NDT Advance Access originally published online on October 1, 2007
Nephrology Dialysis Transplantation 2008 23(1):401-403; doi:10.1093/ndt/gfm627
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Enlarged kidneys and acute renal failure—why is a renal biopsy necessary for diagnosis and treatment?
1Renal Medicine and Transplantation, 2Department of Histopathology and 3Department of Radiology, St. Georges Hospital, London, UK
Correspondence and offprint requests to: Ramaswamy Diwakar, Renal Medicine and Transplantation, Knightsbridge Wing, St. George's Hospital, Blackshaw Road, Tooting, London, SW17 0QT. Tel: +0044-777-614-7118; Fax: +0044-208-725-2068; E-mail: Ramaswamy.diwakar{at}gmail.com
Keywords: enlarged kidneys; E. coli; nalahoplahia; urinary tract infection
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A 50-year-old Caucasian woman with a history of alcoholic liver disease presented with vomiting, oliguria and renal impairment.
She had been drinking heavily till up to 1 week before admission and had one episode of short-lasting witnessed generalized tonic clonic seizure 6 days before admission. She had 2 days of diarrhoea that had settled 6 days prior to admission. Since then she had been feeling generally unwell with nausea, vomiting and reduced urine volume. On examination, at presentation, she was apyrexial with a blood pressure of 131/92 mmHg, pulse rate of 102 per minute, clinically volume deplete and icteric with spider naevi.
The blood test results at presentation are shown in Table 1. Examination of the urine revealed blood (+++), protein (trace), WBC (+++) and nitrite (negative). The urine sodium was 26 mmol/L and fractional excretion of sodium was 2.8%. The abdominal ultrasound scan revealed the kidneys to be enlarged (15 cm bilaterally) with thickened cortex but of normal echogenicity (Figure 1). The liver was diffusely heterogeneous in echotexture and enlarged. Urine culture grew Escherichia coli. She was commenced on intravenous crystalloids and cefotaxime.
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Her past history included an episode of acute renal failure and sepsis secondary to an E. coli urinary infection 2 years prior to presentation. This had, however, recovered completely. At that stage her kidneys measured 13 cm on ultrasound examination.
Her renal function improved and on Day 4 post admission her creatinine was 300 µmol/L. The CRP had improved to 138 mg/L by Day 7 and her antibiotic was changed to oral ciprofloxacin and continued for a further 48 h. Her liver function improved and by Day 8 her bilirubin was 37 µmol/L. However, the improvement in renal function was not sustained and her creatinine increased to 420 µmol/L on Day 11. Further investigations revealed positive C-anti neutrophils cytoplasmic antibody with low proteinase-3 titre of 4.4 U/mL (normal range: 0–2). Rheumatoid factor was 91 IU/mL (normal range: 0–20). The complements C3 and C4 were within normal range. Serum protein electrophoresis revealed polyclonally raised IgG and IgA. Urinary Bence Jones Protein was negative. A renal biopsy was performed.
Question
What is the most likely explanation for the persistent renal failure?
Answer to the quiz
The renal architecture was completely disrupted by an infiltrate of macrophages with abundant eosinophilic cytoplasm (Von Hansemann cells) (Figure 2A). These cells contained numerous Von Kossa positive inclusion bodies (Michaelis–Gutmann bodies, arrows) (Figure 2B). The findings were in keeping with renal malakoplakia. Only scanty residual intact tubules and glomeruli were present. Occasional neutrophilic casts and foci of neutrophilic tubulitis were present.
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Comment
Malakoplakia of the urinary tract was first described in 1903. Renal malakoplakia, though, rare has been known for some time now. It is associated with urinary infection in the majority of cases predominantly E. Coli [1]. Renal failure is common at presentation [1]. The severity of renal failure is variable with some reports of end-stage renal disease requiring renal replacement therapy [2]. However, as this case and those of others [3, 4] suggests, good renal recovery is possible in spite of advanced renal failure at presentation.
The association between malakoplakia and immunosup- pression is also described. In our case, chronic alcohol intake and chronic liver disease might have contributed to the development of malakoplakia. The appearance of the kidneys with malakoplakia on renal imaging at various stages includes diffuse enlargement (unilateral [5] or bilateral), nodular lesions (unifocal or multifocal), abscess formation with perinephric spread and atrophic multinodular kidney. Hence, malakoplakia should be considered in the differential diagnosis in patients with focal nodular lesions in the kidney so as to avoid unnecessary nephrectomies [6]. The pathogenesis of malakoplakia is thought to be reduced intracellular cGMP levels in monocytes resulting in impaired lysosomal bactericidal activity [7]. Hence, bethanecol and ascorbic acid (both known to increase intracellular cGMP levels) have been used in the treatment of malakoplakia in addition to long-term antibiotics particularly fluoroquinolones.
In the above patient, ciprofloxacin was restarted and continued for 8 weeks with improvement of serum creatinine to 150 µmol/L. Most cases of acute renal failure do not require a biopsy to make the diagnosis. The aetiology is usually apparent after a detailed history and thorough clinical examination. However, in the above situation, a firm diagnosis was not possible without a renal biopsy.
In conclusion, the learning points in this case are (i) malakoplakia should be considered in patients with renal failure, urinary infection and enlarged kidneys. (ii) Even though the diagnosis of malakoplakia can be suspected in patients with acute renal failure, urinary tract infection and enlarged kidneys, confirmation of the diagnosis will require renal biopsy. (iii) In patients with malakoplakia renal function recovery may be delayed and prolonged treatment with antibiotics may be required before improvement is noticed.
Conflict of interest statement. None declared.
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See http://www.oxfordjournals.org/our_journals/ndtplus/
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- Hegde S, Coulthard MG. End stage renal disease due to bilateral renal malakoplakia. Arch Dis Child (2004) 89:78–79.
[Abstract/Free Full Text] - Lehmann E, Fries J, Schulze-Lohoff E, et al. A rare case of birenal malacoplakia with renal failure. Dtsch Med Wochenschr (2005) 130:799–802.[CrossRef][Medline]
- Tam VK, Kung WH, Li R, et al. Renal parenchymal malacoplakia: a rare cause of ARF with a review of recent literature. Am J Kidney Dis (2003) 41:E13–E17.[CrossRef][Medline]
- McKeen SK, Tie ML. Renal parenchymal malakoplakia: an unusual cause of unilateral, diffuse renal enlargement. Australas Radiol (2002) 46:69–72.[CrossRef][Medline]
- Burdese M, Repetto L, Lasaponara F, et al. The deceiving image: asymptomatic renal malakoplakia in a patient with chronic renal failure. Nephrol Dial Transplant (2003) 18:1675–1676.
[Free Full Text] - Abdou NI, NaPombejara C, Sagawa A, et al. Malakoplakia: evidence for monocyte lysosomal abnormality correctable by cholinergic agonist in vitro and in vivo. N Engl J Med (1977) 297:1413–1419.[Abstract]
Accepted in revised form: 18. 8.07
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