81 | The top 4 things you need to do to care for patients with leptospirosis

PodcastInfectious diseaseRenal DiseaseLiver Disease
Written By Laura Jones

Today we’re continuing our infectious disease series with a deep dive into an increasingly common and often frustrating condition: leptospirosis.

 

Let’s face it - lepto is basically everywhere. These patients aren’t straightforward to care for, and the use of PPE and barrier nursing only makes it more challenging.

There are several things we can do to support these patients, though. So if you’ve ever found yourself caring for a lepto patient and wondering what you can do to REALLY help them, seen one go south and want a bit of a confidence boost, or you feel like you want to do more to care for these patients than administer treatments and tick boxes on a hospital sheet, then this episode is for you.

Together, we’ll explore what leptospirosis is, its impact on our patients, the common complications we encounter, and how we diagnose and treat it- and, most importantly, the top 4 things you need to do as a nurse or technician when caring for a leptospirosis patient.

What is leptospirosis, and what problems does it cause?

Leptospirosis is an increasingly common and potentially fatal zoonotic disease caused by infection with Leptospira bacteria.

It affects many organ systems and varies in severity, with some patients presenting with mild and self-limiting signs, and others presenting with severe (and sometimes fatal) renal disease, hepatic disease or bleeding disorders.

What causes leptospirosis?

Patients (mostly dogs - cats can become infected and shed the bacteria, but generally don’t show clinical signs) become infected when they come into contact with leptospira-infected urine, or substrates contaminated with infected urine (like water or soil).

Leptospira bacteria are small, thin, flexible and spiral-shaped bacteria. They’re invasive, mobile, and well-protected within a double-layered envelope. 

There are various species of Leptospira bacteria; some are pathogenic, while others are not. In our patients, Leptospira interrogans is the species we need to be aware of. Dogs are the primary host for this pathogen, although many other species can also act as reservoir hosts, including rodents and other wildlife.

There are over 250 individual pathogenic (disease-causing) serovars of Leptospira interrogans, including the ones we vaccinate against: canicola, grippotyphosa, icterohaemorrhagiae and pomona. Vaccine-induced immunity is serovar-specific, meaning that even vaccinated patients can become infected with a serovar not covered by their vaccine.

What happens when a patient becomes infected?

The new host becomes infected with the bacteria through their conjunctival, oral, or nasal mucosa, or broken skin, coming into contact with infected urine. Direct transmission from an infected patient to a susceptible host is also possible, but rare.

Inside the new host, the warm environment triggers genetic changes in the bacteria, increasing their pathogenicity and making them even more disease-causing than before.

These bacteria then migrate to the bloodstream where they multiply and spread rapidly, infecting the kidneys, liver, spleen, central nervous system, eyes and genital tract.

As the infection takes hold, patients produce antibodies that can clear the majority of bacteria from most organs. Some patients can even successfully eliminate all bacteria and recover without developing clinical signs. However, many patients will go on to become persistent carriers, shedding the bacteria via their urine.

Leptospirosis causes varying degrees of organ damage, depending on the host’s immunity and the pathogen’s virulence. Most patients present with acute kidney injury, and/or acute hepatopathy alongside vasculitis. Pancreatitis, myositis, enteritis and ocular changes are also reported. Patients with hepatic involvement usually suffer from a more severe form of the disease and have a poorer prognosis than patients with AKI alone.

The infection can also activate neutrophils and platelets, causing inflammation and increasing the risk of conditions such as systemic inflammatory response syndrome and disseminated intravascular coagulation in severe cases.

Ok, that’s what lepto does - but which patients are at risk?

We used to think of lepto as a disease primarily affecting young, male, large-breed working dogs in rural areas, who were exposed to more wildlife, soil, and standing water. However, studies now show that any dog, in any setting, can be affected.

Urban and suburban dogs are just as at risk due to exposure to wildlife. And previously-vaccinated dogs, or dogs vaccinated with L2 vaccines, are also at risk. So really, we should have leptospirosis as a differential in any patient with an acute kidney injury or acute hepatopathy, and barrier nurse them as if they’re infected until proven otherwise.

What about the clinical signs we see?

Clinical signs depend on the serovar, the patient’s age and immune status, environmental factors, and the stage of infection progression. 

Onset is usually acute, with signs emerging within the first 4 days after infection; however, subacute infections, which have a longer latency period of 5-14 days, are also observed.

Patients with acute infection present with more severe clinical signs, including:

  • Pyrexia

  • Joint and muscle pain

  • Vomiting

  • Haematochezia

  • Haematemesis

  • Melena

  • Epistaxis

  • Petechial haemorrhage

  • Evidence of hypoperfusion, eg, due to anaemia or hypovolaemia - causing signs such as tachycardia, tachypnoea, bounding pulses and a prolonged CRT

  • Hypothermia

  • Lethargy

Patients presenting with subacute infection have milder and more vague clinical signs, including vomiting, anorexia and dehydration. Some patients present with polydipsia and evidence of pain or reluctance to move secondary to muscular, CNS or renal inflammation.

Other clinical signs are more specific to the affected organ or organs.

For example:

  • Weight loss, decreased appetite, abdominal pain and renal pain due to acute kidney injury, uraemia and renal inflammation

  • Changes to urine output (oliguria or anuria) due to acute kidney injury

  • Tachypnoea, dyspnoea and hypoxaemia secondary to pulmonary haemorrhage (known as leptospirosis pulmonary haemorrhage syndrome or LPHS)

  • Uveitis and ocular pain

  • Cardiac arrhythmias (usually ventricular tachycardia) secondary to myocardial damage

  • Jaundice and sometimes neurological signs in patients with acute hepatitis

As you can see, these patients have a wide variety of clinical signs - not ‘just’ kidney disease or liver disease - meaning they need a LOT of support from us as nurses and technicians.

So you suspect your patient has leptospirosis. What diagnostic tests will you perform?

Ok, so as veterinary nurses and technicians we won’t be diagnosing these patients ourselves, but we’re 100% heavily involved in this process - and, like the other infectious diseases we’ve mentioned in this series so far, we must have an awareness of the tests we perform, and what they tell us.

No test is perfect, and there’s a lot to think about when interpreting results - particularly in vaccinated patients. But before we get on to that, let’s look at some of the other tests we perform.

Biochemistry and haematology is our first step.

Around 80-90% of patients will have azotaemia on biochemistry. Additionally, 30-50% will have increased liver enzymes/hyperbilirubinaemia, and many patients will also have thrombocytopenia (low platelets), with or without neutrophilia and anaemia on their haematology.

Hypalbuminaemia and electrolyte disturbances are also common. Depending on the patient’s renal function, we’ll see either hypokalaemia (due to polyuria alongside anorexia) or, more commonly, hyperkalaemia (due to decreased urine production as the kidneys become progressively injured).

Urine analysis is also required, but do this carefully.

We know that lepto is zoonotic, and it’s spread through urine - so make sure you’re wearing appropriate PPE when collecting and processing your sample.

Glucosuria and proteinuria due to renal tubular injury are relatively common. We also need to send this urine sample for a leptospirosis PCR test. Please ensure your patient hasn’t received any antibiotics before collecting the sample, as this can cause a false-negative result.

And then we need to think about infectious disease testing.

There are a few options for this, and like our other infectious disease tests, none of them are 100% perfect. Our options include:

A SNAP/witness test, which is our rapid, in-house, patient-side antibody test. This test indicates whether our patient has leptospirosis antibodies, but doesn’t determine whether they are a result of clinical infection or vaccination, which can lead to false positives.

We need to confirm these results with a microscopic agglutination test (MAT) panel, which tests specific antibody levels against different serovars, and with a PCR test, the gold-standard method for confirming active infection. This is performed on urine, as this sample is expected to contain the highest amount of bacterial DNA.

Many patients also need diagnostic imaging.

Ultrasound often reveals renal and/or hepatic changes, alongside alterations in other organs, depending on the affected organs. Chest x-rays, when performed, may show interstitial or alveolar changes due to infection.

And once your patient has their diagnosis? It’s time to think about treating them.

In theory, the treatment of leptospirosis itself is straightforward - it’s a bacterial infection, so these patients require antibiotics. 

Typically, these patients receive a few initial doses of intravenous penicillin-based antibiotics before transitioning to a course of doxycycline. Oral antibiotics are usually not given in the initial stages of treatment because many patients have GI signs impacting administration.

But we know that lepto is rarely that simple. 

These patients have significant disease associated with their infection, particularly if they have acute kidney injury, hepatitis or bleeding tendencies. Supportive treatment and care are essential, including:

  • Careful use of intravenous fluid therapy depending on renal function and urine output

  • Antiemetics to manage ongoing nausea/GI signs

  • Normalising electrolyte abnormalities through calcium gluconate, insulin or glucose as needed to treat hyperkalaemia

  • Analgesics to manage pain caused by inflammation, hepatic or renal injury, or pancreatitis (ensuring you avoid NSAIDs).

  • Antioxidant medications in patients with acute hepatitis (eg, SAMe)

Patients with severe oliguric or anuric acute kidney injury may require diuretics to increase urine production, or (preferred) renal replacement therapies (aka dialysis) to support kidney function.

Leptospirosis is one of the most common reasons for dialysis in veterinary patients; this treatment restores fluid, electrolyte, and acid-base status, and extends the window for renal recovery. 

Therapeutic plasma exchange can also be performed in leptospirosis patients to remove inflammatory substances and improve patient outcomes. However, both dialysis and TPE require specialised equipment, which is only available in specific referral centres.

What about nursing care - what are OUR priorities with leptospirosis?

I’m going to conclude this episode by highlighting some of the most crucial nursing considerations these patients require. They’re often severely affected and need a LOT of supportive management - and as the ones in the wards carrying out this care, our role in this is absolutely essential.

The top four areas to consider when caring for these patients are:

  • Monitoring and managing renal function

  • Monitoring hepatic function and complications

  • Providing intensive supportive care

  • And preventing the spread of disease.

Let’s start with managing your patient’s renal function.

We know that AKI is VERY common in lepto patients - and whilst we used to think that the way to treat all kidney disease is with lots of fluids, we now know that isn’t always the case.

Lepto patients are at a very real risk of fluid overload. If the kidneys lose their ability to create urine (which they often do with lepto as AKI progresses), any fluid we continue to give them won’t flush waste products out of the system; instead, it’ll sit there and cause fluid overload.

So, manage your patient’s kidneys by:

  • Placing a urinary catheter for accurate output monitoring (which you can then match your fluid rate to)

  • Track ins and outs regularly and adjust your patient’s fluid rate accordingly

  • Weigh them often; acute weight increases are often associated with fluid overload

  • Monitor things like electrolytes and creatinine regularly, under veterinary direction

  • Be especially alert for signs of fluid overload or anuria, and flag any changes to the vet ASAP.

And on top of this, we need to look at the liver, too.

Up to half of lepto patients show hepatic involvement, and that comes with its own set of risks.

The severe inflammation we see in acute hepatitis can interfere with liver function, leading to complications like hypoglycaemia, coagulopathies, and encephalopathy.

  • Monitor your patient’s glucose levels as needed and be prepared to administer glucose as prescribed in the event of hypoglycaemia.

  • Keep an eye on your patient’s bleeding status - including prolonged haemorrhage from venepuncture, petechiation, and mucosal bleeding - alongside measuring clotting times where needed

  • Assess mentation closely, as subtle changes (dull mentation, head-pressing) can signal hepatic encephalopathy.

Remember, bleeding signs in lepto patients aren’t just from the liver. Thrombocytopenia and vasculitis also play a role; therefore, monitoring these patients closely for signs of bleeding is crucial.

There’s also a lot of supportive care to consider.

These patients benefit from a lot of often advanced nursing, particularly when they have severe AKI or hepatic involvement. This means that we can really get hands-on and use lots of nursing skills, including:

  • Placing feeding tubes (often naso-oesophageal)

  • Creating and tracking feeding plans

  • Placing and managing urinary catheters

  • Careful monitoring and spotting subtle changes in patient condition

  • Monitoring and interpreting bloods, including PCV/TS, venous blood gases, and renal/hepatic parameters

  • Place and manage vascular access devices, particularly things like PICC lines or central venous catheters (where the patient’s coagulation status allows).

And lastly, we can’t ignore infection control.

Leptospirosis is a zoonotic disease that causes severe disease in humans, just as it does in our patients. This means we need to protect ourselves, our colleagues, our clients, and our patients, while also delivering effective nursing care.

To do this:

  • Ensure you’re wearing full PPE every time, including gloves, a long-sleeved gown or apron, AND eye protection if splash risk - especially when managing the patient’s environment, which can easily become urine-contaminated

  • Control the source of infection by catheterising your patient if possible (balancing the risk of infection with the risk of catheterisation and the benefits of urine output monitoring)

  • Limit your patient’s movement through the hospital, especially if you’re concerned about urine leakage. Use a trolley if possible, or mop behind them if not.

Full isolation may not be possible (or needed, if your patient is catheterised) - but wherever you’re caring for them, make sure you’re protecting yourself, and able to observe and care for your patient appropriately.

So there you have it - an in-depth look at what leptospirosis is, how it impacts our patients, and the care they need as a result. Yes, these patients can be challenging, but they provide us with numerous opportunities to utilise new skills in caring for them. From monitoring AKI and hepatic function, to catheterisation, supportive care, nutritional support and much more, we are absolutely instrumental in their care. 

To recap, leptospirosis is a severe, potentially fatal infectious disease caused by infection with different serovars of Leptospira interrogans bacteria. The disease attacks various organs and tissues, causing a variety of clinical signs - usually acute kidney injury, acute hepatopathy and bleeding tendencies. And when nursing patients with it, the top 4 things you need to focus on are:

  1. Monitoring renal function

  2. Monitoring hepatic function

  3. Infection control and management

  4. Providing supportive nursing care



Thank you SO much for joining me this week for a long, hard look at caring for dogs with leptospirosis, and the skills we can use in the process. I hope you now feel more confident and prepared to help with your next case, with a list of practical skills you can use in the process.

Did you enjoy this episode? If so, I’d love to hear what you think. Take a screenshot and tag me on Instagram (@vetinternalmedicinenursing) so I can give you a shout-out and share it with a colleague who’d find it helpful!

Thanks for learning with me this week, and I’ll see you next time!

References and Further Reading

Laura Jones
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