Renal + Bariatric surgeries Flashcards
Name 5 indications for bariatric surgery
- BMI ≥ 40
OR - BMI > 35 with significant obesity-related comorbidities (e.g. MetS, OSA, Osteoarthritis, HTN, …)
- Acceptable operative risk (risk of surgery < risk of not undergoing surgery)
- Failure of non-surgical weight loss attempts
- Well-informed, compliant, and motivated patient (need to understand lifestyle habits still have to change despite the surgery being done)
Name 6 contraindications to bariatric surgery
Active substance abuse (drugs, alcohol) Uncontrolled psychiatric illness Cirrhosis Pulmonary hypertension Severe cardiac and respiratory disease Active pregnancy
Name 4 disadvantages of gastric bands
- Requires frequent adjustments (cannot tighten too much at once; requires adjustments –> better for people who live close to the center)
- Unknown durability of the band (research does not support this procedure, poor long-term outcomes – no longer covered by insurance)
- Can lead to band erosion and damage the tissue of the stomach.
- Band can also leak which requires more surgeries to fix.
Where does the common limb start in a RYGB? In a BPD-DS?
RYGB: Common limb starts at proximal jejunum
Switch: ≈ 100 cm of the ileum
How do we calculate excess weight loss (EWL)?
% Excess weight loss (EWL) = (Pre-op BW – CBW)/(Pre-op BW – IBW) x 100
IBW is at BMI 25
Why is there a resolution of T2DM in bariatric surgeries?
Not d/t weight loss but rather to gut hormone changes
What is the pattern of weight loss after bariatric surgery?
o Rapid weight loss occurs over first 12 months post-op
o Most significant loss seen in the first 6 months post-op (fastest loss occurs over 6 months; and for the next 6 months about ½ of the weight lost in the first 6 months is lost) –> patients get discouraged
o Stabilizes after 12 months (goal is maintenance)
What are the 3 mechanisms of weight loss in bariatric surgeries?
- Gastric restriction (all surgeries) –> reduced PO intake
- Alimentary/Roux limb length (RYGB, BPD-DS)
- Longer roux limb means shorter common limb = more malabsorption and vice versa
- Shorter common channel length –> more malabsorption - Gut hormones (RYGB, sleeve, BPD-DS)
- Decreased Ghrelin (orexigenic hormone) secretion - Produced by the parietal cells (in the gastric fundus), which is removed
- Increased leptin (produced by adipocytes)
- PYY hormone involved in DM resolvement – not a lot of evidence
Name late complications of bariatric surgeries
Ulcer, stricture, obstruction, hernia, nutrition deficiencies, dumping syndrome, weight regain or weight loss failure, psychological complications, malnutrition, gastric reflux
Name early complications of bariatric surgeries
Bleeding, anastomotic leak, infection, strictures, obstructions
What are the nutrition guidelines post op for bariatric surgeries?
Texture progression (to prevent vomiting and promote healing)
Clear fluids (1-3 days)
Full fluids/puree (5 weeks) (applesauce, oatmeal, pureed meat…)
Solids (for life)
Portion progression
After surgery, the stomach and SI are swollen and inflamed – can only eat a small amount
o ½ cup to start, increase to 1 cup portions per meal/snack
What is the effect of the removal of the stomach fundus on nutrient absorption?
Removal of fundus (fewer parietal cells)
Reduced gastric acidity (hydrochloric acid helps in the digestion of protein, calcium and iron)
Reduced intrinsic factor (IF)
What are the nutrients to watch for in RYGB? Switch?
Gastric bypass nutrients to watch for: • Calcium • Iron • Vitamin D • Folate • Vitamin B12 (intrinsic factor in the stomach)
Duodenal switch nutrients to watch for: • Calcium • Iron • ADEK (fat-soluble vitamins) – they are usually absorbed in the jejunum and beginning of ileum which are bypassed • Folate • Vitamin B12
Why is calcium citrate preferred over calcium carbonate after surgery?
It is preferred to use calcium citrate instead of calcium carbonate after a surgery because calcium carbonate requires an acidic component to be absorbed while calcium citrate contains an acidic component
Which deficiencies may appear later?
Zinc and copper deficiencies usually appear later (2-3 years) because they have adequate stores before
Differentiate primary protein malnutrition to secondary PM
Primary protein malnutrition (PM) or protein-energy malnutrition (PEM)
o Rare but at risk in all bariatric surgeries
o D/t decreased oral intake/volume restriction
Secondary PM or PEM
o RYGB (rare) and BPD-DS (uncommon, but possible)
o D/t malabsorption
When is there most LBM loss after surgery? What are the implications?
Most LBM loss occurs within 3 months post-op (PO intake is still poor; trying to advance on texture and volumes)
LBM loss may lead to reduced RMR and reduced muscle strength and physical function (and puts them at risk of regaining weight over time)
Importance:
o Inevitable LBM loss, but try to minimize as much as possible
What are the protein recommendations in bariatric surgeries?
Band, sleeve, RYGB
o 1.0-1.5 g/kg IBW (≈ 60-120g/d); may use Adjusted BW d/t very high BMI
BPD/DS
o 1.5-2.0 g/kg IBW (≈ 90-120g/d) d/t significant malabsorption may use Adjusted BW d/t very high BMI
Based on expert opinion
Focus in high biological value/high quality protein
o High PDCAAS: egg white, whey, casein, soy
o Low PDCAAS: collagen, gelatin
Name common tolerance issues after surgery.
Dehydration – hard to drink enough after surgery
Constipation – reduced PO intake = reduced fiber intake (+ we focus more on protein)
Diarrhea o Lactose intolerance (less lactase enzyme if SI has been removed) o Dumping syndrome o Sugar alcohols o Other?
Food intolerances o Dysgeusia (things taste metallic) o Regurgitation (max physical capacity of stomach) o Esophageal dysphagia (hurts)
Name possible causes of vomiting post-sx
- Esophageal dysphagia?
- Poor chewing
- Overeating
- Eating too quickly
- Eating tough, fibrous foods, doughy breads, dry meat
- Stricture (If a patient vomits everything he/she eats (even pureed foods) but can tolerate water = probably a stricture)
With which surgery(ies) is dumping syndrome common?
Occurs with RYGB due to the removal of the pyloric sphincter. Occurs in 85% of patients with GB, 30% of those with sleeves. No pyloric sphincter: Undigested food touches SI too soon –> osmosis
Describe the 2 phases of dumping syndrome
“early” phase:
o Occurs 10-30 minutes PC
o D/t rapid transit of hyperosmotic food into the jejunum (usually simple sugars)
o Symptoms: dizziness, nausea, weakness, rapid pulse, diarrhea (similar to hypo)
“Late” phase:
o Occurs 1-3h PC
o Reactive hypoglycemia due to an exaggerated release of insulin d/t surge of glucose in the SI –> pancreas sends a surge of insulin –> end up with a surge in BG d/t simple sugars entering the blood and then a drop
What nutrition interventions are recommended for dumping syndrome?
o Healthy snacking
o Advise glucometer
o Avoidance of trigger foods (limiting simple sugars)
o Label reading (≤ 25 g absorbable carb)
* ≥ 25 g absorbable carb can lead to dumping syndrome
What is nesidioblastosis and what can be done to avoid?
Nesidioblastosis (hyperinsulinemic hypoglycemia) may happen when patients eat high carb low protein meal
Nutrition intervention
o Increase in protein:carb ratio at lunch and PM snack
o If no change in symptoms, see an endocrinologist (may be put on acarbose)
What are 3 possible causes of hair loss post surgery?
- weight loss (happens in about 50% of bariatric patients); Shock loss – premature loss of hair before growth of next “batch”
Thinning or shedding of hair d/t weight loss and physiological stress of surgery
Occurs between 3-6 months post-op (early hair loss) – can go on to 9 months
Late hair loss (about 2-3 years after surgery) conduct dietary assessment and bloodwork; calculate protein intake
-Protein deficiency (needs are higher)
- zinc deficiency (gummy MVI have less calcium, iron and zinc…)
Prevalence of zinc deficiency among patients with a switch: 70%
Symptoms of Zn deficiency: Hair loss, dysgeusia
Consider zinc deficiency if…
o Hair loss starts > 6-9 months post-op
o Attaining protein needs
o Insufficient zinc supplementation
What can be done to reverse Zn deficiency?
Nutrition intervention
o Zinc supplementation: 60 mg elemental BID
o Monitor plasma zinc in bloodwork
o Suggest complete MVI to patient considering…
Name 5 causes for weight regain post-op
• Dietary habits
Increased calories: sugar and fat; Grazing: emotional eating
Not delaying fluids (drinking and eating at the same time)
• Poorly controlled thyroid
• New medications (weight promoting, antidepressants)
• Stopped exercising
• Surgical reasons? (only in 10% of cases; unlikely…)
Define GFR
Expression of the quantity of glomerular filtrate formed each minute in the nephrons of both kidneys, calculated by measuring the clearance of specific substances (inulin or creatinine)
Name 6 factors that can influence urine creatinine
• Diet, muscle breakdown, lab calibration bias, extra-renal elimination (gut bacteria), age, Antibiotics…
Classify the 5 stakes of CKS based on their GFR.
Stage 1: Kidney damage with normal or increased GFR Stage 2: GFR 60-89 Stage 3: GFR 30-59 Stage 4: GFR 15-29 Stage 5: GFR < 15 or dialysis
How do we calculate dry weight?
- Total body water – Watson Method (Weight in kg, height in cm)
- Estimated dry weight
o Liters of actual body water = 142 mEq/L X Liters of total body water/serum sodium (mEq/L)
o Liters of actual body water – liters of total body water = excess body fluid (kg)
o Weight – XS body fluid (kg) = Estimated dry weight
What are sodium and fluid needs in patients with CKD?
o If output less than 1L/d: Restrict to 1.0-1.5L and 2g sodium
o If output greater than 1L/d: 2L and 2-4 g sodium
PD: 1-3L and 2-3g sodium
Predialysis stage (1-4): No need for fluid restriction/sodium restriction according to BP
What are high P foods?
High phosphorus foods: Dairy products, proteins (livers, oysters, sardines, carp…), legumes (beans, lentils, chickpeas…), bran cereals, seeds, whole grain products, nuts…
How do we calculate adjusted serum calcium?
((4-albumin mg/dL) x 0.8) + Ca mg/dL
Explain the link between CKD and renal bone disease
- Failure of the endocrine function of the kidneys to produce calcitriol (1,25 - dihydroxy cholecalciferol) results in secondary hyperparathyroidism
- This deficiency leads to disorders of calcium, phosphorus, magnesium, and bone and muscle metabolism
Supplement with active form of Vit D: “1-alpha” to increase absorption and raise serum calcium level and suppress PTH secretion
Renal bone disease develops in early stages of CRF
• Patients with CKD have decreased Ca absorption 2°:
- altered metabolism of Vit D
- inability to excrete excess phosphate or hyperphosphatemia
Results in decreased serum calcium or hypocalcemia, hyperparathyroidism and renal osteodystrophy
How can we control hyperphosphatemia in CKD?
To control hyperphosphatemia:
Restrict dietary phosphorus to 12mg/kg/d or 15 mg/gPro/d
** main foods: dairy products, meat, fish, poultry, legumes, nuts, bran, cola, chocolate, beer
Use phosphorus binders (calcium acetate, calcium carbonate or Sevelamer HCl known as RENAGEL {Calcium free})
Avoid aluminum containing binders, because linked with the development of dementia; if necessary, pulse for 2 weeks.
Why do we want to decrease PTH levels?
High calcium x phosphorus product results in metastatic calcification in soft tissue areas:
This is why we want to decrease PTH levels
• Conjunctivae of the eye
• Heart, especially aortic valve and blood vessels
• Lungs
• Extremities
Which vitamins should be supplemented in people on dialysis? Why
Water-soluble vitamin supplements
o Increased losses during PD and HD; anorexia; poor intake
o Diet restrictions
o Impaired synthesis
Why is zinc supplementation useful in patients on HD?
Researchers suggest that zinc supplementation in the amount of 15 mg/d may improve dysgeusia (loss of taste) and may be helpful in the management of impotence in male hemodialysis patients
What are the macronutrient recommendations for patients with CKD?
SFA: 7% E PUFAS: ≤ 10% E MUFAS ≤ 20% E Total fat: 25-35% E CHO: 50-60% E Protein: 15% E Cholesterol < 200 mg Fiber: 20-30g/d with 5-10 g soluble fiber
Name risk factors for CKD
- Diabetes
- Hypertension
- Autoimmune diseases (e.g. systemic lupus erythematosus)
- Systemic infections
- Urinary tract infections
- Urinary stones or lower urinary tract obstruction
- Neoplasia
- Family history of chronic kidney disease
- History of acute kidney injury
- Reduction in kidney mass
- Exposure to certain drugs
- Low birth weight
- Age older than 60 years
- Exposure to certain chemical and environmental conditions
- Low income/education
- Ethnicity (African Americans, Hispanic Americans, Asians, Pacific Islanders, and American Indians.)
Name causes of CKD
Diabetes, HTN, other renal disease (chronic glomerulonephritis, polycystic kidney disease, interstitial nephritis, obstructive nephropathy)
Name symptoms of CKD
Asymptomatic in earlier phases but as failure progresses: Increasing fatigue, N/V, anorexia, insomnia, uremic syndrome –> body is intoxicated by nutrients
Name and explain the 4 phases of CKD
- Decreased renal reserves
Diminishing renal function but without accumulation of the end-products of protein metabolism. The patient is asymptomatic
2. Chronic renal insufficiency Further reduction in kidney function GFR decreases of 30 mL/min (about 90) Waste products begin to accumulate CRI can be mild, moderate, or severe --> Severe CRI will eventually progress to ESRD
- Frank Renal Failure
Serum creatinine and BUN rise steadily due to drop in GFR - End stage renal disease
Remaining kidney function cannot adequately regulate the balance of fluids, salts, and waste products in the body – uremia
< 15% of normal function (DM); < 10% (no DM)
All body systems are impaired
Dialysis and/or transplant is needed to prevent complications and death
Name complications of CKD
- Uremic syndrome (high urea and creatinine)
- Anemia (decreased erythropoietin)
- Fluid imbalances (Na imbalance, edema)
- Electrolyte imbalances (high K, acidity, PO4)
What is pre-dialysis? What is the nutritional goal?
Stage 3-4 (GFR 13-50)
Goal: Minimizing renal impairment while preventing malnutrition (prevent uremia symptoms)
What is considered as CKD in diabetes?
CKD in diabetes = Albumin to creatinine ratio (ACR) ≥ 2.0 mg/mmol and/or eGFR < 60 mL/min/1.73 m2
What are the nutrition recommendations for CKD stage 1-2?
- Protein
- Energy
- Sodium
- K
- P
- Ca
- Fluid
- Protein: 0.8-1.4
- Energy: 25-35 kcal/kg
- Sodium: < 2400
- K: Unrestricted unless blood level high
- P: Maintain serum P WNL
- Ca: DRI, maintain serum levels WNL
- Fluid: Usually unlimited
What are the nutrition recommendations for CKD stage 3-4?
- Protein
- Energy
- Sodium
- K
- P
- Ca
- Fluid
- Protein: 0.6-0.8
- Energy: 25-35 kcal/kg
- Sodium: < 2400
- K: Unrestricted unless blood level high
- P: 800-1000 mg/d
- Ca: DRI, maintain serum levels WNL
- Fluid: Usually unlimited
When should we screen diabetic people for CKD?
Screen annually when no transient cause of albuminuria or low eGFR are present, and when AKI or non-diabetic kidney disease is not suspected
T1DM: Annually in postpubertal individuals with duration of diabetes ≥ 5 years
T2DM: At diagnosis and annually thereafter
Name possible causes of transient albuminuria
Recent major exercise, UTI, febrile illness, decompensated CHF, menstruation, acute severe elevation in BG, acute severe elevation in BP
How do we diagnose CKD in diabetic people?
eGFR ≤ 60 or ACR > ≥ 2.0 mg/mmol?
If so, do random urine ACR –> is it ≥ 20 mg/mmol?
NO –> order SCr and 2 repeat random urine ACRs over next 3 months
Is GFR ≤ 60 OR ACR 2/3 ≥ 2 mg/mmol?
DIAGNOSIS
Name 4 ways to reduce the progression of diabetic nephropathy
- Optimal glycemic control
- Optimal BP control
- ACEi or ARB
- SGLT2i (less certain, but evidence going there)
What do we need to do before starting new drug therapy in CKD?
Before starting new drug therapy: Check serum K and Creat
At baseline
Within 1-2 weeks of initiation or titration
During acute illness
If K+ becomes elevated or Creat > 30% increase review therapy; recheck serum K and Creat
What to do in case of moderate/mild hypokalemia? Severe hypokalemia?
Mild to moderate stable hyperkalemia
o Counsel on a low potassium diet
o If persistent, consider adding non-potassium sparing diuretics and/or oral sodium bicarbonate (in those with metabolic acidosis)
o Consider temporarily holding or discontinuing ACEi, ARB or Direct Renin Inhibitor (DRI)
Severe hyperkalemia
o Hold or discontinue ACEi, ARB or DRI
o Emergency management strategies
Name symptoms of CKD/uremia
Weight loss, weakness, vomiting, loss of appetite, fatigue, nausea, SOB, leg cramps, itching, chest pain, easy bruising, swelling of ankles and legs, bad taste in the mouth, restless legs, forgetfulness, difficulty sleeping, cold intolerance, skin color changes, decreased sexual desire
What can be secondary causes of anemia in CKD?
- Residual blood loss in dialyzer contributes
- Inflammation due to infection and co-morbid conditions
- Hyperparathyroidism can be an adjunctive cause
