Fanconi Syndrome, A Simple Guide To The Condition, Diagnosis, Treatment And Related Conditions

Fanconi syndrome is a medical disorder of the tubes of the kidney in which some substances normally re-absorbed into the bloodstream by the kidneys are excreted into the urine instead. Fanconi syndrome indicates the generalized poor function of the kidney's proximal tubules, not the other nephron segmentsFanconi syndrome results in:1. Aminoaciduria, 2. Glycosuria, 3. Phosphaturia, 4. Renal tubular acidosis (RTA) type 2 (proximal), 5.
Hypophosphatemic rickets (children) or osteomalacia (adults), 6. Renal glycosuriaIt may be inherited or acquired:Inherited1. Primary idiopathic:a. Sporadic or familial (autosomal dominant - chromosome 15). This occurs in the absence of any identifiable reason, and most cases are sporadic. Some cases are genetic, but the mode of inheritance appears to be variable (autosomal-dominant, autosomal-recessive, X-linked).2.
Secondary:a. Cystinosis, tyrosinaemia, b. Wilson's disease, c. Lowe's syndrome (oculo-cerebro-renal syndrome: bilateral congenital cataracts, glaucoma, general hypotonia, hyporeflexia, severe learning disability and Fanconi syndrome), d. Galactosemia, e. Fructose intolerance, f. Glycogen storage disorders andg. Mitochondrial cytopathies. Acquired1. Intrinsic renal disease:a. Acute tubular necrosis, b.
Interstitial nephritis, c. Hypokalemic nephropathy, d. Myeloma, e. Amyloidosis, f. Sjogren's syndrome, g. Rejected transplant.2. Hyperparathyroidism.3. Drugs - e.g., cisplatin, ifosfamide, sodium valproate, tenofovir, aminoglycoside antibiotics and deferasirox4. Toxins:a. Glue sniffing, b. Heavy metals, c. Bee stingsCausesFanconi syndrome can be caused by faulty genes or it may occur later in life due to kidney damage.
Fanconi syndrome is caused by many predominantly rare causes. The most frequent causes of Fanconi syndrome in children are genetic defects that entail the body's capability to break down some substances such as:1. Cystine (cystinosis)2. Fructose (fructose intolerance)3. Galactose (galactosemia)4. Glycogen (glycogen storage disease)Other causes in children are:1. Exposure to heavy metals such as lead, mercury, or cadmium2.
Lowe syndrome, 3. Wilson diseaseIn adults, Fanconi syndrome can be caused by a range of things that damage the kidneys, such as:1. Certain medicines, such as azathioprine, cidofovir, gentamicin, and tetracycline2. Kidney transplant3. Light chain deposition disease4. Multiple myeloma5. Primary amyloidosisSymptoms1. Polyuria, polydipsia, dehydration2. Bone deformitiesDiagnosisThe diagnosis is based on too much loss of substances in the urine (e.g., amino acids, glucose, phosphate, bicarbonate) in the absence of high plasma concentrationsFurther tests are needed to identify the cause.1.
Proteinuria: normally, only in small amounts.2. Hypo-kalemia, hypo-phosphatemia and hyper-chloremic metabolic acidosisFurther tests and a physical examination may show signs of:1. Dehydration due to excess urination2. Growth failure3. Osteomalacia4. Rickets5. Type 2 renal tubular acidosisTreatmentTreatment mainly comprises of the replacement of substances lost in the urine and specific treatment for the underlying cause.
Treatments of the underlying cause are:1. Alkali and potassium for RTA (renal tubular acidosis), phosphate and calcitriol for phosphate wasting.2. Dehydration due to polyuria3. Metabolic acidosis due to the loss of bicarbonate4. Thiazide diuretic: may be essential to prevent volume expansion5. Correction of metabolic acidosis6. Phosphate and vitamin D supplementationRenal losses of glucose, amino acids, and uric acid are not normally symptomatic and do not need replacement....