How is Cystinuria diagnosed?

Cystinuria is a genetic disorder characterized by the presence of high levels of the amino acid cystine in the urine. It is caused by mutations in the genes responsible for the transport of cystine in the kidneys and intestines. Diagnosis of cystinuria is crucial for appropriate management and treatment of the condition.

Medical History: The diagnostic process typically begins with a thorough medical history review. The healthcare provider will inquire about symptoms, family history of kidney stones or cystinuria, and any previous episodes of kidney stones.

Physical Examination: A physical examination may be conducted to check for signs of kidney stones or other related complications. The healthcare provider may palpate the abdomen to identify any tenderness or masses.

Urinalysis: Urinalysis is an essential diagnostic test for cystinuria. A 24-hour urine collection is often performed to measure the levels of cystine and other substances in the urine. Elevated levels of cystine indicate the presence of cystinuria.

Stone Analysis: If a person has passed a kidney stone, the stone can be analyzed to determine its composition. Cystine stones are typically yellow or brown and have a characteristic hexagonal shape. Identifying cystine stones confirms the diagnosis of cystinuria.

Genetic Testing: Genetic testing is the most definitive method to diagnose cystinuria. It involves analyzing the genes responsible for cystine transport. Genetic testing can identify specific mutations that cause cystinuria and help determine the inheritance pattern.

Imaging Studies: Imaging studies such as ultrasound, computed tomography (CT) scan, or magnetic resonance imaging (MRI) may be performed to assess the kidneys and urinary tract. These tests can help identify the presence of kidney stones, their size, and location.

It is important to consult with a healthcare professional for an accurate diagnosis of cystinuria. Early detection and diagnosis allow for appropriate management strategies to prevent complications and reduce the risk of recurrent kidney stones.