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Saudi Journal of Kidney Diseases and Transplantation
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ORIGINAL ARTICLE  
Year : 2011  |  Volume : 22  |  Issue : 6  |  Page : 1164-1168
Renal sonographic parameters in human immunodeficiency virus - infected subjects and relationship to CD4 cell count


1 Department of Radiology, University of Benin Teaching Hospital, Benin City, Nigeria
2 Department of Medicine, University of Benin Teaching Hospital, Benin City, Nigeria

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Date of Web Publication8-Nov-2011
 

   Abstract 

Nephropathy in human immunodeficiency virus (HIV)-infected patient is common and constitutes a major cause of endstage kidney disease. CD4 cell count is a useful parameter in the assessment of the degree of immunosuppression among HIV-infected patients. Manifestations of renal disease are thought to be more profound when CD4 cell counts are low. Sonography is a safe and inexpensive method of evaluating renal disease, including renal sizes and degree of echogenicity. Ultrasound examination was carried out prospectively at the University of Benin Teaching Hospital on 120 HIV-infected patients comprising 45 males (37.5%) and 75 females (63.5%). Renal sizes and degree of echogenicity were assessed. Correlation with CD4 + cell counts of the patients was done. Mean CD4 cell count mean was 18.34 ± 142.18 cells/mm 3 with female patients having a significantly higher cell count compared with males. Seventy-four patients (63.8%) had a cell count of <200 cells/mm 3 . Renal sizes were normal in 85%, small in 7%, and large in 8% of patients. Fifty patients (41.7%) had increased renal echogenicity and 8 (6.7%) had severe increased echo-texture. CD4 cell count did not correlate with renal sizes and echotexture. Results of this study show that large kidneys and marked increase in renal echotexture were not common even in a population of patients where the majority had CD4 cell count < 200 cells/mm 3 . This study shows that increased renal sizes and degree of echogenicity alone are not useful predictors of renal involvement in HIV/AIDS.

How to cite this article:
Adeyekun AA, Unuigbe EI, Onunu AN, Azubike CO. Renal sonographic parameters in human immunodeficiency virus - infected subjects and relationship to CD4 cell count. Saudi J Kidney Dis Transpl 2011;22:1164-8

How to cite this URL:
Adeyekun AA, Unuigbe EI, Onunu AN, Azubike CO. Renal sonographic parameters in human immunodeficiency virus - infected subjects and relationship to CD4 cell count. Saudi J Kidney Dis Transpl [serial online] 2011 [cited 2019 Nov 13];22:1164-8. Available from: http://www.sjkdt.org/text.asp?2011/22/6/1164/87226

   Introduction Top


Acquired immunodeficiency syndrome (AIDS) has reached pandemic proportions and a large majority of infected persons live in sub-Saharan Africa. The infection has its toll on kidneys among other organs and the human immunodeficiency virus-associated nephropathy (HIVAN) is the leading cause of endstage renal disease in American blacks. [1],[2],[3] Sonographic findings and particularly renal echogenicity have been reported as useful tools in predicting or diagnosing HIVAN. [4]

Despite the magnitude of the HIV/AIDS- related problems in the African continent, there is paucity of data from the region on AIDS and the kidneys. Agaba et al reported renal involve ment in 52% of patients with HIV/AIDS in North Central Nigeria, [5] whereas 17 cases of HIVAN were seen over a 12-month period at a tertiary care center in Eastern Nigeria. [6]

Sonography is a simple, rapid, noninvasive, and inexpensive tool that can readily be used in the evaluation of patients with renal disease. It is radiation free and does not involve the administration of intravenous contrast medium. Studies have shown that HIV-infected patients have enlarged, echogenic kidneys on ultrasonography. [7]

CD4 cell count is one of the baseline measurements and an important parameter used in the assessment and follow-up of AIDS patients. CD4 cell depletion in HIV-infected patients results from ongoing viral replication. It occurs late in the history of the disease and patients with CD4 cell counts < 200 cells/mm 3 have an increased risk of HIV-related morbidity and mortality. [8]

This study was undertaken to assess renal parameters by sonography in patients with HIV/AIDS and to determine the relationship, if any, between these and CD4 + cell count.


   Patients and Methods Top


The study was done at the University of Benin Teaching Hospital (UBTH), which is a referral center that serves Edo State and three other neighboring states in Nigeria. Patients with a diagnosis of HIV/AIDS and attending the Dermatology/Infectious Diseases outpatient clinics or admitted into the medical wards of UBTH were studied, following informed consent. Those with a known history of hypertension, diabetes mellitus, renal disease, and cardiac disease were excluded.

Biodata including age, sex, height (m), and body weight (kg) were recorded for all patients. Body mass index (BMI) was calculated using formula weight (kg)/height (m) 2 . BMI < 18.5 was regarded as underweight, 18.5-24.9 as normal weight, 25-29.9 and >30 as overweight and obese respectively. As part of baseline investigations for AIDS patients CD4 + cell count was estimated and results were stratified into 3 categories: >500/mm 3 , 200-499/mm 3 and <200/mm 3 .

Ultrasonographic kidney measurements were obtained on all patients by one of the authors, using an ALOKA SSD_500 machine (Aloka Co. Ltd, Japan), with a 3.5 MHz curvilinear probe.

Measurements taken included kidney length (cm), width (cm), cortical thickness (cm), area (mm 2 ), and volume (cm 3 ). Using bipolar measurement, kidney length of 9.0-11.9 cm was graded as normal, <9.0 cm as small and >12 cm as large. The degree of renal echogenicity was assessed using the right kidney only, and echogenicity was assumed to be equal for both sides. Renal echogenicity was graded into 4 categories: grade 0 (normal) where renal cortex was less echogenic than the liver, grade I (mild), where renal cortex and liver were equally echogenic, grade II (moderate), where renal cortex was more echogenic than the liver and grade III (severe), where the renal cortex and sinus were equally echogenic.

Data are presented as means ± standard deviation. Means were compared using Student's t test, and P values < 0.05 were considered significant. Pearson's correlation coefficient was used to assess correlation.


   Results Top


A total of 120 HIV-infected patients (45 males, 75 females) aged 18-70 years were studied. The age group 30-39 years constituted the largest proportion (41.7%) of the study population [Figure 1].
Figure 1: Histogram showing age distribution of subjects.

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Patients' characteristics

Characteristics of patients are shown in [Table 1]. The mean age of subjects was 36.84 ± 10.15 years. The mean age of males was significantly higher than that of the females (42.31 ± 9.85 year vs 33.65 ± 8.96 years, P < 0.0001).
Table 1: Characteristics of patients according to gender.

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The mean BMI for all subjects was 22.06 ± 4.81, 59% were of normal weight, and 22%, 10%, and 9% were underweight, overweight, and obese, respectively. Males had a lower mean BMI of 21.26 ± 3.69 compared with that of females 22.39 ± 5.19 (P = 0.32).

The results of CD4 cell count were available for statistical analysis in only 116 subjects. Mean CD4 cell count of the study population was 189.34 ± 142.18 cells/m 3 . Female patients had a higher CD4 cell count of 211.51 ± 192.16 cells/m 3 compared with the mean count of 151.70 ± 115.60 cells/m 3 in males (P = 0.028).

Renal sizes

Kidney sizes were normal in 99 (85%), small in 8 (7%), and large in 9 (8%) subjects. The renal measurements are shown in [Table 2]. The mean kidney length was 10.40 ± 0.99 cm for the left and 10.51 ± 0.97 cm for the right (P = 0.02). Likewise, the mean kidney widths differed significantly (4.52 ± 0.63 cm for left and 4.37 ± 0.59 cm for right, P = 0.000). However, there was no significant difference in the mean kidney area 3670.85 ± 769.89 cm 2 for left versus 3620.94 ± 699.97 cm 2 for right, P = 0.43). There were no significant differences between left and right kidney volumes and cortical thickness; the mean kidney volume was 120.76 ±3 7.39 cm 3 on the left and 127.28 ± 85.01 cm 3 on the right (P = 0.42), whereas the mean kidney cortical thickness was 4.67 ± 0.94 cm on the left and 4.57 ± 0.88 cm on the right (P = 0.13).
Table 2: Renal measurements of subjects.

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Renal echotexture

Seventy (58.3%), 16 (13.3%), 26 (21.7%), and 8 (6.7%) patients had normal, grade I, II, and III echogenicity, respectively.

Thus, only 50 (41.7%) of the study population had increased echogenicity.

CD4 cell count and correlates

CD4 cell count ranged from 30-370 cells/mm 3 . Six (5.2%) patients had cell count >500 cells/ mm 3 , 36 (31%) had counts 200-499 cells/mm 3 and 74 (63.8%) had counts <200 cells/mm 3 . [Table 3] shows the relationship between CD4 cell counts and gender, renal size and echotexture. Using Fisher's exact test-There was no association between the different levels of CD4 cell count and gender (P = 0.36), renal size (P = 0.17), and renal echotexture (P = 0.20). There was no correlation between CD4 cell count and renal size (r = -0.12, P = 0.18) and, likewise, CD4 cell count did not correlate with renal echogenicity (r = -0.07, P = 0.49).
Table 3: Correlation of CD4+ cell count with sonographic findings

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   Discussion Top


Ultrasonography is an important tool in the assessment of patients with renal disease, being noninvasive, rapid to perform, and relatively inexpensive. [4],[9] Majority of patients studied had normal sonographic kidney measurements, normal renal echogenicity, and markedly low CD4 + cell count. The low T-cell count in these patients is probably a result of late presentation coupled with poor access to treatment, characteristic of our environment. The mean right kidney length of 10.51 ± 0.97 cm was significantly more than that of the left kidney (10.40 ± 0.99 cm). This is not in agreement with previous reports where the left renal length was longer than the right. [10],[11],[12],[13] A probable explanation for this disagreement is that patients were scanned in the supine position only, and the ribs and spleen not being acoustically friendly could have affected optimal linear measurement.

Although enlarged kidneys are thought to be the consistent finding in HIV-positive patients, some reports have viewed this to be a misconception and have found normal-sized kidneys in HIV-infected patients. [14] Indeed, a majority of the patients (85%) in this study had normal-sized kidneys, which is consistent with reports from other parts of the world. [2],[15] Only 8% of the patients in this study had enlarged kidneys. This low prevalence of enlarged kidneys in HIV/AIDS is consistent with the findings of other workers who reported an 11%-20% prevalence of enlarged kidneys in HIV-infected patients. [12],[15],

There seems to be a relationship between the degree of immunosuppression and development of renal disease in HIV-infected patients. Renal disease in HIV-infected patients occurs as a late manifestation and when CD4 + cell counts are very low. [14] The most common abnormality in patients with HIV-related renal disorder is a highly echogenic renal cortex and the highest level of renal echogenicity has been reported to be suggestive of a diagnosis of HIVAN, particularly in cases where renal biopsies cannot be done or are contraindicated. [4] Despite the finding that more than half of the patients in this study had CD4 + cell counts < 200 cells/mm 3 , and therefore highly immunocompromised and likely candidates for development of HIVAN, only a small proportion (6.7%) had markedly increased echogenicity. Our finding of normal echogenicity in 58.3% of patients studied compared with the report of Hamper et al where 42% of their study population had normal echogenicity. [15] No significant relationship or correlation was found between CD4 + cell counts and renal echogenicity in this study.

The etiology of the highly echogenic kidneys in patients with HIVAN is not quite clear but it has been postulated to be partly due to glomerular changes, tubular dilation and rapidly rising creatinine levels. [4],[16] We are unable to comment on the role of these factors in the degree of echogenicity found in patients because renal biopsies were not done. We therefore suggest that from the apparently low prevalence of renal involvement seen in our patients (using renal echotexture as a tool); probably other factors apart from immunosuppression seem to play a role in the degree of renal echogenicity that may be seen on ultrasound examination of HIV-infected patients.

This report found normal renal dimensions and echotexture among most of the HIV-infected patients that were studied. Even in those with abnormal renal sonographic parameters, there was a poor correlation between these and the degree of immunosuppression. The results of this study indicate that it may be difficult to clinically predict later development of renal disease using these sonographic parameters alone.

 
   References Top

1.D'Agati V, Appel GB. HIV infection and the kidney. J Am Soc Nephrol 1997;8:138-52.  Back to cited text no. 1
    
2.Winston JA, Burns GC, Klotman PE. The human immunodeficiency virus (HIV) epidemic and HIV-associated nephropathy. Semin Nephrol 1988;18:393-7.  Back to cited text no. 2
    
3.US Renal Data System: USRDS 1999 Annual Data Report, Bethseda MD, National Institute of Health, National Institute of Diabetes, and Digestive and Kidney Diseases 1999.  Back to cited text no. 3
    
4.Atta MG, Longenecker JC, Fine DM, et al. Sonography as a predictor of human immunodeficiency virus-associated nephropathy. J Ultrasound Med 2004;23:603-10.  Back to cited text no. 4
    
5.Agaba EL, Agaba PA, Sirisena ND, Anteyi EA, Idoko JA. Renal disease in the acquired immunodeficiency syndrome in north central Nigeria. Niger J Med 2003;12:120-5.  Back to cited text no. 5
    
6.Ijeoma CK. HIV Nephropathy in Enugu. J Coll Med 1996;1:57-9.  Back to cited text no. 6
    
7.Cohen AH. HIV-associated nephropathy: Current concepts. Nephrol Dial Transplant 1998;13:540-2.  Back to cited text no. 7
    
8.Carpenter C, Fischl MA, Hammer SM, et al. Antiretroviral therapy for HIV infection in 1997. JAMA 1997;277:1962-9.  Back to cited text no. 8
    
9.O'Neill WC. Sonographic evaluation of renal failure. Am J Kidney Dis 2000;35:1021-38  Back to cited text no. 9
    
10.Odita JC, Ugbodaga CI. Roentgenologic estimation of kidney size in adult Nigerians. Trop Geog Med 1982;34:177-81.  Back to cited text no. 10
    
11.Oviasu E, Benka-Coker LB. Renal size in sickle cell haemoglobinopathy. J Nephrol 1994;7:175-7.  Back to cited text no. 11
    
12.Oviasu E, Benka-Coker LB. Renal size in healthy adult Nigerians: An ultrasonographic assessment. Niger Med J 1998;34:20-2.  Back to cited text no. 12
    
13.Buchholz NP, Abbas F, Biyabani SR, et al. Ultrasonographic renal size in individuals without known renal disease. J Pak Med Assoc 2000;50:12-6.  Back to cited text no. 13
    
14.Winston JA, Klotman ME, Klotman PE, HIV-associated nephropathy is a late, not early, manifestation of HIV-1 infection. Kidney Int 1999;55:1036-40.  Back to cited text no. 14
    
15.Hamper UM, Goldblum LE, Hutchins GM, et al. Renal involvement in AIDS: sonographic-pathologic correlation. AJR Am J Roentgenol 1988;150:1321-5.  Back to cited text no. 15
    
16.Di Fiori JL, Rodrigue D, Kaptein EM, Ralls PW. Diagnostic sonography of HIV-associated nephropathy: New observations and clinical correlation. AJR Am J Roentgenol 1998;171: 713-6.  Back to cited text no. 16
    

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Correspondence Address:
Ademola A Adeyekun
Department of Radiology, University of Benin Teaching Hospital, PMB 1111 Benin City
Nigeria
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PMID: 22089775

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