Differential Diagnosis – “R”

Osteochondroma

• Benign
• Exclusively with childhood irradiation.
• Histologically identical to spontaneous osteochondroma.

Sarcoma

• Malignant
• Latent period of 4 years or more.
• Histologically identical to spontaneous sarcoma.
• Commonly malignant fibrous histiocytoma or osteosarcoma.
• Occurs in either bone or soft tissue.

Tumors in Other Organ Systems

• Squamous cell cancer of the skin.
• Breast cancer.
• Leukemia, with shorter latent period than sarcoma.

• Rectal carcinoma.
• Rectal polyp.
• Hypertrophied anal papilla.
• Diverticular phlegmon (prolapsing into the pouch of Douglas).
• Sigmoid colon carcinoma (prolapsing into the pouch of Douglas).
• Metastatic deposits at the pelvic reflection (Blumer’s shelf).
• Primary pelvic malignancy (uterine, ovarian, prostatic, or cervical).
• Mesorectal lymph nodes.
• Endometriosis.
• Solitary rectal ulcer syndrome.
• Foreign body.
• Feces.
• Presacral cyst.
• Amebic granuloma.
• Vaginal tampon and even the pubic bone may be mistaken for a rectal mass.

• Anal fissure.
• Thrombosed hemorrhoid.
• Anorectal abscess.
• Foreign bodies.
• Fecal impaction.
• Endometriosis
• Neoplasms (primary or metastatic).
• Pelvic inflammatory disease.
• Inflammation of sacral nerves.
• Compression of sacral nerves.
• Prostatitis
• Other: proctalgia fugax, uterine abnormalities, myopathies, coccygodynia.

• Idiopathic (>50% of cases).
• Medications (most frequent with phenytoin).
• Non-Hodgkin’s lymphoma.
• Viral infections (parvovirus B19, EB virus, mumps, hepatitis).
• Myelodysplastic syndromes.
• Thymoma
• Autoimmune diseases.
• Allogenic bone marrow transplant from ABO incompatible donor.
• Pregnancy

• Damaged microvasculature.
• Thrombotic thrombocytopenic purpura–hemolytic uremic syndrome (TTP–HUS).
• Associated with pregnancy: preeclampsia or eclampsia; hemolysis plus elevated liver enzymes plus low platelets (HELLP syndrome).
• Associated with malignancy, with or without mitomycin C treatment.
• Vasculitis: polyarteritis, Wegener granulomatosis, acute glomerulonephritis, or Rickettsia-like infections.
• Systemic lupus erythematosus.
• Abnormalities of renal vasculature: malignant hypertension, acute glomerulonephritis, scleroderma, or allograft rejection with or without cyclosporine treatment.
• Disseminated intravascular coagulation.
• Malignant hypertension.
• Catastrophic antiphospholipid antibody syndrome.
• Atrioventricular malformations.
• Kasabach-Merritt syndrome.
• Hemangioendotheliomas.
• Atrioventricular shunts for congenital and acquired conditions (e.g., stents, coils, trans-jugular intrahepatic portosystemic shunt, Levine shunts).
• Cardiac abnormalities:
  • Replaced valve, prosthesis, graft, or patch.
  • Aortic stenosis or regurgitant jets (e.g., in ruptured sinus of Valsalva).
• Drugs:
  • Cyclosporine.
  • Mitomycin.
  • Ticlopidine.
  • Clopidogrel.
  • Tacrolimus.
  • Cocaine.
• Systemic infection:
  • Bacterial endocarditis.
  • Brucellosis.
  • Cytomegalovirus.
  • Human immunodeficiency virus.
  • Ehrlichiosis.
  • Rocky Mountain spotted fever

• Infectious conjunctivitis (bacterial, viral).
• Allergic conjunctivitis.
• Acute glaucoma.
• Keratitis (bacterial, viral).
• Iritis.
• Trauma

• Obvious open globe.
• Corneal abrasion.
• Corneal ulcer.
• Subconjunctival hemorrhage.
• Hyphema.
• Occult open globe.
• Herpes simplex virus glaucoma.
• Iritis, traumatic iritis.
• Scleritis.
• Conjunctivitis.
• Blepharitis.
• Ultraviolet keratitis.
• Episcleritis.
• Conjunctival foreign body.
• Dry eye.
• Contact lens overwear syndrome.

• Trauma.
• Gout.
• Infection (septic joint).
• Pseudogout (calcium pyrophosphate dehydrate crystal deposition).
• Psoriatic arthropathy.
• Reactive arthritis.
• Palindromic rheumatism.

• Hematuria.
• Porphyrins.
• Hemoglobinuria.
• Myoglobinuria.
• Medications (phenazopyridine, aminosalicylic acid, deferoxamine, phenazopyridine, phenolphthalein, NSAIDs, rifampin, phenytoin, methyldopa, doxorubicin, phenacetin).
• Foods (beets, berries, maize).
• Urate crystalluria.

Immediate/Delayed Graft Function (1-3 Days)

• Acute tubular necrosis.
• Hyperacute humoral rejection.
• Urinary leak or obstruction.
• Renal artery or vein thrombosis.
• Recurrence of disease (e.g., focal segmental glomerulosclerosis).

Early Posttransplantation Period (First Month)

• Acute cellular rejection.
• Acute humoral rejection.
• Calcineurin inhibitor toxicity.
• Urinary tract obstruction.
• Volume depletion.
• Recurrence of disease.

Late Acute Dysfunction

• Acute rejection.
• Cyclosporine or tacrolimus toxicity.
• Recurrence of primary disease.
• Tubulointerstitial nephritis, drug-induced.
• Renal artery stenosis.
• Infection (bacterial urinary tract infection [UTI], cytomegalovirus, BK virus).
• Hemodynamic (volume; use of angiotensin-converting enzyme inhibitor, angiotensin II receptor blocker).

Chronic Dysfunction

• Chronic rejection.
• Cyclosporine or tacrolimus toxicity.
• Recurrent renal disease.
• De novo renal disease.
• Urinary tract obstruction.
• Bacterial UTI.
• Hypertensive nephrosclerosis.

• Atrial fibrillation.
• Angiography or stent placement.
• Abdominal aortic surgery.
• Trauma.
• Renal artery aneurysm/dissection.
• Vasculitis.
• Thrombosis in patient with fibromuscular dysplasia.
• Atherosclerosis.
• Septic embolism.
• Mural thrombus thromboembolism.
• Atrial myxoma thromboembolism.
• Mitral stenosis thromboembolism.
• Prosthetic valve thromboembolism.
• Renal cell carcinoma.

Vascular:

• Abdominal aortic aneurysm.
• Aortic dissection.
• Renal artery dissection.
• Renal artery stenosis.
• Renal vein thrombosis.
• Renal infarct.
• Mesenteric ischemia.
• Retroperitoneal hemorrhage.

Gastrointestinal:

• Incarcerated hernia.
• Appendicitis.
• Cholecystitis.
• Biliary colic.
• Pancreatitis.
• Bowel obstruction.
• Diverticulitis.

Gynecologic:

• Ectopic pregnancy.
• Ovarian torsion.
• Tuboovarian abscess.
• Pelvic inflammatory disease.
• Endometriosis.

Genitourinary:

• Testicular torsion.
• Pyelonephritis.
• Perinephric abscess.
• Urinary tract tumor.
• Renal papillary necrosis.
• Upper urinary tract hemorrhage.

Musculoskeletal:

• Lumbar strain.
• Radiculopathy.
• Disk herniation.
• Vertebral compression fracture.

Dermatologic:

• Herpes zoster.

Miscellaneous:

• Factitious.

• Simple cysts.
• Acquired cystic kidney disease.
• Autosomal dominant polycystic kidney disease.
• Autosomal recessive polycystic kidney disease.
• Medullary cystic disease.
• Medullary sponge kidney.

Nonspecific

• Pruritus
• Xerosis
• Acquired ichthyosis
• Pigmentary alteration
• Pallor (secondary to anemia)
• Hyperpigmentation
• Dyspigmentation (yellow tint)
• Infections (fungal, bacterial, viral)
• Purpura

Somewhat Specific

• Acquired perforating dermatosis
• Calciphylaxis
• Metastatic calcification
• Blistering disorders
• Porphyria cutanea tarda
• Pseudoporphyria
• Eruptive xanthomas
• Pseudo–Kaposi’s sarcoma

Specific

• Nephrogenic systemic fibrosis
• Dialysis-associated steal syndrome
• Metastatic renal cell carcinoma
• Dialysis-related amyloidosis
• Arteriovenous shunt dermatitis
• Uremic frost

• Rhabdomyolysis and myoglobinuria.
• Vigorous exercise.
• Arterial embolization.
• Status epilepticus.
• Status asthmaticus.
• Coma-induced and pressure-induced myonecrosis.
• Heat stress.
• Diabetic ketoacidosis.
• Myopathy.
• Alcoholism.
• Hypokalemia.
• Hypophosphatemia.
• Hemoglobinuria.
• Transfusion reactions.
• Snake envenomation.
• Malaria.
• Mechanical destruction of RBCs by prosthetic valves.
• G6PD deficiency.

Diabetic glomerulosclerosis (systemic disease involving the kidney).

Hypertensive nephrosclerosis.

Glomerular disease:

• Glomerulonephritis.
• Amyloidosis, light chain disease (systemic disease involving the kidney).
• Systemic lupus erythematosus, Wegener granulomatosis (systemic disease involving the kidney).

Tubulointerstitial disease:

• Reflux nephropathy (chronic pyelonephritis).
• Analgesic nephropathy.
• Obstructive nephropathy (stones, benign prostatic hypertrophy).
• Myeloma kidney (systemic disease involving the kidney).

Vascular disease:

• Scleroderma (systemic disease involving the kidney).
• Vasculitis (systemic disease involving the kidney).
• Renovascular renal failure (ischemic nephropathy).
• Atheroembolic renal disease (systemic disease involving the kidney).

Cystic disease:

• Autosomal dominant polycystic kidney disease.
• Medullary cystic kidney disease.

Abnormalities of the Vasculature

• Renal arteries: atherosclerosis, thromboembolism, arteritis.
• Renal veins: thrombosis.
• Microvasculature: vasculitis, thrombotic microangiopathy.

Abnormalities of Glomeruli (Acute Glomerulonephritis)

• Antiglomerular membrane disease (Goodpasture’s syndrome).
• Immune complex glomerulonephritis: SLE, postinfectious, idiopathic, membranoproliferative.

Abnormalities of Interstitium (Acute Interstitial Nephritis)

• Drugs (e.g., antibiotics, NSAIDs, diuretics, anticonvulsants, allopurinol).
• Infectious pyelonephritis.
• Infiltrative: lymphoma, leukemia, sarcoidosis.

Abnormalities of Tubules

• Physical obstruction (uric acid, oxalate, light chains).
• Acute tubular necrosis:
  • Ischemic.
  • Toxic (antibiotics, chemotherapy, immunosuppressives, radiocontrast dyes, heavy metals, myoglobin, hemolyzed RBCs).

Ureter and Renal Pelvis

Intrinsic obstruction:

• Blood clots.
• Stones.
• Sloughed papillae: diabetes, sickle cell disease, analgesic nephropathy.
• Inflammatory: fungus ball.

Extrinsic obstruction:

• Malignancy.
• Retroperitoneal fibrosis.
• Iatrogenic: inadvertent ligation of ureters.

Bladder

• Prostatic hypertrophy or malignancy.
• Neuropathic bladder.
• Blood clots.
• Bladder cancer.
• Stones.

Urethral

• Strictures.
• Congenital valves.

Decreased Cardiac Output

• CHF.
• Arrhythmias.
• Pericardial constriction or tamponade.
• Pulmonary embolism.

Hypovolemia

• GI tract loss (vomiting, diarrhea, nasogastric suction).
• Blood losses (trauma, GI tract surgery).
• Renal losses (diuretics, mineralocorticoid deficiency, postobstructive diuresis).
• Skin losses (burns).

Volume Redistribution (Decrease in Effective Blood Volume)

• Hypoalbuminemic states (cirrhosis, nephrosis).
• Sequestration of fluid in “third” space (ischemic bowel, peritonitis, pancreatitis).
• Peripheral vasodilation (sepsis, vasodilators, anaphylaxis).

Altered Renal Vascular Resistance

• Increase in afferent vascular resistance (NSAIDs, liver disease, sepsis, hypercalcemia, cyclosporine).
• Decrease in efferent arteriolar tone (ACE inhibitors).

Thrombosis: Spontaneous

• Atherosclerotic disease of aorta and renal artery.
• Fibromuscular dysplasia of renal artery.
• Aneurysms of aorta or renal artery.
• Dissection of aorta or renal artery.
  • Marfan’s syndrome.
  • Ehlers-Danlos syndrome.
• Vasculitis involving renal artery.
  • Polyarteritis nodosa.
  • Takayasu’s arteritis.
  • Kawasaki disease.
  • Thromboangiitis obliterans.
  • Other necrotizing vasculitides.
• Inflammatory disease of the aorta or renal artery.
  • Syphilis.
  • Tuberculosis.
  • Mycoses.
• Hypercoagulable states.
  • Nephrotic syndrome.
  • Antiphospholipid syndrome.
  • Antithrombin III deficiency.
  • Homocystinuria.
• Thrombotic microangiopathies.
  • Hemolytic-uremic syndrome.
  • Thrombotic thrombocytopenic purpura.
  • Antiphospholipid syndrome.
  • Malignant hypertension.
  • Scleroderma.
  • Sickle cell nephropathy.
  • Polycythemia vera.
  • Postpartum hemolytic-uremic syndrome.
  • Hyperacute vascular allograft rejection.

Thrombosis: Induced

• Traumatic.
• Following endovascular intervention.
• Post renal transplantation.

Embolism

• Cardiac source.
  • Atrial fibrillation or other arrhythmias.
  • Native and prosthetic valvular heart disease.
  • Infective endocarditis.
  • Marantic endocarditis.
• Myocardial infarction with mural thrombi.
  • Left atrial myxoma or other tumor.
• Noncardiac sources.
  • Atheromatous embolic disease.
  • Paradoxical emboli.
  • Fat emboli.
  • Tumor emboli.
• Therapeutic renal embolization.
• Segmental renal infarction of childhood.
• Cisplatinum and gemcitabine.
• Sickle cell disease or sickle cell trait.

No Papillary/Caliceal Abnormality

Diffuse Parenchymal Loss

Bilateral:

• Chronic glomerulonephritis.
• Diffuse small-vessel disease.
• Hereditary nephropathies.

Unilateral:

• Renal artery stenosis.
• Postirradiation.
• Rare:
  • Hypoplastic kidney.
  • Postobstructive atrophy.

Focal Parenchymal Loss

Infarct.

Previous trauma.

Papillary/Caliceal Abnormality

Diffuse Parenchymal Loss

• Obstructive nephropathy.
• Generalized reflux nephropathy.

No Parenchymal Loss

• Papillary necrosis.
• TB.
• Medullary sponge kidney.
• Megacalices.
• Pelvicaliceal cyst.

Focal Parenchymal Loss

• Focal reflux nephropathy (chronic atrophic pyelonephritis).
• TB.
• Calculus disease.

• Nephrotic syndrome.
• Renal cell carcinoma.
• Aortic aneurysm causing compression.
• Lymphadenopathy.
• Retroperitoneal fibrosis.
• Estrogen therapy.
• Pregnancy.
• Renal cell carcinoma with vein invasion.
• Severe dehydration.

Noncardiopulmonary

• Hypothermia or hyperthermia.
• Hypoglycemia.
• Metabolic acidosis.
• Drug intoxications; withdrawal.
• Polycythemia.
• Central nervous system insult.
• Asphyxia.
• Hemorrhage.
• Neuromuscular disease.
• Werdnig-Hoffman disease.
• Myopathies.
• Phrenic nerve injury.
• Skeletal abnormalities.
• Asphyxiating thoracic dystrophy.

Cardiovascular

• Left-sided outflow obstruction.
• Hypoplastic left heart.
• Aortic stenosis.
• Coarctation of the aorta.
• Cyanotic lesions.
• Transposition of the great vessels.
• Total anomalous pulmonary venous return
• Tricuspid atresia.
• Right-sided outflow obstruction.

Pulmonary

• Upper airway obstruction.
• Choanal atresia.
• Vocal cord paralysis.
• Meconium aspiration.
• Clear fluid aspiration.
• Transient tachypnea.
• Pneumonia.
• Pulmonary hypoplasia.
  • Primary.
  • Secondary.
• Hyaline membrane disease.
• Pneumothorax.
• Pleural effusions.
• Mass lesions.
• Lobar emphysema.
• Cystic adenomatoid malformation.

Abnormal Respiratory Capacity (Normal Respiratory Workloads)

• Acute depression of central nervous system:
  • Various causes.
• Chronic central hypoventilation syndromes:
  • Obesity-hypoventilation syndrome.
  • Sleep apnea syndrome.
  • Hypothyroidism.
  • Shy-Drager syndrome (multisystem atrophy syndrome).
• Acute toxic paralysis syndromes:
  • Botulism.
  • Tetanus.
  • Toxic ingestion or bites.
  • Organophosphate poisoning.
• Neuromuscular disorders (acute and chronic):
  • Myasthenia gravis.
  • Guillain-Barré syndrome.
  • Drugs.
  • Amyotrophic lateral sclerosis.
  • Muscular dystrophies.
  • Polymyositis.
  • Spinal cord injury.
  • Traumatic phrenic nerve paralysis.

Abnormal Pulmonary Workloads

• Chronic obstructive pulmonary disease:
  • Chronic bronchitis.
  • Asthmatic bronchitis.
  • Emphysema.
• Asthma and acute bronchial hyperreactivity syndromes.
• Upper airway obstruction.
• Interstitial lung diseases.

Abnormal Extrapulmonary Workloads

• Chronic thoracic cage disorders:
  • Severe kyphoscoliosis.
  • After thoracoplasty.
  • After thoracic cage injury.
• Acute thoracic cage trauma and burns.
• Pneumothorax.
• Pleural fibrosis and effusions.
• Abdominal processes.

Disorders of the phrenic nerve

• Guillain-Barré syndrome
• Poliomyelitis

Respiratory muscle atrophy

Disorders of neuromuscular transmission

• Myasthenia gravis
• Ventilator dependence
• Malnutrition
• Myopathy
• Critical illness polyneuropathy/myopathy

Altered diaphragmatic force-length relationship

• Dynamic hyperinflation and diaphragmatic flattening

• Retinal venous obstruction.
• Diabetic retinopathy.
• Ocular ischemic syndrome.
• Hyperviscosity.
• Tortuosity of retinal artery.

• Allergic rhinitis.
• Infectious rhinitis.
• Vasomotor rhinitis.
• Exercise-induced rhinitis.
• Emotional rhinitis.
• Rhinitis medicamentosa.
• Hormone-mediated rhinitis (menses, pregnancy, oral contraceptives, hypothyroidism).
• GERD.
• Chemical- or irritant-induced rhinitis.
• Rhinitis mimics:
  • Deviated septum.
  • Enlarged adenoids.
  • Nasal polyps/tumors.
  • Foreign bodies.
  • CSF rhinorrhea.
  • Sarcoidosis.
  • Midline granuloma.
  • Granulomatosis with polyangiitis.
  • SLE.
  • Sjögren’s syndrome.

• Allergic
  • Systemic.
  • Local (entopy).
• Work-Related
  • Irritant.
  • Corrosive.
  • Immunologic.
• Infectious (Rhinosinusitis)
  • Allergic.
  • Nonallergic.
• Nonallergic
  • Idiopathic.
  • Nonallergic with eosinophilia.
  • Atrophic.
  • Primary.
  • Secondary.
  • Medication-related.
  • Topical vasoconstrictors (rhinitis medicamentosa).
  • Oral medications.
  • Exercise-induced.
  • Cold air–induced.
  • Gustatory.
  • Hormonal.
  • Aging.
  • Systemic diseases.

Allergic Rhinitis

• Seasonal.
• Perennial.
• Combined seasonal and perennial.
• Allergic fungal rhinosinusitis.

Nonallergic Rhinitis

• Nonallergic, noninflammatory idiopathic rhinopathy (vasomotor rhinitis).
• Nonallergic rhinitis with eosinophilia syndrome (NARES).
• Cold dry air–induced rhinitis.
• Gustatory rhinitis.

Infectious Rhinosinusitis

• Bacterial.
• Viral.
• Fungal.
• Granulomatous.

Drug-Induced Rhinitis

• Oral contraceptives.
• Various antihypertensives and ocular β-blockers.
• Topical decongestants (rhinitis medicamentosa).
• Phosphodiesterase-5 antagonists.

Mechanical Causes of Rhinosinusitis

• Septal deviation.
• Nasal foreign body.
• Choanal atresia or stenosis.
• Adenoid hypertrophy.
• Encephalocele.
• Glioma.
• Dermoid.

Innate and Acquired Immunity Disorders

• Congenital or acquired immunodeficiencies.
• Cystic fibrosis.
• Immotile cilia syndrome.

Systemic Inflammatory Disorders

• Sarcoidosis.
• Granulomatosis with polyangiitis.
• Vasculitis.

Neoplastic Causes

• Benign:
  • Polyps.
  • Nasopharyngeal angiofibroma.
  • Inverting papilloma.
• Malignant:
  • Adenocarcinoma.
  • Squamous cell carcinoma.
  • Aesthesioneuroblastoma.
  • Lymphoma.
  • Rhabdomyosarcoma.

Normal

• Isolated defects.
• Projectional artifacts (due to lordosis).

Neurologic

• Paralytic poliomyelitis.
• Quadriparesis.

Collagen Vascular Disease

• Rheumatoid arthritis.
• SLE.
• Systemic sclerosis.

Local Pressure

• Chest drainage tube.
• Osteochondroma.
• Neural tumor.
• Coarctation of aorta.

Hyperparathyroidism Miscellaneous

• Osteogenesis imperfecta.
• Marfan’s syndrome.

ARTERIAL

Aortic Obstruction

• Aortic coarctation.
• Aortic thrombosis.
• Aortitis.

Subclavian Artery Obstruction

• Blalock-Taussig operation.
• Arteritis.
• Atherosclerotic occlusion.

Pulmonary Oligemia

• Pulmonary atresia.
• Tetralogy of Fallot.
• Multiple pulmonary arterial stenoses.

VENOUS

Chronic Superior Vena Caval Obstruction

Arteriovenous Malformation

• Pulmonary.
• Chest wall.
• Neural

Neurofibromas

ICD-10CM # varies with specific diagnosis
Normal variation.
Right ventricular hypertrophy.
Left posterior fascicular block.
Lateral myocardial infarction.
Pulmonary embolism.
Dextrocardia.
Mechanical shifts or emphysema causing a vertical heart.