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Images in medicine
Rat bite fever: an unusual cause of a maculopapular rash INTRODUCTION Rat bite fever (RBF) is a rare zoonosis caused worldwide by Streptobacillus monoliformis with Spirillum minus cases restricted to Asia.1 Transmission arises mainly by scratches or bites from colonised rats.1 At-risk groups include veterinarians, sewerage and laboratory workers or rat owners.1 Patients typically present within 7 days of exposure with an acute febrile illness characterised by headache, myalgia, migratory polyarthralgia and a rash.2 In the UK, one–two cases are diagnosed per year3 predominantly caused by S monoliformis.2 It is likely underdiagnosed due to a wide differential diagnosis and low culture sensitivity.2 If not suspected and treated with an appropriate antibiotic such as penicillin, mortality may reach 13%.1
CASE HISTORY A 28-year-old excavator operator presented with a 5 day history of fever, headache, rash, myalgia, symmetrical wrist arthritis and diarrhoea. He had received multiple bites to his fingers from a friend’s pet rat 10 days previously. A painless non-blanching red maculopapular pustular rash developed affecting the lower extremities, 2 days before admission (figures 1 and 2). Examination revealed no lymphadenopathy, cardiac murmur, hepatosplenomegaly or septic arthritis. The rat bites had almost healed. Laboratory investigations showed a transient leucocytosis with neutrophilia and lymphopenia and an elevated C reactive protein. Clinically rat bite fever was diagnosed and intravenous co-amoxiclav commenced. Blood cultures were negative after 7 days. Serological testing for HIV, syphilis and leptospirosis, and urine screening for Neisseria gonorrhoeae and Chlamydia trachomatis were negative. He was discharged home on oral co-amoxiclav after 3 days of intravenous therapy to finish a 14 day course. When seen in clinic 1 month later, the patient was much better and had returned to work.
Figure 2 Photograph of the left ankle and foot showing a red maculopapular pustular rash.
DISCUSSION Rash is a characteristic clinical feature of patients presenting with RBF due to S monoliformis and S minus, present in 75% and 50% of cases, respectively.1 In S minus cases it has a typical red-brown maculopapular appearance that is often confluent with occasional plaques or urticarial lesions.1 2 S monoliformis cases have a variable appearance including petechial,2 morbilliform1 and maculopapular with pustules4 as with our patient (figure 2). Although the rash may be generalised, it is typically acral affecting the palms and soles2 (figure 1). It may evolve by desquamation, the formation of purpura or vesicles.5 A skin biopsy typically shows a leucocytoclastic vasculitis.2 The differential diagnosis of the rash is wide including Henoch-Schönlein purpura, autoimmune vasculitis, meningococcaemia, gonococcaemia, staphylococcal and streptococcal infections and leptospirosis.5 The diagnosis can be hard to elucidate as rat bites heal quickly, often absent by the time of presentation1 and seemingly innocuous rat exposures such as kissing or faecal exposure can transmit S monoliformis resulting in RBF.5 The complications of RBF include septic arthritis, pericardial effusion, bronchopneumonia, overwhelming sepsis and endocarditis which carries a mortality of 53%.2 In patients with symptoms of fever, polyarthralgia and a rash predominantly affecting the extremities, it is important to seek a history of rodent exposure and consider RBF and to institute appropriate antibiotics to prevent unnecessary morbidity and mortality. Andrew Rosser,1 Martin Wiselka,1 Manish Pareek2 1
Department of Infection and Tropical Medicine, University Hospitals of Leicester, Leicester, UK 2 Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK Correspondence to Dr Manish Pareek, Department of Infection, Immunity and Inflammation, Maurice Shock Medical Sciences Building, University Road, Leicester, LE1 9HN; [email protected] Contributors AR: drafted, wrote and revised the manuscript. MW: made substantial contributions to the conception of the article. MP: made substantial contributions to the conception of the article and revised it for critically important intellectual content.
Figure 1 A close-up photograph of a maculopapular pustular rash of rat bite fever.
236
Competing interests None.
Rosser A, et al. Postgrad Med J April 2014 Vol 90 No 1062
Downloaded from http://pmj.bmj.com/ on June 13, 2015 - Published by group.bmj.com
Images in medicine Provenance and peer review Not commissioned; externally peer reviewed.
REFERENCES 1 2 3
To cite Rosser A, Wiselka M, Pareek M. Postgrad Med J 2014;90:236–237. Received 16 October 2013 Revised 2 December 2013 Accepted 1 January 2014 Published Online First 22 January 2014
4 5
Gaastra W, Boot R, Hoa TK, et al. Rat bite fever. Vet Microbiol 2009;133: 211–28. Elliot SP. Rat bite fever and streptobacillus monoliformis. Clin Microbiol Rev 2007;20:13–22. Public Health England. Zoonoses that may be acquired from rats: England and Wales. http://www.hpa.org.uk/Topics/InfectiousDiseases/InfectionsAZ/Zoonoses/ GeneralInformation/zoo010ZoonosesFromRats/ (accessed 2 Oct 2013). Schachter ME, Wilcox L, Rau N, et al. Rat-bite fever, Canada. Emerg Infect Dis 2006;12:1301–2. Khatchadourian K, Ovetchkine P, Minodier P, et al. The rise of the rats: a growing paediatric issue. Paediatr Child Health 2010;15:131–4.
Postgrad Med J 2014;90:236–237. doi:10.1136/postgradmedj-2013-132420
Rosser A, et al. Postgrad Med J April 2014 Vol 90 No 1062
237
Downloaded from http://pmj.bmj.com/ on June 13, 2015 - Published by group.bmj.com
Rat bite fever: an unusual cause of a maculopapular rash Andrew Rosser, Martin Wiselka and Manish Pareek Postgrad Med J 2014 90: 236-237 originally published online January 22, 2014
doi: 10.1136/postgradmedj-2013-132420 Updated information and services can be found at: http://pmj.bmj.com/content/90/1062/236
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Articles on similar topics can be found in the following collections Drugs: cardiovascular system (318) Epidemiology (335) Pain (neurology) (199) Headache (including migraine) (29) Drugs: infectious diseases (193) Clinical diagnostic tests (356) General surgery (149) HIV/AIDS (51) Immunology (including allergy) (346) Ophthalmology (84) Pneumonia (respiratory medicine) (21) Radiology (368) Sexual transmitted infections (bacterial) (9) Sexual transmitted infections (viral) (52) Surgical diagnostic tests (145) Valvar diseases (24)
Notes
To request permissions go to: http://group.bmj.com/group/rights-licensing/permissions To order reprints go to: http://journals.bmj.com/cgi/reprintform To subscribe to BMJ go to: http://group.bmj.com/subscribe/
Images in medicine
Rat bite fever: an unusual cause of a maculopapular rash INTRODUCTION Rat bite fever (RBF) is a rare zoonosis caused worldwide by Streptobacillus monoliformis with Spirillum minus cases restricted to Asia.1 Transmission arises mainly by scratches or bites from colonised rats.1 At-risk groups include veterinarians, sewerage and laboratory workers or rat owners.1 Patients typically present within 7 days of exposure with an acute febrile illness characterised by headache, myalgia, migratory polyarthralgia and a rash.2 In the UK, one–two cases are diagnosed per year3 predominantly caused by S monoliformis.2 It is likely underdiagnosed due to a wide differential diagnosis and low culture sensitivity.2 If not suspected and treated with an appropriate antibiotic such as penicillin, mortality may reach 13%.1
CASE HISTORY A 28-year-old excavator operator presented with a 5 day history of fever, headache, rash, myalgia, symmetrical wrist arthritis and diarrhoea. He had received multiple bites to his fingers from a friend’s pet rat 10 days previously. A painless non-blanching red maculopapular pustular rash developed affecting the lower extremities, 2 days before admission (figures 1 and 2). Examination revealed no lymphadenopathy, cardiac murmur, hepatosplenomegaly or septic arthritis. The rat bites had almost healed. Laboratory investigations showed a transient leucocytosis with neutrophilia and lymphopenia and an elevated C reactive protein. Clinically rat bite fever was diagnosed and intravenous co-amoxiclav commenced. Blood cultures were negative after 7 days. Serological testing for HIV, syphilis and leptospirosis, and urine screening for Neisseria gonorrhoeae and Chlamydia trachomatis were negative. He was discharged home on oral co-amoxiclav after 3 days of intravenous therapy to finish a 14 day course. When seen in clinic 1 month later, the patient was much better and had returned to work.
Figure 2 Photograph of the left ankle and foot showing a red maculopapular pustular rash.
DISCUSSION Rash is a characteristic clinical feature of patients presenting with RBF due to S monoliformis and S minus, present in 75% and 50% of cases, respectively.1 In S minus cases it has a typical red-brown maculopapular appearance that is often confluent with occasional plaques or urticarial lesions.1 2 S monoliformis cases have a variable appearance including petechial,2 morbilliform1 and maculopapular with pustules4 as with our patient (figure 2). Although the rash may be generalised, it is typically acral affecting the palms and soles2 (figure 1). It may evolve by desquamation, the formation of purpura or vesicles.5 A skin biopsy typically shows a leucocytoclastic vasculitis.2 The differential diagnosis of the rash is wide including Henoch-Schönlein purpura, autoimmune vasculitis, meningococcaemia, gonococcaemia, staphylococcal and streptococcal infections and leptospirosis.5 The diagnosis can be hard to elucidate as rat bites heal quickly, often absent by the time of presentation1 and seemingly innocuous rat exposures such as kissing or faecal exposure can transmit S monoliformis resulting in RBF.5 The complications of RBF include septic arthritis, pericardial effusion, bronchopneumonia, overwhelming sepsis and endocarditis which carries a mortality of 53%.2 In patients with symptoms of fever, polyarthralgia and a rash predominantly affecting the extremities, it is important to seek a history of rodent exposure and consider RBF and to institute appropriate antibiotics to prevent unnecessary morbidity and mortality. Andrew Rosser,1 Martin Wiselka,1 Manish Pareek2 1
Department of Infection and Tropical Medicine, University Hospitals of Leicester, Leicester, UK 2 Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK Correspondence to Dr Manish Pareek, Department of Infection, Immunity and Inflammation, Maurice Shock Medical Sciences Building, University Road, Leicester, LE1 9HN; [email protected] Contributors AR: drafted, wrote and revised the manuscript. MW: made substantial contributions to the conception of the article. MP: made substantial contributions to the conception of the article and revised it for critically important intellectual content.
Figure 1 A close-up photograph of a maculopapular pustular rash of rat bite fever.
236
Competing interests None.
Rosser A, et al. Postgrad Med J April 2014 Vol 90 No 1062
Downloaded from http://pmj.bmj.com/ on June 13, 2015 - Published by group.bmj.com
Images in medicine Provenance and peer review Not commissioned; externally peer reviewed.
REFERENCES 1 2 3
To cite Rosser A, Wiselka M, Pareek M. Postgrad Med J 2014;90:236–237. Received 16 October 2013 Revised 2 December 2013 Accepted 1 January 2014 Published Online First 22 January 2014
4 5
Gaastra W, Boot R, Hoa TK, et al. Rat bite fever. Vet Microbiol 2009;133: 211–28. Elliot SP. Rat bite fever and streptobacillus monoliformis. Clin Microbiol Rev 2007;20:13–22. Public Health England. Zoonoses that may be acquired from rats: England and Wales. http://www.hpa.org.uk/Topics/InfectiousDiseases/InfectionsAZ/Zoonoses/ GeneralInformation/zoo010ZoonosesFromRats/ (accessed 2 Oct 2013). Schachter ME, Wilcox L, Rau N, et al. Rat-bite fever, Canada. Emerg Infect Dis 2006;12:1301–2. Khatchadourian K, Ovetchkine P, Minodier P, et al. The rise of the rats: a growing paediatric issue. Paediatr Child Health 2010;15:131–4.
Postgrad Med J 2014;90:236–237. doi:10.1136/postgradmedj-2013-132420
Rosser A, et al. Postgrad Med J April 2014 Vol 90 No 1062
237
Downloaded from http://pmj.bmj.com/ on June 13, 2015 - Published by group.bmj.com
Rat bite fever: an unusual cause of a maculopapular rash Andrew Rosser, Martin Wiselka and Manish Pareek Postgrad Med J 2014 90: 236-237 originally published online January 22, 2014
doi: 10.1136/postgradmedj-2013-132420 Updated information and services can be found at: http://pmj.bmj.com/content/90/1062/236
These include:
References Email alerting service
Topic Collections
This article cites 4 articles, 1 of which you can access for free at: http://pmj.bmj.com/content/90/1062/236#BIBL Receive free email alerts when new articles cite this article. Sign up in the box at the top right corner of the online article.
Articles on similar topics can be found in the following collections Drugs: cardiovascular system (318) Epidemiology (335) Pain (neurology) (199) Headache (including migraine) (29) Drugs: infectious diseases (193) Clinical diagnostic tests (356) General surgery (149) HIV/AIDS (51) Immunology (including allergy) (346) Ophthalmology (84) Pneumonia (respiratory medicine) (21) Radiology (368) Sexual transmitted infections (bacterial) (9) Sexual transmitted infections (viral) (52) Surgical diagnostic tests (145) Valvar diseases (24)
Notes
To request permissions go to: http://group.bmj.com/group/rights-licensing/permissions To order reprints go to: http://journals.bmj.com/cgi/reprintform To subscribe to BMJ go to: http://group.bmj.com/subscribe/
