Saudi Journal of Kidney Diseases and Transplantation

: 2012  |  Volume : 23  |  Issue : 5  |  Page : 1046--1050

Emphysematous pyelonephritis in a patient infected with the human immunodeficiency virus

PA Mohamed Ashif, P Sandeep, PK Sasidharan 
 Department of Internal Medicine, Calicut Medical College, Thrissur, Kerala, India

Correspondence Address:
P A Mohamed Ashif
Department of Internal Medicine, Calicut Medical College, Thrissur, Kerala


Emphysematous pyelonephritis (EPN) is a rapidly progressive and life-threatening infection that is seen most commonly in persons with diabetes. The infecting organisms usually consist of mixed flora, including Escherichia coli (68%), Klebsiella pneumoniae (9%) and Proteus mirabilis. Females are affected twice as often as men, and mortality rates can be as high as 80%. Obstructive uropathy, urinary calculi, calyceal stenosis and neoplasms are significant predis­posing factors. We report a case of EPN in a patient with the human immunodeficiency virus infection, without diabetes mellitus or urinary tract obstruction, which responded remarkably to conservative management with antibiotics alone.

How to cite this article:
Mohamed Ashif P A, Sandeep P, Sasidharan P K. Emphysematous pyelonephritis in a patient infected with the human immunodeficiency virus.Saudi J Kidney Dis Transpl 2012;23:1046-1050

How to cite this URL:
Mohamed Ashif P A, Sandeep P, Sasidharan P K. Emphysematous pyelonephritis in a patient infected with the human immunodeficiency virus. Saudi J Kidney Dis Transpl [serial online] 2012 [cited 2022 Jan 21 ];23:1046-1050
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Emphysematous pyelonephritis (EPN) is a life-threatening fulminant, necrotizing upper urinary tract infection associated with gas in the kidney and/or peri-nephric space. The usual etiological agents are Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudo­monas, Enterobacter, Candida and, rarely, Clostridia species. Few cases have been reported with Ameba and Aspergillus.

Uncontrolled diabetes with high levels of glycosylated hemoglobin, urinary tract obstruc­tion in non-diabetics and impaired host defense mechanisms are the usual predisposing factors. Only very few cases have been reported in patients infected with the human immuno­deficiency virus (HIV) without evidence of urinary tract obstruction.

 Case Report

A 40-year-old lady, a native of Andhra Pradesh, India, presented to our emergency department with severe abdominal pain, hematuria, vomi­ting and loose stools of one week duration. The abdominal pain was diffuse and was asso­ciated with abdominal distension. The hematuria was described as frank blood.

She had a history of significant weight loss over a period of six months. She had pulmo­nary tuberculosis four years back and received anti-tuberculous therapy. She was not a dia­betic or hypertensive. On clinical examination, she was emaciated and pale, with glossitis, angular stomatitis and oral candidiasis. She was febrile, with an axillary temperature of 102°F. She had diffuse tenderness all over the abdomen. There was gaseous abdominal dis­tension. Her liver was palpable 4 cm below the right costal margin, and was soft in consis­tency with sharp borders.

A plain X-ray of the abdomen, taken in the erect posture, showed a gas shadow in the left upper abdomen that was obliterating the psoas shadow and causing scoliosis of the spine. These features were suggestive of retroperitoneal gas collection [Figure 1]. An ultrasonogram gave a report of the left kidney being not visualized. Blood tests showed a total count of 9700 cells/mm 3 (differential count of 50% polymorphs, 40% lymphocytes and 10% eosinophils), hemoglobin of 6 g/dL and platelet count of 1 lac/mm 3 . The random blood sugar value was 150 mg/dL. Renal function tests showed slightly elevated blood urea and serum creatinine levels (blood urea: 135 mg/dL, serum creatinine: 1.8 mg/dL). Routine examination of the urine revealed plenty of pus cells and numerous red blood cells per high-power field. She tested positive for HIV-1 by enzyme-linked immunosorbent assay (ELISA).{Figure 1}

A repeat ultrasonogram performed the next day showed highly echogenic areas with dirty shadowing in the region of the left kidney, which was suggestive of EPN. A plain compu­terized tomography (CT) scan of the abdomen confirmed the diagnosis of EPN stage-3b [Figure 2]. The CT scan also demonstrated a large amount of gas with minimal fluid col­lection in the renal parenchyma extending into the peri-nephric space. Meanwhile, the blood and the urine cultures grew E. coli, which was sensitive to cefotaxime, ceftriaxone, ciprofloxacin and amikacin.{Figure 2}

She was catheterized and started on ampicillin, cefotaxime and metronidazole according to the culture reports. A urology opinion was sought as to whether surgical intervention was necessary. Taking into consideration the gene­ral condition of the patient, a conservative line of management was chosen. She had no evi­dence of urinary tract obstruction and the blood sugar values (fasting and post-prandial values, 70 mg/dL and 120 mg/dL, respectively) showed that she was not a diabetic. After one week of antibiotic therapy, she improved and became afebrile; hematuria disappeared and her clinical examination was normal except for mild tenderness in the left renal angle. Anti­biotic therapy was continued for two more weeks and X-ray abdomen taken subsequently showed marked reduction in the gas shadow. The general well-being of the patient improved in three weeks and the blood and urine cultures became negative. She was discharged on oral antibiotics and was asked to review in the anti-retroviral therapy clinic for planning therapy.


EPN is a life-threatening, fulminant, necrotizing upper urinary tract infection associated with gas within the kidney and/or peri-nephric space. Some confusion exists regarding the terminology; the term EPN should be reserved for renal tract infections with intra-parenchymal renal gas. Gas confined to the renal pelvis should be called emphysematous pyelitis and gas confined to the peri-nephric space should be called peri-nephric emphysema. EPN is usually a rapidly progressive and life-threa­tening infection that is seen most commonly in persons with diabetes. The infecting organisms usually consist of mixed flora, including E. coli (68%), [1],[2],[3] K. pneumoniae (9%) and P. mirabilis. Other organisms include Pseudomonas, Enterobacter, Candida and, rarely, Clostridia spe­cies. Females are affected twice as often as men, and mortality rates can be as high as 80%. Some salient predisposing factors include obs­tructive uropathy, urinary calculi, calyceal ste­nosis and neoplasms.

EPN is an acute and chronic necrotizing pyelonephritis with multiple renal abscesses. Mixed acid fermentation of glucose by Enterobacteriaceae bacteria is the major pathway of gas formation. In 1889, Muller first identified nitrogen, hydrogen and carbon dioxide in a patient with pneumaturia. [4],[5] Schainuck et al proposed that fermentation products from tissue necrosis produced carbon dioxide. [6] Three in­vestigators analyzed the gas content, and all demonstrated that the major components of the gas in EPN are nitrogen (60%), hydrogen (15%), carbon dioxide (5%) and oxygen (8%). [7]

Huang et al concluded that mixed acid fermen­tation is the mechanism of gas production based on the presence of hydrogen. [7]

Two subtypes of EPN, based on CT appea­rances, have been described. Type-I EPN (33% of patients) is characterized by paren-chymal destruction with either absence of fluid collection or presence of streaky or mottled gas radiating from the medulla to the cortex. A crescent of sub-capsular or peri-nephric gas may be present. The absence of fluid collec­tion implies a poor immune response. The mortality rate is high at 66%. Type-II EPN (66% of patients) typically has a confined bubbly intrarenal gas pattern, probably within abscesses associated with renal and peri-nephric fluid collection, and gas within the renal pelvis. The mortality rate in type-II is 18%. [8] Conversion from type-I to type-II EPN has been described.

Wan et al have shown that serum creatinine levels are the most reliable predictors of the outcome in patients with EPN. [8] By calculating likelihood ratios, patients with creatinine le­vels greater than 1.4 mg/dL and platelet counts of 60,000/mm 3 or less are at high risk. The post-test probability of death increases from 69% to 92% in type-I EPN and 18% to 53% in type-II EPN. Patients with creatinine levels of 1.4 mg/dL or less and platelet counts greater than 60,000/mm 3 are at much lower risk. The post-test mortality risk in these patients de­creases from 69% to 27% and from 18% to 4% for type-I and type-II EPN, respectively.

Patients with EPN often have diabetes (87- 97%). Females are affected twice as often as men. The mortality rate can be as high as 80%. Multiple conditions are associated with EPN, such as poorly controlled diabetes, acidosis, dehydration and electrolyte imbalance. Treat­ment involves aggressive antibiotic therapy, drainage procedures to relieve obstruction and prompt nephrectomy in life-threatening situa­tions.

Patients usually present with chills, fever, flank pain, lethargy and confusion not res­ponding to treatment. EPN may cause fever of unknown origin in 18% of the patients. Septicemic shock and abdominal symptoms are less common manifestations. A crepitant mass may be present. Bacteriuria, positive blood culture results and leukocytosis are often present. A presentation with pneumaturia has been des­cribed. Patients are usually quite ill but, occa­sionally, the symptoms are mild, belying the severity of the disease. This is particularly the case in patients with long-standing diabetes. EPN is bilateral in 5-7% of the patients. Plain X-ray of the abdomen is the initial exami­nation of choice because it better depicts air in the renal collecting system and it is much more specific than ultrasonography. However, in practice, sonography may be the initial exami­nation performed. The findings on CT scan are diagnostic by the presence of air within the renal tract, and also elegantly depict the renal and peri-renal anatomy and the spread of infection to the peri-nephric tissues.

Because function is depressed or even absent in the affected kidney, radionuclide studies are more appropriate for assessing renal function, particularly if surgery is indicated. Intravenous urography may be necessary if renal inter­vention is contemplated. Staging of the disease is done by CT scan assessment. [9]

Class 1 - Gas confined to the collecting systemClass 2 - Gas confined to the renal parenchyma aloneClass 3A - Peri-nephric extension of gas or abscessClass 3B - Extension of gas beyond the Gerota fasciaClass 4 - Bilateral EPN or EPN in solitary kidney

Patients with EPN should be treated with aggressive medical management and, possibly, prompt surgical intervention.

Conservative treatment with or without per­cutaneous drainage with antibiotics is under­taken in the following situations: [10] patients with compromised renal function, early cases associated with gas in the collecting system alone and the patient is otherwise in stable condition, patients with class-1 and class-2 EPN, patients with class-3 and class-4 EPN in the presence of fewer than two risk factors (e.g., thrombocytopenia, elevated serum creatinine, altered sensorium or shock).

Surgical treatment in the form of nephrectomy is the treatment of choice for most pa­tients, particularly in the following situations: patients with no access to percutaneous drai­nage or internal stenting (after patient is stabi­lized), gas in the renal parenchyma or "dry­type" EPN, possible bilateral nephrectomy in patients with bilateral EPN and those with class-3 and class-4 EPN, particularly in the presence of more than two risk factors such as thrombocytopenia, elevated serum creatinine, altered sensorium or shock.

EPN can be life-threatening in the absence of prompt diagnosis and an early start of treatment and carries a mortality rate as high as 78% universally. [11] However, advances in imaging technology, control of diabetes, resuscitative management and minimally invasive treatment have improved the outcome in patients with EPN. While nephrectomy may be the quickest way of treating the source of infection, many patients have compromised renal function and a strategy to save nephrons can be very desirable. The recent series of studies highlights such an approach, reserving nephrectomy only for patients who do not respond to conservative treatment.

In conclusion, EPN is a life-threatening con­dition and is lethal to the patient unless aggres­sively managed with percutaneous nephrostomy with drainage or nephrectomy. Our pa­tient was managed conservatively on antibio­tics and even in the presence of risk factors like thrombocytopenia and altered renal func­tion; there was almost complete cure for this disease entity. Also, it is very rare to see cases of EPN in patients without diabetes or signi­ficant urinary tract obstruction.


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