Autoimmune Disease Differential Diagnosis
The patient's symptoms suggest an autoimmune disease affecting the complement system, specifically with low levels of C3 and C8. Here's a differential diagnosis:
- Single most likely diagnosis
- Atypical Hemolytic Uremic Syndrome (aHUS): This condition is characterized by the formation of blood clots in small blood vessels throughout the body, leading to kidney failure. Low levels of C3 and C8 are common in aHUS due to genetic mutations or autoantibodies that activate the complement system.
- Other Likely diagnoses
- Membranoproliferative Glomerulonephritis (MPGN): This kidney disease is caused by the deposition of immune complexes in the glomeruli, leading to inflammation and damage. Low C3 levels are common in MPGN, and C8 levels may also be affected.
- Systemic Lupus Erythematosus (SLE): SLE is a systemic autoimmune disease that can affect multiple organs, including the kidneys. Low C3 and C4 levels are common in SLE, and C8 levels may also be decreased.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Post-Streptococcal Glomerulonephritis (PSGN): This condition is a rare but potentially life-threatening complication of streptococcal infections. Low C3 levels are characteristic of PSGN, and C8 levels may also be affected.
- Goodpasture's Syndrome: This rare autoimmune disease is caused by antibodies against the glomerular basement membrane, leading to kidney and lung damage. Low C3 and C8 levels may be present, and prompt diagnosis is crucial to prevent irreversible damage.
- Rare diagnoses
- C3 Glomerulopathy: This group of rare diseases is characterized by the deposition of C3 in the glomeruli, leading to kidney damage. Low C3 levels are common, and C8 levels may also be affected.
- Factor H deficiency: This rare genetic disorder is characterized by a deficiency of factor H, a protein that regulates the complement system. Low C3 levels are common, and C8 levels may also be decreased.
It is essential to note that a comprehensive diagnostic workup, including laboratory tests and imaging studies, is necessary to confirm the diagnosis and guide treatment.