Chi Yuen Cheung

Monoclonal gammopathies (MG) represent a group of haematological conditions resulting from excessive monoclonal immunoglobulin (MIg) production by abnormal clonal proliferation of plasma cells or B cells. The diseases can range from malignant conditions such as multiple myeloma and B-cell lymphoproliferative disorders to non-malignant monoclonal gammopathy of undetermined significance. The term monoclonal gammopathy of renal significance (MGRS) was introduced to describe kidney damage in the absence of myeloma-defining events or other haematological malignancies. The clones in MGRS are usually small and low-grade but can cause kidney damage due to the nephrotoxic MIg. There is a wide spectrum of kidney injury caused by the MG with MIgs causing nephrotoxicity either via direct deposition onto various parts of the kidney or indirect mechanisms through the autoantibody activity or dysregulation of the complement alternative pathway. The diagnosis of MIg-associated kidney diseases remains challenging due to its complexity and heterogeneity. Prognosis depends on accurate diagnosis of both kidney lesions and the underlying haematological diseases with early initiation of treatment. Clone-directed therapy has now become the cornerstone for the management of this disorder. Various therapeutic agents including proteasome inhibitors, monoclonal antibodies, immunomodulatory drugs, chimeric antigen receptor T-cells and Bruton tyrosine kinase inhibitors have been used to manage patients with MG and kidney diseases. Further clinical research and close collaboration between nephrologists, pathologists and haematologists can help to improve the prognosis of these patients.

Extreme anaemia (haemoglobin <2g/dL) is rarely encountered, and the clinical manifestation of this entity remains unclear. A woman in her 60s who enjoyed good past health presented with a two-week history of generalized malaise and then a sudden onset of convulsive seizure. Blood tests revealed haemoglobin of 1.7g/dL with acute kidney injury and elevated liver enzymes and creatine kinase. She was subsequently diagnosed with myelodysplastic syndrome with erythroid hypoplasia. After receiving a supportive blood transfusion, she had significant improvement in both clinical and biochemical parameters. Our case illustrates that extreme anaemia can present with seizure and multiple organ dysfunction secondary to tissue ischaemia.

Liposarcoma (LPS) typically occurs in the extremities and retroperitoneum, but rarely occurs in visceral organs such as pancreas. Only few cases of primary pancreatic LPS have been reported in literature. Here we describe the first case of primary pancreatic LPS in a patient receiving continuous ambulatory peritoneal dialysis (CAPD). This patient was a 60-year-old female who had been on CAPD for 3 years due to kidney failure from type 2 diabetes mellitus. She presented with a 2-week history of intermittent fever measuring up to 38 degrees Celsius. The septic workup including peripheral blood, peritoneal dialysis (PD) fluid, urine, and sputum cultures were all negative. Intravenous piperacillin/tazobactam was empirically started but there was persistent fever with increasing blood leukocytosis (blood white cell count up to 37.5×10 ⁹ /L). In addition, she developed cloudy peritoneal dialysate, suggestive of PD peritonitis, 2 weeks into the hospitalization. Piperacillin/tazobactam was then switched to intravenous meropenem and intraperitoneal vancomycin. Computerized tomography scan of the abdomen showed a large heterogeneous enhancing mass with central hypoattenuating area arising from the pancreatic tail. There were also local invasion and multiple metastatic lesions. Ultrasound-guided fine-needle biopsy of the abdominal mass confirmed the diagnosis of primary dedifferentiated LPS of the pancreas. In view of the advanced nature of the disease, she was treated with palliative chemotherapy. Her clinical condition deteriorated progressively and she passed away from pneumonia 10 months after the diagnosis of LPS. Our case shows that patients on CAPD with pancreatic LPS can develop symptoms mimicking infectious peritonitis and also highlights the importance of considering malignancies in the differential diagnosis of fever and unexplained leukocytosis after ruling out infective causes.

We report a rare case of lead poisoning after taking a dietary supplement which was bought online. A woman in her 60s presented with symptomatic anaemia and hepatitis for 2 weeks. Bone marrow examination showed sideroblastic anaemia and subsequent blood tests confirmed lead poisoning. She was successfully treated with a course of the chelating agent succimer. Further history and investigations showed that she had taken a Garcinia cambogia (GC)-based multi-ingredients dietary supplement in the form of capsules for weight reduction and that the lead content within the capsules was very high. Our case illustrates that hepatotoxicity can be associated with the use of dietary supplements. Moreover, blood lead levels should be checked when there is associated sideroblastic anaemia.

Thrombotic microangiopathy (TMA) represents a diverse group of conditions characterized by the presence of microangiopathic hemolytic anemia (MAHA), thrombocytopenia, and ischemic end-organ injury. Thrombotic thrombocytopenic purpura (TTP) is an important cause of TMA requiring urgent identification and therapeutic plasma exchange (TPE). Cancer-related TMA is commonly misdiagnosed as TTP. In contrast to TTP, there is no clear evidence supporting the routine use of TPE in TMA associated with cancers. However, there are some case reports showing that TPE may also be useful in TMA not associated with TTP, such as cancer-related TMA. In fact, there are different postulated pathophysiology leading to this disease entity. Here, we present a rare case of TMA and acute kidney injury (AKI) secondary to metastatic pancreatic carcinoma who had a resolution of bleeding symptoms with complete hematological and renal recovery after four sessions of daily TPE. The patient finally died of cancer six months later. Our case shows that TPE could be valuable in cancer-related TMA in particular patients, especially those with clinical bleeding and thrombosis. The ability of TPE to remove abnormal components in the complement pathway and potential endothelial-damaging agents or autoantibodies and replace them with normal ones may explain its usefulness in some patients with cancer-related TMA.

Cryptococcosis is the third most common invasive fungal infection in solid-organ transplant (SOT) recipients after candidiasis and aspergillosis. These patients are at risk of disseminated cryptococcosis because of immuosuppressive therapy. The median time to disease onset after kidney transplantation is approximately 35 months and it rarely occurs more than 10 years after transplantation. Herein, we report a case of 64-year-old kidney transplant recipient suffering from coexisting disseminated cryptococcosis with brain and skin involvement, together with cytomegalovirus (CMV) antigenemia more than 20 years after transplant. She presented with frontal headache and bilateral hand tremor, in addition to multiple nodular lesions over bilateral lower limbs. The diagnosis was made after lumbar puncture and skin biopsy. She was successfully treated with a course of anti-fungal and anti-CMV regimen without any relapse of central nervous system infection. Our case illustrates that disseminated cryptococcosis can occur very late after organ transplant. It is thus important to watch out for late-onset opportunistic infections and strike the balance between risks of infections and rejections in SOT patients.

Waldenstrom macroglobulinaemia (WM), the predominant subtype of lymphoplasmacytic lymphoma with bone marrow involvement and serum IgM paraprotein, is a haematological condition commonly associated with renal parenchymal involvement. However, antineutrophil cytoplasmic antibody (ANCA)‐negative pauci‐immune crescentic glomerulonephritis (PICGN) in kidney infiltrated by lymphoma is very rare, with only two cases described in chronic lymphocytic leukaemia in English literature so far. We herein report the first patient with WM developing ANCA‐negative PICGN. He was a 76‐year‐old male who presented with elevated serum globulin level and bilateral groin lymph node enlargement, subsequently diagnosed to have WM after pathologic examination of the bone marrow and groin lymph node. One month later, he was found to have acute kidney injury and proteinuria. Renal biopsy confirmed the presence of parenchymal involvement by WM accompanied by PICGN; while ANCA testing was negative. He was treated with pulse methylprednisolone followed by oral prednisolone. In addition, six courses of intravenous rituximab and oral cyclophosphamide were given. There was significant improvement in both his renal and haematological conditions. The clinical course of this case suggested that ANCA‐negative PICGN may represent a paraneoplastic syndrome and a rare manifestation of WM‐associated renal lesion. Early kidney biopsy and prompt treatment may improve the outcome of patients.