Renal Flashcards
Nephrotic syndrome key features
- Massive proteinuria (>3.5g/24h or 40mg/hr/m2 for children)
- Hypoalbuminemia (<30g/L)
- Generalized edema
- HL
Nephrotic syndrome PE findings
- Periorbital edmea
- Ankle edema
- Muehrcke’s nails
- Xanthelasma
- Frothy urine
S/S of CKD
- Fatigue
- Nocturia
- Thirst
- Fluid retention
- Itch
Tx target of DM nephropathy
- Control HT, DM, HL
- ACEI for reducing proteinuria
- Anti-inflammatory/fibrosis
Acidosis/Alkalosis on K
Acidosis –> HyperK
Alkalosis –> HypoK
Normal pH / QM ref range
Normal pH: 7.35-7.45
[H] = 40nmol/L @ 7.4pH
Acid/Alkalosis vs Acid/Alkalemia
- osis = a process
- emia = too much/too little H in blood
Metabolic acidosis features
Decreased HCO3 (Normal: 22-28mmol/L) Hyperventilation to compensate
Dx of Metabolic acidosis
Determine Anion gap
If high –> Done
If normal –> determine Urine anion gap
Look for any osmolar gap
Normal value Anion gap
8-14
[Na - Cl - HCO3]
If normal AG –> Cl is increased
Metabolic acidosis with increased AG
Causes
- DKA
- Alcoholic KA
- Lactic acidosis
- Renal failure
- Rhabdomyolysis
Metabolic acidosis with normal AG
Causes
- HCO3 loss with compensatory Cl increase
- Diarrhea (GI loss), Proximal renal tubular acidosis (RTA; Renal loss)
- Failure to excrete H (Distal RTA / Type 4 RTA)
- Ingestion of NH4Cl
- Increased reabsorption of Cl (Ureterosignmoidostomy)
Osmolar gap (OG) How to calculate
Actual - Calculated plasma osmolarity
Calculated = 2xNa + Urea + Glucose
Increased = Something osmolar inside, e.g. alcohol related compounds)
Lactic acidosis type A and B
Type A - Over-production --> O2 deficiency - Causes: Hypotension Hypoxia CO poisoning Grand mal seizure - Tx = Improve O2 delivery; NaHCO3 won't help unless controlled production; HD with HCO3 dialysis
Type B
- Reduced metabolism, w/o hypoxemia
- Liver problem, alcoholism, thiamine deficiency, Metformin
Risk of NaHCO3 therapy
- HypoK (shifts K into cells)
- HypoCa
- Paradoxical cerebral acidosis if too rapid correction (CO2 can diffuse to brain but not HCO3)
- Volume expansion (from Na load)
RTA (Renal tubular acidosis) types and features
Type 1
- Distal RTA (due to failure of H excretion)
- HypoK
- Acid loading test (NH4Cl): Urine cannot be acidified, pH remains >6.0 (N <5.5)
Type 2
- Proximal RTA (due to loss of HCO3)
- HypoK
- Fractional excretion of HCO3: Test for excessive loss of HCO3 in urine (>15%; cf <5% in Type 1)
Type 3
- Mixed
- HypoK
Type 4
- HyperK
- Aldo deficiency or resistance
Mx of RTA
Type 1,2
- Oral NaHCO3 to correct acidosis (v high dose needed for Type 2; K citrate better for Type 1)
- K supplement for HypoK
- Distal RTA due to Sjogren’s –> Steroids
Type 4
- Stop / decrease inciting drugs
- Loop diuretics + low K diet for HyperK
Causes of Metabolic alkalosis
H loss
- GI loss (Vomiting, Nasogastric drainage)
- Renal loss
- Diuretics, HypoK
- MC excess (Primary/Secondary)
- Bartter’s (looks like Loop diuretics) / Gitelman’s (looks like Thiazides)
HCO3 retention
- Intake of NaHCO3
- Milk-Alkali syndrome (taken too much Ca supplements / alkali for PU)
Tx of Metabolic alkalosis
If ECF contracted –> Give Saline (HCO3 will fall with expansion)
IF ECF expanded –> IV HCl or Oral NH4Cl to correct alkalosis
Correct HypoK
SIADH
Euvolemic hypoNa
Urine [Na] >20 mmol/L
Urine osmolarity >2x serum osmolarity
Tx
- Treat underlying cause (CNS/RS/Drugs)
If asymptomatic + Na>110
- Fluid restriction (<800/day), oral NaCl
If symptomatic + Na <110
- IV 500ml NS + 25ml 5.85% NaCl (=100mol NaCl) over 4-6h + IV Lasix 40mg until Serum Na >120
- Then fluid restriction
- Too rapid correction –> Central pontine myelinolysis
Causes of SIADH
CNS
1. Meningitis, Encephalitis, Brain abscess
2. Head trauma, SAH, CVA, Increase ICP
RS
3. CA Lung
4. Chest infection, positive pressure breathing
Drugs
5. SSRI, Ecstasy
Hypothyroidism
S/S of HypoNa
Non-specific: Malaise, lethargy, headache
Confusion, convulsion, coma
S/S of HyperNa
Thirst
Muscle spasm, twitching
Seizure, coma
Mx of HyperNa
Pure water loss Water deficit = BW x (Na/140 - 1) 1/3 rule in rate of replacement 1/3 in first 8h 1/3 in second 16h 1/3 in third 24h Replace ongoing loss
Too rapid –> Cerebral edema (influx of water into cells due to decreased serum osmolarity)
Max correction rate <12mmol/L/day
TTKG
Transtubular K gradient
Tubular [K] / Serum [K]
= (Urine [K] x Serum osmolarity / Urine osmolarity) / Serum [K]