Jennifer A. Fillaus

Long-term effect of chronic intravenous and inhaled nephrotoxic antibiotic treatment on the renal function of patients with cystic fibrosis

Cystic fibrosis (CF) patients have numerous infectious exacerbations requiring prolonged antibiotic treatments, some of which are nephrotoxic. Inhaled antibiotics can reach detectable serum levels. We studied the impact of chronic nephrotoxic antibiotic exposure on kidney function in CF population. We collected data retrospectively for 113 adult CF patients followed for 8.5 years. Fifty‐seven (50.4%) were males and 56 (49.5%) females (mean age 31.7 years [SD 9.9]), of which 31% had diabetes and 9.7% had hypertension. Over 8.5 years follow up, there were no significant changes in blood urea nitrogen (BUN; P = 0.92) or creatinine (P = 0.2) in the whole group. 22% of patients had ≥1 episodes of acute kidney injury (AKI). The presence of AKI was associated with increased BUN (P = 0.002) and creatinine (P = 0.056) at the end of follow up. Use of intravenous colistin, gentamicin, tobramycin, or vancomycin did not correlate with increased BUN (P = 0.64; P = 0.49; P = 0.51; P = 0.47) or creatinine (P = 0.43; P = 0.49; P = 0.17; P = 0.2) after 8.5 years. Elevated tobramycin peak and trough levels did not correlate with increased BUN or creatinine. Inhaled colistin and gentamicin correlated with increased BUN (P = 0.009; P = 0.02) but not creatinine (P = 0.45; P = 0.46). Inhaled tobramycin did not correlate with increased BUN (P = 0.17) or creatinine (P = 0.58). Only inhaled colistin correlated with AKI episodes (P = 0.03). Chronic inhaled colistin and gentamicin are associated with an increase in BUN but not creatinine at the end of follow up. Inhaled colistin was associated with episodes of AKI. Well‐managed intravenous use of nephrotoxic antibiotics in CF population is associated with no major long‐term renal toxicity.

The effect of statin therapy on the formation of arteriovenous fistula stenoses and the rate of reoccurrence of previously treated stenoses.

Statins reduce inflammation in end‐stage renal disease patients and improve endothelial function beyond cholesterol lowering. Despite this, statins do not improve the maturation rate, primary patency rate, and the cumulative survival of arteriovenous fistulas (AVFs). It is unknown if statins decrease the number of stenoses developing in AVFs or prolong the intervals between angioplasties needed to treat recurring stenoses. We conducted a retrospective chart review of our 265 active dialysis patients. The statin group was significantly more likely to be diabetic (64% vs. 43.6%) and treated with aspirin (64% vs. 40%) when compared to those not treated with statins (P = 0.04 and 0.01). The mean time to first intervention (primary patency) was 16.5 months in statin users and 15.8 months in the nonstatin group (P = 0.49) with standard deviations of ±18.5 and 16.6 months, respectively. Statin use was not associated with a significant decrease in the number of stenoses diagnosed (P = 0.28). The mean time between recurrent stenoses’ angioplasties was 8.9 months in statin users and 7.3 months in the nonstatin patients (P = 0.25). Aspirin users were more likely to have a decreased primary patency (rate ratio = 1.65, P = 0.03) compared with nonaspirin users. Patients who were prescribed aspirin developed 1.6 (P 0.01) times more stenoses than those not treated with aspirin. We report for the first time that statin therapy does not decrease the number of stenotic lesions developing in the AVF or prolong the interval between procedures required to treat recurrent stenoses.

Endovascular treatment of arteriovenous graft pseudoaneurysms, indications, complications, and outcomes: A systematic review

There are limited data regarding endovascular treatment of arteriovenous graft (AVG) pseudoaneurysms using stent grafts. We performed a comprehensive literature review on the use of stent grafts in the treatment of AVG pseudoaneurysms. We included 10 studies (121 patients). The mean AVG age was 3.1 years (95% confidence interval [CI]: 2.2–4) and pseudoaneurysm mean diameter was 34 mm (95% CI: 23–46). The majority (71%) of the pseudoaneurysms were located on the arterial limb of the AVG and 77% presented with venous anastomosis stenosis requiring angioplasty. The mean number of stents used to treat one lesion was 1.4 (95% CI: 1.3–1.5). The technical success rate of pseudoaneurysm isolation was 100% in all studies and 100% of patients received hemodialysis using the AVG after pseudoaneurysm treatment without the need for catheter placement. The primary patency rates for 1, 3, and 6 months were 81%, 73%, and 24%. Secondary patency was 80%, 77%, and 74% at 1, 3, and 6 months. Arteriovenous graft thrombosis occurred in 12% of patients. Arteriovenous graft infection developed in 35% of cases. Arteriovenous graft pseudoaneurysm treatment using stent grafts is effective in managing even large pseudoaneurysms and has acceptable primary and secondary patency rates. Graft infection was a relatively frequent complication.

Type B Lactic Acidosis Associated With Multiple Myeloma

We present a 58-year-old man with recurrent multiple myeloma treated with 2 autologous stem cell transplantations. He was admitted for dyspnea and found to have severe type B lactic acidosis with serum lactate level of 193.6 mg/dL. This case reviews malignancy-associated type B lactic acidosis and discusses its etiology, pathogenesis, and management.

Recognition and Management of Resistant Hypertension

Despite improvements in hypertension awareness and treatment, 30%-60% of hypertensive patients do not achieve BP targets and subsequently remain at risk for target organ damage. This therapeutic gap is particularly important to nephrologists, who frequently encounter treatment-resistant hypertension in patients with CKD. Data are limited on how best to treat patients with CKD and resistant hypertension, because patients with CKD have historically been excluded from hypertension treatment trials. First, we propose a consistent definition of resistant hypertension as BP levels confirmed by both in-office and out-of-office measurements that exceed appropriate targets while the patient is receiving treatment with at least three antihypertensive medications, including a diuretic, at dosages optimized to provide maximum benefit in the absence of intolerable side effects. Second, we recommend that each patient undergo a standardized, stepwise evaluation to assess adherence to dietary and lifestyle modifications and antihypertensive medications to identify and reduce barriers and discontinue use of substances that may exacerbate hypertension. Patients in whom there is high clinical suspicion should be evaluated for potential secondary causes of hypertension. Evidence-based management of resistant hypertension is discussed with special considerations of the differences in approach to patients with and without CKD, including the specific roles of diuretics and mineralocorticoid receptor antagonists and the current place of emerging therapies, such as renal denervation and baroreceptor stimulation. We endorse use of such a systematic approach to improve recognition and care for this vulnerable patient group that is at high risk for future kidney and cardiovascular events.

How I Do It: Endovascular Treatment of Arteriovenous Graft Pseudoaneurysms—Watch Out for the Mouth

We present a case of arteriovenous graft pseudoaneurysms treated endovascularly with stent grafts and make suggestions regarding the technique of evaluating the pseudoaneurysms and choosing the proper location to deploy the stent grafts to maximize the outcomes and minimize the length of the graft covered by the stent. We also comment on the selection of lesions that are suitable to be treated with this technique.

Nocturnal Home Hemodialysis for a Patient With Type 1 Hyperoxaluria

Type 1 primary hyperoxaluria is a genetic disorder caused by deficiency of the liver-specific peroxisomal enzyme alanine-glyoxylate aminotransferase. This enzyme deficiency leads to excess oxalate production and deposition of calcium oxalate salts, resulting in kidney failure and systemic oxalosis. Aside from combined liver/kidney transplantation, no curative treatment exists. Various strategies for optimizing dialysis treatment have been evaluated, but neither conventional hemodialysis nor peritoneal dialysis can keep pace with oxalate production in this patient population. In this report, we describe a patient with end-stage renal disease from type 1 primary hyperoxaluria managed with nocturnal home hemodialysis. Performing hemodialysis 8-10 hours each night with blood flow of 350 mL/min and total dialysate volume of 60 L, she has maintained pre- and postdialysis serum oxalate levels at or below the level of supersaturation. We also review published literature regarding oxalate removal in various modalities of dialysis in patients with type 1 primary hyperoxaluria. In our patient, nocturnal hemodialysis has controlled serum oxalate levels better than conventional hemodialysis therapies. Home nocturnal hemodialysis should be considered an option for management of patients with end-stage renal disease from type 1 hyperoxaluria who are awaiting transplantation.

Takayasu arteritis presenting as new-onset hypertension.

A31-year-old woman was referred for evaluation of newonset hypertension. She presented to her primary care provider with a blood pressure of 160/120 mm Hg. She was taking nifedipine XL, and she was referred for further evaluation. She reported headaches, upper-extremity fatigue and pain, exertional dyspnea, and edema. Her arm pain was aggravated by repetitive motion. Physical examination revealed pulse rate of 80 beats/min, blood pressure in the right arm of 130/90 mm Hg, blood pressure in the left arm of 138/90 mm Hg, and body mass index of 40.83 kg/m. She had no bruits, normal heart sounds, and no edema; peripheral pulses were equal bilaterally. Complete blood count, comprehensive metabolic panel, and urinalysis were normal. Her serum aldosterone level was 64 ng/dL (reference range, 4Y31 ng/dL), and plasma renin activity was 4.5 ng/mL/h (reference, G3.3 ng/mL/h). Erythrocyte sedimentation rate was 56 mm/h (reference, 0Y20 mm/h), and C-reactive protein was 0.5 mg/dL (reference, G1.0 mg/dL). Tests were negative for antineutrophil cytoplasmic antibody, myeloperoxidase antibody, and serine protease 3 antibody. Serologies for hepatitis B, hepatitis C, and HIV were all negative. Her antinuclear antibody titer was positive at 1:320 in a homogeneous pattern. DNA double-stranded antibody immunoglobulin G and nuclear antigen panel (ENA) were negative. Because of new-onset hypertension and her symptoms, imaging studies were obtained. Computed tomography angiography of the abdomen (Fig. 1) and magnetic resonance angiography of the chest (Fig. 2A) are shown. A diagnosis of Takayasu arteritis was made based on American College of Rheumatology criteria. The patient is being treated with glucocorticoids and has had improvements in her symptoms of upper-extremity fatigue and dyspnea. Her hypertension remains controlled on nifedipine XL 60 mg daily.

Approach to the Patient with Renal Disease

A 35-year-old man presents with a 1-week history of progressive shortness of breath and an episode of hemoptysis earlier today. For the past 2 days he has had decreased urine volume and dark colored urine. He has no past medical history and takes no medications. Blood pressure is 145/85 mmHg. Pulse is 110 beats per minute. Temperature is 36.8 °C. Pulse oximetry is 87 % on room air. He is anxious and slightly pale. Pulmonary exam reveals bibasilar crackles. The remainder of his exam is unremarkable. His laboratory data is notable for a hemoglobin level of 10.9 g/dL and serum creatinine of 2.7 mg/dL. His chest X-ray shows bilateral pulmonary infiltrates.