Nephrology Flashcards
___
affects the Efferent arteriole causing increase in GFR but with compensatory Na reabsorption
Angiotensin = responds due to decrease BP
____ facilitate dilation of Afferent arteriole causing increase in GFR but no Na reabsorption
ANP = responds due to increase atrial pressure
Na loss and volume loss
Parathyroid hormone is secreted in response to a decrease in [Ca], increase [PO4], or decrease 1,25OH D3. in response, ___
- Increase Ca reabsorption in DCT
- Decrease PO4 reabsorption in PCT
- Increase 1,25-OHD3 production
- Increase Ca and PO4 absorption from the gut
Most frequent cause of hyperkalemia
decrease in renal K excretion
- RAAS system
- Hyporeninemic, hypoaldosteronism
- Addison disease
What is the most urgent step if hyperkalemia is suspected?
ECG
since hyperkalemia can lead to life threatening arrythmia
[Hyperkalemia ECG changes]
Tall, peaked T waves
5.5 - 6.5
[Hyperkalemia ECG changes]
Loss of P waves
6.5 - 7.5
[Hyperkalemia ECG changes]
widened QRS
7-8
[Hyperkalemia]
Used for immediate antagonism of the cardiac effects
- IV calcium gluconate
[Transcellular Potassium Shift]
K enters the cell due to
- Insulin
- Beta agonist
- Alkalosis
[Transcellular Potassium Shift]
K exits the cell due to
- Hyperosmolarity
- Exercise
- Cell lysis
- Acidosis
[Bartter vs Gitelman]
Mimics loop diuretic
Bartter
[Bartter vs Gitelman]
(+) Polyuria (+) polydipsia (-) HPN Hypokalemia normal Mg Increased urinary Ca excreation
Bartter Syndrome
[Bartter vs Gitelman]
(-) polyuria
(-) polydipsia
(+) tetany
(-) growth retardation
Low urinary CA
Low serum Mg
Gitelmann
Low MG due to TPMR 6 defect
[Bartter vs Gitelman]
mimic Na-Cl co transporter
Gitelman
What is the first step in diagnostic evaluation of hypercalcemia?
Check albumin
Corrected Ca = 40 - albumin x 0.02 + measure Ca
What is the main hormone that regulates Ca levels in the body
Parathyroid hormone
What are the effects of parathyroid hormone in the body?
- Bone resorption to increase serum Ca and P
- Increase Vit D synthesis
- Increase Ca reuptake but increase P excretion in the kidneys
Hypercalcemia in malignancy is usually due to overproduction of what hormone?
PTHrp
Most common PTHrp secreting tumor
- Squamous cell tumors
Vitamin D secreting tumor
Lymphoma
Granulomatous diseases like TB, Fungal infections and sarcoidosis increase Ca absorption in the gut by ___
ectopic production of alpha-1 hydroxylase that converts calcidiol to 1,25OHD3
Paget Disease causes hypercalcemia by ___
abnormal production of RANKL by osteoblast
High RANKL increases osteoclast activity
What is the defect in Familial Hypocalciuric Hypercalcemia which is a cause of hyperparathyroidism leading to hypercalcemia?
Calcium sensing receptor dysfunction
Increased urine volume associated with hypercalcemia is due to
Ca directly inhibits insertion of aquaporin channels in the collecting duct membrane
Inhibition of ROMK in the TAL luminal membrane increases urine volume leading to polyuria and the polydipsia is due to
Osmotic drag of water by increase NaCl in tubule lumen
ROMK facilitates movement of K to the tubule lumen. K drives NaKCl cotransported. Without this, NaCl accumulates in the tubule lumen
[Hypocalcemia]
QT prolongation is due to
Delay in repolarization due to increased myocyte depolarization since myocyte is very permeable to Na influx
[Hypocalcemia]
Laryngospasm, Chvostek sign, Trosseau sign, associated with hypocalcemia is due to
skeletal muscle tetany due to spontaneous action potential.
Hypocalcemia makes the cell permeable to Na influx thereby increasing excitability.
[Hypocalcemia]
Eliciting the Trosseau sign is due to spontaneous action potential in what nerve?
Median nerve
first tetanic sign to develop with hypocalcemia
[Diagnosis]
Low ADH secretion
H2O deprivation test
Positive AVP response
Central DI
[Diagnosis]
increased renal resistance to ADH,
H2O deprivation test no AVP response
Nephrogenic DI
What regulates the plasma [Na] level
Water intake or excretion
Chronic hyponatremia can lead to ___-
Osmotic demyelination syndrome
[Acid-base disorders]
What are the normal ABG values. Cite all
pH = 7.4 H = 40 pCO2 = 40 HCO3 = 24
What is the formula to calculate AG
AG = Na - (Cl + HCO3)
What are the 4 principal causes of HAGMA?
- Lactic Acidosis
- Ketoacidosis
- Toxins
- Renal failure
What are the causes of HAGMA?
Methanol Uremia DKA Paraldehyde Iron, INH Lactate Ethylene glycol Salicylates
What are the 2 causes of NAGMA?
- Bicarbonate loss from GIT
2. RTA
What are the causes of NAGMA?
Hyperalimentation/ Hyperventilation Acetazolamide RTA Diarrhea Ureteral divesion Pancreatic fistula
What is the best treatment for Sjogren’s Syndrome presenting as RTA I?
HCO3 and Potassium replacement
[RTA type]
Basic urine pH
Present urine stone
Low serum K
Type I - Distal
Dx: Acid load by giving NH4Cl
Tx: HCO3 + K tabs
[RTA type]
Acidic urine pH
Absent stones
Low serum K
Type II - Proximal
Dx: Bicarb load by giving HCO3
Tx: HCO3 + K tabs + diuretics (HCTZ)
RTA type II is associated with what diseases
- Amyloidosis
2. Multiple myeloma
[RTA type]
Acidic urine pH
Absent urine stones
High serum K
Patient is diabetic
Type IV (Hypoaldosteronism
Dx: Na restriction since high urine Na
Tx: Fludrocortisone (highest mineralocorticoid effect)
What is the RTA with ELEVATED potassium?
RTA IV
Look for a DM patient with NAGMA
Increase in Crea that is suggestive of AKI
- At least 0.3mg/dL in 48 hours
2. 50% or higher in 1 week
AKI can be inferred if there is a reduction of UO of
<0.5mL/kg/hr for >6 hours
Complete anuria in the early course of AKI can be seen in ____
- Complete UTO
- Renal artery occlusion
- Overwhelming shock
- Severe proliferative GN
Combining NSAID with what antihypertensive medications poses a high risk for AKI
ACEI or ARBs
What are the most common causes of intrinsic AKI?
- Sepsis
- Ischemia
- Nephrotoxin
Congestive heart failure can cause AKI since there is ____
decreased effective circulating volume
Drugs that can cause impairment of renal autoregulation leading to prerenal AKI.
- NSAID
- ACEI/ARB
- Cyclosporine
Drugs that can cause Intrinsic AKI
- Aminoglycosides
- Cisplatin
- Amphotericin B
What are the electrolyte disturbances in rhabdomyolysis?
- Hyperkalemia
- Hyperphosphatemia
- Hyperuricemia
- Hypocalcemia
- Elevated CPK
Hypocalcemia from rhabdomyolysis is due to
Damaged muscle binds to calcium lowering its blood level
What is the best initial test for rhabdomyolysis?
Urinalysis
What is the most accurate test to diagnose rhabdomyolysis?
Urine myoglobin
Recovery due to iodinated contrast nephropathy happens within ___
7 days
Contrast nephropathy peaks within ____
3-5 days
Kidney damage for ___ months can suggest CKD
> / 3 months
What is the most common cause of CKD?
DM nephropathy
What disease entities presents with CKD but has normal-sized kidneys
- DM nephropathy
- Amyloidosis
- HIV nephropathy
- PKCD
What disease entities presents with CKD but has normal-sized kidneys
- DM nephropathy
- Amyloidosis
- HIV nephropathy
- PKCD
Normocytic, normochromic anemia can be seen as early as what CKD stage?
Stage 3 CKD
What are the absolute indications for maintenance dialysis?
- Acidosis
- Electrolytes
- Intoxication
- Overload
- Uremia
Uremia, Intractable hyperkalemia, persistent volume expansion despite diuretics, refractory acidosis, bleeding diathesis, eGF 10
[UTI]
Premenopausal, non-pregnant women with acute onset dysuria, frequency, urgency without vaginal discharge
Acute uncomplicated cystitis
Tx: empiric tx
UA is not a prerequisite
[UTI]
Healthy women, fever, chills, flank pain, CVA tenderness, nausea and vomiting
AUC
Dx: UA and urine culture recommended
Tx: FQ x 14 days
[UTI]
Renal transpant, significant bacteriuria with urologic abnormality, renal transplant, diabetes, sepsis, older male
Complicated UTI
What are the drugs safe for UTI in pregnancy
- Amoxicillin
- Cephalosporin
- Nitrofurantoin
What is the length of treatment for UTI in men
7 to 14 days of a FQ
What is the length of treatment for acute bacterial prostatitis
2-4 weeks
What is the length of treatment for chronic bacterial prostatitis?
4-6 weeks
What is the length of treatment for recurrent UTI in men?
12 weeks
[Diagnose]
sudden onset unilateral flank pain, painless gross hematuria
nephrolithiasis
What is the most common type of stone that causes nephrolithiasis?
calcium oxalate
What is the most common site of impaction of nephrolith?
Ureterovesivular junction
What is the gold standard in diagnosing nephrolithiasis?
Helical CT without contrast
What is the most urgent step needed in an acute case of rhabdomyolysis
ECG to check for hyperkalemia
What are the cardiac arrythmias associated with hyperkalemia?
- Sinus bradycardia
- Sinus arrest
- Slow idioventricular rhythmns
- Ventricular tachycardia
- Ventricular fibrillation
- Asystole