LEPTOSPIROSIS

Question 1

Severe leptospirosis is characterized by ______, ______, _______ , often referred to as ________

Answer 1

Severe leptospirosis is characterized by jaundice, renal dysfunction, and hemorrhagic diathesis, is often referred to as Weil’s syndrome.

Question 2

In this phase of leptospirosis infection, highly motile organisms proliferate, cross tissue barriers, and disseminate hematogenously to all organs.

Answer 2

Leptospiremic phase

*leptospires can be isolated from the bloodstream

Question 3

This phase is characterized by the appearance of antibodies which coincides with the disappearance of leptospires from the blood.

Answer 3

Immune phase

Question 4

TRUE OR FALSE? The incubation period is usually 1–2 weeks but ranges from 2 to 30 days

Answer 4

TRUE

Question 5

Common electrolyte abnormalities in severe leptospirosis?

Answer 5

Hypokalemia and Hyponatremia.

• Loss of magnesium in the urine is uniquely associated with leptospiral nephropathy.

Question 6

A potentially chronic condition that is a recognized sequela of leptospirosis.

Answer 6

Autoimmune associated uveitis

Question 7

In what leptospirosis phase can the organism be cultured from blood and detected by polymerase chain reaction (PCR)?

Answer 7

Acute Leptospiremic phase

* Acute leptospiremic phase - characterized by fever of 3–10 days’ duration, during which time the organism can be cultured from blood and detected by polymerase chain reaction (PCR).

Question 8

In what phase can the organism be cultured from the urine?

Answer 8

Immune phase

* Immune phase - resolution of symptoms may coincide with the appearance of antibodies, and leptospires can be cultured from the urine.

Question 9

TRUE OR FALSE: Leptospira can be cultured from the cerebrospinal fluid (CSF) in the early phase

Answer 9

TRUE

Question 10

TRUE OR FALSE: Loss of magnesium in the urine is uniquely associated with leptospiral nephropathy.

Answer 10

TRUE

Question 11

Most common pulmonary radiographic finding in severe leptospirosis?

Answer 11

patchy bilateral alveolar pattern that corresponds to scattered alveolar hemorrhage.

*predominantly affect the lower lobes

Question 12

Definitive diagnosis of leptospirosis

Answer 12

1) Isolation of the organism from the patient
2) positive result in the PCR
3) seroconversion or a rise in antibody titer

* single antibody titer of 1:200–1:800 (depending on whether the case occurs in a low- or high-endemic area) in the microscopic agglutination test (MAT) is required.
* Fourfold or greater rise in titer is detected between acute- and convalescent-phase serum specimens.

Question 13

TRUE OR FALSE: Serologic testing lacks sensitivity in the early acute phase of the disease (up to day 5)

Answer 13

TRUE

Question 14

TRUE OR FALSE: PCR offers a great advantage and has the capacity to confirm the diagnosis of leptospirosis with a high degree of accuracy during the first 5 days of illness.

Answer 14

TRUE

Question 15

DRUG OF CHOICE for severe leptospirosis?

Answer 15

IV Penicillin

• ceftriaxone, cefotaxime, or doxycycline is a satisfactory alternative to penicillin for the treatment of severe leptospirosis

DOSE:
Penicillin 1.5MU IV or IM q6
Ceftriaxone 2g IV OD
Cefotaxime 1g IV q6
Doxycycline 200mg IV LD then 100mg IV q12

Question 16

TRUE OR FALSE: ALL treatment regimens should be given for 7 days.

Answer 16

TRUE

Question 17

The most important reservoir for leptospirosis?

Answer 17

• Rodents, especially rats, are the most important reservoir

Question 18

Renal pathology seen in the immune phase of leptospirosis?

Answer 18

Renal pathology shows both acute tubular damage and interstitial nephritis.

• Acute tubular lesions progress in time to interstitial edema and acute tubular necrosis.
• Severe nephritis is observed in patients who survive long enough to develop it

Question 19

What is the causative agent of leptospirosis?
A) Borrelia species
B) Treponema species
C) Leptospira species
D) Rickettsia species

Answer 19

Answer: C) Leptospira species

Rationale: Leptospirosis is caused by pathogenic Leptospira species, which are spirochetes belonging to the family Leptospiraceae.

Question 20

Which of the following best describes Leptospira species?
A) Gram-positive, coccoid, and non-motile
B) Gram-negative, rod-shaped, and non-motile
C) Coiled, thin, highly motile organisms with hooked ends
D) Obligate intracellular bacteria with no cell wall

Answer 20

Answer: C) Coiled, thin, highly motile organisms with hooked ends

Rationale: Leptospira species are spirochetes characterized by their thin, coiled structure, hooked ends, and high motility due to periplasmic flagella.

Question 21

What is the most important reservoir for leptospirosis?
A) Dogs
B) Cattle
C) Rats
D) Birds

Answer 21

Answer: C) Rats

Rationale: Rodents, especially rats, are the most important reservoirs of Leptospira and can excrete the bacteria in their urine for years, maintaining transmission.

Question 22

How is leptospirosis most commonly transmitted to humans?
A) Respiratory droplets
B) Ingestion of contaminated food
C) Direct or indirect contact with infected animal urine
D) Vector-borne transmission via ticks

Answer 22

Answer: C) Direct or indirect contact with infected animal urine

Rationale: Transmission occurs through exposure to urine, blood, or tissues from infected animals, or more commonly, through environmental contamination (e.g., water, soil).

Question 23

What is Weil’s syndrome?
A) A mild form of leptospirosis characterized by flu-like symptoms
B) A severe form of leptospirosis with jaundice, renal dysfunction, and hemorrhage
C) A chronic form of leptospirosis causing long-term joint pain
D) A rare allergic reaction to Leptospira antigens

Answer 23

Answer: B) A severe form of leptospirosis with jaundice, renal dysfunction, and hemorrhage

Rationale: Weil’s syndrome is the severe form of leptospirosis, presenting with multiorgan involvement, including jaundice, kidney failure, and hemorrhagic manifestations.

Question 24

During which phase of leptospirosis can Leptospira be cultured from the blood?
A) Incubation phase
B) Acute leptospiremic phase
C) Immune phase
D) Recovery phase

Answer 24

Answer: B) Acute leptospiremic phase

Rationale: During the acute leptospiremic phase, Leptospira can be detected in the blood via culture or PCR. In the immune phase, the bacteria persist in organs but disappear from the bloodstream.

Question 25

Which electrolyte abnormality is uniquely associated with leptospiral nephropathy? A) Hypernatremia B) Hypomagnesemia C) Hyperkalemia D) Hypocalcemia

Answer 25

Answer: B) Hypomagnesemia Rationale: Loss of magnesium in the urine is a unique feature of leptospiral nephropathy, differentiating it from other causes of acute kidney injury.

Question 26

Which of the following is a poor prognostic factor in severe leptospirosis? A) Hypotension B) Age <20 years C) Mild conjunctival suffusion D) Leukopenia

Answer 26

Answer: A) Hypotension Rationale: Poor prognostic factors include age >40, altered mental status, acute renal failure, respiratory insufficiency, hypotension, and arrhythmias.

Question 27

What is the most common radiographic finding in severe leptospirosis? A) Patchy bilateral alveolar pattern B) Bilateral pleural effusions C) Miliary nodules D) Cavitary lung lesions

Answer 27

Answer: A) Patchy bilateral alveolar pattern Rationale: The most common radiographic finding is a patchy bilateral alveolar pattern, corresponding to scattered alveolar hemorrhage.

Question 28

What is the preferred treatment for severe leptospirosis? A) Oral azithromycin B) IV penicillin C) Oral metronidazole D) Topical corticosteroids

Answer 28

Answer: B) IV penicillin Rationale: IV penicillin is the preferred treatment for severe leptospirosis. Alternatives include ceftriaxone, cefotaxime, and doxycycline.

Question 29

How does PCR testing benefit early diagnosis of leptospirosis? A) Detects bacterial DNA within the first 5 days of illness B) Provides results within 24 hours after symptom onset C) Detects antibodies at high sensitivity D) Confirms seroconversion within the first 3 days

Answer 29

Answer: A) Detects bacterial DNA within the first 5 days of illness Rationale: PCR offers a major advantage by confirming leptospirosis during the acute phase when serologic tests may still be negative.

Question 30

What is the recommended management for a patient with leptospirosis-associated pulmonary hemorrhage? A) High-dose corticosteroids B) Mechanical ventilation with low tidal volumes C) Hyperbaric oxygen therapy D) Immediate thoracotomy

Answer 30

Answer: B) Mechanical ventilation with low tidal volumes Rationale: Patients with pulmonary hemorrhage may benefit from mechanical ventilation with low tidal volumes to reduce lung injury, similar to ARDS management.

Question 31

Which of the following laboratory findings is most commonly associated with leptospirosis? A) Leukopenia with right shift B) Leukocytosis with a left shift C) Thrombocytosis D) Hypercalcemia

Answer 31

Answer: B) Leukocytosis with a left shift Rationale: Leptospirosis is associated with leukocytosis (increased white blood cells) with a left shift (increased immature neutrophils), which indicates a bacterial infection.

Question 32

What is a common hematologic finding in severe leptospirosis? A) Thrombocytopenia B) Eosinophilia C) Polycythemia D) Hypercoagulability

Answer 32

Answer: A) Thrombocytopenia Rationale: Thrombocytopenia (low platelet count ≤100,000) is common in severe leptospirosis and is associated with bleeding and renal failure.

Question 33

What is the most common radiographic finding in severe leptospirosis? A) Patchy bilateral alveolar pattern B) Unilateral pleural effusion C) Miliary nodules D) Cavitary lesions

Answer 33

Answer: A) Patchy bilateral alveolar pattern Rationale: The most common radiographic finding is a patchy bilateral alveolar pattern, which corresponds to scattered alveolar hemorrhage, typically affecting the lower lobes.

Question 34

Which diagnostic test is considered the gold standard for confirming leptospirosis? A) Gram stain B) Microscopic agglutination test (MAT) C) Western blot D) Urine dipstick

Answer 34

Answer: B) Microscopic agglutination test (MAT) Rationale: The MAT is the gold standard serologic test for leptospirosis, using live leptospiral strains to detect specific antibodies.

Question 35

What is a major limitation of serologic testing for leptospirosis? A) Cannot differentiate between Leptospira species B) False positives are common in the first week of illness C) Lacks sensitivity in the early acute phase (up to day 5) D) Cannot be performed in endemic areas

Answer 35

Answer: C) Lacks sensitivity in the early acute phase (up to day 5) Rationale: Serologic testing, including MAT and ELISA, lacks sensitivity in the early acute phase because antibodies take time to develop.

Question 36

Which diagnostic method is most useful for confirming leptospirosis during the first 5 days of illness? A) PCR (Polymerase Chain Reaction) B) MAT (Microscopic Agglutination Test) C) ELISA (Enzyme-Linked Immunosorbent Assay) D) Blood culture

Answer 36

Answer: A) PCR (Polymerase Chain Reaction) Rationale: PCR can directly detect Leptospira DNA and is highly accurate in the first 5 days before antibody production begins.

Question 37

What is a unique finding in leptospirosis-associated acute kidney injury (AKI)? A) Proteinuria without electrolyte disturbances B) Hypokalemia and hypomagnesemia C) Hyperkalemia and hyperphosphatemia D) Nephrotic-range proteinuria

Answer 37

Answer: B) Hypokalemia and hypomagnesemia Rationale: Loss of potassium and magnesium in urine is a unique feature of leptospiral nephropathy.