Leptospirosis

by: Jemarie Jimenez
Perpetual Help College Manila

Synonym:
Weil’s Dse, Mud fever, Canicola fever, Flood fever,
Swineherd’s Dse, Japanese Seven Days fever

Definition & Background:

a bacterial zoonotic disease caused by spirochaetes of the genus Leptospira that affects humans and a wide range of animals, including mammals, birds, amphibians, and reptiles
first described by Adolf Weil in 1886 when he reported an “acute infectious disease with enlargement of spleen, jaundice and nephritis”

Causative Agent:

Leptospira-genus bacteria was isolated in 1907 from post mortem renal tissue slice
commonly found: Leptospira pyrogenes, Leptospira manilae, & other species like L. icterohemorrhagiae, L. canicola, L. batavia, L. Pomona, L. javinica
in animals often is subclinical; an infected animal may appear healthy even as it sheds leptospires in its urine; humans are dead-end hosts for the leptospire

Predisposing Factors:

age: < 15 years of age
sex: male
season: rainy months
geographic: prevalent in slum areas

MODES OF TRANSMISSION

Incubation Period:

6 – 15 days/ 2 – 8 weeks

Clinical Manifestations:
1st stage: Septicemic/ Leptospiremic Phase (4 – 7 days)
- onset of high remittent fever, chills, headache, anorexia, nausea & vomiting, abdominal pain, joint pains, muscle pains, myalgia, severe prostration, cough, respiratory distress, bloody sputum.

2nd stage: Immune/ Toxic Phase (4 – 30 days)
- if severe, death may occur between the 9th & 16th day

2 types:

Anicteric (without jaundice) – return of fever of a lower degree with rash, conjunctival injection, headache, meningeal manifestations like disorientation, convulsions & signs of meningeal irritations (with CSF finding of aseptic meningitis)

Icteric (with jaundice) – Weil syndrome; hepatic & renal manifestations: hemorrhage, hepatomegaly, hyperbilirubinemia, oliguria, anuria with progressive renal failure; shock, coma & congestive heart failure in severe cases

3rd stage: Convalescence Phase
- Relapses may occur during 4th or 5th week

Diagnosis:

culture: blood (1st week)

CSF (5th to 12th day)
Urine (after 1st wk til pd of convalescence)

agglutination tests ( 2nd or 3rd week)

PATHOPHYSIOLOGY

Complications:

pneumonia
iridocyclitis, optic neuritis
peripheral neuritis

Prognosis:

cause of death: renal & hepatic failure
dse usually last 1 – 3 weeks but may be more prolonged; relapse may occur

Treatment:

specific measures: beneficial if done < 4 days of dse

Aqueous penicillin G (50,000 units/kg/day in 4-6 divided doses intravenously for 7-10 days

Tetracycline (20-40 mg/kg/day in 4 doses); may not be given to children < 8 years old