The Kidney in Systemic Disease II Flashcards
What causes sickle cell?
Substitution of a valine for glutamic acid as the sixth amino acid of the beta globin chain, which produces a hemoglobin tetramer (alpha2/beta S2) that is poorly soluble when deoxygenated
How does sickle cell present?
- painful ‘crises’
- symptomatic anemia
- renal involvement
- leg ulcers
- recurrent priapism
What labs would you see with sickle cell?
mild to moderate anemia,
reticulocytosis of 3 to 15 percent, unconjugated hyperbilirubinemia,
elevated serum lactate dehydrogenase, and
low serum haptoglobin.
What do Howell-Jolly body presence in SCD suggest?
reflecting hyposplenia secondary to repeated splenic infarctions
What are the renal manifestations of SCD?
Microalbuminuria reaches a prevalence of approximately 60% in patients with hgb SS disease those over 45 years
increased GFR into young adulthood, followed by decreasing GFR from the 40s on
Impaired distal H+ ion and K+ secretion
-Supranormal PT function leading to increased creatinine secretion and hyperphosphatemia
Hyposthenuria
Sickling crises are commonly initiated in the renal medulla. Why?
The relative hypoxia (partial pressure of oxygen 10–35 mmHg), acidosis, and hyperosmolarity of the inner medulla may result in polymerization of deoxygenated hemoglobin S and subsequent sickling of erythrocytes
Progression of renal involvement of SCD?
4 to 12% of patients with hgb SS disease will develop end-stage renal disease (ESRD)
What is early stage sickle cell nephropathy characterized by?
Glomerular hypertrophy,
hemosiderin deposits,
focal areas of hemorrhage or necrosis
What is late stage sickle cell nephropathy characterized by?
Interstitial inflammation,
edema, fibrosis, tubular atrophy, and
papillary infarcts
What is end stage sickle cell nephropathy characterized by?
glomerular enlargement and
focal segmental glomerulosclerosis
What causes amyloidosis?
Misfolded proteins (chemically diverse, but physically similar), all folded into beta-pleated sheets,
Usually first deposited in blood vessel walls, then interstitium, where it squeezes the cells to death, eventually leading to organ failure
What is a rare cancer that only presents in sickle cell patients?
medullary carcinoma of the kidney
What do medullary carcinomas of the kidney arise from?
collecting duct system
What patient population gets medullary carincomas of the kidney?
avg age 21-24; 75% male
75-89% in the right kidney
Prognosis of medullary carincomas of the kidney?
very aggressive (death within 4-6 months)- resistant to radiotherapy and chemo
Describe the histology of renal amyloidosis.
- nonproliferative
- noninflammatory glomerulopathy
So what does renal amyloidosis show on urinalysis?
bland urinalysis (no pyuria) with proteinuria
T or F. Amyloidosis is associated with kidney shrinkage
F. It is associated with enlargement, as is diabetic nephropathy and HIV nephropathy
What causes AL amyloidosis?
primary disorders of immunoglobulin production (MM, Waldenstrom’s amcroglobulinemia)
What causes AA amyloidosis?
more secondary
- persistent acute inflammation
- Cancers
- Familial Mediterranean Fever
Where does amyloidosis affect first in the kidneys?
the vessels first, and then into the interstitium
After confirmation of the presence of amyloid in tissue the next step must be what?
Assessment of the type of amyloid involved.
Amyloid detected in a patient with longstanding rheumatoid arthritis and a nephrotic syndrome is almost undoubtedly __ type.
AA
A patient with amyloid and clinical signs such as shoulder pads and glossomegaly most likely will have __ type.
AL
