Potassium wasting nephropathy in the setting of tizanidine overdose: a case report.

BACKGROUND: Hypokalemia has been rarely attributed to tizanidine, although the precise mechanism is unclear. Severe hypokalemia is a well-established cause of abnormalities involving cardiac conduction. Given this agent's well-known cardiac arrhythmogenic potential, awareness of potential concomitant electrolyte abnormalities is important. CASE PRESENTATION: Electrolyte disorders, including hypokalemia, are rare complications of the antispasmodic medicine tizanidine when taken in doses as outlined by the manufacturer's prescribing instructions. Although cases of severe hypokalemia have also been described in the literature in association with this agent, such reports are few. We report a Caucasian case of an intentional overdose involving a very large ingestion of tizanidine. In addition to the characteristic abnormalities on the electrocardiogram, our patient developed electrolyte derangements as well as self-limited acute kidney injury. These biochemical abnormalities included profound hypokalemia that was refractory to aggressive replacement over the ensuing several days, before eventually dissipating. A thorough assessment of the etiology of this hypokalemia was consistent with a defect in renal potassium handling. CONCLUSION: In our patient with intentional tizanidine overdose, severe and refractory hypokalemia appears to have been due to a transient potassium wasting nephropathy.

Role of sodium thiosulfate therapy in the treatment of digital necrosis due to Mönckeberg sclerosis.

Accelerated vascular calcification is a well-described complication of chronic kidney disease often affecting large and small vessels alike through a variety of mechanisms. Accordingly, dysregulation of calcium and phosphate balance, vitamin D metabolism, hyperparathyroidism, and endothelial injury can lead to both macrovascular and microvascular complications. We describe a 56-year-old Hispanic male with a history of end-stage renal disease, diabetes mellitus type 2, and medical noncompliance who developed sequential digital ischemia and necrosis involving both hands as well as right foot as a result of Mönckeberg sclerosis. An extensive metabolic and serologic workup was unrevealing but radiographic studies and histopathology revealed the diagnosis. A multifaceted approach was instituted including wound debridement and amputations along with intensive medical support. In addition to improving hypertensive control and striving for improved calcium and phosphate balance, sodium thiosulfate solution was administered for more than 1 year. This aggressive approach allowed his wounds to heal and has arrested further digital ischemia from occurring.

Simultaneous double hemodialysis for the control of refractory hyperammonemia.

INTRODUCTION: In adults, hyperammonemia is generally associated with hepatic dysfunction or as a complication of urinary diversions when infected or obstructed. Hyperammonemia has also rarely been reported in association with multiple myeloma. With modest elevations, hyperammonemia often leads to encephalopathy. However, when ammonia reaches extreme levels cerebral edema and herniation may occur leading to coma, seizures, or death. CASE: We describe a 72-year-old Caucasian male with a history of end-stage renal disease (ESRD) and multiple myeloma who developed profound encephalopathy and eventual obtundation. He was found to have severe hyperammonemia that was not due to any identified hepatic impairment. His hyperammonemia proved to be refractory to medical therapy with cathartics and antibiotics, prolonged high-flux hemodialysis, and even continuous venovenous hemodialysis (CVVHD). This metabolic derangement as well as encephalopathy was eventually reversed with simultaneous CVVHD and extended daily hemodialysis (EDD). A more durable response was achieved after vincristine and dexamethasone were administered, which allowed the patient to resume his previous intermittent hemodialysis (IHD) schedule. The patient regained his full sensorium and was eventually discharged to home. CONCLUSIONS: Simultaneous double hemodialysis may be used as an important adjunct in treating refractory hyperammonemia.

Calciphylaxis presenting in early chronic kidney disease with mixed hyperparathyroidism.

Calciphylaxis is a disabling and life-threatening complication that primarily affects patients who are dialysis dependent. Reports have grown in the literature of cases occurring in those who have advanced chronic kidney disease (pre-end-stage renal disease) or in the setting of transplantation. There are also a few reports of cases occurring in those without any form of chronic kidney disease but with primary hyperparathyroidism. This disease entity is characterized by calcification, intimal hypertrophy, and thrombosis of small vessels that result in necrotizing, nonhealing ulcers - many of which are life threatening. Although several strategies aimed at treating and preventing this affliction have been reported in the literature, the outcome for most patients with calciphylaxis remains quite poor. We describe a patient with comparatively early stage-3 chronic kidney disease who developed calciphylaxis in the setting of both primary and secondary hyperparathyroidism. Predictably, after subtotal parathyroidectomy, her wounds did not completely heal and her biochemical markers of hyperparathyroidism did not completely normalize until her underlying secondary hyperparathyroidism was treated medically. It was only after initiating cinacalcet that the patient experienced complete wound healing and resolution of her calciphylaxis. It also supports other authors' findings that cinacalcet may be an important adjunct in the treatment of calciphylaxis.

Cause for inadequate clearance: hemodialysis catheter migration into the coronary sinus.

Complications associated with central dialysis catheters prove to be an important source of morbidity that challenge patients and clinicians alike. While thrombosis, stenosis, and infection remain the most common threats to functioning central dialysis catheters, malposition of such devices may similarly result in serious consequences. Despite advanced techniques used to confirm initial catheter placement, the very nature of these catheters entails frequent manipulation for vascular access and therefore they may migrate after repeated use. When compared with the loss of patency and infection, complications involving malposition or migration may present in a more insidious fashion, such as a gradual decline in achievable blood flow rate or observed clearance over time. We describe a patient who acutely developed both clinical and biochemical evidence of inadequate clearance after several months of suboptimal catheter function. When the central dialysis catheter was examined fluoroscopically, it was found to have migrated into the coronary sinus.

Serum sickness-like reaction associated with cefazolin.

BACKGROUND: Although rare, serum sickness-like reactions have been documented to occur following the administration of many antibiotics. Cefazolin, a first generation cephalosporin, is a commonly prescribed antibiotic which is considered to be generally safe and well tolerated. There have been no prior reports linking this drug with sickness-like reactions. We report a probable case of serum sickness-like reaction following a single dose of cefazolin. CASE PRESENTATION: A 23 year old man with no significant past medical history was admitted to undergo a laparoscopic donor nephrectomy as part of a living-related renal transplant. One gram of intravenous cefazolin was administered perioperatively. The surgery was completed without complication and the remainder of his hospital course was uneventful. Ten days following discharge the patient developed fevers, painful and swollen joints, and a cutaneous eruption overlying his trunk and extremities. There was no evidence of systemic vasculitis. These clinical findings were most consistent with a serum sickness-like reaction. A brief course of corticosteroids and antihistaminergic therapy was initiated, and complete resolution of the patient's symptoms followed. The Naranjo probability scale indicated that this adverse drug event was probable. CONCLUSION: Serum sickness-like reaction may be associated with cefazolin therapy.

Long-term intravenous sodium thiosulfate in the treatment of a patient with calciphylaxis.

Calciphylaxis is a disabling and life-threatening complication that primarily affects patients who are dialysis dependent. This disease entity is characterized by calcification, intimal hypertrophy, and thrombosis of small vessels, which results in necrotizing, nonhealing ulcers. The development of these lesions portends a grim prognosis, as they are often accompanied by severe and sometimes fatal infectious complications. Although several strategies aimed at treating and preventing this affliction have been reported in the literature, the outcome for most patients with calciphylaxis remains quite poor. We describe an anuric hemodialysis patient who developed severe calciphylaxis that proved refractory to conventional treatment. Following extensive debridement of several wounds, intravenous sodium thiosulfate was utilized as an adjunctive therapy four times a week. Within 6 months, excellent wound healing ensued as well as a dramatic improvement in the lesions that were not previously resected. Aside from occasional nausea, these treatments were well tolerated, despite the development of an anion gap metabolic acidosis. After 34 months of continued treatment the patient remains free from disease recurrence and has demonstrated no untoward effect of prolonged therapy. In an effort to delineate the pharmacokinetics of this drug in a hemodialysis patient, serum thiosulfate levels were obtained 15 minutes after infusion as well as before and after subsequent dialysis treatments. Consistent with prior studies in anuric canines, we found measurable quantities of the drug more than 50 hours after treatment, in addition to a markedly elevated half life of 478 minutes. However, given the lack of significant toxicity, as well as a dramatic clinical improvement, we feel that sodium thiosulfate may have an important adjunctive role in the treatment of calciphylaxis in dialysis patients.

Reversal of citalopram-induced junctional bradycardia with intravenous sodium bicarbonate.

The cardiotoxicity of tricyclic antidepressants is a well-described phenomenon requiring serious consideration in patients who have taken an overdose. In patients who are at high risk for suicide attempts, selective serotonin reuptake inhibitors (SSRIs) were thought to constitute a safe alternative. However, evidence is accumulating that they, too, possess proarrhythmic properties, which must be reconciled in the setting of an overdose. An 82-year-old woman intentionally ingested citalopram 1.6 g. Several hours after presentation, she developed sinus arrest and junctional bradycardia that resolved after infusion of intravenous sodium bicarbonate solution. Thereafter, she demonstrated no further electrocardiographic abnormalities and was safely transferred to the psychiatry service without the need for a temporary transvenous pacemaker. The dramatic effect of the sodium bicarbonate on the arrhythmia represents a probable event according to the Naranjo probability scale. Intravenous sodium bicarbonate may serve as an effective antidote to SSRI-induced bradyarrhythmias.