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Leptospirosis: A Risk to People and Their Pets

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Leptospirosis: A Risk to People and Their Pets

Patient Information: Martini R.

  • Species/Breed: Canine/ Bernadoodle

  • Age:15

  • Sex: FS

  • Weight: 18.70kg

  • Relevant History:

    • Martini originally presented in late July for further evaluation of increased thirst and urination that had been noted for several weeks. Martini had then had some vomiting, lethargy, and inappetence for the last few days.

    • Previous Diagnostics 8/8/24 Lepto PCR was POS 8/6/24 kidney profile- mild azotemia (BUN- 26 Crea- 2.0) PCV/TP- 42%, 8.7 8/04/24 TS 8.4, Renal profile: Creatinine 1.8

Presenting Complaint

  • Chief Complaint: Increased thirst and urination (polyuria and polydipsia), inappetence, vomiting

  • Duration of Symptoms: 4 weeks for increased thirst and urination, a few days of other signs

Physical Examination Findings

  • Initial exam on ER visit 7/31/24: quiet, alert, responsive, no other significant findings

  • Exam at recheck after ER visit with internal medicine on 8/15/24: bright, alert, responsive, small, soft 10mm pedunculated dermal perianal mass at 10 o'clock position (noted historically), no other significant findings

Diagnostic Tests

  • 7/31/24 (presentation to ER):

    • CBC (Complete blood count): inflammatory leukogram (WBC 24.95k, neutrophils 20.29k, lymph 1.78k, mild thrombocytopenia (Plt 56k)

    • 3-view abdominal radiographs (AXR): unremarkable (in-house review)

    • Chemistry: ALP 270 (mildly elevated), Tbili 0.4 (mildly elevated), BUN 30 (moderately elevated), Crt 2.8 (elevated), Phos 5.8 (mildly elevated), Globulins 5.5 (mildly elevated), Alb 2.5 (low normal),

    • Urinalysis (UA): USG 1.010 (isosthenuria, poorly concentrated), bacterial rods present, protein 30 – indicating urinary tract infection (UTI)

  • 8/1/24 (2nd day hospitalization ER)

    • Kidney panel: BUN 26, Crt 2.5 (elevated, improving from previous), Alb 2.2 (low), Phos normalized

  • 8/2/24 (3rd day hospitalization ER)

    • Kidney panel: BUN 25, Crt 2.9 (elevated, worse from previous), Alb 2.2 (low, static from yesterday)

    • PCV/TS: 27%/7 (mild anemia)

    • Leptospirosis in-house WITNESS Rapid Test: Positive

  • 8/3/24 (4th day hospitalization ER)

    • Kidney panel: BUN 18, Crt 2.4 (improved from previous but still elevated), Alb 2.4 (low, improved from yesterday)

    • PCV/TS: 29%/7 (mild anemia, improved)

  • 8/4/24 (5th day hospitalization ER)

    • Kidney panel: BUN 18, Crt 1.8 (improved from previous but still elevated), Alb 2.6 (low-normal, improved from yesterday)

    • PCV/TS: 40%/8.4 (anemia resolved, increased protein levels, improved)

  • 8/5/24 (6th day hospitalization ER)

    • Kidney panel: BUN 23, Crt 2 (slightly increased from yesterday), Alb 2.6 (low-normal, static from yesterday)

    • PCV/TS: 42%/8.7 (anemia resolved, increased protein levels, improved)

  • 8/6/24 (7th day hospitalization ER, day of discharge)

    • Kidney panel: BUN 26, Crt 2 (static from yesterday), Alb 3 (normalized)

    • PCV/TS: 42%/8.7 (anemia resolved, increased protein levels, improved)

  • Leptospirosis PCR urine test: positive

Diagnosis

  • Final Diagnosis: Leptospirosis

  • Differential Diagnosis: Other bacterial pyelonephritis (infection of kidneys)

Treatment Plan

  • Initial Treatment:

    • Baytril (enrofloxacin) - antibiotic

    • Entyce (capromorelin) - antibiotic

    • Gabapentin – pain medication

    • Cerenia (maropitant) – anti-nausea

    • Unasyn (ampicillin/sulbactam) – antibiotic

    • Doxycycline – antibiotic

  • Surgical Interventions: None

  • Supportive Care:

    • IV fluid therapy

Outcome

  • Immediate Outcome: How did the patient respond to the initial treatment?

    • Martini initially had slow improvement, requiring several days of hospitalization, but her kidney values and attitude improved over time with continued supportive care and antibiotics

    • Upon discharge, kidney values had slightly worsened, but due to financial constraints after several days in the hospital, Martini’s owners elected to take her home with continued follow-up with internal medicine to evaluate trends

  • Long-term Follow-up:

    • 1st recheck with Dr. Heinrich MVES Internal Medicine Team 8/15/24 (10 days post-discharge from ER) – Martini’s kidney values were improved (BUN 23, Crt 1.8) but not back to normal (normal Crt <1.4 in dogs). We suspected resolving leptospirosis infection as Martini was still taking antibiotics.

    • 2nd recheck with Dr. Heinrich MVES Internal Medicine Team 9/5/24 – Martini’s kidney values were further improved (BUN32, Crt 1.6) but still not quite normal. We suspected resolving kidney injury following acute insult from infection and dehydration, which can sometimes take several months to fully resolve. Another possibility is persistent chronic kidney disease following acute infection. Recommend rechecking in another month to evaluate trends in kidney values.

  • Prognosis:

    • Even though Martini’s kidney values are taking longer to return fully to normal, we expect a good overall prognosis.

Discussion

  • Key Takeaways:

    • When Martini presented, primary bacterial pyelonephritis was initially suspected based on azotemia (elevated kidney values), and bacteria were noted on urinalysis. Given this, Martini was started on Baytril (enrofloxacin), the recommended treatment for pyelonephritis. However, leptospirosis was later discovered using an in-house WITNESS Rapid test (Zoetis). Recommended treatment for leptospirosis is amoxicillin (to clear bacteremia, infection in the bloodstream) and doxycycline (to clear bacteriuria, shedding of bacteria in urine). Alternatives may include cephalosporins or macrolides. However, fluoroquinolones may not be as effective in treating leptospirosis in experimentally infected animals. It is important to keep leptospirosis on a differential list and treat it with appropriate antibiotics.

    • In dogs with leptospirosis and signs of acute kidney injury (AKI), their fluid needs may be very high due to severe polyuria and polydipsia (PU/PD, increased thirst and urination). In Martini’s case, this required several days of IV fluid therapy in the hospital. Even when Martini was discharged, her kidney values were still mildly elevated. Ideally, dogs should be kept on higher rates of IV fluids to match their losses (which can be easily underestimated with severe PU/PD) until kidney values stabilize, and then IV fluids should be slowly tapered back to maintenance levels. However, this is very time-intensive and costly, with several days of hospitalization often required. In cases where owners cannot continue to keep pets in the hospital, recommend step-down in IV fluids to subcutaneous (SQ) or enteral fluids (such as through esophageal feeding tube) to help further support kidneys through acute injury. This may have contributed to further damage to Martini’s kidneys, resulting in continued mild azotemia.

    • Remember, leptospirosis as a possible diagnosis for any animal that is severely PU/PD (even if chronically noted, as in Martini’s case), azotemic, and has elevated liver values (even independent of azotemia). This is an important and common zoonotic disease that is easy to treat but can sometimes also be easy to miss!

Innovations:

  • New in-house tests can help with the diagnosis of Leptospirosis, but it is important to understand which tests are better than others and when to use them

    • PCR (urine or blood) = benefit early in the disease process or to confirm dz in a vaccinated animal

      • The highest concentration of leptospirosis in blood within ten days of infection – after this, urine is best, so recommend test both (19)

      • Antibiotics can cause false negatives! Get samples BEFORE starting antibiotic tx

      • PCR does NOT rule out leptospirosis, BUT positive is confirmatory

    • IDEXX SNAP Lepto test – NOT good, DO NOT USE due to poor sensitivity and specificity

    • WITNESS Lepto Rapid Test by Zoetis – GOOD test – USE THIS!

      • Can detect early in disease (within 7 days of infection)

      • Sn 83.7%

      • Sp 90.3% (Zoetis website)

      • Other papers Sn 76% Sp 100%

      • 24% chance of false positives within 12 weeks of vaccination

    • Recently vaccinated dogs (< 3 months) best to do PCR (unaffected by vaccine) but also MAT to confirm a 4-fold rise in titers

    • MAT (microscopic agglutination test) = Gold standard

      • Caution – can be negative early in infection

      • Usually positive within 3-5 days but can be up to 1 week

      • Usually acute & convalescent titers – wait one week to demonstrate infection by 4-fold rise in tiers

      • Post-vaccine titers persist for a long time esp if exposed to vaccine strain and can be very high (>1600), so single MAT + does NOT confirm disease if vaccinated

Client Communication:

  • Zoonotic risk!

    • Avoid contact with dog urine and use gloves when cleaning up urine

    • Take dogs to isolated areas to urinate away from standing water or areas where children have access

    • Wash hands after contact with dog or cleaning urine

    • Signs of leptospirosis in humans:

      • Mild, flu-like symptoms that resolve and then return

      • Renal failure, hepatic dysfunction, meningitis

      • Pulmonary hemorrhage

    • If symptoms occur, be sure to inform healthcare professionals of the dog’s leptospirosis diagnosis

  • Need to treat your other dogs!

    • Recommend doxycycline prophylaxis for other pets in the household

Conclusion

  • Summary: Martini presented for severe increased thirst and urination, elevated kidney and liver values, and bacteria on urinalysis. Using an in-house WITNESS Rapid Test, she was diagnosed with leptospirosis. Martini required prolonged hospitalization with aggressive IV fluid therapy and appropriate antibiotics to recover from leptospirosis. She still has some residual increase in her kidney values; however, her prognosis still should be very good.

  • Clinical Relevance: Martini’s case is a fairly classic presentation for leptospirosis that highlights the need for appropriate antibiotic treatment and fluid therapy in leptospirosis cases, the advancements in diagnostic tools for leptospirosis, such as the in-house WITNESS Rapid Test, and the need for zoonotic risk communication to hospital personnel and owners

References

  • Literature Cited:

    • Sykes, JE. Canine and Feline Infectious Diseases. St. Louis, Mo., Elsevier/Saunders, 2014. Table 89-3, Ch. 89 Bacterial Infections of the Genitourinary Tract, Jane E. Sykes and Jodi L. Westropp pp. 876-877.

    • Sykes JE, et al. 2010 ACVIM small animal consensus statement on leptospirosis: diagnosis, epidemiology, treatment, and prevention. J Vet Intern Med. 2011, 25, 1-13. PMID:21155890 DOI:10.1111/j.1939-1676.2010.0654.

    • Greene CE. Infectious Diseases of the Dog and Cat. Fourth Edition. Elsevier. ISBN: 978-1-4160-6130-4. 2012. Ch 42 Leptospirosis. pg 445.

    • Lizer, J., Velineni, S., Weber, A., Krecic, M., & Meeus, P. (2018). Evaluation of 3 Serological Tests for Early Detection Of Leptospira-specific Antibodies in Experimentally Infected Dogs. Journal of veterinary internal medicine, 32(1), 201–207.https://doi.org/10.1111/jvim.14865

    • Chappel RJ, Goris M, Palmer MF, et al. Impact of proficiency testing on results of the microscopic agglutination test for diagnosis of leptospirosis. J Clin Microbiol 2004;42:5484–5488.

    • Barr SC, McDonough PL, Scipioni-Ball RL, et al. Serologic responses of dogs given a commercial vaccine against Leptospira interrogans serovar Pomona and Leptospira kirschneri serovar Grippotyphosa. Am J Vet Res 2005;66:1780–1784.

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