Renal tubular acidosis due to Wilson's disease presenting as metabolic bone disease

Unusual presentation of Wilson's disease as proximal renal tubular acidosis with isolated phosphaturia

An adolescent girl presented with recurrent lower limb fractures and was managed as osteogenesis imperfecta. Low phosphate levels noted on routine investigation were the clue for the phosphaturia and subsequent diagnosis of proximal renal tubular acidosis (RTA). Further, with a history of jaundice, she was diagnosed with Wilson's disease, which was the underlying cause of proximal RTA with isolated phosphaturia and consequent fractures. Standard treatment for Wilson's disease along with supplementation of oral phosphate and bicarbonate led to complete recovery of fragile bones.

Osteochondral lesions in Wilson's disease: case report and literature review

Background

Wilson's disease (WD) is a rare genetic disorder characterized by copper accumulation in the body, leading to a spectrum of health issues, such as liver disease, neurological disturbances, and psychiatric disorders. In recent years, there has been increasing recognition that WD can also result in osteoarticular defects. Research has shed light on the potential of WD to cause these findings, which in some instances, can progress to osteoarthritis and persistent pain. However, the exact pathophysiological process through which WD leads to osteochondral defects remains unclear.

Case Description

We present a case of a 30-year-old male diagnosed with WD exhibiting musculoskeletal symptoms. The patient's medical history revealed chronic intermittent knee pain. Radiographic and magnetic resonance imaging (MRI) studies revealed a substantial osteochondral lesion with high-grade chondral fissuring. This report reviews the proposed pathophysiology of orthopedic pathology in WD, offers an updated literature review, and provides clinical recommendations for management. Treatment options including nonsurgical options and surgery are discussed.

Conclusions

This case underscores the significance of identifying the orthopedic manifestations of WD, even in the absence of classic signs and symptoms. Any WD patient suspected of having osteoarticular defects should be thoroughly evaluated, with a low threshold for initiating imaging studies. Moreover, treatment plans should be tailored to the patient's specific presentation, emphasizing the importance of individualized patient care. This case highlights key findings in WD and provides important insights, particularly on the clinical relevance of osteoarticular defects in WD, the potential application of nonsurgical and surgical treatments, and the importance of individualized patient care in the management of WD.

Clinical profile of adult and pediatric patients with hepatic Wilson's disease

BACKGROUND

The clinical profile varies in patients with Wilson's disease (WD). There is paucity of data regarding adult and pediatric patients with hepatic WD.

METHODS

As many as 140 consecutive patients diagnosed with hepatic WD between December 2006 and January 2021 were included in the study. Data was collected regarding the demographic parameters, clinical presentation, extrahepatic organ involvement, liver histology and laboratory investigations. Adult and children (0-14 years) with hepatic WD were compared regarding these features.

RESULT

Eighty-eight adults and 52 children were included in the study. The median age of presentation was 17 years (range: 1.1-42 years). Male preponderance was seen (adult 68/88, 69%; children 40/52, 77%). Adults as compared to children presented more commonly as cirrhosis (52/88 vs. 15/52, p = 0.0005) and with hepatic decompensation (35/88 vs. 9/52, p = 0.005). Presentation with acute-on-chronic liver failure (ACLF) was more common in children (10/52 vs. 2/88, p = 0.0005). Twenty-eight-day mortality was 50% (5/10) in children and none in adults presenting with ACLF. Nazer's Prognostic Index (≥ 7) and New Wilson Index were more accurate in predicting mortality among children with ACLF with AUROC 1, while AARC (APASL ACLF Research Consortium) was less accurate with AUROC 0.45. Liver histology findings were similar in adults and children. Extrahepatic involvement was also similar. (8/88 in adults vs. 3/52 children, p value 0.48).

CONCLUSION

Most patients with WD present as cirrhosis in adulthood. ACLF is more common in children. Nazer's prognostic index and new Wilson Index score are accurate in predicting mortality in children with ACLF.

Renal Cell Carcinoma and Hepatocellular Carcinoma in a Patient with Wilson's Disease

No reports of renal cancer in patients with Wilson's disease (WD) exist. We herein report a 37-year-old Japanese man diagnosed with WD who had been treated with d-penicillamine 9 years prior. Hepatocellular carcinoma had been diagnosed at 36 years old and treated with radiofrequency ablation therapy. One year later, renal cancer and recurrent hepatocellular carcinoma had developed. The hepatocellular carcinoma was treated after renal cancer surgical resection of a clear-cell-type renal cell carcinoma, with iron, rather than copper, deposited on the renal cancer cells. This patient harbored a novel mutation, p. Leu1395Terfs in ATP7B.

Distal renal tubular acidosis as presenting manifestation of Wilson disease in a 11-year-old girl

A 11-year-old girl was referred to the pediatric nephrology services of our hospital for evaluation of vitamin-D-refractory rickets. She was born to second-degree consanguineous parents. On examination, she had wrist widening and bilateral genu varum. She had normal anion gap metabolic acidosis, hypokalemia, and hyperchloremia. The fractional excretion of bicarbonate was 3% and the urine anion gap was positive. She also had hypercalciuria, but no phosphaturia, glucosuria or aminoaciduria. In view of a family history of an elder sister having rigidity with cognitive and speech impairment, an ophthalmic evaluation by slit lamp examination was performed in the index case that revealed bilateral Kayser-Fleischer rings. Serum ceruloplasmin was low and 24-h urine copper was elevated in the index case. Whole exome sequencing unveiled a novel pathogenic variant in exon 2 of the ATP7B gene (chr13: c.470del; Depth: 142x) (homozygous) that resulted in a frameshift and premature truncation of the protein, 15 amino acids downstream to codon 157 (p. Cys157LeufsTer15; NM_000053.4) confirming Wilson disease. There were no mutations in the ATP6V0A4, ATP6V1B1, SLC4A1, FOXI1, WDR72 genes or other genes that are known to cause distal RTA. Therapy with D-penicillamine and zinc supplements was initiated. A low dose of 2.5 mEq/kg/day of potassium citrate supplementation normalized the serum bicarbonate levels. This case was notable for the absence of hepatic or neurological involvement at admission. Wilson disease is well known to cause proximal renal tubular acidosis and Fanconi syndrome, with relatively lesser involvement of the distal renal tubules in the literature. However, isolated distal renal tubular involvement as presenting manifestation of Wilson disease (without hepatic or neurological involvement) is rare and can lead to diagnostic confusion.

Stunting and wasting in neurological Wilson disease: Role of copper, zinc, and insulin-like growth factor-I

OBJECTIVES

Copper (Cu) and zinc (Zn) are important trace elements for the growth and development of children. In Wilson disease (WD), impaired Cu metabolism may affect growth. This study was conducted to evaluate the height and weight of children with neurological WD and correlate these with serum Cu, Zn, and insulin-like growth factor-I (IGF-I).

METHODS

This prospective cohort study was conducted in a tertiary care teaching institute. Children with neurologic WD were included. The height, weight, and body-mass index of each child were measured and categorized according to the revised national growth chart. Serum Cu, Zn, calcium, alkaline phosphatase, albumin, thyroid-stimulating hormone, and urinary-Cu were measured. Serum IGF-1 was measured by enzyme-linked immunosorbent assay. The relationship between height and weight with trace elements and IGF was analyzed using parametric or non-parametric tests.

RESULTS

There were 52 children (5-18 years) with neurologic WD. Thirty-six (69.2%) children had normal height, 12 (23.1%) were tall, and 4 (7.7%) were stunted. Forty-six (88.5%) children had normal weight and six (11.5%) children were underweight. IGF-1 correlated with height, weight, duration of treatment, and serum Zn level. About 15.4% of children had stunting and/or wasting, which was associated with low levels of serum IGF-I, Zn, and calcium.

CONCLUSIONS

Stunting and/or wasting occurs in 15.4% of children with neurologic WD and is associated with reduced serum IGF-I, Zn, and calcium concentration. Adjunctive Zn and calcium treatment may help in achieving normal growth.

Challenges and dilemmas in pediatric hepatic Wilson's disease

Wilson disease is an autosomal recessive disorder affecting the ATP7B gene located on chromosome 13q. This leads to copper deposition in various organs, most importantly in the liver and brain. The genetic mutations are vast, well reported in the West but poorly documented in developing countries. Hence the diagnosis is made with a constellation of clinico-laboratory parameters which have significant overlap with other liver diseases and often pose a significant dilemma for clinicians. Diagnostic scoring systems are not fool-proof. The availability and affordability of chelators in developing countries impact the drug compliance of patients. While D-penicillamine is a potent drug, its side effects lead to drug discontinuation. Trientine is cost-prohibitive in developing countries. There is no single test to assess the adequacy of chelation. Exchangeable urinary copper is an essential upcoming diagnostic and prognostic tool. In the presence of cirrhosis, hypersplenism clouds the assessment of myelosuppression of drugs. Similarly, it may be difficult to distinguish disease tubulopathy from drug-induced glomerulonephritis. Neurological worsening due to chelators may appear similar to disease progression. Presentation as fulminant hepatic failure requires rapid workup. There is a limited window of opportunity to salvage these patients with the help of plasmapheresis and other liver-assisted devices. This review addresses the challenges and clinical dilemmas faced at beside in developing countries.

Metabolic bone disease heralding the diagnosis of Wilson's disease

We report a short-statured, young man in his 20s presenting with bilateral cataract, recurrent kidney stones, history of refractory rickets and bone deformity. He had been consuming calcium and vitamin D supplements and had been operated for cataract and renal stone disease, prior to reporting in our clinic without any significant laboratory or clinical improvement. The patient was diagnosed as having Fanconi's syndrome attributable to Wilson's disease. This patient highlights that in case of resistant rickets, a high index of suspicion must be invoked for Wilson's disease. Timely recognition of this entity results in prompt ministrations and prevention of disability.

Movement Disorders and Renal Diseases

Movement disorders often emerge from the interplay of complex pathophysiological processes involving the kidneys and the nervous system. Tremor, myoclonus, ataxia, chorea, and parkinsonism can occur in the context of renal dysfunction (azotemia and electrolyte abnormalities) or they can be part of complications of its management (dialysis and renal transplantation). On the other hand, myoglobinuria from rhabdomyolysis in status dystonicus and certain drugs used in the management of movement disorders can cause nephrotoxicity. Distinct from these well-recognized associations, it is important to appreciate that there are several inherited and acquired disorders in which movement abnormalities do not occur as a consequence of renal dysfunction or vice versa but are manifestations of common pathophysiological processes affecting the nervous system and the kidneys. These disorders are the emphasis of this review. Increasing awareness of these conditions among neurologists may help them to identify renal involvement earlier, take timely intervention by anticipating complications and focus on therapies targeting common mechanisms in addition to symptomatic management of movement disorders. Recognition of renal impairment in a patient with complex neurological presentation may narrow down the differentials and aid in reaching a definite diagnosis.

Renal Tubular Function, Bone Health and Body Composition in Wilson's Disease: A Cross-Sectional Study from India

There is limited literature from India with regard to the prevalence and magnitude of renal tubular and bone manifestations in Wilson's disease (WD). Thus, we studied the prevalence of renal tubular acidosis among Indian patients with WD and also evaluated bone health and body composition in them. It was a cross-sectional study conducted at a south Indian tertiary care center. Twenty-five consecutive patients with WD aged more than 12 years attending the hepatology and neurology departments and 50 age, sex and BMI-matched controls were recruited. After clinical assessment, they underwent biochemical testing to assess renal tubular dysfunction. Bone mineral density (BMD) and body composition were assessed using a dual energy X-ray absorptiometry (DXA) scanner. Fifty-six percent (14/25) of patients with WD had renal tubular acidosis (RTA). Of them, 24% were diagnosed to have distal RTA. RTA was more common in hepatic WD patients who had prolonged duration of illness. Patients with WD had significantly lower BMD as compared to control subjects (p < 0.05). Low BMI, low IGF-1 and a shorter duration of therapy were key determinants of low bone mass in them (p < 0.05). Patients with WD had significantly more body fat (p = 0.01) and lower lean muscle mass (p = 0.03) when compared to age, sex and BMI-matched controls. In conclusion, renal tubular acidosis was common in patients with Wilson's disease. These patients had a lower bone mineral density, higher body fat percentage and lower lean muscle mass as compared to controls.

Other organ involvement and clinical aspects of Wilson disease

Wilson disease (WD) is a rare disorder of copper metabolism that presents mainly with hepatic and neuropsychiatric features. Copper accumulates not only in the liver and brain, but also in other organs. Liver injury can also be the cause of secondary impairment of other tissues. Therefore, the clinical manifestation of WD may be renal, cardiac, skin, osteoarticular, or endocrinologic and include other organ disturbances. Renal abnormalities include tubular dysfunction (e.g., renal tubular acidosis, aminoaciduria) and nephrolithiasis. Bone demineralization is a common manifestation in patients with WD. Cardiac injury may include arrhythmia, cardiomyopathy, and autonomic dysfunction. Different endocrine system manifestations, such as infertility or repeated miscarriages, growth and puberty disturbances, and hypoparathyroidism, are observed. Other important clinical aspects of WD include pancreas involvement, immunologic abnormalities, the presence of lipomas, and skin changes. Although other organ involvement is not common in WD and usually not severe, delayed diagnosis may lead to irreversible changes in organs and tissues. Therefore, awareness of other possible WD presentations is important in the differential diagnosis of WD.

Wilson's disease - A rare cause of renal tubular acidosis with metabolic bone disease

We report a 16-year-old boy who presented with weakness of lower limbs. He was diagnosed to have Wilson's disease, renal tubular acidosis and osteoporosis. Screening of siblings showed that his younger sister was also affected by the disease.

Pathological fractures as an initial presentation of Wilson's disease

Wilson's disease (WD) has varied phenotypic presentations. Here we report the case of a 16-year-old boy who presented with a history of multiple pathological fractures, severe joint deformities, hepatic dysfunction, cognitive decline and limb dystonia. On examination, the patient had pinched out facies, pallor and leukonychia totalis. Bilateral Kayser Fleischer (KF) ring was present. Musculoskeletal examination revealed pectus carinatum, bilateral genu valgus and gun-stock deformity of the left elbow joint. Splenomegaly and moderate ascites were present. Neurological examination revealed mild rigidity and intermittent episodes of dystonic posturing of all four limbs. On this basis a diagnosis of WD with dystonia with cirrhosis of liver with portal hypertension with renal tubular acidosis with renal rickets was thought likely. Investigations confirmed the diagnosis. The patient was started on treatment but he did not improve. He suffered aspiration pneumonia during his hospital stay and succumbed to the illness.