COVID-19 effects on the kidney.

Apart from pulmonary disease, acute kidney injury (AKI) is one of the most frequent and most severe organ complications in severe coronavirus disease 2019 (COVID-19). The SARS-CoV­2 virus has been detected in renal tissue. Patients with chronic kidney disease (CKD) before and on dialysis and specifically renal transplant patients represent a particularly vulnerable population. The increasing number of COVID-19 infected patients with renal involvement led to an evolving interest in the analysis of its pathophysiology, morphology and modes of virus detection in the kidney. Meanwhile, there are ample data from several autopsy and kidney biopsy studies that differ in the quantity of cases as well as in their quality. While the detection of SARS-CoV­2 RNA in the kidney leads to reproducible results, the use of electron microscopy for visualisation of the virus is difficult and currently critically discussed due to various artefacts. The exact contribution of indirect or direct effects on the kidney in COVID-19 are not yet known and are currently the focus of intensive research.

[Subacute kidney injury in a 40-year-old female Northern African patient]. / Subakutes Nierenversagen bei einer 40-jährigen nordafrikanischen Patientin.

A 40-year old woman from Eritrea was admitted due to worsening renal function of unknown origin. The basic nephrologic workup provided no further information. Renal biopsy was performed and revealed acute interstitial nephritis (AIN) while no offending medication could be identified. Further investigations showed a recurrence of the urogenitary tuberculosis that had already been in 2015. The finding of AIN in the absence of a typical medical history should raise suspicion of infection-related forms or AIN associated with systemic diseases.

[COVID-19 effects on the kidney]. / COVID-19-Auswirkungen auf die Niere.

Apart from pulmonary disease, acute kidney injury (AKI) is one of the most frequent and most severe organ complications in severe coronavirus disease 2019 (COVID-19). The SARS-CoV­2 virus has been detected in renal tissue. Patients with chronic kidney disease (CKD) before and on dialysis and specifically renal transplant patients represent a particularly vulnerable population. The increasing number of COVID-19 infected patients with renal involvement led to an evolving interest in the analysis of its pathophysiology, morphology and modes of virus detection in the kidney. Meanwhile, there are ample data from several autopsy and kidney biopsy studies that differ in the quantity of cases as well as in their quality. While the detection of SARS-CoV­2 RNA in the kidney leads to reproducible results, the use of electron microscopy for visualisation of the virus is difficult and currently critically discussed due to various artefacts. The exact contribution of indirect or direct effects on the kidney in COVID-19 are not yet known and are currently the focus of intensive research.

[COVID-19 and kidney involvement]. / COVID-19 und Nierenbefall: Pathologie.

Apart from the pulmonary disease, acute kidney injury is one of the most frequent and most severe organ complications in severe coronavirus disease 2019 (COVID-19). Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) could also be detected in renal tissue. Patients with chronic kidney disease and on dialysis as well as kidney transplantation patients represent a particularly vulnerable population. The increasing number of patients infected with SARS-CoV­2 has aroused increased interest in the exact pathophysiology and morphology of kidney damage as well as the direct detection of the virus in the kidneys, which in contrast to the lungs is overall more difficult to perform. Meanwhile, data from several large autopsy and kidney biopsy studies are now available. While the detection of SARS-CoV­2 RNA in tissue leads to consistently reproducible results, the use of electron microscopy for visualization of the virus is critically discussed due to various artefacts. The exact and direct effects of SARS-CoV­2 on the kidneys are not yet known in detail and are currently the focus of intensive research.

[Lupus nephritis]. / Lupusnephritis.

Lupus nephritis (LN) is a common major organ manifestation of systemic lupus erythematosus (SLE) and causes significantly increased morbidity and mortality. Thus, all patients with SLE should be regularly screened for LN. While new onset glomerular hematuria or proteinuria are suggestive for LN, a kidney biopsy is the gold standard for diagnosis and classification. The treatment of LN comprises strict blood pressure control and administration of hydroxychloroquine. Aggressive forms of LN require additional treatment with immunosuppressive induction therapy followed by a maintenance phase for several years. Given the high rate of disease recurrence, life-long follow-up control in specialized centers is necessary. Despite optimal care a significant proportion of patients still develop chronic kidney failure. Better disease activity markers as well as more potent and specific therapeutic agents are thus urgently needed.

[Acute renal failure in a 75-year-old woman with a high-output ileostoma]. / Akutes Nierenversagen bei einer 75-jährigen Patientin mit High-output-Ileostoma.

We report on a 75-year old woman who presented with acute oliguric renal failure. The kidney biopsy revealed calcium oxalate depositions in the tubular lumen, caused by an overload of intravenous ascorbic acid (cumulative dose of 240 g). Due to a lack of specific therapeutic interventions, the patient remained dialysis-dependent. Iatrogenic causes of kidney failure play an important role in the pathogenesis of kidney diseases and should always be considered in patients with acute renal failure. Detailed evaluation of the patient history is often suggestive, while renal biopsy can establish the diagnosis.

Rapidly progressive hepatic alveolar echinococcosis in an ABO-incompatible renal transplant recipient.

We report on the case of an ABO-incompatible renal re-transplant recipient maintained on an intensified immunosuppressive regimen for recurrent cellular rejection episodes and transplant glomerulopathy who presented with rapidly growing hepatic tumors, radiologically suggestive of hemangiosarcoma. Upon resection and pathological work-up, the lesions revealed alveolar echinococcosis, a rare but potentially life-threatening parasitosis. Usually infection with Echinococcus multilocularis remains asymptomatic for extended periods of time and can go unrecognized for years. In the case presented, we observed an atypically rapid growth pattern of E. multilocularis that might have been due to the extent of the immunosuppressive regimen, which included repetitive anti-CD20 treatments. Retrospectively performed serological studies with enzyme-linked immunosorbent assays known to provide high sensitivity and specificity for the detection of echinococcosis in the general population, yielded ambiguous results in our immunocompromised host, which could be, in part, explained by B-cell depletion and its effects on antibody production and indirect actions on cellular immunity. In conclusion, this is the first report to our knowledge of hepatic alveolar echinococcosis in a renal transplant recipient. This case documents an altered clinical course of the parasitosis and the challenge of serological diagnostic tools under an intensified regimen of immunosuppressive agents, including rituximab.

[Preoperative staging of rectal cancer]. / Präoperatives Staging des Rektumkarzinoms.

Accurate preoperative staging of rectal cancer is crucial for therapeutic decision making, as local tumor extent, nodal status, and patterns of metastatic spread are directly associated with different treatment strategies. Recently, treatment approaches have been widely standardized according to large studies and consensus guidelines. Introduced by Heald, total mesorectal excision (TME) is widely accepted as the surgical procedure of choice to remove the rectum together with its enveloping tissues and the mesorectal fascia. Neoadjuvant radiochemotherapy also plays a key role in the treatment of locally advanced stages, while the use of new drugs will lead to a further improvement in oncological outcome. Visualization of the circumferential resection margin is the hallmark of any preoperative imaging and a prerequisite for high-quality TME surgery. The aim of this article is to present an overview on current cross-sectional imaging with emphasis on magnetic resonance imaging. Future perspectives in rectal cancer imaging are addressed.

Histopathological classification of nonneoplastic and neoplastic gastrointestinal submucosal lesions.

This article provides an overview of the histopathologically defined nonneoplastic and neoplastic entities involved in submucosal lesions (SMLs) of the gastrointestinal tract, particularly those in the upper gastrointestinal tract. The gross appearance and the histomorphological and cytomorphological features of the most frequent SMLs are described, including gastrointestinal stromal tumor (GIST), leiomyoma, lipoma, carcinoid, granular-cell tumor, glomus tumor, schwannoma, submucosal metastases, Brunner's gland hamartoma, pancreatic rests, and cysts. The current state of important technical aspects of biopsy processing and the role of histology and cytology in the diagnosis of SMLs are discussed.