Nephro Final

Roles of kidney

* excretory
* metabolic
* endocrine

Excretory function of kidneys

* filtration - glomerulus
* secretion - proximal tubules
* reabsorption - distal tubules & collecting ducts

Assessment of kidney function

urinanalysis

pH

glucose, nitrates, ketones, leukocytes, protein, albumin

eGFR & CrCl

Pros / Cons Creatinine

Pros

* freely filtered, not secreted/reabsorbed
* rises in kidney dysfunction
* endogenous protein

Cons

* input impacted by muscle mass & diet
* output influenced by medication
* lags\*

CKD: G1

GFR > 90 ml/min

normal or increased GFR

CKD: G2

GFR 60-89 ml/min

CKD: G3a

GFR 45-59 ml/min

CKD: G3b

GFR 30-44 ml/min

CKD: G4

GFR 15-29 ml/min

CKD: G5

GFR < 15 ml/min

Albuminemia A1

ACR < 30

negative for protein

Albuminemia A2

ACR 30-300

positive for protein +1

Albuminemia A3

ACR > 300

positive > 1

what are the most common causes of CKD?

HTN & Diabetes

what 3 parameters are most important to control in CKD?

Proteinuria, blood pressure & blood glucose

CKD susceptibility factors

increased age

low birth weight

small kidney

racial minority

dyslipidemia

family history

low income

low education

systemic inflammation

Initation factors CKD

diabetes

HTN

glomerulonephritis

polycystic kidney disease

Diabetic kidney disease

* vascular changes in kidney = impaired TGF
* proteinuria & declining GFR
* high risk for progression

DKD Type 1

wait 5 years from diagnosis before screening

DKD Type 2

screen at diagnosis

Nephritic glomerulonephritis

inflammation, hematuria & proteinuria

nephrotic glomerulonephritis

proteinuria, edema, hyperlipidemia, hypercoagulable

Complications of CKD

CV events, anemia, bleeding, HTN, electrolyte abnormalities, hypoglycemia, malnutrition, impaired immunity, bone/mineral disorder

Normal Na

135-145 mEq/L

Normal K

3\.4 - 4.5 mEq/L

Normal Cl

97 - 110 mEq/L

Normal CO2

22 - 26 mEq/L

Normal BUN

8 - 25 mEq/L

Normal SCr

0\.6 - 1.3 mg/dl

Normal Glucose

65 - 109 mg/dL

Normal Ca (total)

8\.5 - 10.5 mg/dL

Normal Ca (ionized)

4\.5 - 5.4 mg/dL

Normal Mg

1\.5 - 2.5 mg/dL

Normal Phos

2\.5 - 4.5 mg/dL

KDIGO BP goal

A1 → < 140/90 mmHg

A2/A3 → < 130/80 mmHg

AHA BP goal

< 130/80 mmHg

Thiazide diuretics

CV protection

GFR > 30

enhance fluid removal

Loop diuretics

fluid management

can be used with thiazides

Proteinuria treatment

ACR > 30 → ACEi/ARB

start low and monitor monthly

monitor K+ and Scr

causes of anemia

blood loss

excess red blood cell production

deficiency in red blood cell destruction

medications

B9, B12 & iron deficiencies

Consequences of anemia

increased mortality & morbidity

Anemic Hb men

< 13%

Anemic Hb women

< 12%

Hematocrit

volume of red blood cells in 100ml of blood

affected by fluid status

Acute onset of anemia s/s

tachycardia

light-headedness

SOB

Hypotension

angina

Chronic onset of anemia s/s

tired

malaise

cold & pallor

weak

s/s HF

Increased MCV

macrolytic anemia

decreased MCV

microlytic anemia

MCV normal

80 - 98 fL

mean corpuscular volume

increased RDW

B12 / B9 / iron deficiencies

RDW normal

red blood cell distribution width

11\.5 - 14.5

MCH normal

26 - 34 pg

Mean corpuscular hemoglobin

increased MCH

Macrolytic anemia

(B12 / B9 deficiencies)

decreased MCH

hypochromia

(iron deficiency)

MCHC normal

32 - 36%

mean corpuscular hemoglobin concentration

low MCHC

hypochromia

Macrolytic Anemia types

Megaloblastic

Non-megaloblastic

Megaloblastic macrolytic anemia

impaired DNA synthesis

B12 / B9 deficiency

non-megaloblastic macrolytic anemia

hemolysis (increased reticulocyte count)

B12 (cyanocobalamin)

* water soluble vitamin
* sources: fish, meat, poultry, eggs, dairy
* absorbed in distal ileum

B12 deficiency causes

Reduced Absorption

* pernicious anemia (autoimmune disorder)
* atrophic gastritis
* GI surgery / disorders

Medication-Induced

* PPIs / H2RAs
* Metformin

B12 deficiency symptoms

weakness, fatigue & sore mouth

\*CNS effects\*

ataxia, depression, confusion, dementia, psychosis

memory loss, paraesthesias

B12 deficiency signs

increased MCV / homocysteine / MMA

B12 deficiency treatment

Cyanocobalamin

* IM 1mg QD x 7 days, then weekly x 1 month then monthly
* PO 1-2 mg QD
* IN 1 spray weekly

B9 (folate)

* water soluble vitamin
* sources: green leafy vegetables, citrus, beans, dairy, mushrooms
* normal absorption in small intestine

B9 deficiency causes

Inadequate Intake

* Alcoholics / chronic illness

Inadequate Absorption

* pregnancy
* Alcoholics
* dialysis
* burn patients

Medication-induced

* Azathioprine
* 6 mercaptopurine
* 5 FU
* Hydroxyurea
* AZT
* Phenytoin, Phenobarbital, Primidone
* Methotrexate

B9 deficiency signs

increased MCV / homocysteine

B9 deficiency treatment

Folic Acid 1 mg PO QD

(usually for 4 months or maintenance)

Treatment Megaloblastic anemia

* Clotrimoxazole: Leucovorin 5-10 mg/day
* Phenytoin or Phenobarbital (+ Folic Acid)

Iron Absorption

* absorbed in the duodenum (and jejunum)
* tightly regulated by hepcidin
* heme x3 more absorbed than non-heme

transferrin

iron transport protein

ferritin

storage iron

iron deficiency

Microcytic anemia

microcytic anemia populations at risk

children < 2 yo

adolescent females

pregnancy / lactation

elderly

Iron deficiency signs

decreased MCV / CHr

decreased TSAT / ferritin

increased RDW / TIBC

Oral Iron

200 mg ELEMENTAL iron daily (BID/TID)

AE: dark stool, constipation, N/V

TAKE ON EMPTY STOMACH

1-3 month trial

Ferrous sulfate

325 mg = 65 ELEMENTAL

Need 3 tablets for PO maintenance

Ferrous gluconate

325 mg = 36 ELEMENTAL

Need 6 tablets for PO maintenance

Polysaccharide iron

50 mg = 50 ELEMENTAL

Need 4 tablets for PO maintenance

Heme polypeptide

12 mg = 12 ELEMENTAL

Need 17 tablets for PO maintenance

Ferrous Fumarate

300 mg = 99 ELEMENTAL

Need 2 tablets for PO maintenance

IV iron structure

carbohydrate shell

* stabilizes molecules
* prevents rapid release
* maintains colloidal suspension

iron core

labile iron

free, ionic first released from IV iron agent

max 8 mg dose

how often should iron stores be monitored?

every 6-12 months

indication for IV iron

TSAT < 30%

Ferritin < 500 ng/ml

how long should a patient be monitored after receiving an IV iron infusion?

60 minutes

IV iron initial dose

1000 mg divided over several doses

IV iron maintenance dose

1 - 2 g / year

IV iron contraindications

active infection

what can be given before IV Iron Dextran to pre-treat anaphylaxis?

IV Diphenhydramine or corticosteroids

IV Iron Dextran

INFeD / DexFerrum

BBW: anaphylaxis

requires a test dose before infusion

IV Ferric Gluconate

Ferrlecit

which IV iron formulation is safe for patients with an allergy to iron salts?

IV iron sucrose

IV Iron Sucrose

Venofer

well tolerated\*

IV Ferumoxytol

Feraheme

* superparamagnetic iron oxide, polyglucose sorbitol & carboxymethylether shell
* BBW: hypersensitivity reaction
* 15 min infusion

IV Ferric Carboxymaltose

Injectafer

weight based

risk HTN

IV Ferric Pyrophosphate Citrate

Triferic

non-carbohydrate based iron salt

\*Hemodialysis only\*

delivered via dialysate in hemodialysis

Epoetin Alfa

Epogen / Procrit

T1W (short-acting)

Darbepoeitn Alfa

Aranesp

Q1-2 weeks

Methoxy polyethylene glycol (epoetin beta)

Micera

Q2-4 weeks