Changes

===Gastro-intestinal Disease===

===Gastro-intestinal Disease===

*'''Oral ulceration''' - This occurs especially at the [[Oral Cavity Overview - Anatomy & Physiology|fauces of the mouth ]]and on the margins of the [[Tongue - Anatomy & Physiology|tongue]]. Halitosis is often a feature of this syndrome as the lesions become secondarily infected with oral bacteria such as ''[[Fusobacterium necrophorum]]''. In severe cases, there may be extensive subepithelial necrosis and sloughing of the tip of the tongue. The lesions are often very painful and contribute to the anorexia often observed in animals with chronic kidney disease. Excessive dental calculus may be evident in animals with chronic kidney disease on oral examination.

*'''Oral ulceration''' - This occurs especially at the [[Oral Cavity Overview - Anatomy & Physiology|fauces of the mouth ]]and on the margins of the [[Tongue - Anatomy & Physiology|tongue]]. Halitosis is often a feature of this syndrome as the lesions become secondarily infected with oral bacteria such as ''[[Fusobacterium necrophorum]]''. In severe cases, there may be extensive subepithelial necrosis and sloughing of the tip of the tongue. The lesions are often very painful and contribute to the anorexia often observed in animals with chronic kidney disease. Excessive dental calculus may be evident in animals with chronic kidney disease on oral examination.

*'''[[Gastric Ulceration - all species|Gastric ulceration]]''' - This occurs for three main reasons. First, urea crosses lipid membranes freely and enters the gastro-intestinal lumen of azotaemic animals. The urea is degraded to ammonia by bacterial urease and the ammonia irritates the intestinal mucosa. This is compounded by damage to the blood vessels of the gastric submucosa by the fibrinoid necrosis that is a common feature of uraemia.  Elevated serum concentrations of gastrin (which is normally metabolised in the kidney) also lead to excessive production of gastric acid from parietal cells in the stomach. Animals with gastro-duodenal ulceration may show '''anorexia''', '''vomiting''', '''haematemesis''' and [[Peritonitis - Cats and Dogs|'''peritonitis''']] and '''haemorrhage''' if the ulcers perforate. Hypergastrinaemia may also cause incompetence of the pyloric sphincter of the stomach, permitting reflux of irritant bile into the stomach. Similar processes result in the development of '''uraemic colitis'''.

*'''[[Gastric Ulceration - all species|Gastric ulceration]]''' - This occurs for three main reasons. First, urea crosses lipid membranes freely and enters the gastro-intestinal lumen of azotaemic animals. The urea is degraded to ammonia by bacterial urease and the ammonia irritates the intestinal mucosa. This is compounded by damage to the blood vessels of the gastric submucosa by the fibrinoid necrosis that is a common feature of uraemia.  Elevated serum concentrations of gastrin (which is normally metabolised in the kidney) also lead to excessive production of gastric acid from parietal cells in the stomach. Animals with gastro-duodenal ulceration may show '''anorexia''', '''[[vomiting]]''', '''haematemesis''' and [[Peritonitis - Cats and Dogs|'''peritonitis''']] and '''haemorrhage''' if the ulcers perforate. Hypergastrinaemia may also cause incompetence of the pyloric sphincter of the stomach, permitting reflux of irritant bile into the stomach. Similar processes result in the development of '''uraemic colitis'''.

*'''[[Peritonitis - Cats and Dogs|Uraemic peritonitis]]''' - This is a form of chemical peritonitis that results from inflammation of the small mesothelial blood vessels.

*'''[[Peritonitis - Cats and Dogs|Uraemic peritonitis]]''' - This is a form of chemical peritonitis that results from inflammation of the small mesothelial blood vessels.

===Respiratory Disease===

===Respiratory Disease===

*'''[[Pulmonary Oedema|Pulmonary oedema]]''' - Damage to the small vessels of the pulmonary vasculature may result in the development of vasogenic pulmonary oedema and pleural effusion with dyspnoea, tachypnoea and coughing.

*'''[[Pulmonary Oedema|Pulmonary oedema]]''' - Damage to the small vessels of the pulmonary vasculature may result in the development of vasogenic pulmonary oedema and pleural effusion with dyspnoea, tachypnoea and coughing.

*'''Uraemic pneumonitis''' - This disease occurs due to movement of leucocytes into the alveoli and alveolar septa.

*'''Uraemic pneumonitis''' - This disease occurs due to movement of leucocytes into the alveoli and alveolar septa leading to oedema.

*Can have patchy or diffuse deposition of calcium on the alveolar walls.

===Electrolyte and Acid/Base Imbalances===

===Electrolyte and Acid/Base Imbalances===

*'''Electrolyte imbalances''' - The failure to excrete phosphate through the damaged kidneys results in hyperphosphataemia. This electrolyte complexes with calcium and also prevents the activation of vitamin D (dihydroxycholecalciferol), resulting in hypocalcaemia. This hypocalcaemia directly stimulates the production of parathyroid hormone (PTH) to try to maintain normal blood calcium levels and, in ~10% dogs with renal failure, hypercalaemia may develop due to an alteration in the set-point at which PTH is secreted. In the remaining 90%, calcium is mobilised from bone causing '''secondary renal hyperparathyroidism''' with resorption of bone, pathological fractures and fibrous osteodystrophy of the bones of skull ('rubber jaw').

*'''Electrolyte imbalances''' - The failure to excrete phosphate through the damaged kidneys results in hyperphosphataemia. This electrolyte complexes with calcium and also prevents the activation of vitamin D (dihydroxycholecalciferol), resulting in hypocalcaemia. This hypocalcaemia directly stimulates the production of parathyroid hormone (PTH) to try to maintain normal blood calcium levels and, in ~10% dogs with renal failure, hypercalaemia may develop due to an alteration in the set-point at which PTH is secreted. In the remaining 90%, calcium is mobilised from bone causing '''secondary renal hyperparathyroidism''' with resorption of bone, pathological fractures and fibrous osteodystrophy of the bones of skull [[Hyperparathyroidism|('rubber jaw')]].

*'''Metastatic mineralisation''' - The presence of excessive blood concentrations of phosphate leads to metastatic calcification in multiple tissues, particularly the rugae of the gastric mucosa, the pulmonary parenchyma and the heart.

*'''Metastatic mineralisation''' - The presence of excessive blood concentrations of phosphate leads to metastatic calcification in multiple tissues, particularly the rugae of the gastric mucosa, the pulmonary parenchyma and the heart.

*'''Metabolic acidosis''' - The kidney plays a vital role in the regulation of the normal acid/base balance.

*'''Metabolic acidosis''' - The kidney plays a vital role in the regulation of the normal acid/base balance.

===Cardiovascular Disease===

===Cardiovascular Disease===

*'''Atrial rupture''' - Mineralisation of the atria reduces their normal compliance and renders them susceptible to rupture. The resultant haemopericardium is often fatal as it causes acute cardiac tamponade.

*'''Atrial rupture''' - Mineralisation of the atria reduces their normal compliance and renders them susceptible to rupture. The resultant haemopericardium is often fatal as it causes acute cardiac tamponade.

*'''[[Arrhythmias Overview|Arrhthymias]]'''

*'''[[Arrhythmias Overview|Arrhthymias]]'''

===Haematological Disease===

===Haematological Disease===