When the metabolism of nucleoproteins is disturbed (they consist of protein, DNA (deoxyribonucleic acid), and RNA (ribonucleic acid) and the production of uric acid and its salts is abundant, gout, urolithiasis and uric acid infarct develop.
Gout is characterized by periodic sedimentation of sodium urate in the joints, which is accompanied by pains. Uric acid amount in the blood and urine is increased (hyperuricemia and hyperuricuria). The salts accumulate in the cartilages, synovial membranes of
the small joints of feet, hands, knees, talocrural articulation, in the tendons, in the cartilage of the auricle floor. The tissues where the salts accumulate necrotize with the development of agranulomatous reaction and accumulation of giant cells around them. The process is followed by connective tissue growth with formation of gouty nodes. In the kidneys, uric acid accumulates in the tubules and collecting tubes obstructing their lumina, which causes inflammation and atrophy (gouty kidney).The most frequent cause of gout is congenital metabolic disturbance, in rare cases, gout is a complication of nephrocirrhosis, blood diseases.
Urolithiasis is characterized by urates (stones) formation in the kidneys.
Uric acid infarction occurs in newborns living not less than 2 days. It manifests by sedimentation of amorphic masses of sodium urate and ammonium urate in the tubules and collecting tubes. On incision accumulation of the salts looks like yellow-red bands joining together near the papillae of the medullary layer. This pathological condition is due to intensive metabolism in the first days of life and is an adaptation process.
Stages of individual work in class Study and describe macrospecimens
Brown induration of the lungs. Determine the colour and texture of the specimen under section. In which diseases can we find such pathology? What reactions do you know which can help to trace iron containing pigments?
Spleen hemosiderosis. Describe the appearance of the organ, its colour, size. In which diseases can we find general hemosiderosis?
Spleen hemomelanosis. Describe the appearance of the organ, its colour and size. In which disease can we find spleen hemomelanosis?
Liver in posthepatic jaundice. Describe the appearance of the organ, its colour, the condition of bile ducts. Name diseases the which can be characterised by mechanical jaundice. What is the outcome of bile stasis?
Melanoblastoma of the skin. What is the appearance of the skin? Which pigment is responsible for such skin colour? Which group of pigments is it? How is it classified according to the spread of the process?