Besides uric acid and oxalate of lime concretions; small calculi of the of ammonia and soda may be formed. Often the concretions are compound, and contain a nucleus of uric acid round which oxalate of lime or urate of ammonia has been deposited. If the concretion be encrusted with phosphates, it is a sign. that irritation has been set up in the bladder or pelvis of the kidney.
Causation.—Some children have a greater tendency than others to the deposition of uric acid in the urinary passages. This tendency often runs in families, and is then commonly associated with the gouty constitution. The form of scrofula which is connected with a stout, heavy build, and much flabbiness of flesh, is also said to be distinguished by a similar ten dency. In both of these cases there is no doubt an inclination to gastric disturbances and the generation of acid in the stomach. The actual deposi tion of uric acid crystals in the form of sand and gravel is apt to be excited by excessive or unwholesome diet—especially of indulgence in the more fermentable articles of food. Thus, large quantities of farinaceous sub stances, particularly where the starch is imperfectly cooked, and of fruit or sweets, may give rise to the formation of acid in the digestive organs. Too close confinement to the house, especially in cold damp weather, may in some subjects load the urine with uric acid or its compounds. Indeed, any influence which interferes with the assimilative processes, such as fear, grief, and other depressing passions of the mind, over-fatigue of the body, temporary febrile ailments—all these causes may determine a precipita tion of uric acid in the urinary passages. According to Dr. Garrod, con centration of the urine from deficiency in the amount of water excreted by the kidneys is a common cause of gravel in early life. In these cases the habitual passage of red sand is compatible with every evidence of good health. Amongst other cases he refers to that of a boy aged five and a half years, whose urine from day to day contained either uric acid crys tal or deposited a copious red sediment almost immediately after it was voided. The whole quantity of urine passed in the twenty-four hours was only sixteen ounces, with a specific gravity of 1.031. Directly the child was made to take more fluid, so as to increase the quantity of water passed from the kidneys, uric acid ceased to be discoverable in the secretion.
Symptoms.—The passage of the ordinary lithates is no more a cause of irritation in the young child than it is in the adult. A baby may pass
water, thick and milky from the presence of urates without showing that he is sensible of any unusual sensation while voiding the contents of his bladder. When, however, free uric acid is discharged with the urine, we usually notice signs of discomfort. Water is passed more frequently and in smaller quantities. The child screams and strains during its passage, and, if old enough, complains of pain in the urethra. In these cases we shall often find red gritty matter on the infant's diaper, or red sand at the bottom of the chamber-pan. Sometimes, this irritation is a cause of wet ting the bed at night, and therefore the water should always be examined for uric acid crystals in cases of nocturnal incontinence of urine.
While still in the kidney these concretions may give rise to few or even no symptoms. Sometimes the only sign of their presence is a more or less copious admixture of blood with the urinary water. If the concre tions are of some size, the may be accompanied by attacks of pain in the kidney. Ilnaaturia in children, especially in infants, is usually to be attributed to this cause. In the case of infants a stain of bright blood is noticed on the wet diaper. In older children the blood is inti mately blended with the urine, and the mixture may have a deep red colour if the haemorrhage be copious. The urine is acid, deposits albumen on boiling, and often crystals of 'uric acid can be discovered with the abun dant blood-corpuscles under the microscope.
A little girl, aged four years, the ninth child of healthy parents, was admitted into the East London Children's Hospital. No history of gout could be discovered in the family. Of the other children, four had died, one from whooping-cough, the others of brain disease, nature unknown. The patient herself had always been a healthy child, with the exception of an attack of varicella in infancy, until twelve months before admission. At that time the mother had begun to notice that the child's water con tained blood. At first this had only occurred about once a week ; but the frequency of the haemorrhage had gradually increased, and durina the previous fortnight blood had been passed every day. The morning urine, passed after the night's rest, had, however, been always uncoloured until a week before admission ; since that time the passage of blood had been continuous.