Pyelonephritis differential diagnosis

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Usama Talib, BSc, MD [2] Syed Hassan A. Kazmi BSc, MD [3]

Overview

Pyelonephritis must be differentiated from other causes of dysuria such as cystitis, urethritis, prostatitis, vulvovaginitis, urethral strictures or diverticula, benign prostatic hyperplasia, STDs and neoplasms such as renal cell carcinoma and from causes of abdominal pain such as ectopic pregnancy, renal stone, peritoneal or iliopsoas abscess, and rib fracture.

Differential Diagnosis

The differential diagnoses of pyelonephritis include:

• Cystitis
• Ectopic pregnancy
• Ovarian torsion
• Ruptured ovarian cyst
• Rib fracture
• STDs
• Renal stone
• Benign prostatic hyperplasia
• Urethritis
• Prostatitis
• Vulvovaginitis
• Cervicitis
• Urethral strictures or diverticula
• Ureteritis
• Syphilis
• Neoplasms such as renal cell carcinoma
• Renal vein thrombosis

Differential Diagnosis on the basis of Urinary Symptoms

Pyelonephritis can be differentiated from other diseases that cause lower urinary tract irritation symptoms, such as: dysuria, urgency, and frequency, in addition to urethral discharge. The differential list includes: urethritis, cystitis, cervicitis, vulvovaginitis, epididimitis, prostatitis, and syphilis.

Disease	Findings
Cystitis	Bladder inflammation, Features with increased frequency and urgency, dysuria, and suprapubic pain. Is more common among women. E.coli is the most common pathogen.
Urethritis	Infection of the urethra,causes dysuria and urethral discharge
Bacterial vulvovaginitis	Presents with dysuria and pruritus, vaginal discharge and odor are almost always present, caused by Gardnerella species.
Cervicitis	Often asymptomatic,some women have an abnormal vaginal discharge and vaginal bleeding (especially after sexual intercourse)
Prostatitis	Bacterial infection of the prostate, causes discomfort during ejaculation
Epididymitis	Presents with scrotal pain and swelling accompanied by fever and lower urinary tract irritation symptoms(dysuria and frequency).
Syphilis	Presents with generalized systemic symptoms such as malaise, fatigue, headache and fever. Skin eruptions may be subtle and asymptomatic. It is classically described as 1) non-pruritic bilateral symmetrical mucocutaneous rash; 2) non-tender regional lymphadenopathy; 3) condylomata lata and 4) patchy alopecia.

Differential Diagnosis of flank pain

Since the pain of pyelonephritis radiates to the flank, it must be differentiated from various other causes of flank pain.

• Right flank pain can have the following life threatening causes:
  • Ischemic colitis
  • Ovarian torsion
  • Renal abscess
  • Renal artery dissection
  • Renal cyst rupture or hemorrhage
  • Ruptured abdominal aortic aneurysm
  • Renal vein thrombosis

• Left flank pain can have the following life threatening causes:
  • Abdominal compartment syndrome
  • Acute kidney injury
  • Acute pancreatitis
  • Adrenal hemorrhage
  • Eclampsia
  • Heavy metal toxicity
  • Hepatorenal syndrome
  • Ketoacidosis
  • Malignant hypertension
  • Mesenteric artery ischemia
  • Perforated gastric ulcer
  • Peritonitis
  • Pulmonary embolism
  • Pulmonary infarction
  • Renal abscess
  • Renal artery dissection
  • Traumatic splenic rupture

• The following table differentiates pyelonephritis from other conditions presenting with acute flank or upper abdominal pain, hematuria, nausea and vomiting. The differentials include the following:

Category	Disease	History	Signs and Symptoms											Physical Examination			Laboratory abnormalities
			Nausea/vomiting	Hematuria	Location of pain	Fever	Tachycardia	Hypotension	Hypertension	Anorexia	Constipation	Rebound abdominal tenderness	Urinary frequency/Urgency/Dysuria	Costovetebral angle tenderness	Pelvic Examination	Rectal Examination	Complete Blood Count (CBC)	Urinalysis	BUN	Creatinine	Stone analysis	Urine Beta- hCG	Abnormal Liver Function Tests (LFTs)	Serum Amylase/Lipase	Abdominal/Pelvic CT scan	Serum Parathyroid hormone levels (PTH)
Renal Pathology	Nephrolithiasis	Primary hyper parathyroidism Inadequate dietary calcium intake Hypercalciuria Hyperoxaluria Cystinuria Renal tubular acidosis Infection with urease producing bacteria (Ureaplasma urealyticum, Klebsiella, Protues)	+	+	Flank/back pain radiating to groin	-	+	-	-	+/-	-	-	+	-	-	-	-					-	-	-	Non-contrast CT scan may show stone as radiolucency	+/-
	Pyelonephritis	Urinary tract infection Immunocompromised state (Diabetes, immunosuppressive medications) Urinary tract obstruction History of pyelonephritis Pregnancy Presence of urinary catheter, stent, nephrostomy tube	+	+ (microscopic)	Costovertebral angle Positive renal punch sign	+	+	+	-	+/-	-	+	+	+	Urethritis Vaginitis	-	Leukocytosis	Pyuria Positive leukocyte esterase			-	-	-	-	Globaly decreased contrast uptake  Foci from abscess pockets	-
	Renal infarct	Sickle cell disease or trait Thrombosis Trauma Hypertension Cardiac arrhythmia Coagulopathy Atherosclerosis	+	+	Flank pain	+	+	-	+	-	-	-	-	-	-	-	Leukocytosis	Red blood cells Proteinuria			-	-				-
	Renal papillary necrosis	Analgesic use (Phenacetin, acetaminophen, NSAIDs) Pyelonephritis Urinary tract obstruction Sickle cell disease Tuberculosis Cirrhosis Diabetes Vasculitis Renal vein thrombosis	-	+ (microscopic)	Flank pain	+	+/-	-	+	-	-	-	+	-	-	-		Bacteriuria Pyuria Microscopic hematuria			-	-	-	-	Blunted renal calyces Contrast material–filled clefts in the renal medulla Non-enhanced lesions surrounded by rings of excreted contrast material Hyperattenuated medullary calcifications	-
	Renal cell carcinoma	Weight loss History of smoking Obesity Von-Hippel Lindau disease Night sweats Malaise Flank mass	+	+ (microscopic)	Flank pain	-	-	-	+	+	+/-	-	-	-	-	-	Anemia	Microscopic hematuria Renal cell casts Urinary aquaporin-1 (AQP1) and adipophilin (ADFP)- proximal renal tubular cancer			-	-	-	-	Non-contrast CT: Lesions are soft tissue attenuation  Areas of calcification and necrosis Contrast-enhanced: Homogenous (small lesions) to irregular (large lesions) contrast enhancement	-
	Uretral stricture	Prior urinary tract surgery Congenital Urinary catheterization Direct penile trauma	-	+/-	-	-	-	-	-	-	-	-	+	-	-	-	-	-			-	-	-	-	-	-
Gynecological Pathology	Pelvic inflammatory disease	Endometritis Saplingitis Cesarian section Septic abortion Urinary tract infection Tuberculosis Actinomycosis	-	-	Right/left upper quadrant	+	+	+	-	+	-	-	+	-	Cervical motion tenderness Adnexal tenderness Foul smelling vaginal/urtetheral discharge	-	Leukocytosis	Bacteriuria (Neisseria gonorrhoeae or Chlamydia trachomatis, polymicrobial) Pyuria			-	-	-	-	Thickening of the uterosacral ligaments Haziness of the pelvic fat Periovarian stranding Enhancement of the adjacent peritoneum Thick-walled, complex fluid collection with septa formation (abscess pockets)	-
	Ovarian torsion	Sudden acute pain Sharp pain aggravated by walking Intermittent/colicky pain	+	-	Unilateral poorly localized lower abdominal	-	+	-	-	-	-	-	-	-	Adnexal tenderness Adnexal mass	-	-	-	-	-	-	-	-	-	Twisted ovarian pedicle Enlarged ovary (>4.0 cm) Distended pedicle Possible underlying ovarian lesion	-
	Ectopic pregnancy	History of previous ectopic pregnancy Tubal surgery Intrauterine device usage History of pelvic surgery History of pelvic inflammatory disease Sub-fertility Sternous excercise Increased maternal age Cigarette smoking	+	-	Lower abdominal Unilateral shoulder or neck pain (referred)	-	+	-	-	+	-	+ (if ruptured)	+	-	Vaginal bleeding	-	Low platelet distribution width (decreased platelet activation) Monocytosis	-	-	-	-	+	+/-	-	N/A	-
Prostate Pathology	Prostatitis	Bacterial infection by: Ureaplasma urealyticum Proteus Chlamydia Gonorrhea E.Coli Pseudomonas Mycoplasma Prior history of prostatitis Urinary tract infection Urinary catheterization	-	+	Perineal pain Lower back pain Suprapubic pain	+	+	-	-	-	-	-	+	-	-	Enlarged prostate Rectal pain	Leukocytosis	Bacteriuria Pyuria Microscopic hematuria	-	-	-	-	-	-		-
	Prostatic cancer	Family history of prostate cancer (1st degree relatives) Germline mutation of HOXB13 (G84E variant) Black ethnicity Age > 50 years	-	+	-	-	-	-	-	+	-	-	+	-	-	Enlarged prostate Firm and hard	-	Positive prostate specific antigen (PSA) High levels of TMPRSS2:ERG and PCA3			-	-	-	-	Focal areas of mass-like enhancement in the peripheral prostate Calcifications	-
Testicular Pathology	Testicular torsion	Age 12 - 16 years Previous history of testicular torsion Family history of testicular torsion Prematurity Undescended testes Low birth weight	+	-	Sudden onset unilateral testicular pain	-	+	-	-	+/-	-	-	+/-	-	Absent cremasteric reflex Testicle may be swollen, tender, and high-riding, with an abnormal transverse lie.	-	-	-	-	-	-	-	-	-	Doppler ultrasound > CT scan for diagnosis (abscence of blood flow in the affected testis)	-
	Orchitis	Unprotected sexual intercourse Mumps, coxsackie virus infection Concurrent epididymitis Congenital abnornmalities Prostatitis Prostatic hypertrophy or calculi	+	-	Abrupt onset of testicular pain	+	+	-	-	-	-	-	+/-	-	Testicular swelling and tenderness Normal cremasteric reflex	-	Leukocytosis	-	-	-	-	-	-	-	Ultrasound > CT scan for diagnosis (Testicular masses or swollen testicles with hypoechoic and hypervascular areas)	-
Abdominal Pathology	Cholecystitis	Female gender Obesity Pregnancy (increased progesterone promotes biliary stasis) Rapid weight loss Oral contraceptive use Increasing age Total parenteral nutrition	+	-	Right upper abdominal quadrant pain Flank pain	+	+	-	-	+	-	-	-	-	-	-	Leukocytosis	-	-	-	Bilirubin (pigment) stones Cholesterol stones	-	+	+/-	Gallbladder distention Wall thickening Mucosal hyperenhancement, Pericholecystic fat stranding or fluid Gallstones	-
	Appendicitis	Male gender Adolescents Diet low in fiber and high in refined carbohydrates History of appendicitis in first degree relatives	+	-	Pain in umblical area Radiating to right lower abdominal quadrant	+	+	-	-	+	-	+	+/-	-	-	-	Leukocytosis	-	-	-	-	-	-	+ (if perforation)	Larger than 6 mm in diameter, Appendiceal wall thickening Wall enhancement after contrast media infusion Inflammatory fat stranding Phlegmon Free fluid Free air bubbles Abscess Adenopathy	-
	Diverticulitis	Diverticulosis Low fiber diet Old age	+	-	Left lower abdominal quadrant	+	+	-	-	+	+	-	-	-	-	Bleeding Rectal mass Rectal tenderness	Leukocytosis	-	-	-	-	-	-	+ (if perforation)	Colonic wall thickening (wall thickness is greater than 3 mm on the short axis of the lumen) Pericolic fat stranding	-
	Abdominal aortic aneurysm	Hypertension Cigarette smoking Pulsatile abdominal mass	-	-	Epigastric pain Deep boring pain in the back May radiate to flank	-	+	+	-	-	-	+ (if rupture)	-	-	-	-	-	-	-	-	-	-	-	-	Ultrasound more sensitive than CT scan CT scan may accurately predict the aneurysmal size Helical CT has faster scanning time (30 to 60 seconds) and the ability to obtain all images in one breath hold	-
	Portal vein thrombosis	Mutated JAK2 V617F Anti-phospholipid syndrome Paroxysmal nocturnal hemoglobinuria Homocysteinuria Factor V Leiden Prothrombin mutation G20210A Protein C or S deficiency Oral contraceptive use Cirrhosis Pregnancy and post-partum	+	-	Abdominal or lumbar pain	+	+	+	-	+	-	+ (if bowel ischemia or infarction-secondary to extension of thrombus to superior mesenteric vein)	-	-	-	Hematochezia	Anemia Thrombocytopenia	-	-	-	-	-	+	+ (if bowel infarction, perforation)	On non-contrast CT: Hyperdense thrombus On contrast CT Non-enhancing defect of bland thrombus Tumor thrombus exhibits enhancement
	Duodenal ulcer	Pain relieved by intake of food Helicobacter pylori infection Tobacco smoking NSAID use EtOH use Older age Female gender Family history of duodenal ulcers	+	-	Epigastric pain	+	+	+	-	-	-	+ (if perforation)	-	-	-	Melena	Anemia	-			-	-	-	+ (if bowel perforation)	Endoscopy > CT scan for diagnosis	-
	Ischemic colitis	Age > 60 years Hemodialysis Hypertension Hypoalbuminemia Diabetes mellitus	+	-	Acute-onset abdominal cramping	+	+	+ (if necrosis and sepsis)	+	+	+	+ (if transmural necrosis)	-	-	-	Hematochezia	Leukocytosis (if necrosis) Anemia (if perforation and bleeding)	-			-	-	-	+ (if bowel perforation)	Bowel wall thickening Thumbprinting Pericolonic stranding with or without ascites. Double halo or target sign  Submucosal edema or hemorrhage Pneumatosis coli (if infarction)	-

For a detailed review of the causes of right flank pain and left flank pain please visit the page on flank pain.