A most often asymptomatic, sporadically occurring
disorder resulting in cystic dilatation of the collecting tubules of the
kidneys. Complications include urinary tract infections, hematuria,
nephrocalcinosis, and, rarely, renal dysfunction.
Medullary Sponge Kidney (MSK); Precaliceal Canalicular
Ectasia; Ricci-Cacchi Syndrome.
Described in 1948 and named after R. Cacchi, an Italian
urologist, and V. Ricci, an Italian radiologist.
Up to one in 200 urograms may show signs of Cacchi-Ricci
syndrome (CRS). The actual incidence in the general population is not
exactly known (because it may be asymptomatic), but the estimated incidence
ranges from 1:5000-10,000. CRS has been found in 13% of 800 patients
with calcium urolithiasis, with a higher frequency in women (19%) than in
men (12%). However, in most series, men are more frequently affected than women,
but morbidity seems to be higher in females. No racial predilection has been
Most cases are sporadic, although a few
familial cases have been described.
The exact pathophysiology is unknown. However,
most researchers consider CRS to be a developmental defect affecting the
formation of the collecting tubules, whereas others consider it a primary
progressive degeneration of the collecting tubules manifesting later on in
life. The kidney size is usually normal or slightly enlarged.
Histopathologic examination reveals cystic dilatation of the distal
collecting tubules. Proximally, these cysts often communicate with the
collecting tubules, while distally they are connected to the papillary ducts
or the renal calyx. The cysts often contain calculi.
Made on radiologic findings (sonography, plain
radiography, intravenous urography, computed tomography scanning) and/or
confirmed by histopathology (renal biopsy). Nephrocalcinosis is a common
finding and often is the symptom that results in discovery of the disease
(abdominal radiographs taken during evaluation of urinary tract infections
or abdominal pain). Most patients remain asymptomatic throughout their life,
but a minority of patients develop symptoms (typically in the second or
third decade of life) that often are related to complications such as
infection, hematuria, and nephrocalcinosis rather than to the CRS itself.
The disease process may affect only one medullary pyramid in one or both
kidneys or involve several medullary pyramids diffusely in both kidneys.
Common features are pain (38%), ureteral
colics (28%), polyuria (28%), urinary tract infections, or hematuria.
Often it is an incidental finding during evaluation of the abdomen or the
urinary tract for other reasons. In the absence of complications, the
overall renal function is and remains normal. Other features can include
hypercalciuria (common), hyperuricosuria, urolithiasis, acidification of the
urine, or impairment of urinary concentration. If renal involvement is
segmental, surgical resection may be beneficial. A higher incidence of Wilms
tumor and other abdominal malignancies has been reported in patients
diagnosed with CRS during childhood. Regular followup in this population is
Assess renal function and evaluate
for recurrent urinary tract infections and hematuria. In the absence of
complications, CRS does not require therapy. However, the progression of ...