Fanconi syndrome is an uncommon renal disorder that affects the way minerals and nutrients are processed by the kidneys. The proximal tubules in the kidneys normally facilitate the absorption of nutrients into the bloodstream, including amino acids, phosphates, glucose, and potassium. In the case of Fanconi syndrome, such compounds are not sufficiently metabolized and instead are expelled from the body in urine. Several different symptoms and health problems can develop, such as fatigue, dehydration, and bone thinning. Most patients respond well to treatment in the form of a carefully planned diet and daily medication use, though some people need to receive kidney transplants to avoid life-threatening complications.
There are many potential causes of Fanconi syndrome. When the disorder affects infants and young children, it is usually due to an inherited genetic abnormality. People of any age may acquire the disease if they have an underlying cancer or blood disorder that affects blood protein production, such as multiple myeloma or amyloidosis. Certain chemotherapy drugs and HIV medications have also been correlated with the onset of kidney damage and Fanconi syndrome. In addition, heavy metal poisoning can lead to kidney dysfunction in some patients if they are not immediately treated.
Symptoms of Fanconi syndrome in infants often include failure to thrive, irritability, chronic fatigue, and poor appetite. A lack of phosphates and other minerals vital to bone growth may cause deformities in the legs and arms, weakness, and little or no muscle tone. Adults who acquire the disease are highly prone to stress fractures, as their bones become thin and brittle. Excessive urination is a key finding in all age groups and may lead to additional physical symptoms related to dehydration.
Doctors diagnose Fanconi syndrome by carefully reviewing patient histories and performing a series of tests. Blood and urine samples are evaluated in hospital laboratories to check for unusual levels of phosphates, calcium, and other minerals. Toxicity screenings are useful in confirming or ruling out heavy metal poisoning as a potential cause. Ultrasounds are often taken as well, to determine if the renal tubules are deformed, blocked, or injured.
Treatment decisions are made based on the severity of symptoms and the underlying causes. Patients may need to be hospitalized to receive intravenous fluids and medications if they show signs of dehydration or heavy metal poisoning. Medications are available to enhance bone strength and boost the blood's supply of nutrients lost in the urine. Doctors may also suggest certain nutritional supplements, foods, and exercises that promote bone and muscle health in both children and adult patients. If the condition fails to improve despite medical care, patients may be placed on dialysis machines and scheduled for kidney transplants.
