Renal Flashcards
What is acute chemical peritonitis/intraperitoneal bladder rupture?
Etiology: rupture of bladder dome causes urine to spill into peritoneum; due to blunt trauma
Presentation: chemical peritonitis = diffuse abdominal pain, guarding, rebound
Irritation of peritoneal lining of R or L hemidiaphragm may cause referred pain to ipsilateral shoulder (Kehr sign)
What is an extraperitoneal bladder injury?
Consists of either contusion or rupture of the neck, anterior wall, or anterolateral wall of bladder
Pelvic fracture is almost always present; gross hematuria, urinary retention
Signs of peritonitis (diffuse abd tenderness, guarding, rebound) should not be present
What are uric acid kidney stones?
RF: increased uric acid excretion (gout, myeloproliferative disorders), increased urine concentration (hot, arid climates; dehydration), low urine pH (chronic diarrhea -GI bicarb loss; metabolic syndrome/DM)
Pathophys: acidic urine favors formation of uric acid (insoluble) over urate (soluble); supersaturation of urine with uric acid precipitates crystal formation (“sand” in urine)
Clinical characteristics: radiolucent stones (not visible on x-ray), uric acid crystals on urine microscopy, urine pH usually <5.5
Can be seen on CT scan
Presentation: flank pain, hematuria, hydronephrosis
Tx: alkalinization of urine (potassium citrate)
What is a posterior urethral injury?
Assoc. w/ pelvic fracture
Abrupt upward shifting of the bladder and prostate lead to urethral tearing, which commonly affects the membranous urethra at the bulbomembranous junction
Presentation: blood at the urethral meatus, inability to void, perineal or scrotal hematoma, HIGH-RIDING prostate on DRE
Dx: retrograde urethrogram - Involves an XR of lower GU tract obtained during the injection of radiopaque contrast into the urethra.
Normal study: contrast enters the bladder uninterrupted
Positive study: Extravasation of contrast from the urethra or inability of contrast to reach the bladder is diagnostic of urethral injury
What is urinary retention?
RF: male sex, advanced age (>80), hx of BPH, hx of neurologic disease (eg mild cognitive impairment), surgery (especially abdominal surgery, pelvic surgery, and jt arthroplasty), meds (eg anesthetics, opioids, anticholingerics - TCAs)
Dx: confirmed on bladder U/S demonstrating >300ml of urine; postvoid residual bladder volume >50ml
Tx: foley catheter insertion
What is urethral stricture?
Etiology: male>female, urethral trauma (eg catheterization), urethritis, radiotherapy
Sxs: weak or spraying stream, incomplete emptying, irritative voiding (eg dysuria, frequency)
Complications: acute urine retention, recurrent UTI, bladder stones
Dx: postvoid residual, uroflowmetry, urethrography, cystourethroscopy
Mgmt: dilation, urethroplasty
What is fibromuscular dysplasia?
Systemic non-inflammatory disease typically affecting renal and internal carotid arteries
Presentation: 90% women (in adults), internal carotid artery STENOSIS (leads to recurrent headache, pulsatile tinnitus, TIA, stroke), renal artery stenosis (leads to secondary hypertension/hyperaldosteronism, flank pain)
PE: subauricular systolic bruit, abdominal bruit*
Dx: duplex US, CTA, MRA; catheter-based arteriography
Tx: antihypertensives (ACE inhibitors or ARBs 1st line), PTA (percutaneous transluminal angioplasty), surgery (if PTA unsuccessful)
What is scleroderma renal crisis?
Typically presents with acute renal failure (w/o previous kidney disease) and malignant HTN (eg headache, blurry vision, nausea)
Urinalysis may show mild proteinuria.
Peripheral blood smear: schistocytes and thrombocytopenia
What are the causes of non-AG metabolic acidosis?
Hyperalimentation Acetazolamide use RTA Diarrhea Uretosigmoid fistula Pancreatic fistula
What are the indications of the following casts?
Muddy brown granular casts - acute tubular necrosis
RBC casts - glomerulonephritis
WBC casts - interstitial nephritis and pyelonephritis
Fatty casts - nephrotic syndrome
Broad and waxy casts - chronic renal failure
What is hypostenuria?
Inability of the kidneys to concentrate urine; can occur in pts with sickle cell disease and sickle cell trait
Pts have polyuria, low specific gravity, and normal serum Na
What are the dietary recommendations for pts with renal calculi?
Decreased Na intake
Increased fluid intake
Normal dietary Ca intake
What is primary adrenal insufficiency (Addison’s disease)?
Common cause: TB
Causes aldosterone deficiency
Presents w/ non-AG hyperkalemic and hyponatremic metabolic acidosis (increase in H+)
Benign prostatic hyperplasia
RF for bladder cancer: smoking, occupational exposures (painters, metal workers), chronic cystitis, iatrogenic causes (cyclophosphamide), pelvic radiation exposure
Cystoscopy is recommended for pts w/ gross hematuria or w/ microscopic hematuria + other risk factors for bladder cancer
What is finasteride?
5 alpha reducatase inhibitor used to treat BPH
Amikacin.
Can be used to treat pyelonephritis w/ multidrug resistant organisms (gram negatives).
Likely to cause acute renal failure.
Beckwith-Wiedeman syndrome.
Patients are at increased risk of developing Wilms tumor and hepatoblastoma.
What is AA amyloidosis?
Occurs in the setting of chronic inflammation; most commonly seen in pts w/ long-standing rheumatoid arthritis.
Most common manifestation is renal disease characterized by proteinuria and nephrotic syndrome; cardiac and GI diseases may also occur.
Dx: renal biopsy demonstrating amorphous hyaline material staining w/ congo red
Nephrotic syndrome + Rheumatoid arthritis = AA amyloidosis
Tx: colchicine for treatment and PPX
Imaging to visualize ureteral stones.
U/S and NON-contrast spiral CT scan of the abdomen and pelvis.
What is membranoproliferative glomerulonephritis?
Nephrotic range proteinuria + hematuria
Caused by IgG antibodies (C3 nephritic factor) directed against C3 convertase of the alternate complement pathway, which leads to persistent complement activation and kidney damage
Imaging: dense intramembranous deposits that stain for C3
Has assoc. w/ Hep B, but it is LESS COMMON than membranous nephropathy
Goodpasture’s
Caused by Anti-GBM IgG auto-antibodies directed against the glomerular and alveolar basement membrane
Hematuria, proteinuria, respiratory sxs (dyspnea, cough, hemoptysis)
Circulating immune complexes
Account for group of glomerulonephritis called immune complex-mediated glomerulopathies (SLE, post-strep glomerulonephritis)
What is urodynamic testing?
Involves measurement of bladder filling and emptying (ie cystometry), urine flow, and pressure (eg urethral, leak point)
Typically reserved for pts w/ complicated urinary incontience (ie those who do not response to treatment) or who are considering surgical intervention.
Siezures and acidosis.
Seizure activity, esp. tonic-clonic seizure, can signficantly raise serum lactic acid levels due to skeletal muscle hypoxia and impaired hepatic lactic acid uptake.
Post-ictal lactic acidosis is transient and self limited, resolves w/in 90m.
Repeat chemistry panel after approx. 2h.
Acidosis + tx with bicarb
Recommended in pts w/ severe acute metabolic acidosis w/ pH less than 7.1
Administration of sodium bicarb may cause myocardial depression and increased lactic acid production.
Constipation in toddlers.
Recurrent cystitis in toddlers is caused by constipation as fecal retention can cause rectal distension, which in turn compresses the bladder and prevents complete voiding.
Anal fissures are a common manifestation of chronic constipation.
What is transient proteinuria?
Typically caused by fever, exercise, seizure, stress, or volume depletion and results from variation in glomerular blood flow. Condition results once the provoking factor is removed.
Confirm with morning urine protein/creatinine ratio and repeat u/a
Dx: NO protein on subsequent u/a
What is orthostatic proteinuria?
Most common in adolescent boys and presents w/ proteinuria when the pt is upright (ie daytime) and absent urinary protein after a prolonged recumbent period (ie morning).
Confirm w/ morning urine protein/creatinine ratio and repeat u/a
Dx: POSITIVE protein on subsequent u/a
Refractory hypokalemia.
Chronic alcoholism is common cause of hypoMg (due to poor nutritional intake)
HypoMg commonly occurs with hypoK known as refractory hypokalemia that cannot be corrected with K replacement
Etiology: intracellular Mg inhibits K secretion by renal outer medullary K (ROMK) channels in the collecting tubules of the kidney (stops K from being lost);
therfore, low intracellular Mg results in excessive renal K loss and refractory hypoK
Mg saves K!
Renal vascular HTN due to renal artery stenosis.
ACE-i and ARBs indicated as 1st line therapy due to their ability to reduce angiotensin II levels, which improves systemic blood pressure and dilates the glomerular efferent arterioles.
Have long-term nephroprotective effects.
REnal artery stenting or surgical revascularization is reserved for pts w/ resistent HTN or recurrent flash pulmonary edema and/or refractory HF due to severe HTN.
What is crystal-induced acute kidney injury?
Causes include acyclovir; kidney rapidly excretes acyclovir into the urine, but drug has low urine solubility as a result it easily precipitates in renal tubules causing intratubular obstruction and direct tubular toxicity
More common w/ large IV doses of acyclovir and rarely occurs w/ oral acyclovir
RF: underlying volume depletion or CKD
AKI develops w/in 1-2d after drug exposure
U/A: hematuria, pyuria, crystals visualized w/ a polarizing microscope
Tx: discontinue drug, IVF while giving drug to prevent AKI
