Breathing Difficulty in Chronic Kidney Disease is an inevitable accompaniment in advanced stages. But why does CKD make you breathless in the first place? Learn here.
The other day, some of us at Team ATK just sat reflecting on our pre-transplant days with Kidney Failure. And we all concurred on the helplessness we felt about that relentless “out-of-breath” sensation even at the slightest exertion. In fact, right after transplant, this was one of the first positive changes that I remember as uplifting my quality of life. I could breathe fully, freely & effortlessly again!
So, what is this “breathlessness” or as the fancy medical terminology would have it, “Dyspnoea” (pronounced as “disp-neah”) in Chronic Kidney Disease (CKD) all about?
That is what this article aims to look at today. We will be highlighting all the possible explanations that medical research on this rather less understood topic has unlocked for us, so far. The article also touches upon the basic treatment outline for each of the causes of dyspnoea (shortness of breath) in CKD. Go through the article to understand why your body reacts in a certain manner in CKD, and combat some of that apprehension of the unknown.
But first, a brief overview of what the process of breathing-in and breathing-out entails, and the various organs involved in it. Knowing this would help you easily correlate breathing difficulty with Chronic Kidney Disease.
ANATOMY OF THE BREATHING PROCESS
Breathing or Respiration involves the repetitive cycles comprising of intake of air with oxygen and “involuntary” exhalation of excess toxic carbon dioxide from our body. The purpose is, to facilitate the delivery of life-supporting Oxygen gas to all our organs and relieving them of the excess carbon dioxide load that is produced after cellular metabolism.
For inhalation to begin, our Ribs and the Diaphragm (muscle sheath that separates the chest from the abdomen) play a crucial “initiator” role. Every time we attempt to breathe-in, the ribs spread outwards & the Diaphragm muscles expand downwards. This enlarges the inner space of the rib cage, thereby “inflating the lungs” in the process. They do so, with the help of special muscles lining the vertical space between each rib as shown in the picture below. The fancy name for these muscles is “Inter-costal muscles” where the word “costal” derives from the root word “costa” (Latin) meaning rib. Hence quite literally, Intercostal muscles refer to the “muscles between the ribs”. Enlargement of the rib cage and inflation of the lungs creates a sort of a “pull-in” force and air from the outside gushes-in.
Now, after we take-in oxygen from our Nostrils, it takes a U-turn from the nose, down towards our Lungs via a series of tube-like spaces of various shapes & sizes, namely the – Pharynx, Larynx, Trachea (Wind-Pipe), Bronchus of each lung, Bronchioles & finally to the air-pockets that make up our lungs, called the Alveoli. Check out the successive illustrations below for reference.
OXYGEN PATH FROM THE LUNGS TO OTHER ORGANS
The walls of these Alveoli serve as the “Port of Entry” for Oxygen in the body. These lung-walls are richly lined with tiny blood vessels where the whole “exchange” of toxic Carbon Dioxide from the body and Fresh Oxygen from outside, takes place.
Once the blood gets rid of excess carbon dioxide & gets loaded with Oxygen, it travels to our heart that “pumps” fresh oxygenated blood to all our body organs to fulfil their metabolic requirements. In return, the cells in the body organs empty their load of metabolic wastes into the blood cells.
The gaseous waste such as Carbon Dioxide returns to our heart for “Exhalation” (Breathing-out) via Lungs. This completes one cycle of respiration and is followed by repeating the whole Oxygen intake process as mentioned above.
Therefore, for a seamless breathing experience, you need each of the “organ-soldiers” listed below, to stay in good health and work in co-ordination:
- Nose, Pharynx, Larynx, Trachea, Bronchus
- Lungs (Alveoli)
- Ribs & Intercostal Muscles between them
- Nerves supplying the above organs
- Blood cells & blood vessels
If even one of the above organs gets affected by any disease process, it can affect “timely oxygen delivery” to, and “excess carbon dioxide removal” from our organs. This glitch is what manifests itself as “trouble in breathing”.
This explanation holds true for Chronic Kidney Disease as well.
SO, WHAT GOES WRONG DURING CHRONIC KIDNEY DISEASE?
During Chronic Kidney Disease (CKD), kidneys begin to shrink, get scarred & harden-up over the years such that they gradually lose their functionality. As a result, our body is unable to maintain the precise water & mineral balance, which is central to the functioning of literally every organ in our body.
With time, CKD brings forth a number of complications that are diagnostic of clinical kidney damage. The nature of these complications is such, that they interfere with the normal functioning of a number of other non-kidney body functions as well. This is where breathing difficulty in CKD comes in.
CKD COMPLICATIONS THAT CONTRIBUTE TO BREATHING DIFFICULTY
Let’s take a look at the possible reasons for breathing difficulty in kidney failure in the order of their appearance and how commonly these are encountered.
PROTEIN LOSS IN URINE
Soldier down: Rib muscles (Inter-costal muscles) & Diaphragm
Losing protein in urine is the hallmark of established kidney disease. In initial stages, it is usually a blood (plasma) protein named Albumin that leaks out in the urine.
However, as the condition advances, many different proteins start leaking out of our body. These include proteins that would otherwise strengthen our muscles. As an obvious effect, muscles start to go weak. This condition is called Protein-Energy Wasting or PEW.
Such Protein Energy Wasting doesn’t even spare the Diaphragm & the inter-costal muscles between individual ribs. As explained above, these muscles help initiate the breathing process by expanding the ribcage. Their weakening due to muscle protein-loss becomes an impediment to proper inflation of lungs while breathing in. This is a significant part of why there’s breathing difficulty in advanced stages of Chronic Kidney Disease.
Soldier affected: Red Blood Corpuscles (cells)
Anaemia refers to a reduction in the effective numbers of Red Blood Cells in our body. Red blood cells have a protein called Haemoglobin, that normally serves as the “in-house transporters” of oxygen & carbon dioxide. In other words, Red Blood Cells ferry Life-sustaining Oxygen to different organs in the body in exchange for getting them rid of excess toxic carbon dioxide.
Low RBC count in Anaemia in CKD implies a low Hemoglobin content in our body. This means the delicate Oxygen transport system gets jeopardised. As a result, our organs get “deprived “ of adequate oxygen, especially after any physical activity. At the same time, carbon dioxide levels increase beyond normal limits which turns the blood acidic and starts harming all other cells in the body. This scheme of things signals our brain to make us breathe more frequently and as fully as we can, to take in a fresh load of oxygen stat. Unless otherwise treated, Anaemia in CKD tends to deteriorate. So, the whole episode of deep breathing becomes repetitive with little relief to the sensation of breathing difficulty.
Fortunately, medical research has afforded us effective therapies to resolve Anaemia from Kidney Disease. It forms an integral part of CKD management in the clinic and most patients respond well.
HIGH BLOOD ACIDITY
Soldier hit: Rib muscles (Inter-costal muscles) & Diaphragm
One of the major functions of our Kidneys is to see to it that our blood turns neither too acidic nor too alkaline such that it’s just right for all the life-supporting activities. This ability takes a hit with declining kidney function in CKD and our blood progressively turns overtly acidic. [Medical term: “Metabolic Acidosis”].
NOTE: Blood can turn abnormally acidic with many other conditions. Kidney disease is just one of the prominent causes for it.
Now, Acidic blood in advanced kidney disease also causes muscle wasting & weakening just like Protein loss in urine does. Intercostal muscles and the Diaphragm again become a target here. Weak rib & diaphragm muscles mean compromised lung inflation. This translates as breathing difficulty.
Further, high blood acidity is itself, a trigger for signalling the brain to make us breathe more frequently and deeply. This is called “Kussmaul’s Breathing” named after the person who first officially reported it.
Rapid breathing infuses the body with more oxygen which partially counters some of the acidity of the blood by “washing-off” substances that make the blood acidic in the first place.
Since in CKD, metabolic acidosis is an essential part of the disease process itself, no amount of rapid deep breathing seems to be “enough” to compensate for the blood acidity permanently. As a result, deep and rather effortful breathing becomes the default. This also contributes to the sense of breathing difficulty in Chronic Kidney Disease.
FLUID IN THE LUNGS
Soldier suffering: Lungs (!)
Our lungs happen to be a collection of numerous tiny, thin airbags or alveoli. A special tissue lining around the whole lung namely Pleura holds these airbags in place and protect them. Normally, the space between the lungs and their pleura (Pleural Cavity) is extremely tiny with virtually no fluid there.
In Chronic Kidney disease (CKD), unwell kidneys are unable to flush out excess water from our body via urine. As a result, such excess fluid tends to accumulate in certain natural spaces in our body, such as beneath the skin over feet, legs and face. The technical name for such abnormal fluid collection in tissue spaces is “Oedema”(pronunciation: idee-mah). In some severe cases, excess fluid could “overflow” and start to collect between the Lungs and their protective sheath (pleura). The fancy word for such fluid accumulation outside the lungs is “Pleural Effusion”.
Other causes for Fluid in Lungs during your CKD journey may include either of the following:
“Uremic Lung” — High blood Urea levels in Kidney Failure promote “secretion” of fluid into the space between pleura besides promoting the accumulation of excess fluid from the blood.
Complication of long-term Haemodialysis (due to complications from the procedure itself).
Heart disease and subsequent cardiac failure due to CKD (explained in the section below)
Infections such as Lung Tuberculosis (TB)
Certain Cancers that may develop in patients on medicines that dampen our immune-system. (Normal immune systems can otherwise fight off Cancer Cells)
The tendency of this collected fluid is to press inwards upon the lungs. This restricts our lungs from inflating fully which in turn, creates breathing trouble.
HEART-RELATED COMPLICATIONS IN KIDNEY DISEASE
Soldier targetted: Heart & Blood Vessels
Kidneys and Heart function in close coordination. Kidneys purify and balance the various blood components. Heart ensures that such clean blood reaches all organs including the kidneys themselves, via blood vessels at optimum blood pressure.
The process of Chronic Kidney Disease causes a rise in our blood pressure. In effect, this means blood exerts an abnormally high pressure on the internal walls of the heart and blood vessels. And this causes multiple “micro-damages” in the process. Repeated aggressive healing attempts by our body scar the damage sites and harden-up the blood vessel walls. Further, ironically, some medicines meant to curb protein leakage in urine may disturb blood lipid-levels (cholesterol) as a side-effect. Such excess blood cholesterol starts “sticking and depositing” onto the hardened scarred patches within the blood vessel walls. In the process, the space within blood vessels narrows down which greatly burdens the heart. All of this promotes heart disease and in some cases, severe weakening of heart muscles leading to Cardiac Failure.
Unwell heart fails to pump blood efficiently, which compromises timely oxygen delivery to our body organs. Poor oxygen levels within the body signals our brain to “induce” rapid breathing to compensate for this deficiency. This again manifests as breathing difficulty in advanced Kidney Disease.
So you see just how involved kidneys are, in ensuring that other body functions not directly related to them such as our Respiration (breathing), go on seamlessly. Any decline in kidney function and these functional systems go haywire! Our affected organs communicate their issues to us via clinical symptoms, which help the clinicians reach a diagnosis & plan treatments.
TREATMENT IN A NUTSHELL
Speaking of treatments, Breathing Difficulty in advanced Chronic Kidney Disease is BEST TREATED with a Kidney Transplant provided no separate illness affecting your breathing co-exists. The donor kidney “replaces” the function of existing, unwell kidneys, restores the normal balance of all blood components as necessary and in effect, “reverses” all mechanisms that contribute towards the sensation of breathlessness.
But till the time you are waiting for a matched organ donor, the treatment focuses on the measures as below.
Curbing the mechanisms by which CKD causes breathlessness that involves prescribing:
Meds to treat blood acidity & restore normal blood pH
“Water pills” (diuretics) to reduce excess water load in your blood, curb oedema & prevent fluid accumulation in Lungs
If fluid persists in the lungs, and does not respond to medication, it may be sucked-out with a special syringe. This process usually does not require hospital admission. Sometimes a Chest Tube may need to be put in place, in some cases. This procedure requires hospital admission.
Added measures to prevent worsening of breathlessness
Depending on the extent of the impact of CKD on the heart, there may be restrictions on your daily activity/ exercise levels.
For patients in Dialysis, there will be restrictions on daily fluid intake to prevent any “water-load” in the blood
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