature of severe malaria:

• Schizonts on a blood film
• Parasitaemia > 2%
• Hypoglycaemia
• Temperature > 39 °C
• Severe anaemia
• Complications as below 

Complications: 

• Cerebral malaria: seizures, coma
• Acute renal failure: blackwater fever, secondary to intravascular haemolysis, mechanism unknown
• Acute respiratory distress syndrome (ARDS)
• Hypoglycaemia
• Disseminated intravascular coagulation (DIC)

Uncomplicated falciparum malaria: 

• Strains resistant to chloroquine are prevalent in certain areas of Asia and Africa
• The 2010 WHO guidelines recommend artemisinin-based combination therapies (ACTs) as first-line therapy
• Examples include artemether plus lumefantrine, artesunate plus amodiaquine, artesunate plus mefloquine, artesunate plus sulfadoxine-pyrimethamine, dihydroartemisinin plus piperaquine Severe falciparum malaria
• A parasite counts of more than 2% will usually need parenteral treatment irrespective of clinical state
• Intravenous artesunate is now recommended by WHO in preference to intravenous quinine
• If parasite count > 10% then exchange transfusion should be considered
• Shock may indicate coexistent bacterial septicaemia - malaria rarely causes haemodynamic collapse

Question 165#

A phlebotomist gives herself a needlestick injury whilst taking blood from a patient who is known to have the HIV infection.

What is the chance that the phlebotomist will develop HIV? 

A. 0.03%

Correct Answer B: The transmission rate of HIV is relatively low compared to hepatitis B and C.

Post-exposure prophylaxis:

Hepatitis A: 

• Human Normal Immunoglobulin (HNIG) or hepatitis A vaccine may be used depending on the clinical situation

Hepatitis B: 

• HBsAg positive source: if the person exposed is a known responder to HBV vaccine then a booster dose should be given. If they are in the process of being vaccinated or are a non-responder they need to have hepatitis B immune globulin (HBIG) and the vaccine
• Unknown source: for known responders the green book advises considering a booster dose of HBV vaccine. For known non-responders HBIG + vaccine should be given whilst those in the process of being vaccinated should have an accelerated course of HBV vaccine 

Hepatitis C: 

• Monthly PCR - if seroconversion then interferon +/- ribavirin 

HIV:

• A combination of oral antiretrovirals (e.g. Tenofovir, emtricitabine, lopinavir and ritonavir) as soon as possible (i.e. Within 1-2 hours, but may be started up to 72 hours following exposure) for 4 weeks
• Serological testing at 12 weeks following completion of post-exposure prophylaxis
• Reduces risk of transmission by 80%

Varicella zoster: 

• VZIG for IgG negative pregnant women/immunosuppressed

Estimates of transmission risk for single needlestick injury: