The video version of this podcast can be found here:

·      https://youtu.be/k6amIFy84Bc

This episode makes reference to guidelines produced by the "National Institute for Health and Care Excellence" in the UK, also referred to as "NICE". The content on this channel reflects my professional interpretation/summary of the guidance and I am in no way affiliated with, employed by or funded/sponsored by NICE.

My name is Fernando Florido and I am a General Practitioner in the United Kingdom. In this episode I go through the NICE guideline on acute kidney injury, NG148, focusing on what is relevant to Primary Care only, covering the diagnosis, and investigations, as well as the recommendations on the use of contrast media.

In the next episode we will cover the management recommendations by NICE, and the Primary Care flowchart on AKI by Barnsley Hospital NHS Trust and King’s College Hospital NHS Trust, so stay tuned.

I am not giving medical advice; this video is intended for health care professionals, it is only my summary and my interpretation of the guidelines and you must use your clinical judgement.  

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There is a podcast version of this and other videos that you can access here:

Primary Care guidelines podcast:

·      Redcircle: https://redcircle.com/shows/primary-care-guidelines

·      Spotify: https://open.spotify.com/show/5BmqS0Ol16oQ7Kr1WYzupK

·      Apple podcasts: https://podcasts.apple.com/gb/podcast/primary-care-guidelines/id1608821148

There is a YouTube version of this and other videos that you can access here: 

• The Practical GP YouTube Channel: 

https://youtube.com/@practicalgp?si=ecJGF5QCuMLQ6hrk

The links to the guidance covered in this episode can be found here:

Acute kidney injury: prevention, detection and management (NG148):

·      https://www.nice.org.uk/guidance/ng148

The 1-page visual summary on assessing the risk of acute kidney injury in adults having iodine-based contrast media: outpatient, non-urgent inpatient and community settings:

·      https://www.nice.org.uk/guidance/ng148/resources/visual-summary-pdf-13551376429

The algorithm for early identification of acute kidney injury, endorsed by NHS England:

·      https://www.england.nhs.uk/akiprogramme/aki-algorithm/

The Management of acute kidney injury in adults in Primary Care by Barnsley Hospital NHS Trust:

·      https://best.barnsleyccg.nhs.uk/media/hruaaymn/best-december-2015-barnsley-aki-primary-careguidance-pathway.pdf?form=MG0AV3

The Adult Acute Kidney Injury Care Pathway for Primary Care by King’s College Hospital NHS Trust:

·      https://www.kch.nhs.uk/wp-content/uploads/2023/01/mi-169.2-adult-acute-kidney-injury-care-pathway.pdf

A calculator for the National Early Warning Score (NEWS):

·      https://www.mdcalc.com/calc/1873/national-early-warning-score-news

Transcript

If you are listening to this podcast on YouTube, for a better experience, switch to the video version. The link is in the top right corner of the video and in the episode description.

Hello and welcome, I am Fernando, a GP in the UK. Today, we will go through the NICE guideline on acute kidney injury focusing on what is relevant in Primary Care only. In this episode, we will cover the diagnosis, and investigations, as well as the recommendations on the use of contrast media. In the next episode we will cover the management recommendations by NICE, and the Primary Care flowchart on AKI by Barnsley Hospital NHS Trust and King’s College Hospital NHS Trust, so stay tuned.

Right, let’s jump into it.

In order to identify acute kidney injury, we will check serum creatinine and compare it with baseline. AKI is most often seen during episodes of acute illness so we should do this screening in people with acute illness if there is:

• Pre-existing CKD (or eGFR less than 60)
• heart failure
• liver disease
• diabetes
• history of acute kidney injury
• oliguria (that is, a urine output less than 0.5 ml/kg/hour)
• neurological or cognitive impairment or disability, which may mean limited access to fluids
• hypovolaemia
• use of certain drugs such as NSAIDs, aminoglycosides, ACE inhibitors, ARBs and diuretics within the past week, especially if hypovolaemic
• use of iodine-based contrast media within the past week
• symptoms or risk of urological obstruction,
• sepsis
• deteriorating early warning scores and
• young age or age 65 years or over 

In addition, for children and young people we should also screen for AKI if there is:

• severe diarrhoea (particularly bloody diarrhoea)
• symptoms or signs of nephritis (such as oedema or haematuria)
• haematological malignancy and
• hypotension

However, AKI can also happen in the absence of an acute illness. So, if there is a rise in serum creatinine, we should still consider AKI rather than a worsening of their chronic disease if there is:

• CKD, especially if eGFR is less than 45
• urological disease or symptoms
• symptoms suggesting complications of acute kidney injury, like fluid overload, oliguria, hypertension, electrolyte imbalance or hypertension and finally
• symptoms of a multi‑system disease, such as, for example a purpuric rash 

There is a small but increased risk of acute kidney injury associated with an eGFR less than 30 when having iodine-based contrast media. Iodine contrast media is commonly used in a variety of investigations such as CT scans, angiography, and intravenous urography.

So, how do we assess the risk of AKI in these patients?

Well, before requesting a non-urgent CT scan with contrast, we should assess whether the person has pre-existing kidney disease. 

If available, we will use an eGFR measurement from the past 6 months. If the person has been acutely unwell or clinically unstable since their last eGFR test, we should request a more recent eGFR. 

If no eGFR is available from the past 6 months, we will ask the following screening questions:

• do they have kidney disease or a kidney transplant?
• have they seen or are waiting to see a nephrologist or urologist?
• do they have symptoms of acute illness likely to cause acute kidney injury such as diarrhoea, vomiting, fever, hypovolaemia, infection or difficulty passing urine? 

If the answer to any of the screening questions is yes, then we should request a new eGFR. However, if the screening questions do not indicate a problem and the person is clinically stable, NICE says that we could consider proceeding without the need for further blood tests before the scan. However, in practice and as a safety measure, it is likely that we will request the eGFR anyway, just in case.

In order to prevent and reduce the risk of AKI, we will encourage oral hydration before and after procedures using intravenous iodine-based contrast media. In addition, we will consider temporarily stopping ACE inhibitors and ARBs if they have CKD with an eGFR less than 30. NICE has produced a 1-page visual summary on assessing the risk of AKI in adults having iodine-based contrast media and I have put the link to it in the episode description.

Now, how do we prevent deterioration in people with AKI or at high risk of it?

Well, we will obviously use our clinical judgement, follow prescribing recommendations in our electronic clinical systems and consider optimising medication, such are stopping nephrotoxic drugs and adjusting doses according to renal function.

We should also consider temporarily stopping ACE inhibitors and ARBs in people with diarrhoea, vomiting or sepsis until they have improved. 

So, we screen for AKI by checking renal function on a blood test. But, how do we actually diagnose acute kidney injury?

Well, we will use any of the following criteria:

• a fall in urine output to less than 0.5 ml/kg/hour for more than 6 hours in adults and more than 8 hours in children and young people
• a rise in creatinine of 26 micromol/litre or greater within 48 hours
• a 50% or greater rise in creatinine known or presumed to be within the past 7 days or
• a 25% or greater fall in eGFR in those aged under 18 years within the past 7 days. 

There is also an algorithm that we can follow for early identification of acute kidney injury. However, it is fairly complex so I will not go through it here. You can find a link to it in the episode description.

We will obviously monitor creatinine regularly in those with AKI or at risk of it. The frequency of monitoring should vary according to clinical need. 

In terms of investigations, in order to identify the cause of AKI, NICE recommends that:

·      We should do a urine dipstick for urinalysis as soon as possible and take appropriate action when results are abnormal. For example, we should think about a diagnosis of acute nephritis when there is no obvious cause and the urine dipstick shows haematuria and proteinuria, without a UTI or trauma due to catheterisation. 

·      We should not routinely request an ultrasound scan if the cause of the AKI is known. However, if there is no identified cause for the AKI or the patient is at risk of urinary tract obstruction, the patient should have an urgent ultrasound within 24 hours, so, in practice, these patients are likely to need referral to the emergency department. This is even more so when pyonephrosis (that is, an infected and obstructed kidney) is suspected, given that the ultrasound should be performed within 6 hours in these cases.

So that is it, a review of the NICE guideline on AKI covering the diagnosis, and initial investigations. Make sure not to miss the next episode where we will cover the management recommendations.

We have come to the end of this episode. Remember that this is not medical advice but only my summary and my interpretation of the guidelines. You must always use your clinical judgement.

Thank you for listening and goodbye.