[Cystinuria and cystine kidney lithiasis. Diagnosis and therapeutic approach]

OBJECTIVE

Cystine renal stone is the only clinical consequence of cystinuria, an autosomal recessive hereditary disease that affects an average of 1 out of 7,000 newborns, and whose geographical distribution varies significantly. The diagnosis and treatment of this condition is reviewed in the light of the advances in genetics and molecular biology.

METHODS

The evolution of current knowledge about this disease is reviewed.

RESULTS/CONCLUSIONS

The advances over the last 8 years have led to the characterization, at the present time, of two genes responsible for this disease, which demonstrates its polygenic origin. By phenotype, cystinuria can be classified into two types: type 1 and non-type 1. Both types show genetic and biochemical, but not clinical differences. From the therapeutic viewpoint, the main objective is to eliminate existing calculi and, above all, prevent recurrence by acting on the pathophysiologic mechanisms of renal cystine. Experience shows that despite the correct use of our current therapeutic armamentarium and the application of the general guidelines discussed in this paper, some cystinuric patients still maintain an important stone-forming activity. Patient clinical evaluation and a genetic study of both patient and family will be decisive for phenotyping.

Preliminary data of a prospective study on neuropsychiatric side effects after initiation of efavirenz

OBJECTIVE

To assess baseline variables able to predict neuropsychiatric side effects (NPSEs) associated with the initiation of an efavirenz (EFV)-containing regimen in HIV-1-infected patients.

DESIGN

Open-label, prospective, observational study.

METHODS

Consecutive HIV-1-infected outpatients in whom EFV was prescribed underwent a psychiatric interview. At baseline and at 2, 4, and 12 weeks, patients completed the Symptoms Check List-90-Revised (SCL-90-R), the Medical Outcome Study for HIV-positive patients (MOS-HIV), and a standardized questionnaire concerning potential NPSEs.

RESULTS

Preliminary data showed that discontinuation of EFV because of NPSEs occurred in 4 of 31 patients (13%). Patients who completed the follow-up showed a decrease in SCL-90-R total score (p =.004) and in several subscales such as Interpersonal Sensitivity (p =.009), Depression (p =.001), and Anxiety (p =.040), whereas no changes in MOS-HIV were observed. Having fewer years of education (p =.006), having fewer baseline central nervous symptoms (p =.000), reporting better baseline physical status (p =.013), and having higher baseline scores in the Heath Transition subscale of the MOS-HIV (p =.000) and in the Somatization subscale of the SCL-90-R (p =.002) were associated with more NPSEs.

CONCLUSION

Patients maintained on EFV showed a decrease in psychologic distress related to self-image, depression, and anxiety, without any effect on quality of life. Patients with a lower level of education, those who feel physically and psychologically better at baseline than in the past, and those who suffer from more distress as a result of physical complaints may be at greater risk of reporting more NPSEs after EFV initiation.

[2,8 dihydroxyadenine(2,8 DHA) lithiasis. Report of 3 cases]

Presentation of three cases of 2,8 dihydroxyadenine calculi. This is an infrequent but potentially serious form of lithiasis, of purinic origin, caused by a genetic abnormality (deficit of adenine phosphoribosyltransferase, APRT) affecting both sexes. Frequent confusion of this form with uric lithiasis forces to try the use of IR spectrum or X-ray diffraction. Long-term follow-up of these patients and treatment with allopurinol, avoiding alkalinizating agents, is essential.

Randomized double-blind study of potassium citrate in idiopathic hypocitraturic calcium nephrolithiasis

In an attempt to document the efficacy of potassium citrate in stone formation, 57 patients with active lithiasis (2 or more stones during the preceding 2 years) and hypocitraturia were randomly allocated into 2 groups, with 1 group taking 30 to 60 mEq. potassium citrate daily in wax matrix tablet formation and the other group receiving placebo. In 18 patients receiving potassium citrate for 3 years stone formation significantly declined after treatment from 1.2 +/- 0.6 to 0.1 +/- 0.2 per patient year (p < 0.0001), in 13 patients (72%) the disease was in remission and all patients showed a reduced stone formation rate individually. In contrast, 20 patients taking placebo medication for 3 years showed no significant change in stone formation rate (1.1 +/- 0.4 to 1.1 +/- 0.3 per patient year) and in only 4 patients (20%) was the disease in remission. The stone formation rate during potassium citrate treatment was significantly lower than during the placebo treatment (0.1 +/- 0.2 versus 1.1 +/- 0.3 per patient year, p < 0.001). Potassium citrate therapy caused a significant increase in urinary citrate, pH and potassium, whereas placebo did not. Adverse reactions to potassium citrate were mild causing only 2 patients in the potassium citrate group and 1 in the placebo group to withdraw from the study. In summary, our randomized trial showed the efficacy of potassium citrate in preventing new stone formation in idiopathic hypocitraturic calcium nephrolithiasis.

Renogastric fistula

During the study of chronic anemia in a 38-year-old woman, a nonfunctioning left kidney due to multiple asymptomatic ureteral calculi was found on excretory urography. She had self-limited episodes of left flank pain 10 years previously. Antegrade pyelography through the nephrostomy tube and computerized tomography showed a pyonephrotic renogastric fistula on that side.

[Pyeloduodenal fistula, secondary to lithiasic pyonephrosis]

Report on one patient presenting pyelo-duodenal fistula secondary to pyonephrosis by an obstructive calculus in lumbar ureter, treated conservatively with percutaneous nephrostomy.

[Treatment of lithiasis during pregnancy]

We report on 10 pregnant women with renal calculi who presented with fever and recurrent renal colic. They were treated with analgesics and fluids. Antibiotics were administered to those with fever and/or positive urine culture. Seven were submitted to endoscopic maneuvers. A flute tipped (Couvelaire) catheter was placed in 4 and a double-J in 3 patients.