Lead nephropathy chronic

Renal Effects. The characteristics of early or acute lead-induced nephropathy in humans include nuclear inclusion bodies, mitochondrial changes, and cytomegaly of the proximal tubular epithelial cells dysfunction of the proximal tubules (Fanconi s syndrome) manifested as aminoaciduria, glucosuria, and phosphaturia with hypophosphatemia and increased sodium and decreased uric acid excretion. These effects appear to be reversible. Characteristics of chronic lead nephropathy include progressive interstitial fibrosis, dilation of tubules and atrophy or hyperplasia of the tubular epithelial cells, and few or no nuclear inclusion bodies, reduction in glomerular filtration rate, and azotemia. These effects are irreversible. The acute form is reported in lead-intoxicated children, whose primary exposure is via the oral route, and sometimes in lead workers. The chronic form is reported mainly in lead workers, whose primary exposure is via inhalation. Animal studies provide evidence of nephropathy similar to that which occurs in humans, particularly the acute form (see Section 2.2.3.2). 

The lead-induced nephropathy observed in humans and rodents shows a comparable early pathology (Goyer 1993). However, in rodents, proximal tubular cell injury induced by lead can progress to adenocarcinomas of the kidney (see Section 2.2.3.8). The observation of lead-induced kidney tumors in rats may not be relevant to humans. Conclusive evidence for lead-induced renal cancers (or any other type of cancer) in humans is lacking, even in populations in which chronic lead nephropathy is evident. 

Lilis R. 1981. Long-term occupational lead exposure, chronic nephropathy, and renal cancer A case report. Am J Ind Med 2 293-297. 

Chronic high-dose lead exposure, usually associated with months to years of blood lead concentrations in excess of 80 g/dL, may result in renal interstitial fibrosis and nephrosclerosis. Lead nephropathy may have a latency period of years. Lead may alter uric acid excretion by the kidney, resulting in recurrent bouts of gouty arthritis ("saturnine gout"). Acute high-dose lead exposure sometimes produces transient azotemia, possibly as a consequence of intrarenal vasoconstriction. 

The clinical circumstances that lead to chronic "analgesic abuse" nephropathy [111] are quite distinct to the rare occurrence of acute papillary necrosis associated with exposure of fhe patient to a single NSAID and often with only a short period of drug exposure. In these acute circumstances, the patient will typically present clinically with gross hematuria and may have flank pain suggestive of ureteric obstruction consequent to the passage of a sloughed papilla. 

Chronic lead nephropathy from moonshine came to medical attention because of the dramatic symptoms of acute lead poisoning. Lead colic and anemia were... 

Chronic lead nephropathy in moonshiners, more often than not, is accompanied by gout and hypertension, in accord with 19 century descriptions of plumbism and reports from Austraha [1]. A statistically significant odds ratio of 2.4 has been reported for moonshine consumption and end-stage renal disease, suggesting a causal association with lead in fhe absence of symptomatic lead poisoning [31]. 

Renal biopsies in chronic lead nephropathy show nonspecific tubular atrophy and interstitial fibrosis with minimal inflammatory response as well as mitochondrial swelling, loss of cristae, and increased lysosomal dense bodies within proximal tubule cells [4,18]. (Figure 1)... 

Figure 1. Tubular atrophy and interstitial fibrosis in a case of chronic lead nephropathy.

The functional changes in chronic lead nephropathy appear to be less specific than those observed in acute poisoning. As in other forms of interstitial nephritis, proteinuria and glycosuria are initially absent. In contrast to cadmium nephropathy, the excretion of a large array of urinary marker proteins such as retinal binding protein, lysozyme, and iriicroglobulin [33, 34] is not increased in the absence of a reduced GFR. 

The increase in urinary N-acetyl- -D-glucosamini-dase (NAG) with increasing blood lead concentrations reflects the proximal tubule dysfunction seen in acute lead nephropathy rather than the chronic interstitial nephritis associated with occupational lead exposure [35, 36]. NAG excretion correlates positively with the blood lead concentration but not with the bone lead concentration [37]. Eicosanoid excretion in lead workers is similar to that in patients with essential... 

Lead-induced hyperuricemia may contribute to chronic lead nephropathy. Uric acid per se induces endothelial cell injury, renal microvascular disease, and hypertension, at least in part mediated by oxidative stress [38]. Independent of uric acid, reactive oxygen species induced by lead have been imphcated in endothelial cell injury, increased vascular reactivity, and the production of hypertension in humans and experimental animals [39]. 

Lead nephropathy is important because it is one of the few renal diseases that is preventable. Moreover, lead-induced acute renal dysfunction can sometimes be reversed by chelation therapy [19, 28, 63]. The salutary effect of chelation therapy appears to be on the acute reduction in GFR and the acute elevation of blood pressure associated with elevated blood lead concentration rather than on the long-term effects of cumulative exposure associated with endothelial dysfunction, hypertension, and interstitial nephritis. There is no evidence that such therapy reverses established interstitial nephritis. The partial remission achieved among moonshiners and lead workers appears to represent reversal of the physiologic effects of acute poisoning superimposed on chronic lead nephropathy. No improvement in renal function has been observed once advanced interstitial nephritis is present and the steady-state serum creatinine concentration exceeds about 3 mg/ dL [64]. 

Emmerson BT. Chronic lead nephropathy. The diagnostic use of calcium EDTA and the association with gout. Aust Med J 1963 12 310-324. 

Chronic exposure to low levels of lead results in lead accumulation within the body. Workers who have been chronically exposed to lead develop interstitial fibrosis, vascular and glomerular sclerosis, and tubular atrophy and/or hypertrophy. Although acute lead nephropathy is reversible with chelator therapy and/or removal from exposure, chronic effects may be irreversible. In addition, chronic exposure to lead may result in a gouty nephropathy as lead reduces uric acid excretion and elevates blood uric acid levels. 

Acute exposure to unleaded gasoline and a variety of light hydrocarbons present in gasoline produces a nephropathy in male rats characterized by (1) an excessive accumulation of protein (hyaline droplets) in epithelial cells of proximal tubule, (2) accumulation of casts at the corticomedullary junction, and (3) evidence of mild tubular regeneration. This nephropathy only occurs in male rats female rats and mice do not show any renal pathology. A number of chemicals present in unleaded petrol when tested alone have been shown to produce nephropathy and, in particular 2,2,4-trimethylpentane and decalin have been used as model compounds. Certain other industrial chemicals (1,4-dichlorobenzene and isophorone), natural products (o-limonene), and pharmaceuticals (levamisole) also produce this male-rat-specific nephropathy. Chronic exposure of male rats to unleaded petrol, 1,4-dichlorobenzene, isophorone, or o-limonene ultimately leads to the induction of a low incidence of renal adenomas and carcinomas. 

Solvents have been implicated as inducers of glomerulonephritis [72], while the association between chronic interstitial nephritis and analgesic abuse is acknowledged [73] and the association between hypertensive renal disease (nephrosclerosis) and lead nephropathy continues to be explored [74, 75]. According... 

By the 1%0 s, the pattern of patients with chronic lead nephropathy had changed from being principally an adolescent condition (as in the 1930 s) so that most of the patients were in their 40 s. At that time, criteria for diagnosis were established which consisted of longstanding chronic renal disease which was only slowly... 

Of particular interest was the fact that the cohort surviving into the 1%0 s had developed a high prevalence of gouty arthritis in comparison with patients with chronic nephritis due to causes other than lead. There was also a disproportionate hyperuricemia in these patients with chronic lead nephropathy, which was caused by a significantly lower urate clearance for any particular degree of renal insufficiency [32]. Studies of discrete tubular functions suggest that this was due to excessive reabsorption of filtered urate [33]. 

There is also clear evidence that the sequel of lead inducing a chronic nephropathy with hypertension can occur. At times, this hypertension may be sufficiently severe to be malignant and may precipitate an early demise [22]. In more chronic cases, the hypertension may be of moderate degree and not be sufficient to cause progressive deterioration of renal function [43]. However, when confronted with a patient with hypertension and mild renal damage, it can be difficult to determine which came first and particularly difficult to determine whether lead was a contributor to the renal damage that caused the hypertension. In such cases, the hypertensive mechanism would be the same as those associated with other varieties of chronic renal disease. By contrast, many patients with chronic lead nephropathy have demonstrated suppressed plasma renin concentrations indicative of a hyporeninemic hypoaldosteronism [44]. 

Although chelation therapy effectively reverses acute lead nephropathy and the preclinical renal dysfunction of occupational lead nephropathy, there is no evidence that such therapy reverses established interstitial nephritis due to lead. The partial remissions achieved among moonshiners and symptomatic lead workers may represent reversal of acute poisoning superimposed on chronic lead nephropathy. No improvement in renal function can be expected once ad-... 

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