Leptospirosis

OVERVIEW

  • Leptospirosis is an infection caused by the spirochaete genus of Leptospira
  • It is an emerging infectious disease with a worldwide distribution, it is prevalent in tropical areas such as South East Asia and Northern Australia
  • Severe forms may result in critical illness, including Weil disease and severe pulmonary haemorrhage

CAUSE

Leptospira species

  • 20 species, 9 are pathogenic with over 200 serovars
  • 8 serovars cause most of the infections in Australia
  • transmitted by animal vectors and survives in contaminated soil and water

Vectors

  • numerous
  • livestock (e.g. cows, pigs, and sheep)
  • rodents (e.g. rats and mice)
  • bats
  • marsupials (e.g. bandicoot, possum and kangaroo)

Pathophysiology

  • Leptospira enter the body via abrasions or mucous membranes
  • incubation period of 2–20 days
  • biphasic disease
  • acute spiraemic phase (~1 week)
  • subsequent immunogenic phase
  • systemic illness results from widespread vasculitis and endothelial damage causing multiorgan dysfunction

RISK FACTORS

  • occupational activities (e.g. cattle farming, banana cultivation)
  • direct contact with vectors (e.g. handling carcasses)
  • indirect contact with vectors (e.g. exposure to contaminated urine)
  • recreational exposure (e.g. bushwalking, hunting, swimming, camping, and adventure sports such as white water rafting and kayaking)
  • travel to endemic regions, especially those with high rainfall and temperatures

CLINICAL FEATURES

Assess for risk factors

Features of acute spiremic phase (~1 week)

  • may resemble a flu-like illness
  • typical symptoms include: fever, headaches, myalgia, rigors, arthralgia, nausea, vomiting and jaundice
  • Less common signs include hepato-splenomegaly and lymphadenopathy

Features of immunogenic phase

  • acute renal failure
  • hepatic failure
  • aseptic meningitis
  • severe pulmonary hemorrhage syndrome
  • conjunctival suffusion or haemorrhages (diagnostic clue)
  • myositis, rhabdomyolysis
  • myocarditis
  • coagulopathy and purpura

INVESTIGATIONS

  • culture: blood, urine, CSF (use Ellinghausen McCullough Johnson harris (EMJh) media containing 0.5% agar ); organisms may be seen on dark field microscopy at 1-2 weeks, may take 1 month for positive cultures
  • Leptospira PCR testing (96.4% sensitivity and 99.5% specificity)
  • serology: microscopic agglutination test (MAT) is the gold standard

DIAGNOSTIC CRITERIA

Definitive criteria

  • Isolation of pathogenic Leptospira sp., or
  • Fourfold or greater increase in Leptospira MAT titre, or
  • A single high Leptospira MAT titre greater than or equal to 400 against a pathogenic species

Suggestive criteria

  • Detection of pathogenic Leptospira sp. by nucleic acid test (NAT), or
  • A positive Leptospira (EIA) IgM result

DIFFERENTIAL DIAGNOSIS

Infectious diseases

  • malaria
  • viral — dengue, cytomegalovirus, Epstein-Barr virus, influenza, coronavirus, hepatitis, Ross River virus, Barmah Forest virus, Murray Valley encephalitis virus and Japanese encephalitis virus, viral haemorrhagic fever
  • bacterial — typhoid, typhus, Q-fever, brucellosis
  • overwhelming sepsis of any cause

Other

  • hematological disorders such as leukemia
  • other causes of pulmonary haemorrhage, aseptic meningitis, rhabdomyolysis, myocarditis, liver and renal failure

MANAGEMENT

Resuscitation

Specific therapy

  • Doxycycline 100 mg bd po
  • Ceftriaxone 1 g IV once daily
  • Cefotaxmine 1 g IV q6h
  • Benzylpenicillin 1.2 g IV q6h

Supportive care and monitoring

Prevention

Notifiable disease

Consult infectious diseases specialist


References and Links

Journal articles

  • Helmerhorst HJ, van Tol EN, Tuinman PR, de Vries PJ, Hartskeerl RA, Grobusch MP, Hovius JW. Severe pulmonary manifestation of leptospirosis. Neth J Med. 2012 Jun;70(5):215-21. Review. PubMed PMID: 22744922.
  • Slack A. Leptospirosis. Aust Fam Physician. 2010 Jul;39(7):495-8. Review. PubMed PMID: 20628664. [Free Full Text]
  • Vickery B, Flynn SA, Calder L, Freebairn RC. Leptospirosis presenting to an intensive care unit in provincial New Zealand: a case series and review. Crit Care Resusc. 2006 Sep;8(3):192-9. Review. PubMed PMID: 16930102.

CCC 700 6

Critical Care

Compendium

Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also the Innovation Lead for the Australian Centre for Health Innovation at Alfred Health and Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.

After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.

He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE.  He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.

His one great achievement is being the father of two amazing children.

On Twitter, he is @precordialthump.

| INTENSIVE | RAGE | Resuscitology | SMACC

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