Systemic infections

Systemic infections

 

Australian spotted fevers (tick typhus: Rickettsia australis, R. honei), scrub typhus (Orientia tsutsugamushi)

 

1	doxycycline (child >8 years: 2 mg/kg up to) 100 mg orally, 12-hourly for 7 to 10 days
	OR
2	chloramphenicol (child: 12.5 mg/kg up to) 500 mg orally or IV, 6-hourly for 7 to 10 days.

 

In severe disease or children less than 8 years old, consultation with an infectious diseases physician or clinical microbiologist is recommended.

 

Brucellosis

 

For children aged less than 8 years old, use

	trimethoprim+sulfamethoxazole 4+20 to 6+30 mg/kg orally, 12-hourly for 6 weeks
	PLUS EITHER
1	rifampicin 15 mg/kg orally, daily for 6 weeks
	OR
2	gentamicin 7.5 mg/kg IV, daily for 2 weeks (adjust dose for renal function, see Monitoring of aminoglycosides).

 

For adults and older children, use

	doxycycline (child >8 years: 2 mg/kg up to) 100 mg orally, 12-hourly for 6 weeks
	PLUS EITHER
1	rifampicin (child: 15 mg/kg up to) 600 mg orally, daily for 6 weeks
	OR
2	gentamicin (child <10 years: 7.5 mg/kg; >=10 years: 6 mg/kg) 4 to 6 mg/kg IV, daily for 2 weeks (adjust dose for renal function, see Monitoring of aminoglycosides).

Cat-scratch disease

 

In immunocompetent patients the condition is self-limiting and most cases do not require antibiotic therapy.

Bartonella henselae and other Bartonella species cause skin disease (bacillary angiomatosis) and internal organ disease (bacillary peliosis) in patients with AIDS, and treatment is mandatory.

1	roxithromycin 300 mg orally, daily (child: 4mg/kg up to 150 mg orally, 12-hourly) for 10 days
	OR
2	erythromycin (child: 10 mg/kg up to) 500 mg orally, 12-hourly for 10 days
	OR
3	doxycycline (child >8 years: 2 mg/kg up to) 100 mg orally, 12-hourly for 10 days.

 

Alternative therapies that may be as effective include azithromycin, ciprofloxacin, rifampicin, trimethoprim+sulfamethoxazole or gentamicin. For infection in patients with AIDS, IV erythromycin may have to be used initially and the duration of treatment may have to be prolonged. Expert advice should be sought.

 

Cytomegalovirus (CMV) infections

 

For disseminated CMV infection see Prophylaxis and treatment of opportunistic infections. Also see CMV retinitis and CMV colitis or oesophagitis. For perinatal CMV infections, see also:

·            Palasanthiran P, Starr M, Jones C, editors. Management of perinatal infections. Sydney: Australasian Society for Infectious Diseases; 2002.

 

Hydatid cyst

 

Seek expert advice. Surgery is often the treatment of choice for infection with Echinococcus granulosus, sometimes combined with prolonged high-dose albendazole.

albendazole (child >6 years: 7.5 mg/kg up to) 400 mg orally, 12-hourly.

 

Albendazole is sometimes cycled, with 4 weeks therapy followed by 2 drug-free weeks. Percutaneous drainage with ultrasound guidance plus prolonged high-dose albendazole has been effective for liver cysts. Percutaneous aspiration, introduction of a protoscolicidal agent (eg hypertonic saline or ethanol), with reaspiration after at least 15 minutes (the PAIR procedure) is used in selected patients. Praziquantel followed by prolonged high-dose albendazole is used if there is cyst spillage from trauma or surgery. Praziquantel may also be used with albendazole before surgery.

Leptospirosis

 

Use

1	doxycycline (child >8 years: 2 mg/kg up to) 100 mg orally, 12-hourly for 5 to 7 days
	OR
2	benzylpenicillin (child: 30 mg/kg up to) 1.2 g IV, 6-hourly for 5 to 7 days.

 

Lyme disease

 

This disease, which is caused by a spirochaete, Borrelia burgdorferi, is not known to be endemic in Australia. Patients in whom Lyme disease is suspected should be referred for specialist advice.

Melioidosis

 

Melioidosis is caused by the soil saprophyte Burkholderia pseudomallei. It occurs in northern Australia and parts of the Asia-Pacific region and may present in returned travellers, occasionally even months or years after exposure.

A wide spectrum of presentations occurs, with diabetics and alcoholics being at risk of developing a more severe illness. Pneumonia is the commonest presentation but bacteraemic spread can cause abscesses in any organ, especially the spleen and prostate. Localised cutaneous ulcers or abscesses are also common and asymptomatic infection, latency and relapse are well-recognised. Selective culture media, serology and a polymerase chain reaction test may assist diagnosis. Seek expert advice.

For initial intensive therapy, use

	trimethoprim+sulfamethoxazole (child: 8+40 mg/kg up to) 320+1600 mg orally or IV, 12-hourly for at least 14 days
	PLUS EITHER
1	ceftazidime (child: 50 mg/kg up to) 2 g IV, 6-hourly for at least 14 days
	OR
1	meropenem (child: 25 mg/kg up to) 1 g IV, 8-hourly for at least 14 days
	OR
2	imipenem (child: 25 mg/kg up to) 1 g IV, 6-hourly for at least 14 days. [Note]

 

In critically ill patients with septicaemic melioidosis, granulocyte colony-stimulating factor (G-CSF) therapy should be considered.

Prolonged IV therapy (4 to 8 weeks) is necessary for deep-seated infection, osteomyelitis and septic arthritis.

After the initial intensive therapy, eradication is recommended with oral trimethoprim+sulfamethoxazole at the same high dose as above for at least 3 months. Alternative eradication regimens include various combinations of trimethoprim+sulfamethoxazole with doxycycline, chloramphenicol and amoxycillin+clavulanate

Q Fever

 

For acute infection with Coxiella burnetii, use

1	doxycycline (child >8 years: 2 mg/kg up to) 100 mg orally, 12-hourly for 14 days
	OR
2	chloramphenicol (child: 12.5 mg/kg up to) 500 mg orally or IV, 6-hourly for 14 days.

 

In chronic disease or endocarditis, prolonged combination therapy including hydroxychloroquine and cardiac surgery may be required, see Culture-negative endocarditis. Seek expert advice.

Schistosomiasis (bilharziasis)

 

Diagnosis is confirmed by identification of species-specific eggs in stool, urine or biopsy samples. Serology may be helpful for presumptive diagnosis in travellers from endemic areas, but interpretation of serology results can be difficult. Seek expert advice.

For infection with Schistosoma haematobium and S. mansoni, use

praziquantel 20 mg/kg orally, for 2 doses after food, 4 hours apart.

 

Extra doses may be recommended under some circumstances.

For infection with S. japonicum and S. mekongi, use

praziquantel 20 mg/kg orally, for 3 doses after food, 4 hours apart.

 

Typhoid and paratyphoid fevers (enteric fevers)

 

Use

ciprofloxacin (child: 15 mg/kg up to) 500 mg orally, 12-hourly for 7 to 10 days.

 

If oral therapy cannot be tolerated, initial therapy should be

ciprofloxacin (child: 10 mg/kg up to) 400 mg IV, 12-hourly , until oral ciprofloxacin can be tolerated.

 

If reduced susceptibility to ciprofloxacin is found or the clinical response is delayed, eg fever longer than 7 days, an alternative drug is

ceftriaxone (child: 75 mg/kg up to) 3 g IV, daily.

 

Continue ceftriaxone until adequate clinical response and susceptibility results become available, then choose an appropriate oral regimen. Depending on susceptibilities, use

1	amoxycillin (child: 25 mg/kg up to) 1 g orally, 6-hourly for a further 14 days
	OR
2	trimethoprim+sulfamethoxazole (child: 4+20 mg/kg up to) 160+800 mg orally, 12-hourly for a further 14 days
	OR
3	chloramphenicol (child: 25 mg/kg up to) 500 to 750 mg orally, 6-hourly for a further 14 days.

 

Some patients with enteric fever become long-term carriers, and expert advice should be sought on their management.