genitourinary tuberculosis ( tb ) is the second most common extrapulmonary form of tb after lymphadenopathy .
genitourinary tb accounts for 27% ( range 1441% ) of nonpulmonary cases and is usually a late complication of pulmonary tb .
renal damage due to caseous destruction of renal parenchyma or obstructive uropathy is well known .
made the first clinical description of granulomatous interstitial nephritis ( gin ) as the only manifestation of renal tb .
overall , data on gin as the only manifestation of renal tb is limited to case reports and the most common clinical presentation is chronic renal insufficiency .
interestingly , most patients of gin express active extrarenal foci , often pulmonary or peritoneal .
we report a case of tuberculous gin associated with active cervical lymphadenitis and review the pertinent literature on gin due to tb in immunocompetent individuals .
a 24-year - old previously healthy man developed fever and left cervical lymphadenopathy for which he was prescribed antibiotics ( erythromycin ) and antipyretics ( paracetamol ) for 2 weeks .
he was also prescribed two antihypertensive drugs and advised further evaluation for proteinuria , which he deferred .
two weeks later , he was referred to our center for fever , lymphadenopathy and recently detected renal failure .
there was no history of treatment or contact with tb , loss of weight , red urine , skin rash , joint pains or use of native medicines .
physical examination revealed pallor , bilateral pedal edema , pulse rate 92/min , blood pressure of 160/100 mmhg , temperature 38c and respiratory rate 15/min .
g / l ) was decreased and erythrocyte sedimentation rate was elevated to 94 mm / h .
white blood cell count of 10.9  10/l ( 410  10/l ) with neutrophils 72% , lymphocytes 23% , eosinophils 3% and monocytes 2% , platelet count 205  10/l ( 150400  10/l ) and reticulocyte count 1.2% were normal .
serum creatinine was increased to 660 mol / l ( 44140 mol / l ) and the estimated four - variable modification of diet in renal disease- glomerular filtration rate was 9.59 ml / min/1.73 m .
serum uric acid , calcium , inorganic phosphorus , liver function tests and lipid profile were within normal limits .
there were 01 white blood cells per high power field , 810 red blood cells per high power field and no evidence of casts on microscopic examination of the urine sediment .
antinuclear antibody ( negative ) , anti - dsdna ( 12.25 , 030 iu / ml ) and anti - gbm titers ( <3
cervical lymph node aspiration cytology showed granulomatous necrotizing inflammation with acid - fast bacilli ( afb ) suggestive of tb .
he was initiated on antitubercular treatment ( att ) , maintenance hemodialysis and ultrasound - guided percutaneous renal biopsy were done to identify the cause of rapidly progressive renal failure ( rprf ) . on light microscopy , 19 of the 22 glomeruli were normal and 3 showed global sclerosis .
interstitium showed lymphoid aggregates with well - formed epitheloid granulomas along with intense mononuclear infiltrate comprising of lymphocytes , histiocytes and plasma cells ( figures 1 and 2 ) .
immunofluorescent micrography revealed absence of specific immunoglobulin or complement ( c3 , c1q ) deposits .
afb were not seen on ziehl  nielsen staining and cultures for tubercle bacilli in renal biopsy were negative .
on further evaluation , three samples of urine microscopy and culture for mycobacterium were negative and bone marrow examination was unremarkable .
mantoux test was negative . however , urine dna - polymerase chain reaction ( pcr ) for mycobacterium tuberculosis was positive .
he was started on steroid ( oral prednisolone 1 mg / kg / day ) together with att .
six months since the onset of illness , his lymphadenopathy resolved but renal failure did not recover .
steroids were tapered and withdrawn after 3 months and the patient is now on att and maintenance hemodialysis through radial arteriovenous fistula .
renal biopsy showing epithelioid cell granuloma ( a ) , sclerosed glomerulus ( b ) , atrophic tubules ( c ) and interstitial inflammation ( d ) ; ( hematoxylin and eosin stain ; 20 magnification ) .
( a , b ) epithelioid cell granuloma surrounded by mantle of lymphocytes ( hematoxylin and eosin stain ; 40 magnification ) ( epithelioid cell marked with arrow in figure 2b ) .
the interesting features in our patient were ( i ) coexistence of active renal and cervical lymph node tb in a 24-year - old male , ( ii ) gin presenting as rprf and nephrotic range proteinuria and ( iii ) diagnosis was made by positive urine pcr for m. tuberculosis , when afb could not be demonstrated in urine or renal biopsy .
renal tb is rarely present in patients < 25 years of age and can occur during primary infection or pulmonary reactivation . if there is a history of pulmonary infection , the latency period from the time of the initial infection to diagnosis with renal disease ranges from 5 to 40 years .
coexistence of active renal and cervical lymph node tb is a deviation from the normal time frame for development of renal tb .
similar case reports of gin with pulmonary and peritoneal foci are described , but to the best of our knowledge , this is the first report of cervical adenitis in a patient with gin due to tb .
it is possible that our patient had a primary infection involving the lymph node and the kidneys .
another remarkable feature is the clinical presentation of hypertension , rprf and nephrotic range proteinuria , mimicking a glomerular disease
. similar presentation of gin has so far been reported in only one other patient   and there is no possible explanation for the nephrotic proteinuria seen in these patients .
such presentations may be seen with non - steroidal anti - inflammatory drug - induced acute interstitial nephritis but in our case , detailed evaluation for other causes of gin like drugs , infections and systemic conditions like sarcoidosis , wegener s granulomatosis revealed negative results .
urine cultures ( three to five samples ) of the first urine of the day are considered 
gold standard in diagnosis of genitourinary tb but are often negative . in comparison to urine cultures , pcr primers and probe derived from m. tuberculosis species - specific dna insertion sequence , is6110 has an overall sensitivity of 95.59% and specificity of 98.12% in the diagnosis of genitourinary tb .
summary of case reports with gin due to renal tba 
  esrd  end - stage renal disease ; na  not available ; neg  negative ; cr  complete recovery ; pr  partial recovery . other diagnostic techniques .
gin is seen in only in 0.50.9% of renal biopsy and of this 5% is caused by infections [ 1113 ] . often , features on biopsy do not help to determine the cause of gin .
afb may be demonstrated in the renal biopsy tissue with ziehl  nielsen or auromine - o stain but is positive only in 3243% of specimens .
we suspected tb as the cause of gin due to the presence of afb in the cervical lymph node and subsequently , a positive urine dna pcr for m. 
  tuberculosis helped to confirm the diagnosis .
att ( two , three or four drugs of isoniazid , rifampicin , pyrazinamide and ethambutol ) has been used to treat all these patients .
it has been observed that concomitant use of steroids bring about favorable recovery in these patients . since granulomatous inflammation heals by fibrosis ; steroids may decrease the inflammation and thereby reduce the amount of interstitial fibrosis .
reported a similar case presenting as rprf with nephrotic proteinuria and obtained complete renal recovery with a combination of att and steroids .
remarkably , the majority of these ( rare ) cases were observed in patients from india or black africans or african - americans . this could be due to a genetic predisposition causing varied host immune response or due to variations in phage type of m. tuberculosis
, tb must be considered as a cause of gin particularly in patients with asian or african origin .
urine pcr can have a significant role in the diagnosis of culture negative renal tb .
steroids in combination with att should be considered as the first - line treatment for gin due to tb .
 granulomatous interstitial nephritis ( gin ) is a rare manifestation of renal tuberculosis ( tb ) . 
 we report a case of rapidly progressive renal failure ( rprf ) , granulomatous inflammation of cervical lymph node and gin as presenting manifestations of tb . 
 aspiration cytology of cervical lymph node showed granulomatous necrotizing inflammation with acid - fast bacilli ( afb ) . 
 the renal biopsy and urine specimen did not show afb . 
 urine polymerase chain reaction ( pcr ) for mycobacterium tuberculosis was positive . 
 we observe that gin due to tb can present as rprf and emphasize the value of pcr - based techniques in making a correct diagnosis . 
Introduction
Case history
Discussion