Question 166#

Which one of the following statements regarding hepatitis B is correct?

A. Ribavirin is the treatment of choice for chronic hepatitis B

Correct Answer C: Only those at risk of occupational exposure (i.e. Healthcare workers) and patients with chronic kidney disease require an anti-HBs check.

Hepatitis B:

• Hepatitis B is a double-stranded DNA virus and is spread through exposure to infected blood or body fluids, including vertical transmission from mother to child. The incubation period is 6-20 weeks. Immunization against hepatitis B:
• Contains HBsAg adsorbed onto aluminium hydroxide adjuvant and is prepared from yeast cells using recombinant DNA technology
• Most schedules give 3 doses of the vaccine with a recommendation for a one-off booster 5 years following the initial primary vaccination
• At risk groups who should be vaccinated include: healthcare workers, intravenous drug users, sex workers, close family contacts of an individual with hepatitis B, individuals receiving blood transfusions regularly, chronic kidney disease patients who may soon require renal replacement therapy, prisoners, chronic liver disease patients
• Around 10-15% of adults fail to respond or respond poorly to 3 doses of the vaccine. Risk factors include age over 40 years, obesity, smoking, alcohol excess and immunosuppression
• Testing for anti-HBs is only recommended for those at risk of occupational exposure (i.e. Healthcare workers) and patients with chronic kidney disease. In these patients anti-HBs levels should be checked 1-4 months after primary immunization
• The table below shows how to interpret anti-HBs levels:

Complications hepatitis B infection of: 

• Chronic hepatitis (5-10%)
• Fulminant liver failure (1%)
• Hepatocellular carcinoma
• Glomerulonephritis
• Polyarteritis nodosa
• Cryoglobulinaemia

Management of hepatitis B: 

• Pegylated interferon-alpha used to be the only treatment available. It reduces viral replication in up to 30% of chronic carriers. A better response is predicted by being female, < 50 years old, low HBV DNA levels, non-Asian, HIV negative, high degree of inflammation on liver biopsy
• However due to the side-effects of pegylated interferon it is now used less commonly in clinical practice

Oral antiviral medication is increasingly used with an aim to suppress viral replication (not in dissimilar way to treating HIV patients): 

• Examples include lamivudine, tenofovir and entecavir

Question 167#

A 35-year-old man returns from a two week holiday in Italy. He has a 10 day history of rectal bleeding associated with lower back pain. On examination there is a painful swelling of his right knee.

What is the most likely diagnosis?

A. Gonococcal septicaemia

Correct Answer A: Gonococcus contracted via anal sex may cause proctitis. The knee swelling seen in this patient is septic arthritis, which is characteristic of the second stage of disseminated gonococcal infection. Proctitis may present with either lower back or rectal pain.

Gonorrhoea:

Gonorrhoea is caused by the Gram negative diplococcus Neisseria gonorrhoea. Acute infection can occur on any mucous membrane surface, typically genitourinary but also rectum and pharynx. The incubation period of gonorrhoea is 2-5 days.

Features: 

• Males: urethral discharge, dysuria
• Females: cervicitis e.g. leading to vaginal discharge
• Rectal and pharyngeal infection is usually asymptomatic Local complications that may develop include urethral strictures, epididymitis and salpingitis (hence may lead to infertility). Disseminated infection may occur 

Management: 

• Ciprofloxacin 500mg PO used to be the treatment of choice
• However, there is increased resistance to ciprofloxacin and therefore cephalosporins are now used
• Options include cefixime 400mg PO (single dose) or ceftriaxone 250mg IM

Disseminated gonococcal infection (DGI) and gonococcal arthritis may also occur, with gonococcal infection being the most common cause of septic arthritis in young adults. The pathophysiology of DGI is not fully understood but is thought to be due to haematogenous spread from mucosal infection (e.g. Asymptomatic genital infection). Initially there may be a classic triad of symptoms: tenosynovitis, migratory polyarthritis and dermatitis.

Later complications include septic arthritis, endocarditis and perihepatitis (Fitz-Hugh-Curtis syndrome).

Key features of disseminated gonococcal infection:

• Tenosynovitis
• Migratory polyarthritis
• Dermatitis (lesions can be maculopapular or vesicular)