Leptospirosis: Difference between revisions
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The illness lasts from a few days to 3 weeks or longer. Without treatment, recovery may take several months. | The illness lasts from a few days to 3 weeks or longer. Without treatment, recovery may take several months. | ||
==Diagnostics== | ==Diagnostics== | ||
Revision as of 14:34, 10 August 2015
Template:DiseaseDisorder infobox
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Leptospirosis Microchapters |
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Diagnosis |
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Treatment |
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Case Studies |
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Leptospirosis On the Web |
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American Roentgen Ray Society Images of Leptospirosis |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Synonyms and keywords: Cane cutter's fever; Harvest fever; Infection due to Leptospira; Japanese autumnal fever; Queensland fever; Rice-field worker's disease; Seven day fever; Spirochaetal jaundice; Spirochetal jaundice
Overview
Historical Perspective
Classification
Pathophysiology
Causes
Differentiating Leptospirosis from other Diseases
Epidemiology and Demographics
Risk Factors
Natural History, Complications and Prognosis
Diagnosis
History and Symptoms | Physical Examination | Laboratory Findings | CT | Other Imaging Findings | Other Diagnostic Studies
Treatment
Medical Therapy | Surgery | Primary Prevention | Secondary Prevention | Cost-Effectiveness of Therapy | Future or Investigational Therapies
Case Studies
Related Chapters
How do people get leptospirosis?
Outbreaks of leptospirosis are usually caused by exposure to water contaminated with the urine of infected animals. Many different kinds of animals carry the bacterium; they may become sick but sometimes have no symptoms. Leptospira organisms have been found in cattle, pigs, horses, dogs, rodents, and wild animals. Humans become infected through contact with water, food, or soil containing urine from these infected animals. This may happen by swallowing contaminated food or water or through skin contact, especially with mucosal surfaces, such as the eyes or nose, or with broken skin. The disease is not known to be spread from person to person.
How long is it between the time of exposure and when people become sick?
The time between a person's exposure to a contaminated source and becoming sick is 2 days to 4 weeks. Illness usually begins abruptly with fever and other symptoms. Leptospirosis may occur in two phases; after the first phase, with fever, chills, headache, muscle aches, vomiting, or diarrhea, the patient may recover for a time but become ill again. If a second phase occurs, it is more severe; the person may have kidney or liver failure or meningitis. This phase is also called Weil's disease.
The illness lasts from a few days to 3 weeks or longer. Without treatment, recovery may take several months.
Diagnostics
On infection the microorganism can be found in blood for the first 7 to 10 days (invoking serologically identifiable reactions) and then moving to the kidneys. After 7 to 10 days the microorganism can be found in fresh urine. Hence, early diagnostic efforts include testing a serum or blood sample serologically with a panel of different strains. It is also possible to culture the microorganism from blood, serum, fresh urine and possibly fresh kidney biopsy. Kidney function tests (Blood Urea Nitrogen and creatinine) as well as blood tests for liver functions are performed. The later reveal a moderate elevation of transaminases. Brief elevations of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and gamma-glutamyltransferase (GGT) levels are relatively mild. These levels may be normal, even in children with jaundice. Diagnosis of leptospirosis is confirmed with tests such as Enzyme-Linked Immunosorbent Assay (ELISA) and PCR. Serological testing, the MAT (microscopic agglutination test), is considered the gold standard in diagnosing leptospirosis. As a large panel of different leptospira need to be subcultured frequently, which is both laborious and expensive, it is underused, mainly in developing countries.
Differential diagnosis list for leptospirosis is very large due to diverse symptomatics. For forms with middle to high severity, the list includes dengue fever and other hemorrhagic fevers, hepatitis of various etiologies, viral meningitis, malaria and typhoid fever. Light forms should be distinguished from influenza and other related viral diseases. Specific tests are a must for proper diagnosis of leptospirosis. Under circumstances of limited access (e.g., developing countries) to specific diagnostic means, close attention must be paid to anamnesis of the patient. Factors like certain dwelling areas, seasonality, contact with stagnant water (swimming, working on flooded meadows, etc) and/or rodents in the medical history support the leptospirosis hypothesis and serve as indications for specific tests (if available).
Leptospira can be cultured in [[Ellinghausen-McCullough-Johnson-Harris medium], which is incubated at 28 to 30ºC.[1] The median time to positivity is three weeks with a maximum of 3 months. This makes culture techniques useless for diagnostic purposes, but is commonly used in research.
Differentiating Leptospirosis from other Diseases
The table below summarizes the findings that differentiate Leptospirosis from other conditions that cause fever, diarrhea, nausea and vomiting:
| Disease | Findings |
|---|---|
| Ebola | Presents with fever, chills vomiting, diarrhea, generalized pain or malaise, and sometimes internal and external bleeding, that follow an incubation period of 2-21 days. |
| Typhoid fever | Presents with fever, headache, rash, gastrointestinal symptoms, with lymphadenopathy, relative bradycardia, cough and leucopenia and sometimes sore throat. Blood and stool culture can confirm the presence of the causative bacteria. |
| Malaria | Presents with acute fever, headache and sometimes diarrhea (children). A blood smears must be examined for malaria parasites. The presence of parasites does not exclude a concurrent viral infection. An antimalarial should be prescribed as an empiric therapy. |
| Lassa fever | Disease onset is usually gradual, with fever, sore throat, cough, pharyngitis, and facial edema in the later stages. Inflammation and exudation of the pharynx and conjunctiva are common. |
| Yellow fever and other Flaviviridae | Present with hemorrhagic complications. Epidemiological investigation may reveal a pattern of disease transmission by an insect vector. Virus isolation and serological investigation serves to distinguish these viruses. Confirmed history of previous yellow fever vaccination will rule out yellow fever. |
| Shigellosis & other bacterial enteric infections | Presents with diarrhea, possibly bloody, accompanied by fever, nausea, and sometimes toxemia, vomiting, cramps, and tenesmus. Stools contain blood and mucous in a typical case. A search for possible sites of bacterial infection, together with cultures and blood smears, should be made. Presence of leucocytosis distinguishes bacterial infections from viral infections. |
| Others | Viral Hepatitis, rheumatic fever, typhus, and mononucleosis |
Treatment
Leptospirosis treatment is a relatively complicated process comprising two main components - suppressing the causative agent and fighting possible complications. Aetiotropic drugs are antibiotics, such as doxycycline, penicillin, ampicillin, and amoxicillin (doxycycline can also be used as a prophylaxis). There are no human vaccines; animal vaccines are only for a few strains, and are only effective for a few months. Human therapeutic dosage of drugs is as follows: doxycycline 100 mg orally every 12 hours for 1 week or penicillin 1-1.5 MU every 4 hours for 1 week. Doxycycline 200-250 mg once a week is administered as a prophylaxis. In dogs, penicillin is most commonly used to end the leptospiremic phase (infection of the blood), and doxycycline is used to eliminate the carrier state.
Supportive therapy measures (esp. in severe cases) include detoxication and normalization of the hydro-electrolytic balance. Glucose and salt solution infusions may be administered; dialysis is used in serious cases. Elevations of serum potassium are common and if the potassium level gets too high special measures must be taken. Serum phosphorus levels may likewise increase to unacceptable levels due to renal failure. Treatment for hyperphosphatemia consists of treating the underlying disease, dialysis where appropriate, or oral administration of calcium carbonate, but not without first checking the serum calcium levels (these two levels are related). Corticosteroids administration in gradually reduced doses (e.g., prednisolone starting from 30-60 mg) during 7-10 days is recommended by some specialists in cases of severe haemorrhagic effects.
Antimicrobial regimen
- Preferred regimen: Penicillin 1.5 MU IV q6h for 5-7 days
- 2. Less severe
- Preferred regimen (1): Amoxycillin
- Preferred regimen (2): Ampicillin
- Preferred regimen (3): Doxycycline 100 mg IV/PO q12h/bid for 5-7 days
- Preferred regimen (4): Erythromycin
- Preferred regimen (5): Ceftriaxone 1 g IV q24h for 5-7 days
- Preferred regimen (6): Cefotaxime
- Preferred regimen (7): Quinolone PO
Research
Leptospirosis: a zoonotic disease of global importance. Lancet Infect Dis. 2003 Dec;3(12):757-71 Bharti AR, Nally JE, Ricaldi JN, Matthias MA, Diaz MM, Lovett MA, Levett PN, Gilman RH, Willig MR, Gotuzzo E, Vinetz JM; Peru-United States Leptospirosis Consortium.
In the past decade, leptospirosis has emerged as a globally important infectious disease. It occurs in urban environments of industrialised and developing countries, as well as in rural regions worldwide. Mortality remains significant, related both to delays in diagnosis due to lack of infrastructure and adequate clinical suspicion, and to other poorly understood reasons that may include inherent pathogenicity of some leptospiral strains or genetically determined host immunopathological responses. Pulmonary haemorrhage is recognised increasingly as a major, often lethal, manifestation of leptospirosis, the pathogenesis of which remains unclear. The completion of the genome sequence of Leptospira interrogans serovar lai, and other continuing leptospiral genome sequencing projects, promise to guide future work on the disease. Mainstays of treatment are still tetracyclines and beta-lactam/cephalosporins. No vaccine is available. Prevention is largely dependent on sanitation measures that may be difficult to implement, especially in developing countries.
In a study of 38 dogs diagnosed and properly treated for leptospirosis published in the February 2000 issue of the Journal of the American Veterinary Association, the survival rate for the dialysis patients was slightly higher than the ones not put on dialysis, but both were in the 85% range (plus or minus). Of the dogs in this study that did not die, most recovered adequate kidney function, although one had chronic renal problems.
Can leptospirosis be prevented?
The risk of acquiring leptospirosis can be greatly reduced by not swimming or wading in water that might be contaminated with animal urine. Protective clothing or footwear should be worn by those exposed to contaminated water or soil because of their job or recreational activities.
See also
- Marine Mammal Center
References
- ↑ Rule PL, Alexander AD (1986). "Gellan gum as a substitute for agar in leptospiral media". J Clin Microbiol (3): 500&ndash, 504. PMID 3754265. Unknown parameter
|volum=ignored (help) - ↑ LastName, FirstName (2003). Human leptospirosis guidance for diagnosis, surveillance and control. Geneva: World Health Organization. ISBN 9241545895.
- ↑ Bartlett, John (2012). Johns Hopkins ABX guide : diagnosis and treatment of infectious diseases. Burlington, MA: Jones and Bartlett Learning. ISBN 978-1449625580.
External links
- The Leptospirosis Information Center
- U.S. Disease Control and Prevention Center page on Leptospirosis
- www.leptonet.net - the Leptospirosis information portal
- International Leptospirosis Society page
- A Symposium on Leptospirosis: Collection of peer-reviewed articles from The Journal of Postgraduate Medicine
- leptoinfo.com - A website for Dog Owners and Veterinary Professionals dedicated to sharing information on Leptospirosis in Canada
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