Differentials
Common
Minimal change disease
History
common in children (occasionally found in adults), can be secondary to Hodgkin lymphoma
Exam
typically not hypertensive, otherwise physical exam is nonspecific
1st investigation
- serial creatinine and estimated GFR:
typically normal
- renal biopsy:
normal by light microscopy, but podocyte effacement on electron microscopy
More
Other investigations
Focal segmental glomerulosclerosis (FSGS)
History
asymptomatic, or may have edema and other symptoms of renal dysfunction; HIV, reflux nephropathy, class III obesity (BMI 40 or above), chronic glomerular hyperfiltration from a solitary kidney, or any other cause of extensive nephron loss (e.g., renal obstruction, prior glomerulonephritis), or history of drug use (e.g., pamidronate, heroin)
Exam
may be hypertensive, otherwise physical exam is nonspecific
1st investigation
- serial creatinine and estimated GFR:
may be abnormal
- renal biopsy:
focal and segmental sclerosis of the glomeruli
More
Other investigations
- HIV test:
positive
More
Membranous nephropathy
History
may be primary or secondary; secondary disease associated with malignancy, infections (e.g., hepatitis B, hepatitis C, syphilis, malaria, or tuberculosis), autoimmune disease (e.g., lupus membranous nephropathy), or drugs (e.g., gold, penicillamine. and NSAIDs)
Exam
physical exam is nonspecific
1st investigation
Other investigations
- chest x-ray or chest CT for lung cancer:
mass (consistent with lung tumor) may be present
More - occult blood in stool:
stool may be heme-positive
More - hepatitis and HIV serologies:
may be positive
More - rapid plasma reagin (RPR) syphilis test:
may be positive
More - anti-nuclear antibody, anti-double-stranded DNA:
elevated in systemic lupus erythematosus (SLE)
More - complement levels (C3 and C4):
Low in SLE
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Diabetic nephropathy
History
long-standing history of diabetes often in conjunction with symptoms suggestive of diabetic retinopathy (impaired vision) or slowly progressive renal dysfunction (e.g., fatigue, swelling of the extremities)
Exam
diabetic retinopathy (microaneurysms, hard and soft exudates, microinfarcts, macular edema, increased tortuosity of veins, and neovascularization) seen on funduscopic exam
1st investigation
- HbA1c:
often elevated
- renal biopsy:
diagnostic
More
Other investigations
- urinalysis:
may show microscopic hematuria
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Multiple myeloma-associated AL amyloidosis
History
weight loss, symptoms suggestive of anemia (e.g., fatigue, decreased exercise tolerance), bone pain (especially back pain), history suggestive of pathologic fractures (e.g., low-impact fractures)
Exam
weight loss, anemia, abnormal bone x-ray (e.g. osteopenia, osteolytic lesions)
1st investigation
Other investigations
IgA nephropathy
History
episodes of dark urine that often occur along with pharyngitis; may be a history of liver disease, seronegative arthropathy, celiac disease, Henoch-Schonlein purpura (especially in children), purpuric skin lesions, melena, or bright red blood per rectum
Exam
rarely presents with edema, otherwise physical exam is nonspecific
1st investigation
- renal biopsy:
IgA deposits seen on immunofluorescent exam of renal biopsy
More
Other investigations
Uncommon
Membranoproliferative (mesangiocapillary) glomerulonephritis
History
increased BP, fluid retention, non-visible hematuria, low-grade occasionally heavy proteinuria, variably abnormal kidney function
Exam
diagnosis is histological following a renal biopsy
1st investigation
- urinalysis:
hematuria, proteinuria, dysmorphic RBCs, leukocytes, and RBC casts
More
Other investigations
- renal biopsy:
histological findings
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Amyloidosis
History
neuropathy (including loss of pain and temperature sensation), easy bruising, positive family history (for familial type)
Exam
distal symmetric sensory neuropathy, bruising
1st investigation
- renal biopsy:
diagnostic
More
Other investigations
Lupus nephritis
History
rash, photosensitivity, arthralgias, mouth ulcers, fevers
Exam
malar rash, petechiae, arthritis
1st investigation
Other investigations
Fabry disease
History
painful neuropathy, rash, exercise intolerance, heat intolerance, nausea, abdominal pain; mostly occurs in males (X-linked disease); positive family history
Exam
characteristic skin rash (angiokeratomas), corneal opacities
1st investigation
Other investigations
Alport syndrome
History
acquired hearing loss, occurs mostly in males (X-linked disease), positive family history, hearing loss, ocular abnormalities, commonly presents with hematuria, very rarely causes nephrotic syndrome
Exam
anterior lenticonus and perimacular flecks on ophthalmic exam
1st investigation
- renal biopsy:
electron microscopy reveals abnormalities of the basement membrane such as thickening and stranding of the lamina densa
- audiometry:
possible high-frequency sensorineural hearing loss
Other investigations
- molecular genetic testing:
Identification of pathogenic mutation (COL4A5 or COL4A3/4)
More
Nail-patella syndrome
History
positive family history (autosomal dominant)
Exam
hypoplastic patella, dystrophic nails
1st investigation
- clinical diagnosis:
diagnosis is clinical
Other investigations
- renal biopsy:
clusters of fibrils of type III collagen seen on electron microscopy
Malignant hypertension
History
prior history of hypertension, blurred vision, dizziness, loss of sensation or movement, chest pain, dyspnea, peripheral edema, decreased urine output
Exam
very high blood pressure (often >210/130 mmHg), fundoscopic arteriolar spasm, retinal edema, retinal hemorrhages, retinal exudates, papilledema, or engorged retinal veins, signs of cardiac failure
1st investigation
- serum creatinine:
elevated
- hemolysis screen:
increased lactate dehydrogenase (LDH), low serum haptoglobins, increased reticulocyte count, red cell fragmentation (schistocytosis >1%) on blood film
- urinalysis and microscopy:
presence of protein
- echocardiogram:
signs of cardiac ischemia
- chest x-ray:
signs of cardiac failure
Other investigations
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