Sandbox: sadaf

Differential Diagnosis

Abbreviations: ABG = Arterial blood gases, BUN = Blood urea nitrogen, CBC = Complete blood count, CT = Computed tomography, CRP = C – reactive protein, ECG = Electrocardiogram, ESR = Erythrocyte sedimentation rate, IVP = Intravenous pyelography, KFT = Kidney function test, GI = Gastrointestinal, GFR = Glomerular filtration rate, MRI = Magnetic resonance imaging, PT = Prothrombin time

Etiology		Clinical manifestations									Paraclinical findings											Comments
		Symptoms and signs									Lab findings						Imaging
		Fatigue/ Lethargy	Thirst	Dizziness/ Confusion	Muscle weakness/ cramp	Somatic/ visceral pain	Vomiting	Diarrhea	Tachypnea	Edema	Blood indices	Renal Funtion test	Electrolytes	Urine analysis	ABG	Other	Ultrasound	X–ray	CT	MRI	Other
Prerenal causes	Alcohol poisoning	+	–	±	–	±	+	±	–	–	↑PT	↑BUN, ↑Cr (isopropyl alcohol)	↓Na	NA	↓HCO3	Abnormal LFT	NA	NA	NA	NA	–	Administer thiamine to prevent Wernicke's encephalopathy
	Aspergillosis	±	–	–	–	–	–	–	±	–	NA	NA	NA	NA	NA	Allergy test, ↑IgE (>1000 IU/dl), Direct visualization of fungal hyphae	NA	Pulmonary infiltrates, Mucus plug, Mass in the upper lobe surrounded by a crescent of air, Solitary or multiple cavities	Halo sign, Wedge–shaped pulmonary infarction, Granuloma	NA	–	Polymerase chain reaction (PCR)
	Cholera	±	+	–	–	–	±	+	–	–	Leukocytosis, ↑HCT	↑BUN, ↑Cr	↓Na, ↑Ca, ↑Mg	NA	↑Lactate, ↓HCO3	Stool PCR, Stool culture, Serotyping	NA	NA	NA	NA	–	–
	Congestive heart failure (CHF)	+	–	–	–	–	–	+	–	+	Anemia, Leukocytosis	↑BUN, ↑Cr	↓Na, ↑K	NA	↑Lactate, ↓HCO3,	↑BNP, ↑Troponin	Cardiomegaly, Pulmonary hypertension, Pleural effusions	Pulmonary edema	NA	Valvular heart disease	Decreased ejection fraction in echocardiography, Heart function and damage in nuclear imaging	–
	Dehydration	+	+	–	±	–	±	±	–	–	NA	↑BUN, ↑Cr	↓Na, ↑K, ↓Cl	Ketones and glucose, ↑Urine specific gravity	↑Lactate, ↓HCO3	Hypoglycemia	NA	NA	NA	NA	–	–
	Diarrhea and/or vomiting	±	±	–	–	–	+	+	–	–	Leukocytosis with predominant neutrophilia, ↑ ESR	NA	NA	Ketones, Organic acids, Porphobilinogen, Aminolevulinic acid	NA	Stool anion gap, Stool pH < 5.5, Stool culture, Serotyping, Enzyme immunoassay (rotavirus or adenovirus), LFT, Amylase, Lipase	Normal	NA	NA	NA	–	–
	Drugs/toxins	±	±	±	±	±	±	±	±	±	NA	↑BUN, ↑Cr, ↑CK	↑K, ↓Mg, ↓Ca, ↓P	Ingested drug, Glucose, Aminoacid, Phosphate, Ketone, Hyaline cast, RBC	↑Lactate, Metabolic acidosis	Toxicology, Rapid immunoassay	Nephropathy	Radioopaque substances, Ingested drug packets	NA	NA	–	–
	Esophageal varices bleeding	±	–	–	–	±	–	–	–	–	Normocytic normochromic anemia	↑BUN, ↑Cr	NA	NA	NA	NA	Velocity and direction of portal flow	Abnormal opacities outside ofesophageal wall, Posterior mediastinal or intraparenchymal mass, Dilated azygous vein	Entire portal venous system	Portrays esophageal varices as flow voids	Portal hypertension and esophageal varices in positron emission tomography, Flexible endoscope, Barium swallow of snake–like filling defects	–
	Heart disease	±	–	–	–	–	–	–	±	±	↑ESR and CRP	↑BUN, ↑Cr	NA	NA	NA	Throat culture, Rapid streptococcal antigen test, Hyperoxia test, Pulse oximetry	NA	Cardiomegaly, Dextrocardia	NA	NA	Ventricular dysfunction, Left and right ventricular hypertrophy, Valvular disease in echocardiography	–
	Hemorrhage	–	–	–	–	–	–	–	–	–	Normocytic normochromic anemia, ↑PT, ↑PTT	↑BUN, ↑Cr	↑Na, ↑Cl, ↓Ca	NA	Metabolic acidosis	NA	Peritoneal cavity fluid in FAST	Bilateral opacities in the lung field, Hemothorax, Hemoperitoneum, Ruptured abdominal aortic aneurysm	Intrathoracic, intra–abdominal, and retroperitoneal bleeding	NA	Source of bleeding in the upper GI in EGD, Angiography	–
	Hemolysis	±	–	–	–	–	–	–	–	–	Thrombocytopenia, Microcytic hypochromic anemia, ↑RDW, ↑Retic count	NA	NA	NA	NA	↑LDH, ↓Haptoglobin, ↑Unconjugated bilirubin	Hepatomegaly,Splenomegaly	NA	NA	NA	–	–
	Etiology	Fatigue/ Lethargy	Thirst	Dizziness/ Confusion	Muscle weakness/ cramp	Somatic/ visceral pain	Vomiting	Diarrhea	Tachypnea	Edema	Blood indices	Renal Funtion test	Electrolytes	Urine analysis	ABG	Other	Ultrasound	X–ray	CT	MRI	Other	Comments
	Hepatorenal syndrome	±	–	–	–	±	±	–	–	±	Leukocytosis, ↑PT	↓GFR, ↑BUN, ↑Cr	↓Na	Proteinuria, Na < 10 mEq/L, Urine osmolality > plasma osmolality	NA	Alpha feto–protein, Cryoglobulinemia	Exclude hydronephrosis and intrinsic renal disease	NA	NA	NA	Right ventricular preload, ventricular filling pressures, and cardiac function in echocardiography	–
	Ischemic cardiomyopathy	±	–	–	–	–	–	–	±	±	Anemia	↑Cr	↓Na, ↓K, ↓Mg	NA	NA	Troponin, Creatine kinase, Creatine kinase – MB, BNP	NA	Abnormal cardiac silhouette	Biventricular volume, Wall motion abnormality, Myocardial perfusion, Hypertrophic cardiomyopathy	Mid–wall fibrosis in MRI	Ejection fraction ≤35%, Pulmonary embolism, Right ventricular dilation or pericardial effusion with tamponade in echocardiography	–
	Liver cirrhosis	±	–	±	±	±	–	–	–	±	NA	NA	NA	NA	NA	LFT, Aspartate aminotransferase to platelet ratio, FibroTest/FibroSure, Hepascore, FibroSpectatio	Portal blood flow velocity, Hepatic artery enlargement, Multifocal lesions or masses, Hepatic contour, Ascites, Splenomegaly	Bowel perforation, Gynecomastia, Azygos vein enlargement, Pleural effusion	Morphologic changes in the liver, Collaterals and shunts, Hyperattenuating nodule of hepatocellular carcinoma, Portal vein thrombosis	Vacular patency, Tumor invasion, Portal vein thrombosis, Steatosis	Hepatic function and portal hypertension in nuclear imaging, Hepatic perfusion and the development of shunts and tumors in angiography	Irreversible and a transplant is usually needed
	Malignant hypertension	±	–	+	–	–	±	–	±	±	Microangiopathic hemolytic anemia	↑BUN, ↑Cr	↑Na, ↑K, ↑P	Proteinuria, Microscopic hematuria	Acidosis	Cardiac enzymes, Urinary catecholamines, TSH, ↑Renin	NA	Cardiomegaly, Pulmonary edema, Rib notching, Aortic coarctation, Mediastinal widening, Aortic dissection	NA	NA	Left atrial enlargement and left ventricular hypertrophy in echocardiography	–
	Myocarditis	±	–	–	–	±	–	–	±	–	Leukocytosis (eosinophilia),↑ESR and CRP	NA	NA	NA	NA	Cardiac enzymes, Viral antibodies	NA	NA	NA	Inflammatory edema, Degree of scarring	Endomyocardial biopsy, Echocardiography, Scintigraphy	NA
	Peritonitis	±	–	±	–	±	±	±	–	–	Leukocytosis	NA	NA	NA	NA	Ascitic fluid neutrophil count > 500 cells/µL	NA	NA	NA	NA	–	–
	Polycythemia	±	–	–	–	–	–	–	±	–	↑RBC, ↑HCT, ↑HGB, Thrombocytosis, Leukocytosis, ↑PT and aPTT	↓Erythropoietin	NA	NA	NA	Hyperuricemia	Splenomegaly	NA	NA	NA	–	Phlebotomy is the usual treatment
	Respiratory distress syndrome	+	–	±	–	–	–	–	+	–	NA	NA	NA	NA	Metabolic and respiratory acidosis	Pulse oximetry	NA	Bilateral, diffuse, reticular granular or ground–glass appearance ± Cardiomegaly	NA	NA	Patent ductus arteriosus in echocardiography	–
	Shock	±	±	±	±	±	±	–	±	–	↑HCT, ↑PT and aPTT, Eosinophilia, Leukocytosis	↓GFR, ↑BUN, ↑Cr	NA	NA	↑Lactate	LFT, ↑BNP, ↑Troponin, D–dimer, Fibrinogen	Pulmonary embolism, Pericardial effusion, Cardiac tamponade, Pneumothorax, Thoracic or abdominal aortic aneurysm in RUSH (Rapid Ultrasound for Shock and Hypotension)	Pneumonia, Pneumothorax, Pulmonary edema, Widened mediastinum, Free air under the diaphragm	Traumatic brain injury, Stroke, Spinal injury, Pneumonia, Pneumothorax, Ruptured aneurysm, Aortic dissection, Pulmonary embolism	NA	–	–
	Toxic megacolon	±	±	±	–	+	+	±	–	–	Leukocytosis, Anemia, ↑ESR and CRP	↑BUN, ↑Cr	↓Na	NA	NA	Loss of haustra, Hypoechoic and thick bowel walls, Dilated colon > 6cm, Dilatation of ileal loops	Dilated colon, Free intraperitoneal air	Bowel perforation, Abscess	NA	NA	Endoscopy and colonoscopy	–
Etiology		Fatigue/ Lethargy	Thirst	Dizziness/ Confusion	Muscle weakness/ cramp	Somatic/ visceral pain	Vomiting	Diarrhea	Tachypnea	Edema	Blood indices	Renal Funtion test	Electrolytes	Urine analysis	ABG	Other	Ultrasound	X–ray	CT	MRI	Other	Comments
Renal causes	Acute interstitial nephritis	±	–	±	–	±	±	±	±	±	Eosinophilia	↑BUN, ↑Cr, ↑FENa	NA	Eosinophiluria, Sterile pyuria, Microscopic hematuria, Proteinuria	NA	↑Total IgG, ↑IgG4	Normal–sized kidneys	NA	NA	NA	–	History of long term analgesic use
	Acute tubular necrosis	±	–	–	–	–	±	–	–	±	Anemia	↑BUN, ↑Cr, ↑FENa	↓Na, ↑K, ↑Mg, ↑P, ↓Ca	Pigmented, muddy brown, granular casts	NA	NA	Obstructive uropathy, Renal size, Cortical thickness, Hydronephrosis	Nephrolithiasis	Nephrolithiasis, Area of obstruction	Nephrolithiasis, Area of obstruction	Loss of tubular cells or the denuded tubules, Swollen tubular cells, Loss of the cell brush border in renal biopsy	Furosemide stress testing for staging
	Cancer	+	–	–	–	±	±	–	–	±	Normocytic or microcytic anemia, Leukocytosis or lymphocytosis, ↑Reticulocytes, Thrombocytopenia	↓GFR, ↑BUN, ↑Cr, ↓Erythropoietin	↓Na, ↑K, ↓Mg, ↑P, ↓Ca	Gross hematuria	NA	LFT	Fluid collection and morphological change, Flank mass	Calcification and widened mediastinum, Filling defects in barium contrast	Metastasis and staging, Cystic and solid masses, Lymph node, renal vein, and inferior vena cava involvement	Soft tissue invasion and staging	Malignant cystic lesions percutaneous cyst puncture	Renal cell carcinoma types: Clear cell (75%), Chromophilic (15%), Chromophobic (5%), Oncocytoma (3%), Collecting duct (2%)
	Congenital kidney disease – Agenesis – Dysplasia – Hypoplasia – Polycystic	±	–	–	–	±	±	–	–	±	↑HCT	↓GFR	↓P, ↓Ca	Microalbuminuria, Uricosuria	NA	Genetic testing forADPKD2	Visualization of kidney cysts	Small kidney cysts (0.5 cm)	Kidney size, Intracranial aneurysms	NA	–	–
	End stage renal disease	+	–	–	–	±	–	–	–	+	Anemia	↓GFR, ↑BUN, ↑Cr	↑K	Hypoalbuminuria	↓HCO3	Phosphate, 25–hydroxy vitamin D, Alkaline phosphatase, Parathyroid hormone	Hydronephrosis, Retroperitoneal fibrosis, Enlarged or shrunken kidneys	Obstruction in retrograde pyelogram	Renal masses, stones, and cysts	Renal vein thrombosis, Renal artery stenosis in magnetic resonance angiography	Percutaneous renal biopsy	–
	Endogenous toxins – Hemoglobin – Myoglobin – Uric acid	±	–	±	+	–	±	–	–	±	Anemia, Thrombocytopenia	↓GFR, ↑BUN, ↑Cr	↑K, ↑Urate, ↓Ca	Uricosuria, Hematuria, Myoglobinuria, Casts	NA	Creatine kinase > 1000 U/L	Malignant or cystic lesions, Hydronephrosis, Nephrocalcinosis, Urolithiasis	NA	Urolithiasis, Wilms tumor, Polycystic kidney disease	NA	Ureter or bladder abnormality in voiding cystourethrography	–
	Glomerulonephritis	±	–	–	–	–	–	–	–	+	Pleocytosis, Anemia, Leukocytosis, ↑ESR	↑BUN, ↑Cr	NA	Specific gravity > 1.020, Proteinuria, Hematuria, Red blood cell casts, White blood cell casts, Cellular casts, Oval fat bodies	NA	NA	↑C3, ↑C4, ↑CH50, Blood and tissue culture, Antinuclear antibodies, Cryoglobulins,Hepatitis B and C serologies, Antineutrophil cytoplasmic antibody (ANCA)	Kidney size, Echogenicity of the renal cortex, Obstruction, Degree of fibrosis	Pulmonary congestion	Visceral abscesses	–	Renal biopsy, Light and electron microscopy, Immunofluorescence aid diagnosis
	Goodpasture syndrome	±	–	–	–	–	–	–	±	±	Anemia, Leukocytosis, ↑ESR	↑BUN, ↑Cr	NA	Low–grade proteinuria, Gross or microscopic hematuria, RBC casts	NA	Anti– glomerular basement membrane antibody Antineutrophilic cytoplasmic antibody	NA	Bilateral, basal, patchy parenchymal consolidations	NA	NA	Diffuse alveolar hemorrhage in pulmonary biopsy	–
	Hemolytic uremic syndrome	±	–	±	±	±	+	+	–	±	Severe anemia, Thrombocytopenia, ↑ aPTT	↑BUN, ↑Cr	NA	Mild proteinuria, Red blood cells, Red blood cell casts	NA	Schistocytes, ↑FDP and D–dimer, ↑ Bilirubin, ↑LDH, ↓Haptoglobin, Stool culture (for E coli 0157:H7 or shigella), ↓ADAMTS–13 activity	Ruling out obstruction	NA	NA	NA	Diffuse thickening of the glomerular capillary wall, Swelling of endothelial cells, Fibrin thrombi in renal biopsy	–
	Nephrolithiasis	–	–	–	–	±	±	–	–	–	Mild leukocytosis, ↑CRP	↑BUN, ↑Cr	↑Na, ↑K, ↑P, ↑Ca, ↑Urate	Gross or microscopic hematuria, Red blood cells, Urinary crystals of calcium oxalate, uric acid, or cystine, Hypercalciuria, Urinary pH > 7 in struvite stones (Proteus, Pseudomonas, Klebsiella), Urinary pH < 5 in uric acid stones	↓HCO3, Renal tubular acidosis	–	All types of stones are visible, Hydronephrosis, Abdominal aortic aneurysm, Cholelithiasis	Calcium – containing stones, Uric acid or cystine stones, Stone movement	Stone density, size and composition, Hydronephrosis, Nephromegaly, Perinephric fat streaking	NA	Intravenous pyelography (IVP), Renal tomography, Nuclear renal scan	–