Patents vs patients 1-0: The case of chenodeoxycholic acid.

Profit-driven games with the availability and prices of chenodeoxycholic acid led to the discontinuation of proper treatment for this cerebrotendinous xanthomatosis patient with disastrous consequences to his health.

Development and validation of diagnostic algorithms for the laboratory diagnosis of porphyrias.

Porphyrias are rare metabolic disorders of the haem synthesis. They can present with acute neurovisceral attacks, cutaneous symptoms, or a combination of both. As they present with a wide variety of clinical symptoms, diagnosis is often delayed and correct interpretation of porphyria-related tests remains a challenge for many physicians. We developed and validated two algorithms for the laboratory diagnosis of porphyrias based on presenting symptoms. Based on a literature search and clinical/laboratory expertise, we developed algorithms for acute and cutaneous porphyrias. We validated these algorithms using all porphyria related laboratory test requests between January 1st 2000 and September 30th 2020 in UZ Leuven. In addition, we also evaluated our algorithm using samples from the European porphyria network (EPNET) external quality assessment scheme (2010-2021). Sensitivity of the algorithm for acute porphyria was 100.0% [74.9%-100.0%] (13 acute intermittent porphyria (AIP) and 1 variegate porphyria [VP]) with a specificity of 98.5% [91.0%-100.0%] (65 patients). Sensitivity of the algorithm for cutaneous porphyria was 100% [95.1%-100.0%] (7 VP, 59 porphyria cutanea tarda (PCT), 23 erythropoietic protoporphyria (EPP), 2 X-linked erythropoietic protoporphyria [XLEPP]) with a specificity of 93.9% [82.9%-98.5%]. There were no diagnostic samples of other types of porphyria. The algorithms correctly identified 18 of the 19 EPNET porphyria cases. One of the two hereditary coproporphyria cases was missed. The algorithms for acute and cutaneous porphyria showed high sensitivity and specificity and can be used to aid the clinician in correctly interpreting the laboratory findings of porphyria-related tests.

Liver Transplantation for Acute Intermittent Porphyria.

Recurrent attacks of acute intermittent porphyria (AIP) result in poor quality of life and significant risks of morbidity and mortality. Liver transplantation (LT) offers a cure, but published data on outcomes after LT are limited. We assessed the pretransplant characteristics, complications, and outcomes for patients with AIP who received a transplant. Data were collected retrospectively from the European Liver Transplant Registry and from questionnaires sent to identified transplant and porphyria centers. We studied 38 patients who received transplants in 12 countries from 2002 to 2019. Median age at LT was 37 years (range, 18-58), and 34 (89%) of the patients were women. A total of 9 patients died during follow-up, and 2 patients were retransplanted. The 1-year and 5-year overall survival rates were 92% and 82%, which are comparable with other metabolic diseases transplanted during the same period. Advanced pretransplant neurological impairment was associated with increased mortality. The 5-year survival rate was 94% among 19 patients with moderate or no neuropathy at LT and 83% among 10 patients with severe neuropathy (P = 0.04). Pretransplant renal impairment was common. A total of 19 (51%) patients had a GFR < 60 mL/minute. Although few patients improved their renal function after LT, neurological impairments improved, and no worsening of neurological symptoms was recorded. No patient had AIP attacks after LT, except for a patient who received an auxiliary graft. LT is a curative treatment option for patients with recurrent attacks of AIP. Severe neuropathy and impaired renal function are common and increase the risk for poor outcomes. If other treatment options fail, an evaluation for LT should be performed early.

Facial nerve palsy in giant-cell arteritis: case-based review.

Acute peripheral facial nerve palsy is most frequently idiopathic (Bell's palsy) or virally induced, but can also be due to several other conditions. A rare cause is underlying systemic or autoimmune disease. A 79-year-old man presented with peripheral facial nerve palsy, malaise, and fever. Physical examination revealed tenderness of the left temporal artery and reduced pulsatility. 18F-FDG-PET/CT and biopsy of the temporal artery confirmed the diagnosis of giant cell arteritis (GCA). Prompt institution of corticosteroid therapy produced rapid decrease in inflammatory markers and gradual improvement of the facial nerve palsy. We searched the MEDLINE, Embase, and Scopus databases to identify previous reports of peripheral nerve palsy in GCA, other vasculitides, and autoimmune diseases. Facial nerve palsy as the presenting symptom of GCA has very rarely been reported. Although temporal artery biopsy is the gold standard for diagnosis, it may be negative in up to one-third of cases. In doubtful cases, imaging can help establish the diagnosis. Ultrasound, 3 T MRI, and 18F-FDG-PET/CT have all been previously reported to be useful. Peripheral facial nerve palsy may very rarely be the presenting symptom of GCA. Early correct diagnosis is essential for starting appropriate therapy. In patients with atypical features, 18F-FDG-PET/CT may be useful for establishing the diagnosis.

Hypophosphatasia in Adults: Clinical Spectrum and Its Association With Genetics and Metabolic Substrates.

BACKGROUND: Hypophosphatasia (HPP) is a rare metabolic bone disorder caused by mutations in the alkaline phosphatase (ALPL) gene, and characterized by low circulating alkaline phosphatase (ALP) levels and bone, muscle, dental and systemic manifestations. In this case series we investigate the clinical spectrum, genetic and biochemical profile of adult HPP patients from the University Hospitals Leuven, Belgium. METHODOLOGY: Adults with HPP were identified through medical record review. Inclusion criteria were: (1) age ≥ 16 yr; (2) consecutively low ALP levels not explained by secondary causes; (3) one or more of the following supporting criteria: biochemical evidence of elevated enzyme substrates; subtrochanteric fractures, metatarsal fractures or other typical clinical features; family history of HPP; a known or likely pathogenic ALPL mutation. RESULTS: Nineteen patients met our inclusion criteria (n = 2 infantile, n = 6 childhood, n = 10 adult-onset HPP and one asymptomatic carrier). Fractures and dental abnormalities were the most reported symptoms. Fatigue was reported in n = 7/19 patients (37%), three of which had previously been misdiagnosed as having chronic fatigue syndrome and/or fibromyalgia. Empirical pyridoxine therapy in four patients (without seizures) did not provide symptomatic relief. N = 7/19 patients (37%) were inappropriately treated or planned to be treated with antiresorptive treatment. Two patients developed atypical femoral fractures following exposure to bisphosphonates and/or denosumab. Patients detected by screening were less severely affected, while patients with homozygous or compound heterozygous mutations had the most severe symptoms, significantly lower circulating ALP levels (p = 0.013) and significantly higher pyridoxal-5'-phosphate (p = 0.0018) and urinary phosphoethanolamine (p = 0.0001) concentrations. CONCLUSIONS: Screening may detect mainly less severely affected individuals, which may nevertheless avoid misdiagnosis and inappropriate antiresorptive drug exposure. Patients with biallelic mutations had more severe symptoms, significantly lower ALP and higher substrate levels. Whether the latter finding has implications for the classification and treatment of HPP should be investigated further in larger cohorts.

Long-term follow-up in PMM2-CDG: are we ready to start treatment trials?

PURPOSE: PMM2-CDG is the most common congenital disorder of glycosylation (CDG), which presents with either a neurologic or multisystem phenotype. Little is known about the longitudinal evolution. METHODS: We performed data analysis on PMM2-CDG patients' clinical features according to the Nijmegen CDG severity score and laboratory data. Seventy-five patients (28 males) were followed up from 11.0 ± 6.91 years for an average of 7.4 ± 4.5 years. RESULTS: On a group level, there was no significant evolution in overall clinical severity. There was some improvement in mobility and communication, liver and endocrine function, and strabismus and eye movements. Educational achievement and thyroid function worsened in some patients. Overall, the current clinical function, the system-specific involvement, and the current clinical assessment remained unchanged. On follow-up there was improvement of biochemical variables with (near) normalization of activated partial thromboplastin time (aPTT), factor XI, protein C, antithrombin, thyroid stimulating hormone, and liver transaminases. CONCLUSION: PMM2-CDG patients show a spontaneous biochemical improvement and stable clinical course based on the Nijmegen CDG severity score. This information is crucial for the definition of endpoints in clinical trials.

Bone demineralisation in a large cohort of Wilson disease patients.

AIMS AND BACKGROUND: We compared the bone mineral density (BMD) of adult Wilson disease (WD) patients (n = 148), with an age- and gender-matched healthy control population (n = 148). Within the WD cohort, correlations of BMD with WD disease parameters, lab results, type of treatment and known osteoporosis risk factors were analysed. METHODS: Hip and lumbar spine absolute BMD and T-score were measured by dual-energy X-ray absorptiometry. Osteoporosis and osteopenia were defined as a T-score ≤ -2.5, and between -1 and -2.5, respectively. RESULTS: There were significantly more subjects with abnormal T-scores in the WD population (58.8%) than in the control population (45.3%) (χ(2) = 6.65, df = 2, p = 0.036), as there were 50.0% osteopenic and 8.8% osteoporotic WD patients, vs. 41.2% and 4.1%, respectively, in the controls. Especially L2-L4 spine BMD measurements (BMD and T-scores) differed significantly between the WD population and matched controls. L2-L4 spine BMD for WD patients was on average 0.054 g/cm(2) (5.1%) lower than in matched normal controls (0.995 ± 0.156 vs 1.050 ± 0.135; p = 0.002). We found no significant correlation between BMD values and any of the WD disease parameters (e.g. the severity of liver disease), lab results, type of treatment or known osteoporosis risk factors. Duration of D-penicillamine treatment was negatively correlated with femoral BMD value, but in a clinically irrelevant manner, compared to age and gender. Importantly, BMD remained significantly lower in WD patients (n = 89) vs. controls after excluding WD patients with cirrhosis (p = 0.009). CONCLUSIONS: Our study suggests that WD is intrinsically associated with bone demineralisation.

Epidemiology of invasive aspergillosis in critically ill patients: clinical presentation, underlying conditions, and outcomes.

INTRODUCTION: Invasive aspergillosis (IA) is a fungal infection that particularly affects immunocompromised hosts. Recently, several studies have indicated a high incidence of IA in intensive care unit (ICU) patients. However, few data are available on the epidemiology and outcome of patients with IA in this setting. METHODS: An observational study including all patients with a positive Aspergillus culture during ICU stay was performed in 30 ICUs in 8 countries. Cases were classified as proven IA, putative IA or Aspergillus colonization according to recently validated criteria. Demographic, microbiologic and diagnostic data were collected. Outcome was recorded 12 weeks after Aspergillus isolation. RESULTS: A total of 563 patients were included, of whom 266 were colonized (47%), 203 had putative IA (36%) and 94 had proven IA (17%). The lung was the most frequent site of infection (94%), and Aspergillus fumigatus the most commonly isolated species (92%). Patients with IA had higher incidences of cancer and organ transplantation than those with colonization. Compared with other patients, they were more frequently diagnosed with sepsis on ICU admission and more frequently received vasopressors and renal replacement therapy (RRT) during the ICU stay. Mortality was 38% among colonized patients, 67% in those with putative IA and 79% in those with proven IA (P < 0.001). Independent risk factors for death among patients with IA included older age, history of bone marrow transplantation, and mechanical ventilation, RRT and higher Sequential Organ Failure Assessment score at diagnosis. CONCLUSIONS: IA among critically ill patients is associated with high mortality. Patients diagnosed with proven or putative IA had greater severity of illness and more frequently needed organ support than those with Aspergillus spp colonization.

Excruciating Low Back Pain After Strenuous Exertion: Beware of Lumbar Paraspinal Compartment Syndrome.

BACKGROUND: Low back pain is extremely common and usually a minor self-limiting condition. Rarely, however, it is a harbinger of serious medical illness. Paraspinal compartment syndrome is a rare condition, but its timely recognition is important to allow adequate treatment. CASE REPORT: A 16-year-old boy presented to the Emergency Department (ED) with severe low back pain, necessitating intravenous opioids. Laboratory results showed severe rhabdomyolysis. Magnetic resonance imaging of the lumbar spine showed diffuse edema and swelling in the paraspinal muscles. Aggressive fluid therapy was started but despite narcotic analgesia the pain persisted and creatine kinase (CK) levels increased. Compartment pressures of the erector spinae were found to be increased. The decision was made to proceed with bilateral paraspinal fasciotomies. Postoperatively, the patient noted immediate pain relief with rapid decrease of CK level. The patient is pain free and resumed running and swimming 3 months after admission in the ED. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Although paraspinal compartment syndrome is a rare condition, its recognition is of paramount importance to allow adequate surgical treatment, preventing muscle necrosis. Although back pain most often has a benign course, a careful history and physical examination in patients presenting with low back pain allows determination of "red flags." Mandatory further diagnostic tests can identify underlying serious illness.

Pharmacokinetics of anidulafungin in critically ill patients with candidemia/invasive candidiasis.

The pharmacokinetics of intravenous anidulafungin in adult intensive care unit (ICU) patients were assessed in this study and compared with historical data from a general patient population and healthy subjects. Intensive plasma sampling was performed over a dosing interval at steady state from 21 ICU patients with candidemia/invasive candidiasis. All patients received the recommended dosing regimen (a 200-mg loading dose on day 1, followed by a daily 100-mg maintenance dose), except for a 54-year-old 240-kg female patient (who received a daily 150-mg maintenance dose instead). Plasma samples were assayed for anidulafungin using a validated liquid chromatography-tandem mass spectrometry method. Pharmacokinetic parameters in ICU patients were calculated by a noncompartmental method. With the exclusion of the 240-kg patient, the median (minimum, maximum) age, weight, and body mass index (BMI) of 20 ICU patients were 57 (39, 78) years, 65 (48, 106) kg, and 23.3 (16.2, 33.8) kg/m(2), respectively. The average anidulafungin area under the curve over the 24-hour dosing interval (AUC(0-24)), maximum concentration (C(max)), and clearance (CL) in 20 ICU patients were 92.7 mg · h/liter, 7.7 mg/liter, and 1.3 liters/h, respectively. The exposure in the 240-kg patient at a daily 150-mg dose was within the range observed in ICU patients overall. The average AUC(0-24) and Cmax in the general patient population and healthy subjects were 110.3 and 105.9 mg · h/liter and 7.2 and 7.0 mg/liter, respectively. The pharmacokinetics of anidulafungin in ICU patients appeared to be comparable to those in the general patient population and healthy subjects at the same dosing regimen.

A clinical algorithm to diagnose invasive pulmonary aspergillosis in critically ill patients.

RATIONALE: The clinical relevance of Aspergillus-positive endotracheal aspirates in critically ill patients is difficult to assess. OBJECTIVES: We externally validate a clinical algorithm to discriminate Aspergillus colonization from putative invasive pulmonary aspergillosis in this patient group. METHODS: We performed a multicenter (n = 30) observational study including critically ill patients with one or more Aspergillus-positive endotracheal aspirate cultures (n = 524). The diagnostic accuracy of this algorithm was evaluated using 115 patients with histopathologic data, considered the gold standard. Subsequently, the diagnostic workout of the algorithm was compared on the total cohort (n = 524), with the categorization based on the diagnostic criteria of the European Organization for the Research and Treatment of Cancer/Mycoses Study Group. MEASUREMENTS AND MAIN RESULTS: Among 115 histopathology-controlled patients, 79 had proven aspergillosis. The algorithm judged 86 of 115 cases to have putative aspergillosis. This diagnosis was confirmed in 72 and rejected in 14 patients. The algorithm judged 29 patients to have Aspergillus colonization. This was confirmed in 22 and rejected in 7 patients. The algorithm had a specificity of 61% and a sensitivity of 92%. The positive and negative predictive values were 61 and 92%, respectively. In the total cohort (n = 524), 79 patients had proven invasive pulmonary aspergillosis (15.1%). According to the European Organization for the Research and Treatment of Cancer/Mycoses Study Group criteria, 32 patients had probable aspergillosis (6.1%) and 413 patients were not classifiable (78.8%). The algorithm judged 199 patients to have putative aspergillosis (38.0%) and 246 to have Aspergillus colonization (46.9%). CONCLUSIONS: The algorithm demonstrated favorable operating characteristics to discriminate Aspergillus respiratory tract colonization from invasive pulmonary aspergillosis in critically ill patients.

Detection of galactomannan in bronchoalveolar lavage fluid samples of patients at risk for invasive pulmonary aspergillosis: analytical and clinical validity.

Invasive pulmonary aspergillosis (IPA) is frequent and often fatal in immunosuppressed patients. Timely diagnosis of IPA improves survival but is difficult to make. We examined the analytical and clinical validity of galactomannan (GM) testing of bronchoalveolar lavage (BAL) fluid in diagnosing IPA in a mixed population by retrospectively reviewing records of 251 consecutive at-risk patients for whom BAL fluid GM testing was ordered. The performance of the enzyme immunoassay was evaluated by using a range of index cutoffs to define positivity. Three samples were associated with proven IPA, 56 were associated with probable IPA, 63 were associated with possible invasive fungal disease (IFD), and 129 were associated with no IFD. Using a BAL fluid GM index of ≥0.8 (optimal optical density [OD] index cutoff identified by a receiver operating characteristic curve), the sensitivity in diagnosing proven and probable IPA was 86.4%, and the specificity was 90.7%. At this cutoff, positive and negative predictive values were 81% and 93.6%, respectively. However, an OD index value of ≥3.0 corresponded to a 100% specificity, thus ruling the disease in, irrespective of the pretest probability. Conversely, an OD index cutoff of <0.5 corresponded to a high sensitivity, virtually always ruling the disease out. For all values in between, the posttest probability of IPA depends largely on the prevalence of disease in the at-risk population and the likelihood ratio of the OD index value. Detection of GM in BAL fluid samples of patients at risk of IPA has an excellent diagnostic accuracy provided results are interpreted in parallel with clinico-radiological findings and pretest probabilities.

Cytomegalovirus serostatus and outcome in nonimmunocompromised critically ill patients.

OBJECTIVE: The impact of cytomegalovirus reactivation during critical illness remains unclear and studies investigating prophylaxis in cytomegalovirus seropositive patients are being considered. This study investigates the association between cytomegalovirus seropositivity and outcome in a large population of nonimmunocompromised critically ill patients. DESIGN: Cytomegalovirus serostatus was determined on prospectively collected serum samples. The primary end point was intensive care unit mortality. The secondary end points were in-hospital mortality, time to alive discharge from intensive care unit and hospital, time to alive weaning from mechanical ventilation, and need for renal replacement therapy. SETTING: This retrospective study was performed in a 17-bed medical and 56-bed surgical intensive care unit in a 1,900-bed referral hospital. PATIENTS: We analyzed serum of 1,504 nonimmunocompromised critically ill patients with an intensive care unit length of stay of 3 days or more. Patients with hematologic malignancy, transplantation, immunosuppressive therapy (calcineurin inhibitors, antitumor necrosis factor-α drugs, antilymphocyte antibodies, or chemotherapeutic agents), or a do-not-resuscitate order were excluded. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Sixty-four percent of the studied patients were cytomegalovirus seropositive. Multivariable analysis revealed no associated risk for intensive care unit or hospital mortality, or for time to alive discharge from intensive care unit or hospital. The risk for alive weaning from mechanical ventilation and the need for renal replacement therapy were also comparable in seropositive and seronegative groups. CONCLUSION: : No association was found between the cytomegalovirus serostatus and the studied major clinical outcomes. Based on these results, the design of an intervention study assessing the impact of cytomegalovirus prophylaxis in all cytomegalovirus seropositive critically ill patients appears premature.

Porphyria: awareness is the key to diagnosis!

Porphyrias are disorders of the haem biosynthesis which are encountered infrequently and which often present themselves atypically as a combination of gastrointestinal, neurologic and/or dermatologic symptoms. Although they are primarily caused by enzyme defects, inheritance patterns are mostly not evident. Considering all of these characteristics, it is not surprising that there is a long delay between the onset of symptoms and the diagnosis of the disease, with as possible consequences impaired quality of life, irreversible neurologic damage and even death. This review aims to increase the clinical suspicion of the three most common porphyrias in adults: acute intermittent porphyria (AIP), porphyria cutanea tarda (PCT) and protoporphyria. Their relevant pathophysiology, clinical manifestations, diagnosis and treatment are discussed aiming at increasing the awareness of these diseases among physicians.

A case of vitamin B12 deficiency neurological syndrome in a young adult due to late-onset cobalamin C (CblC) deficiency: a diagnostic challenge.

Vitamin B12 deficiency can present with neurologic and psychiatric symptoms without macrocytic anaemia. We describe a case of late-onset cobalamin C deficiency which typically presents with normal serum vitamin B12 concentrations, posing an additional diagnostic challenge. A 23-year-old woman with decreased muscle strength and hallucinations was diagnosed with 'catatonic depression' and admitted to a residential mental health facility. She was referred to our hospital for further investigation 3 months later. Heteroanamnesis revealed that the symptoms had been evolving progressively over several months. Magnetic resonance imaging (MRI) of the brain showed diffuse symmetrical white matter lesions in both hemispheres. Routine laboratory tests including vitamin B12 and folic acid were normal except for a slight normocytic, normochromic anaemia. Over the next 6 weeks her symptoms deteriorated, and she became unresponsive to stimuli. A new MRI scan showed progression of the white matter lesions. The neurologist requested plasma homocysteine (Hcys) which was more than 8 times the upper limit of normal. Further testing revealed increased methylmalonic acid and the patient was diagnosed with adult-onset cobalamin C deficiency. This case illustrates that Hcys and/or methylmalonic acid should be determined in patients presenting with neuropsychiatric symptoms suggestive of vitamin B12 deficiency with a normal serum vitamin B12 to rule out a late-onset cobalamin C deficiency.

Beta-D-glucan detection as a diagnostic test for invasive aspergillosis in immunocompromised critically ill patients with symptoms of respiratory infection: an autopsy-based study.

Beta-(1,3)-D-glucan (BG) detection is an emerging tool to diagnose invasive fungal infections (IFIs). Invasive aspergillosis (IA) is the second most common IFI in immunocompromised intensive care unit (ICU) patients. We retrospectively analyzed the serum BG concentration (Fungitell; Associates of Cape Cod) in immunocompromised ICU patients with proven IA and in immunocompromised ICU patients in whom autopsy failed to show IFI. The study was performed in a 17-bed medical ICU in a 1,900-bed referral hospital. Patients at risk for IA were eligible for inclusion when at least two additional clinical signs were present. Patients with other IFIs were excluded. Fourteen patients with IA and 33 patients who had no IFI were eligible for inclusion. Serum BG levels were significantly higher in patients with IA than patients without an IFI (P < 0.01). Using a cutoff of 140 pg/ml, the sensitivity and specificity were 85.7 and 69.7%, respectively; the positive and negative predictive values were 54.5 and 92.0%, respectively. The positive and negative likelihood ratios were 2.83 and 0.21, respectively. Although serum BG concentrations were higher in immunocompromised ICU patients with IA than in patients with the same risk factors who did not have IFI on autopsy, the moderate performance characteristics of this test limit its use as a diagnostic test for IA in this population.

Candida tropicalis pylephlebitis with persistent fungaemia in a 72-year-old lady with severe pancreatitis.

Pylephlebitis is defined as septic thrombophlebitis of the portal venous system, usually secondary to infection or inflammation in the abdomen. In the current report, we present a case of fungal pylephlebitis that complicated the course of pancreatitis and resolved with echinocandins.

Quantification and Explanation of the Variability of First-Dose Amikacin Concentrations in Critically Ill Patients Admitted to the Emergency Department: A Population Pharmacokinetic Analysis.

BACKGROUND: There may be a difference between the determinants of amikacin exposure in emergency department (ED) versus intensive care (ICU) patients, and the peak amikacin concentration varies widely between patients. Moreover, when the first dose of antimicrobials is administered to septic patients admitted to the ED, fluid resuscitation and vasopressors have just been initiated. Nevertheless, population pharmacokinetic modelling data for amikacin in ED patients are unavailable. OBJECTIVE: The aim of this study was to quantify the interindividual variability (IIV) in the pharmacokinetics of amikacin in patients admitted to the ED and to identify the patient characteristics that explain this IIV. METHODS: Patients presenting at the ED with severe sepsis or septic shock were randomly assigned to receive amikacin 25 mg/kg or 15 mg/kg intravenously. Blood samples were collected at 1, 6 and 24 h after the onset of the first amikacin infusion. Data were analysed using nonlinear mixed-effects modelling. RESULTS: A two-compartment population pharmacokinetic model was developed based on 279 amikacin concentrations from 97 patients. The IIV in clearance (CL) and central distribution volume (V1) were 71% and 26%, respectively. Body mass index (BMI), serum total protein level, serum sodium level, and fluid balance 24 h after amikacin administration explained 30% of the IIV in V1, leaving 18% of the IIV unexplained. BMI and creatinine clearance according to the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation 24 h after amikacin administration explained 46% of the IIV in CL, and 39% remained unexplained. CONCLUSION: The IIV of amikacin pharmacokinetics in ED patients is large. Higher doses may be considered in patients with low serum sodium levels, low total protein levels, or a high fluid balance. TRIAL REGISTRATION: ClinicalTrials.gov ID: NCT02365272.