Primer for APN Nephrology Practice or CNN-NP Certification Preparation

Renal Anatomy/PhysiologyLinda Shenton, MN, RN, ACNP, CNN-NP

References

•ANNA Certification Review •ANNA Certification Study Guide•ANNA Core Curriculum•KDOQI•KDIGO•National Kidney Foundation•Renal Physicians Association

Objectives

1.Interpret key lab and clinical data to develop the diagnosis of renal disease

2.Explain factors that contribute to chronic kidney disease and progression of renal disease and or AKI

3.Develop treatment strategies for management of a person with CKD

Kidney - Anatomy

1. 2 kidneys 150 grams each2. Size 5-7cm wide, 11-13cm long 3. Blood Supply: 1,200 ml/minute or

approximately 25% of CO4. Nephron 1 Million per kidney 5. Efferent arteriole/afferent arteriole6. Tubules

Basic Renal Anatomy

•Kidneys-Retroperitoneal

•Weight-120-160 gm

•Size-4.5 cm x 9 cm x 2.5 cm

•Functional Unit- Nephron

Nephron

•Filters the blood of it’s small molecules and ions

•Reclaims the amount of useful materials Did you Know?

In 24 hrs the kidneys reclaim•1,300g of NaCl•400 g NaHCO3•180 g Glucose

Anatomy

•Blood supply: renal artery arises from the aorta and divides into 3 branches; renal vein is formed by a series of small veins

•The kidney receives approximately 25% of the cardiac output.

Blood Supply

•Afferent artery supplies blood to the kidney

•Efferent artery returns blood to the systemic circulation

•Total blood volume circulates through the kidneys every 5 minutes

Functions of Healthy Kidney

1. Regulation of water and inorganic ion balance

2. Removal of metabolic waste products3. Removal of chemical toxins and drugs4. Regulates acid base balance of body fluids5. Production of hormones/enzymes

a) Erythropoietinb) Reninc) 1,25-dihydroxyvitamin D

Statistics

Anemiain

CKD

Definition of Anemia

World Health Organization

•Males: hemoglobin less than 13g/dl•Females: hemoglobin less than 12g/dl

RBC Formation

•Undifferentiated cells gradually differentiate to become stem cells, that form blood cells

• Occurs in myeloid tissue (bone marrow of long bones) and lymphoid tissue

• 2 types of Hematopoiesis:Erythropoiesis: Formation of RBCsLeukopoiesis: Formation of WBCs

Hematopoiesis/Erythropoiesis

Erythropoiesis

•Relative or absolute iron deficiency•Decreased erythropoetin production• Increased risk for bleeding due to uremic effects

on platelets•Blood losses – GI, dialysis, lab draws•B12 and or folate deficiencies

•Hyperparathyroidism•Low grade hemolysis or hypersplenism•Other conditions: cancer, infections, medication

related

Causes of Anemia in CKD

Iron Metabolism

•Relative or absolute iron deficiency•Decreased erythropoetin production• Increased risk for bleeding due to uremic effects

on platelets•Blood losses – GI, dialysis, lab draws•B12 and or folate deficiencies

•Hyperparathyroidism•Low grade hemolysis or hypersplenism•Other conditions: cancer, infections, medication

related

Causes of Anemia in CKD

Bone and Mineral Disorder

Normal Phosphate MetabolismNormal Phosphate Metabolism

60% to 70% of dietary intake is absorbed in

small intestine

PTH stimulates release of PO4 and

Ca from bone

PTH stimulates kidneys to resorb or

excrete PO4, as needed.

85% of PO4 is stored in

bones; 14% in soft tissue; 1% extracellular

90% is filtered through the glomerulus; only 10%25% is excreted in urine

1,25-dihydroxy vitamin D3

enhances gut absorption of PO4 and Ca

Phosphorus HomeostasisPhosphorus Homeostasis

Hyperphosphatemia PathophysiologyHyperphosphatemia Pathophysiology

Secondary Hyperparathyroidism, Secondary Hyperparathyroidism, Bone Disease, and CalcificationBone Disease, and Calcification

High Bone Turnover Low Bone Turnover Mixed

Chronic Kidney Disease

Phosphorus

Ca x P product

Calcitriol

Parathyroid Hormone

Renal Osteodystrophy1,2

Soft-Tissue Calcification3,4

Vascular Nonvascular

1. Malluche H & Faugere MC. Kidney Int. 1990;38:193-211. 2. Malluche HH & Monier-Faugere MC. Kidney Int. 1992;42 (suppl 38):S62-S67. 3. Moe SM. Perit Dial Int. 2001;21(suppl 3):S241-246.4. Reslerova M & Moe SM. Am J Kidney Dis. 2003;41( suppl 1):S96-S99.

Normal Laboratory ValuesNormal Laboratory Values

Parameter Range

Vit D 25 hydroxide (OH) 25-80 ng/mL

Vit D 1,25 22-67 ng/mL

Calcium (Ca) 8.5–10.2 mg/dL

Phosphate (PO4 ) 2.4–4.5 mg/dL

Ca x P 30–55 mg/dL

Intact Parathyroid Hormone (iPTH)

12–72 pg/mL

(bio intact PTH 6-40pg/mL)