Inherited Renal Diseases Flashcards
Mention causes of renal glucosura
- Impaired renal tubular function that lowers renal glucose threshold, usually inherited as AR trait
- Renal glucosuria may occur as part of Fanconi syndrome
Mention associations of hereditary Fanconi syndrome
Cystinosis, Wilson disease, hereditary fructose intolerance, galactosemia, tyrosinemia
Mention causes of acquired Fanconi syndrome
Cartain cancer chemotherapy drugs, antiretroviral , expired tetracycline
Describe causes of Fanconi syndrome
Various defects of proximal tubular transport function including impaired glucose, phosphate, AAs, bicarbonate, water, Ca, Na & K reabsorption. Amnioaciduria is generalized. Low Ca & PO4-2 & defective activation of vitamin D result in rickets
Describe C/P & TTT of Fanconi syndrome
In children, failure to thrive, growth retardation, rickets
In adults, osteomalacia & muscle weakness
Diagnosis is based on detecting glucosuria, phosphaturia & aminoaciduria
TTT, bicarbonate & potassium replacement, removal of nephrotoxins & measures directed at renal failure
What is the cause of cystinuria?
Inherited defect in the transport of protein that carries cystine, lysine, ariginine, ornithine into intestinal epitheial cell & that reabsorbs these AAs by renal tubular cell. Cystine is slightly soluble in urine forms renal calculi (stones)
Describe C/P & diagnosis of renal cystinuria
C/P: renal colic caused by stones perhaps urinary infection or consequences of renal failure
Diagnosed by measurement of cystine excretion in urine, inc fluid intake & alkalinization of urinr
Describe causes of cystinosis
Rare disorder chracterised by defective carrier that transports cystine across lysosomal membrane from lysosomal vesicles to cytososl. Thus cystine accumulates in lysosomes in may tissues esp affecting kidneys & eyes.
C/P of cystinosis
It has 3 different forms known as nephropathic cystinosis, internediate & ocular. Age of inset, symptoms & severity vary. Nephropathic is most common & severe form presents in infancy. Growth retardation & renal Fanconi are usually the 1st noticeable complications of cystinosis.
Describe treatment & diagnosis of cytinosis
Diagnosed by measuring cystine levels in PMNL
Treated by cysteamine drug is cystine depleting agent that can greatly lower cystine levels within cells. This slows development & progression of kidney damage & enhances growth in children.
Describe cause & C/P of Hartnup’s disease
-It is inherited as an AR disorder caused by mutation in gene encoding Na-dependent transporter protein of neutral amino acids in GIT & renal tubules
-Pellagra-like symptoms as diarrhea, dermatitis, dementia, neuropsychiatric symptoms, rash, photosensitivity
Describe symptoms & TTT of Hartnup
They result from dietary def of B3 & amino acid tryptophan which form the nicotinamide moiety of NAD & NADP. Aminoaciduria is a hallmark of the disease
TTT: High-protein diet can overcome the deficient transport of neutral amino acids in most patients. Poor nutrition leads to more frequent & severe attacks of disease.
Daily supplementation with nicotinic acid or nicotinamide reduces number & severity of attacks.
Explain why drinking excess water causes loss of urea in urine? What is the change in medullary interstitial space osmolarity?
Bec the blood osmolarity dec & ADH secretion is suppressed, thus:
1. Dec water reabsorption in CD & so conc of urea in inner medulla CD will not inc & it will not be reabsorbed
2. Dec permeability of inner MCD to urea & dec passive urea reabsorption from MCD.
Osmolarity is diminished from 1200 mOsm/L to 600 mOsm/L due to loss of urea.
Describe the role ADH in urine concentration
- Inc water reabsorption by late CDT & CD
- Inc permeability of inner medullary CD to urea causing inc osmolarity
- Act on efferent arteriolein juxtamedullary nephron leading to dec blood flow in vasa recta and wash out of solutes & inc filtered Na+ and more Na+ reabsorption in interstitial space in LH
In basal ADH, urine osmolarity is…….& volume is……
600 mOsm/L
1.5 L/d
