Clinical Symptoms

Clinical symptoms of CKD

The clinical symptoms of CKD are as diverse and numerous as the functions of the kidney. In addition, each cat has its own individual kidney-related vulnerability. That means that every cat presents a different pattern of symptoms and not every symptom occurs in every cat.

Mostly, the symptoms appear gradually over weeks, months and years and are often only noticed when 2/3 to 3/4 of the nephrons have already been destroyed.

Many of the known symptoms have several causes. And some clinical symptoms are also interrelated. For example, nausea leads to an aversion to eating, which in turn leads to emaciation and, ultimately, bodily weakness. Weakness, in turn, can cause a cat to become “wobbly” on its legs, which is also apparent in the hind limbs (hind-limb weakness).

Vomiting can exacerbate dehydration. Inflammation of oral mucous membranes and peptic ulcers can lead to malnutrition and nausea.

Anorexia, apathy, lethargy, weakness and weight loss as well as increased drinking (polydipsia) and excessive urine production (polyuria) are the main symptoms of chronic kidney disease (CKD).

Most symptoms are easily treated. Reducing their causes, in particular, is effective in alleviating clinical symptoms. It constitutes an important part of treatment.

The main symptoms of chronic kidney disease (CKD) are listed below.

Symptoms of CKD

Consequences of renal insufficiency in CKD


Regulation of water balance

Loss of the ability to reabsorb water and loss of regulation of salt and other electrolytes in the body.

  • Increased drinking (polydipsia)
  • Increased urine production (polyuria)
  • Dehydration → until collapse
  • Fatigue (apathy), weakness, lethargy
  • Accumulation of fluid in tissues (oedema)
  • Increased blood pressure (hypertension)

Regulation of electrolyte balance

Loss of fine regulation of the electrolyte balance can lead to secondary hyperparathyroidism

  • Lack of appetite (anorexia)
  • Fatigue (apathy), weakness, lethargy
  • Weight loss
  • Itchiness
  • Twitching
  • Teeth grinding
  • Impaired movement (for example weakness of the hind legs) and abnormal movements like walking on hocks (plantigrade gait), uncoordinated movements
  • Constipation
  • Eating cat litter
  • Hypothermia

Regulation of pH balance

The loss of fine regulation of pH in the body can lead to increased acidity of the blood (metabolic acidosis)

  • Weight loss and muscle atrophy
    → spine becomes visible and bony
  • Breathlessness, increased panting
  • Mucosal ulcers in the mouth (stomatitis)
  • Vomiting

Production of hormonal substances

Reduced calcitriol production (vitamin D)

A decrease in calcitriol production can lead to secondary hyperparathyroidism.

Disruption of renin synthesis

Disruption of renin synthesis can be associated with high blood pressure.

  • Central nervous disorders such as seizures, convulsions, lethargy, stroke
  • Walking difficulties
  • Visual disorders → blindness due to retinal detachment
  • Proteinuria

Reduction in erythropoietin synthesis

Disruption of erythropoietin synthesis can lead to anaemia

  • Fatigue (apathy), weakness, lethargy → hind leg weakness
  • Lethargy
  • Paleness of the mucous membrane of eyes, ears and mouth
  • Hypothermia, cat cold to the touch, feels cold, shivers
  • Nausea, lack of appetite (anorexia), eats cat litter
  • Increased heart and breathing rate

Removal of toxins

  • Diarrhoea → emaciation, dehydration
  • Shaggy coat
  • Fatigue (apathy)
  • Stomach ulcers which can lead to bleeding
  • Tremor, cramps, abnormal movements, muscle disorders, comatose states