Pancreaticopleural fistula, a rare mediastinal emergency.

A pancreaticopleural fistula (PPF) is a rare condition that causes thoracic symptoms such as dyspnea and chest pain secondary to exudative pleural effusions. While PPF is a very rare complication with only 52 cases reported between 1960 and 2007, they typically occur in patients who are male, middle aged, and have a history of chronic alcohol use and chronic pancreatitis (Aswani and Hira, 2015; Francisco et al., n.d.; Valeshabad et al., 2018; Ali et al., 2009). The fistula between the pancreas and pleural cavity causes large, rapidly accumulating, and recurrent pleural effusions which cause symptoms that can be difficult to differentiate from other acute thoracic pathologies (Francisco et al., n.d.). As a result, it is essential that providers have a high index of suspicion for PPF in these appropriate populations. We present a case study to review the typical presentation, pathophysiology, and current approach to treatment of PPF. This case is unique as the patient had no known risk factors. Due to limited data on this topic, there are no evidence-based guidelines on this topic, leaving a variety of case reports to inform clinical management in the emergency department.

Pancreaticopleural fistula, a rare mediastinal emergency: A case report.

A pancreaticopleural fistula (PPF) is a rare condition that causes thoracic symptoms such as dyspnea and chest pain secondary to exudative pleural effusions. While PPF is a very rare complication with only 52 cases reported between 1960 and 2007, they typically occur in patients who are male, middle aged, and have a history of chronic alcohol use and chronic pancreatitis (Aswani and Hira, 2015; Francisco et al., n.d.; Valeshabad et al., 2018; Ali et al., 2009). The fistula between the pancreas and pleural cavity causes large, rapidly accumulating, and recurrent pleural effusions which cause symptoms that can be difficult to differentiate from other acute thoracic pathologies (Francisco et al., n.d.). As a result, it is essential that providers have a high index of suspicion for PPF in these appropriate populations. We present a case study to review the typical presentation, pathophysiology, and current approach to treatment of PPF. This case is unique as the patient had no known risk factors. Due to limited data on this topic, there are no evidence-based guidelines on this topic, leaving a variety of case reports to inform clinical management in the emergency department.

Pulmonary Congestion by Lung Ultrasound in Ambulatory Patients With Heart Failure With Reduced or Preserved Ejection Fraction and Hypertension.

BACKGROUND: Although pulmonary congestion can be quantified in heart failure (HF) by means of lung ultrasonography (LUS), little is known about LUS findings (B-lines) in different HF phenotypes. This prospective cohort study investigated the prevalence and clinical and echocardiographic correlates of B-lines in ambulatory HF patients with preserved (HFpEF) or reduced (HFrEF) ejection fraction compared with hypertensive patients. We related LUS findings to 12-month HF hospitalizations and all-cause mortality. METHODS AND RESULTS: We used LUS to examine hypertensive (n = 111), HFpEF (n = 46), and HFrEF (n = 73) patients (median age 66 y, 56% male, 79% white, and median EF 55%) undergoing clinically indicated outpatient echocardiography. B-line number was quantified offline, across 8 chest zones, blinded to clinical and echocardiographic characteristics. The proportion of patients with ≥3 B-lines was lower in hypertensive patients (13.5%) compared with both HFrEF (45.2%, P < .001) and HFpEF (34.8%; P = .05). HF patients with ≥3 B-lines had a higher risk of the composite outcome (age- and sex-adjusted hazard ratio 2.62, 95% confidence interval 1.15-5.96; P = .022). CONCLUSIONS: When performed at the time of outpatient echocardiography, LUS findings of pulmonary congestion differ between patients with known HF and those with hypertension, and may be associated with adverse outcomes.

Right atrial structure and function in patients with hypertension and with chronic heart failure.

BACKGROUND: Prior studies have shown that both heart failure (HF) and atrial fibrillation (AF) are factors that impact left atrial function and structure. However, right atrial (RA) function measured as RA emptying fraction (RAEF) on echocardiography has not been analyzed systematically in a chronic HF population. The aim of this study was to assess RA volume index (RAVI) and RAEF in patients with chronic HF and patients with hypertension (HTN) and to relate these findings to other cardiopulmonary ultrasound parameters and 12-month outcomes. METHODS AND RESULTS: In this prospective observational study, we identified 119 patients with chronic HF (64 patients without a history of AF [HF without AF], 55 with AF [HF with AF]), and 127 patients with HTN but without important cardiac disease who underwent routine outpatient transthoracic echocardiography. We found that RAEF was impaired in patients with HF without AF compared to patients with HTN (35% ±2 vs 50% ±1, P < .001), whereas RAVI did not differ between these two groups. Lower RAEF was associated with larger RAVI and higher estimated RA pressures but not with a higher degree of pulmonary congestion by lung ultrasound. Both lower RAEF and higher RAVI were associated with an increased risk of 12-month HF hospitalizations or all-cause death (age, sex, and AF adjusted HR: 4.07, 95% CI: 1.69-9.79; P = .002, vs 2.74, 95% CI: 1.15-6.54, P = .023). CONCLUSIONS: In an outpatient HF cohort, both lower RAEF and increased RAVI were associated with other markers of impaired cardiac function and 12-month adverse events.

A Case of Hematogenous Osteomyelitis in a 5-Week-Old Male.

Pediatric osteomyelitis is a rare diagnosis associated with devastating consequences when treatment is delayed. We report a case of hematogenous osteomyelitis in a 5-week-old male presenting to the emergency department (ED) with a flaccid right upper extremity. In the ED, the patient was evaluated with comprehensive infectious and trauma workups. Initial CT imaging of the head and X-ray imaging of the extremity were unremarkable. C-reactive protein was elevated at 0.8; all other laboratory markers were within normal range. Over the course of the ED evaluation, the extremity weakness spontaneously resolved; however, the infant developed a fever of 100.5 F. Empiric broad spectrum antibiotics were initiated, and the infant was admitted to the pediatric service. At 48 hours following presentation, cultures resulted positive for Staphylococcus aureus and MRI imaging revealed osteomyelitis of the proximal right humeral metadiaphysis. Given the subtle presentation of early hematogenous osteomyelitis, emergency providers should maintain a high index of suspicion for infection as the underlying cause in infants presenting with a flaccid extremity.

A Review of 75th Ranger Regiment Battle-Injured Fatalities Incurred During Combat Operations From 2001 to 2021.

INTRODUCTION: The 75th Ranger Regiment is an elite U.S. military special operations unit that conducted over 20 years of sustained combat operations. The Regiment has a history of providing novel and cutting-edge prehospital trauma care, advancing and translating medical initiatives, and documenting and reporting casualty care performance improvement efforts. MATERIALS AND METHODS: A retrospective case fatality rate (CFR) review, mortality review, and descriptive analysis of fatalities were conducted for battle-injured personnel assigned or attached to the 75th Ranger Regiment from 2001 to 2021 during combat operations primarily in Afghanistan and Iraq. Fatalities were evaluated for population characteristics, cause of death, mechanism of death, injury severity, injury survivability, and death preventability. RESULTS: A total of 813 battle injury casualties, including 62 fatalities, were incurred over 20 years and 1 month of continuous combat operations. The Regiment maintained a zero rate of prehospital preventable combat death. Additionally, no fatalities had a mechanism of death because of isolated extremity hemorrhage, tension pneumothorax, or airway obstruction. When comparing the CFR of the Regiment to the U.S. military population as a whole, the Regiment had a significantly greater reduction in the cumulative CFR as measured by the difference in average annual percentage change. CONCLUSIONS: Documentation and analysis of casualties and care, mortality and casualty reviews, and other performance improvement efforts can guide combatant commanders, medical directors, and fighting forces to reduce preventable combat deaths and the CFR. Early hemorrhage control, blood product resuscitation, and other lifesaving interventions should be established and maintained as a standard prehospital practice to mitigate fatalities with potentially survivable injuries.

Thyroid Storm, Rhabdomyolysis, and Pulmonary Embolism: An Unusual Triad Case Report.

INTRODUCTION: Thyroid storm is a medical emergency associated with significant mortality. Hyperthyroid states have been associated with hypercoagulability as well as rhabdomyolysis. However, the pathophysiology of this association remains under investigation. CASE REPORT: A 62-year-old male patient presented to the emergency department with weakness and was found to have thyroid storm with concurrent submassive pulmonary embolisms and rhabdomyolysis. To our knowledge, this is the first reported presentation of this triad. CONCLUSION: This case highlights the potentially difficult diagnosis and management of thyroid storm, as well as associated life-threatening complications, including venous thromboemboli and rhabdomyolysis.

Body mass index and B-lines on lung ultrasonography in chronic and acute heart failure.

AIMS: Increased body mass index (BMI) is common in heart failure (HF) patients and is associated with lower levels of N-terminal pro-brain natriuretic peptide (NT-proBNP). We evaluated the influence of BMI on lung ultrasonography (LUS) findings indicative of pulmonary congestion (i.e. B-lines) in patients with chronic and acute HF (AHF). METHODS AND RESULTS: We analysed ambulatory chronic HF (n = 118) and hospitalized AHF (n = 177) patients (mean age 70 years, 64% men, mean BMI 29 kg/m2 , mean ejection fraction 42%) undergoing echocardiography and LUS in eight chest zones. B-lines and chest wall thickness (skin to pleura) on ultrasound were quantified offline and blinded to clinical findings. NT-proBNP was available in AHF patients (n = 167). In chronic HF, B-line number decreased by 18% per 5 unit increase in BMI [95% confidence interval (CI) -35% to +5%, P = 0.11]. In AHF, the number of B-lines decreased by 12% per 5 unit increase in BMI (95% CI -19% to -5%, P = 0.001), whereas NT-proBNP concentration decreased by 28% per 5 unit increase in BMI (95% CI -40% to -16%, P < 0.001). For AHF, B-line number declined to a lesser degree than NT-proBNP concentration with increasing BMI (P = 0.020), and >6 B-lines were observed in half of AHF patients with severe obesity. There was an inverse relationship between B-line number and chest wall thickness, and this association varied by chest region. CONCLUSIONS: Despite an inverse relationship between B-lines and BMI, B-lines declined to a lesser degree than NT-proBNP with increasing BMI. These data suggest that LUS may be useful in patients with HF despite obesity.

Quantification of pleural effusions on thoracic ultrasound in acute heart failure.

BACKGROUND: Although pleural effusions are common among patients with acute heart failure, the relevance of pleural effusion size assessed on thoracic ultrasound has not been investigated systematically. METHODS: In this prospective observational study, we included patients hospitalised for acute heart failure and performed a thoracic ultrasound early after admission (thoracic ultrasound 1) and at discharge (thoracic ultrasound 2) independently of routine clinical management. A semiquantitative score was applied offline blinded to clinical findings to categorise and monitor pleural effusion size. RESULTS: Among 188 patients (median age 72 years, 62% men, 78% white, median left ventricular ejection fraction 38%), pleural effusions on thoracic ultrasound 1 were present in 66% of patients and decreased in size during the hospitalisation in 75% based on the pleural effusion score (P<0.0001). Higher values of the pleural effusion score were associated with higher pleural effusion volumes on computed tomography (P<0.001), higher NT-pro brain natriuretic peptide values (P=0.001) and a greater number of B-lines on lung ultrasound (P=0.004). Nevertheless, 47% of patients were discharged with persistent pleural effusions, 19% with large effusions. However, higher values of the pleural effusion score on thoracic ultrasound 2 did not identify patients at increased risk of 90-day heart failure rehospitalisations or death (adjusted hazard ratio (HR) 1.05, 95% confidence interval (CI) 0.92-1.19; P=0.46) whereas seven or more B-lines on lung ultrasound at discharge were independently associated with adverse events (adjusted HR 2.43, 95% CI 1.11-5.37; P=0.027). CONCLUSION: Among patients with acute heart failure, pleural effusions are associated with other clinical, imaging and laboratory markers of congestion and improve with heart failure therapy. The prognostic relevance of persistent pleural effusions at discharge should be investigated in larger studies.

Diuretic MAG3 scintigraphy (F0) in acute pyelonephritis: regional parenchymal dysfunction and comparison with DMSA.

UNLABELLED: 99mTc-DMSA late static planar imaging or SPECT is being used for the investigation of focal acute pyelonephritis (APN), especially in children with urinary tract infection (UTI). Diuretic 99mTc-mercaptoacetyltriglycine (MAG3) dynamic scintirenography has been applied in the evaluation of kidney function and structure, frequently to exclude obstruction. However, in children and adults with a clinical picture of APN, diuretic MAG3 scintigraphy with zero time injection of furosemide (MAG3-F0) was observed to display focal parenchymal abnormalities; regional dysfunction (focal parenchymal decrease in early uptake; slow filling in and prolonged late retention of activity); or, less frequently, fixed defects. This observation was further studied both retrospectively and prospectively, and its sensitivity and specificity for APN were compared with those of dimercaptosuccinic acid (DMSA). METHODS: In the retrospective study, for 36 children with UTI and regional parenchymal findings on MAG3-F(0), data were reviewed, analyzed, and compared with the results of concurrent DMSA studies. In the prospective study, for 57 children with clinical and laboratory findings suggestive of APN, the 2 radiopharmaceuticals were used for imaging sequentially and the results of the 2 studies were compared. The criteria for abnormal findings compatible with the diagnosis of APN were, for MAG3-F(0), regional parenchymal dysfunction and fixed focal defects and, for DMSA, focal defects without parenchymal loss. RESULTS: In all groups of patients, most abnormal MAG3-F(0) studies (80%) showed regional parenchymal dysfunction, but in some (20%) a fixed defect was found. Compared with DMSA and when both regional dysfunction and focal defects were considered, MAG3-F(0) was as sensitive as DMSA. Some patients had only MAG3-F(0) abnormalities, suggesting a slightly lower specificity for MAG3-F(0) compared with DMSA (86%); this finding needs further study, because it also raises questions about the sensitivity of DMSA, considering that only a small percentage of patients with clinically suggestive findings had abnormal study findings. In most patients with fixed defects on both DMSA and MAG3-F(0), follow-up studies showed no resolution, suggesting that a fixed defect on MAG3-F(0) may indicate either more severe APN or preexistent scars and that regional dysfunction may be a sign more specific for APN and prognostic of potential recovery. In addition, a pattern more specific for a scar--a fixed defect with a dilated regional calyx--was seen on follow-up MAG3-F(0). CONCLUSION: A fast (25-min) planar dynamic MAG3-F(0) study was found to be as sensitive at depicting focal parenchymal abnormalities in APN as was the 3- to 4-h DMSA routine procedure. The sensitivity and specificity of both studies need further evaluation.

Diuretic MAG3 scintirenography in children with HIV nephropathy: diffuse parenchymal dysfunction.

UNLABELLED: HIV nephropathy (HIVN) is prevalent in 15%-56% of HIV-infected children and induces mild to severe progressive nephropathy. METHODS: A total of 33 renal diuretic scintirenographic studies with 99mTc-mercaptoacetyltriglycine (MAG3) were reviewed and analyzed from 23 HIV pediatric patients, 21 of whom had HIVN with varying degrees of renal impairment. Results were compared with 10 studies of control patients of matching ages. Visual interpretation of images and renograms as well as semiquantitative analyses were performed. Variables compared were size of kidneys, time of peak and one-half peak activities, residual (or retained) cortical activity at 20 min, ratio of cortical activity at 2.5-20 min, and ratio of kidney activity to kidney plus background activity at 2 min. The results of MAG3 renal studies were also compared with laboratory data pertaining to creatinine clearance in all patients and with sonography in 17 patients. RESULTS: In most patients with HIVN (18/21), the kidneys were larger than normal, with a diffuse parenchymal dysfunction (decreased uptake, slow processing, and increased retention of activity) and flat renograms, findings similar to those observed in other diffuse parenchymal diseases. In all patients with HIVN, semiquantitative analysis (paired t test) showed statistically significant differences from control patients for all variables. On ANOVA, a statistically significant correlation was found between most scintigraphic parameters and the severity of renal impairment. Of the 17 concurrent sonographic studies in HIVN patients, 7 showed no abnormalities, whereas the results of scintigraphy were abnormal. CONCLUSION: Diuretic MAG3 scintirenography shows nonspecific diffuse parenchymal dysfunction in pediatric patients with HIVN. Such dysfunction may provide corroborative evidence of HIVN and should be recognized when the test is performed for standard indications. Further work is necessary to prove that the test has indeed the high sensitivity and good correlation with the seventy of HIVN suggested in this population; the test may be useful to follow up the progression of disease and the effect of treatment.

Fungal peritonitis in pediatric patients.

Fungal peritonitis (FP) is a rare complication of peritoneal dialysis (PD). Although treatment with fluconazole (FCZ) has improved catheter survival and preservation of the peritoneal membrane, FP still carries a high morbidity and mortality in pediatrics. High-risk factors for FP include previous usage of systemic antibiotics and recurrent bacterial peritonitis. A prospective experience in the treatment of FP was conducted at the University of Miami/Jackson Children's Hospital from 1992 to 1997. All patients received either oral or intravenous loading dose of FCZ (5-7 mg/kg) followed by intraperitoneal (i.p.) FCZ (75 mg/L). Amphotericin B (amp B) was added when clinical sepsis was present. A total of 6 patients had FP (all Candida sp.; mean age: 6 years). Two of these patients were neonates with Tenckhoff-catheter placement at less than 1 week of age. Five patients achieved sterilization of the peritoneal fluid. One patient required catheter removal (C. tropicalis). The 2 neonates were infection free for 29 and 41 days, respectively, but both died of superimposed bacterial sepsis. The remaining 4 patients survived and completed 6 weeks of FCZ treatment. Two have had preservation of the peritoneal membrane for more than 1 year. The other 2 were switched to hemodialysis. We conclude that FCZ is an effective treatment for fungal peritonitis in pediatric patients. Adjunct therapy with amp B is usually necessary if sepsis is present. Although eradication of the fungus is possible in a majority of cases, neonates and immunocompromised hosts remain at high risk for morbidity and mortality.

Growth of uremic infants on forced feeding regimens.

Infants born with congenital renal insufficiency generally grow poorly during the first years of life and incur a height deficit that is rarely regained. Actual energy and protein requirements have not been determined for these children. In 12 infants with creatinine clearances less than 70 ml/min per 1.73 m2, growth and nutrient intakes were monitored during the first 2 years of life. Forced feeding regimens after 3 months of age, including gastrostomy in 3 patients, were necessary to maintain energy intakes near 100% of the recommended dietary allowance (RDA). Protein intakes averaged in excess of 140% RDA. Linear growth did not correlate with either energy or protein intakes, suggesting that neither was a limiting factor to growth. Length velocity standard deviation score (LV-SDS) did not correlate with degree of renal insufficiency at any age, but average LV-SDS did relate significantly and inversely to C-terminal parathyroid hormone (PTH) levels. Growth parameters, including LV-SDS and weight velocity SDS (WV-SDS) were lowest at 6 months of age. Weight and length SDS followed with a maximum decline at 12 months of age. While weight for length SDS remained normal and WV-SDS showed recovery during the 2nd year, LV-SDS remained negative. Length SDS stabilized near--2 SDS. In summary, these data suggest that the major height deficit in infants with renal insufficiency is incurred during the first 6 months of life. Ponderal indices suggested that very early nutritional deficits may have been a primary contributor to subsequent height deficits.(ABSTRACT TRUNCATED AT 250 WORDS)

Renal tubular abnormalities in infants with hydronephrosis.

PURPOSE: Abnormalities in renal tubular function have been observed in hydronephrotic urinary tract disease, resulting in metabolic acidosis, hyperkalemia and excessive free water diuresis. The frequency of these abnormalities, particularly in our infant population, was the impetus for our study. MATERIALS AND METHODS: We studied 50 infants selected from 199 patients followed for hydronephrosis before any surgical intervention during a 5-year period. Mean patient age was 1.5 +/- 1.0 months at the time of diagnosis by ultrasound, voiding cystourethrography and a radionuclide renal scan. Lesions were classified as unilateral or bilateral and graded according to severity of renal pelvic dilatation or grade of vesicoureteral reflux. RESULTS: At least 1 abnormality of tubular function was present in 29 patients (58%) of whom the predominant abnormality was renal tubular acidosis in 23 (79%, 46% of the total study group). Renal tubular acidosis was diagnosed on the basis of a serum total carbon dioxide of 19 mM./l. or less with urinary pH 5.5 or greater. The defect appeared to be distal in most cases. Other abnormalities included defects in urinary concentrating ability in 10 patients (4 with unilateral urinary tract dilatation). Distal tubular aldosterone resistance in 6 patients (3 with unilateral dilatation) was demonstrated by hyperkalemia with a low transtubular potassium gradient of 3 or less and low fractional excretion of potassium. Although common in unilateral lesions, renal tubular dysfunction became more prevalent with an increase in severity score and bilaterality. CONCLUSIONS: Renal tubular dysfunction is frequent in hydronephrotic infants with unilateral or bilateral disease. Although rarely life threatening and usually self-limiting, the metabolic consequences of these abnormalities require investigation to allow for appropriate medical management.

Human immunodeficiency virus nephropathy.

Varying components of the syndrome of human immunodeficiency virus nephropathy (HIVN) have been described, the most pertinent including proteinuria/nephrotic syndrome, progressive azotemia, normal blood pressure, enlarged and hyperechoic kidneys, rapid progression to end-stage renal disease (ESRD), and no response to treatment regimens. The diagnosis of HIVN requires identification of excessive proteinuria or albuminuria, determined by a total protein excretion on a timed urine collection or a high protein/creatinine ratio in a random specimen. Various pathological lesions have been found in HIVN. The lesion of focal and segmental sclerosis (FS/FSS) is most characteristic in adults and usually is associated with a rapid demise. FS/FSS also has been described in approximately one-half of the pediatric patients reported in the literature (31/64). Despite progression to ESRD, the clinical course in children with HIVN is less fulminant than in adults. Other reported histological findings include primarily mesangial hyperplasia as well as minimal change, focal necrotizing glomerulonephritis or lupus nephritis, and hemolytic uremic syndrome. In addition to glomerular pathology, interstitial findings of dilated tubules filled with a unique proteinaceous material, atrophied tubular epithelium, and interstitial cell infiltration are very common. On electron microscopy, most investigators have found tubuloreticular inclusion bodies in endothelial cells of glomerular capillaries. Treatment of patients who develop ESRD remains highly controversial. Most adult patients treated with hemodialysis have succumbed rapidly; peritoneal dialysis has been better tolerated. Transplantation in patients with HIV infection must be considered to be tentative, with reports of acceleration towards full blown acquired immunodeficiency syndrome in some and uneventful 5-year survival in others.(ABSTRACT TRUNCATED AT 250 WORDS)

Beneficial effects of continuous overnight catheter drainage in children with polyuric renal failure.

OBJECTIVE: To determine the possible beneficial effect of providing decompression of the collecting system by continuous overnight catheter drainage (COCD) in children with progressive renal disease and dysfunctional bladder syndrome, commonly associated with polyuria which may overwhelm bladder capacity. PATIENTS AND METHODS: COCD was used in seven patients (four boys) with progressive polyuric kidney failure associated with dysfunctional bladders (current age 18.7 years, SD 5; age at COCD 12 years, SD 6). Five children had surgical bladder augmentation and all were prescribed daytime intermittent catheterization (IC) for a mean (SD) of 4.7 (3.4) years before COCD. All had significant polyuria, with a mean (SD) urine output of 2370 (971) mL/m2 per day. RESULTS: The mean (SD) glomerular filtration rate at the start of COCD was 48 (21) mL/min/1.73 m2, which is currently stable in the five patients continuing treatment. The mean (SD) duration of COCD was 4.9 (2) years. One patient showed no improvement and had a pre-emptive transplant within 1.2 years; another was transplanted after 5.5 years. Six patients showed evidence of benefit from COCD, with significant attenuation in the slope of renal functional decay (P = 0.02) and a mean (sd) prolongation of the predicted time to end-stage renal disease of 12.2 (5.6) years (P < 0.002). Hospitalization for febrile urinary tract infections was decreased from a mean (sd) of 1.7 (1.4) to 0.4 (0.7) times (P = 0.03) in the first year of COCD and eliminated by the second year (P < 0.01). CONCLUSION: COCD of the dysfunctional bladder in patients with progressive polyuric renal failure appears to offer the potential for preserving kidney function in selected patients. It does not replace surgical bladder augmentation or daytime IC in the core management.

Validity of random urines to quantitate proteinuria in children with human immunodeficiency virus nephropathy.

Accurate assessment of proteinuria in pediatric patients infected with the human immunodeficiency virus (HIV) is limited by constraints imposed by timed urine collections and low creatinine excretion in very ill patients with low muscle mass. We therefore sought to validate the use of random urine specimens to quantitate total protein and creatinine excretion in a population of 236 HIV-positive children. A mathematical derivation for estimating urine volume (V) was constructed. The accuracy of the final calculation [V = 832 (kL/Ucr)BSA] (where k = constant, L body length, UCr urine creatinine and BSA body surface area) was tested by regression analysis comparing the calculated and measured volume of 31 urines from ambulatory HIV-negative patients. The correlation coefficient was highly significant (r = 0.77, P < or = 0.0001). The relationship was also applied to 23 timed urine specimens from HIV-positive patients with similar significance (r = 0.87, P < 0.0001). A regression analysis of measured proteinuria against the urine protein: creatinine ratio (Upr/Ucr) in these same urines from the HIV-positive patients yielded a significant relationship both in the linear (r = 0.95, y = 0.4x) and the logarithmic regression (r = 0.97, y = x + 0.4). These data support the use of random Upr/Ucr ratios to estimate daily proteinuria in HIV-infected pediatric patients despite low creatinine excretion rates. The previously accepted values continue to apply, with Upr/Ucr < or = 2.0 considered normal and > 2.0 representative of nephrotic proteinuria.