Brain fog in CKD: How can kidney disease affect memory and thinking?

Chronic kidney disease (CKD) means the kidneys are damaged or not working well for at least 3 months. The kidneys normally filter waste and extra fluid from the blood. When they slow down, waste can build up and health problems can follow. CKD can stay stable or worsen over time.

What are neurocognitive disorders, and what might people with CKD notice?

“Neurocognitive disorders” is an umbrella term for problems that affect thinking, memory, and day-to-day brain function. In CKD, people might notice:

• Brain fog or slower thinking
• Trouble focusing, especially when tired
• Forgetting words, dates, or small tasks more often
• Difficulty planning, organising, or multitasking
• Feeling mentally drained faster than before
• Mood changes that make thinking harder (anxiety, low mood, irritability)

Some people describe it as feeling “less sharp.” Others notice it most when they are under stress, not sleeping well, or after medical appointments or treatment days.

Is cognitive impairment more common in people with CKD?

Yes, many studies have shown that cognitive impairment is more common in people with CKD than in people without it and that the risk tends to rise as kidney function declines. Research also suggests that people with more albumin in their urine may have a higher risk of cognitive decline over time.

It is important to say this clearly:

Cognitive problems can happen at any stage, and they can be mild. But they are common enough that they should not be dismissed.

Why would kidney disease affect the brain?

There is not one single cause. Most researchers explain it as several factors working together. Here are the main ones:

Shared risk factors that affect blood vessels

The kidneys and the brain both rely on tiny blood vessels. Conditions that often come with CKD, like high blood pressure, diabetes, and cardiovascular disease, can also affect blood flow in the brain. Over time, this can raise the risk of vascular-related cognitive changes.

Build-up of waste products in the body

When kidneys do not filter as well, certain waste products can stay in the blood longer. Some research suggests that this “toxin load” may play a role in brain symptoms like slower thinking or reduced attention.

Ongoing inflammation

CKD is often linked with chronic inflammation in the body. Inflammation is also being studied as a factor in brain ageing and cognitive decline.

Anemia and low energy to the brain

Many people with CKD develop anemia (low red blood cell count or low hemoglobin). This can worsen fatigue and can also affect concentration, mental stamina, and memory.

Sleep problems

Sleep disruption is very common in CKD, whether it is insomnia, restless legs, itching, sleep apnea, or waking often during the night. Poor sleep alone can cause strong “brain fog," even in people without CKD.

Medication burden and side effects

CKD often comes with multiple medications. Some medicines can cause drowsiness, confusion, or slowed thinking, especially when doses need adjusting due to reduced kidney function.

Does dialysis change the picture?

For people on dialysis, cognitive problems are reported even more often. Dialysis is a life-sustaining treatment, but it can also be physically demanding, and some people feel wiped out afterward.

Possible reasons include the following:

• Fluctuations in blood pressure during dialysis sessions
• Stress on the body from fluid shifts
• Higher overall illness burden (more comorbidities, older age in many groups studied)
• Inflammation and nutritional issues in some patients

Not everyone on dialysis will have cognitive symptoms, but if someone notices confusion or major brain fog around treatment days, it is worth discussing with the dialysis team.

Why does this matter so much in real life?

Because CKD is a condition that asks people to manage a lot on their own.

Remembering medication schedules, following diet guidance, tracking symptoms, attending appointments, and making sense of lab results all depend on brain energy. When cognition is affected, self-management becomes harder, and people may feel ashamed or judged for struggling with things that used to be easy.

This is one reason why recognizing cognitive changes early can be protective. It allows care to be adapted with more support, clearer instructions, and safer systems.

How can someone tell if it is CKD-related cognitive impairment, depression, or something else?

This can be tricky because symptoms overlap. For example:

• Depression and anxiety can strongly affect focus, memory, and motivation
• Sleep deprivation can mimic cognitive impairment
• Thyroid issues, vitamin deficiencies, infections, dehydration, and medication side effects can all affect thinking
• A sudden change in thinking can be a medical emergency, not “CKD brain fog”

A useful rule of thumb is this:

• Slow, gradual changes over months should be discussed at routine visits, ideally with screening
• Sudden confusion or rapid worsening needs urgent medical evaluation

What can help, practically and realistically?

There is no single fix. But there are many ways to reduce cognitive strain and protect brain health.

Ask for cognitive screening

If symptoms are affecting daily life, a simple screening test can help document what is going on. It can also help the care team tailor support. If someone feels brushed off, it can help to describe specific examples, like the following:

• “I forget doses unless I set alarms.”
• “I struggle to follow multi-step instructions now.”
• “I feel confused after dialysis.”

Review treatable contributors

This is often where the biggest improvement happens. A care team may check and manage:

• Blood pressure and blood sugar
• Anemia and iron levels
• Sleep problems (including sleep apnea if suspected)
• Depression and anxiety
• Medication side effects and dose adjustments

If someone is taking many medications, asking for a “medication review” can be very worthwhile.

Reduce the mental load of self-management

This is not about “trying harder.” It is about building a system that supports the brain.

Helpful tools include:

• Pill boxes or pharmacy blister packs
• Phone reminders for meds and appointments
• A single notebook or notes app for symptoms, questions, and lab results
• Bringing a trusted person to appointments
• Asking for written instructions in plain language
• Repeating key information at the end of visits, to confirm understanding

Mention symptoms tied to dialysis sessions

If confusion, dizziness, or extreme brain fog happens during or after dialysis, the team may be able to adjust aspects of treatment (for example, fluid removal goals or blood pressure management). The goal is not to “push through,” but to make treatment safer and more tolerable.

Protect emotional well-being

Cognitive symptoms can be humiliating. People may withdraw socially or stop asking for help because they fear being seen as incapable. That emotional burden matters.

Support can include:

• Talking therapy or counselling
• Peer support groups
• Involving caregivers or family, especially for appointment support
• Asking the care team to explain what is happening in a non-blaming way

Feeling supported often improves coping, and coping affects symptoms too.

When should someone seek urgent help?

Seek urgent medical help if there is:

• Sudden confusion, disorientation, or extreme sleepiness
• New weakness, facial droop, trouble speaking, or vision changes
• Severe headache that is unusual for the person
• New hallucinations or intense agitation
• Symptoms that quickly start after a medication change

These are not typical slow cognitive changes and should be checked promptly.

Key takeaways

• Cognitive symptoms like brain fog, slower thinking, and memory trouble are common in CKD and deserve to be taken seriously.
• The kidney-brain link is real and usually involves several factors, including blood vessel health, inflammation, anemia, sleep issues, and medication effects.
• People on dialysis may be at higher risk, and symptoms sometimes worsen around treatment sessions.
• Screening and practical supports can make daily life safer and less exhausting. This is about support, not blame.
• Sudden confusion or rapid worsening is urgent and should be evaluated right away.

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Take care!