Note: the following material is for personal use only see below for
Download 3.95 Mb.
|
- Navigate this page:
- Diabetes Mellitus ( see other
- Systemic Thrombosis
- Treatment
Acute Hydronephrosistakes 24 hrs to develop / 24 hrs to resolve Diagnosis: decreased urine output, FeNa, ultrasound – not IVP (may see ascites) Psychogenic polydipsia Fluid builds up in bladder, it can’t keep up Mechanical obstruction Note: if one ureter is blocked, the other may go into spasm or intermittent spasm causing oliguria (10-20% of cases) [is this really true?] Renal disease causing hypertension Chronic Renal Failure (see other) Renal Artery Stenosis (RAS) Causes systemic HTN via renin-angiotensin pathway Causes: idiopathic, fibromuscular dysplasia in young women
malignant nephrosclerosis tiny hemorrhages (flea-bitten) /infarcts / fibrinoid necrosis and onion skin proliferation
rare but rapidly progressive, serious, can be fatal / clinically resembles systemic scleroderma / believed to be caused by gadolinium MRI contrast dye) given in patients with moderate to severe kidney disease Systemic Diseases Affecting Kidney Diabetes Mellitus (see other)most common cause of adult nephrotic syndrome ACE inhibitors are beneficial even in normoalbuminuric patients (current thinking is that they should be used up to a Cr of ~ 4.5, at which point it’s too late) Amyloidosis [NEJM] primary or secondary (tumors, chronic skin disease such as ‘skin poppers’ or IVDA) 20% of cases are localized amyloidosis (½ involve lungs, benign course)
Lymphadenopathy (> 33%): may present with stable pulmonary nodules Neuropathy (35%), retinopathy [pic] slowly progressive, distal, symmetric, dysautonomia, mechanisms unclear / may occur early, up to 4 yrs before diagnosis mononeuritis multiplex carpal tunnel syndrome (25%) (palmar cutaneous n. does not go through the tunnel) Heart constrictive cardiomyopathy Renal failure: deposits found anywhere in kidney / r/o fibrillary GN / kidneys first enlarge, then shrink / proteinuria and/or nephrotic syndrome Diagnosis: SPEP (IgG kappa monoclonal protein (usu. < 2000), may have elevated ESR, EMG, MRI might reveal thickening in areas / echocardiogram may shows starry sky pattern Biopsy of sural nerve, fat pad biopsy, lymph node, bone marrow Pathology: acellular increase, sub-epi, sub-endo or spikes in BM, 8-10 nm fibrils by EM (random distribution) / stain with Congo red (apple-green birefringence), Gomori’s trichrome for myelin, crystal violet, thioflavin T / eosinophilic, glossy Treatment: high-dose melphalan with autologous stem cell rescue may delay progression of disease / measure response at 3 months then yearly Multiple Myeloma (see leukemias) Gout (see rheum) tophi deposition in kidney is relatively infrequent complication Bacterial Endocarditis (see other) embolic or immune complex deposits / MGN or MPGN Systemic Lupus Erythematosis (see rheum) anti-nuclear Ab (against snRPS) / anti-dsDNA factor Membranoproliferative good prognosis Focal GN okay, but may become diffuse later Diffuse proliferative most common, bad prognosis, wire loop capillaries Vasculitis Interstitial nephritis Membranous C3, Ig, C1q / indolent course childhood lupus: prognosis determined by extent of renal involvement / immunosuppressive treatments often lead to opportunistic infection as the other major cause of death Polyarteritis Nodosa (see vasculitides) hypersensitivity angiitis (microscopic form) has glomerular involvement (focal or proliferative) classic PAN (infarcts in kidney) Wegener’s Granulomatosis (see vasculitides) most-common cause of RPGN / cANCA / similar to microscopic PAN Scleroderma (see connective) hyaluronic acid accumulation in medium and small arteries similar lesions as malignant HT (may have normal BP)
Other risk factors: late pregnancy (milk leg), OTC, smoking Treatment: see PE / if confined to calf, consider withholding anticoagulation and re-imaging / treatment duration highly individualized (depends on cause and patient profile) / 1/07 current recommendations [annals][annals] Pulmonary Embolism (see lungs) Prosthetic Valve Thrombosis (PVT) 4% risk per patient/year without anticoagulation (0.016%/day), 2% with anti-platelet drugs, 1% with warfarin / mitral, caged-ball and multiple prostheses increases risk / known thrombus carries high risk of stroke (~10%) / consider operation for mobile thrombi or non-responders to medical therapy / consider thrombolysis (repeat TEE every few hours, continue 24-72 hrs) in high-risk surgical candidates with left-sided PVT / medical therapy is heparin warfarin ASA Fat Embolism Multiple cholesterol embolization (atheroembolic syndrome) Risk Factors: vascular disease, catheterization, grafting, repair procedures, warfarin (mechanism unclear) Findings: ecchymoses and necrosis similar to vasculitis: livedo reticularis (skin) [pic][dermis], Hollenhorst plaques (eyes), renal failure (progressive, step-wise) / note: peripheral pulses are preserved, despite marked peripheral ischemia Bergman’s Triad: mental status changes, petechiae, dyspnea / complications: ARDS, DIC Diagnosis: eosinophilia/eosinophiluria, renal biopsy is immediately diagnostic as ethanol preparation washes out cholesterol emboli leaving empty spaces Treatment: steroid therapy may be harmful (unlike true vasculitides), if necessary, PEEP, treat any DIC Prognosis: usu. severe but a significant number of patients have some recovery of renal function Neutral Fat Embolism 12-36 h after bone trauma or fracture Systemic ThrombosisDisseminated Intravascular Coagulation (DIC) [NEJM] Fulminant DIC Intravascular hemolysis: hemolytic transfusion reaction, autoimmune diseases Infection: sepsis (gram positive or gram negative), meningococcemia, viremia Malignancy: mets, leukemia, other Ob/Gyn: pre-eclampsia, amniotic fluid emboli, retained products of conception, HELLP Burns/Crush/Trauma Acute liver disease: obstructive jaundice, acute hepatic failure Vascular disorders: giant hemangiomas, other Prosthetic devices: LeVeen or Denver shunts, aortic balloon assist devices Drugs: lamotrigine, penicillamine? Low-grade DIC cardiovascular, peripheral vascular, renal vascular, autoimmune disorders, hematologic disorders, inflammatory disorders Labs: increased D-dimers, fibrinogen split products, decreased fibrinogen Peripheral smear: RBC fragments [pic], schizocytes [pic] Treatment:remove trigger / treat underlying problem Stop intravascular clotting process (this is complicated) activated protein C (promising new agent) use of heparin (early on) is debated ATIII concentrates / dose (given q 8 hrs) = (desired - initial level) × 0.6 × total body weight (kg) Other choices: IV heparin, LMWH, Hirudin, antiplatelet agents (less effective but sometimes a safer choice) Note: ~75% will respond to above therapeutic steps / failure is probably component depletion / replace factors (try to leave out fibrinogen) Components (as indicated): platelet concentrates, packed red cells (washed), ATIII concentrate, FFP, prothrombin complex, cryoprecipitate Relatively Safe to Give: washed PRBC’s, platelets, ATIII concentrates (if available), and nonclotting protein containing volume expanders (plasma protein fraction, albumin, and hydroxyethyl starch) Inhibit residual fibrinogenolysis Aminocaproic acid given as initial 5 to 10 g by slow IV push then 2 to 4 g/hr for 24 hrs or until bleeding stops / may cause ventricular arrhythmias, severe hypotension, and severe hypokalemia Tranexamic acid (newer) given as 1 to 2 g IV q 8 to 12 hrs / more potent, may have fewer side effects HELLP (hemolysis, elevated LFT’s, low platelets) (see pre-eclampsia) occurs in late 3rd trimester in pregnancy (70% antepartum, 30% post-partum, usually < 48 hrs, almost always < 7 days) Presentation: +/- elevated BP, fever (less common), may have proteinuria, severe renal failure, thrombocytopenia / 5-30% with DIC Ddx: appendicitis, diabetes, gallbladder disease, gastroenteritis, PUD, glomerulonephritis, hepatic encephalopathy, ITP, renal stones, pyelonephritis, SLE, HUS, TTP, viral hepatitis Course: delivery alone is not always curative, consider plasma exchange with FFP if not resolved by 72 hrs / recurrence risk for HELLP is 5-30%, for preeclampsia (40%) Treatment: anti-platelet agents recommended by many for treatment and some say for prevention of recurrence Thrombotic Thrombocytopenic Purpura (TTP) 1 in 1000 / female:male 10:1 Malignancy: gastric >> breast, colon, small cell lung Drugs: tacrolimus, mitomycin C, cyclosporin, gemcitabine, bleomycin, cisplatin, plavix (rare, would happen in first 2 weeks of plavix therapy) Infections: HIV, others Presentation: fever, viral prodrome hemorrhage, pallor, CNS signs, jaundice, pulmonary edema / young women Pentad: thrombocytopenia, microangiopathic hemolytic anemia, CNS, renal, fever CNS (confusion, mental status, seizures et al) Renal is often mild, but in 80-90% (proteinuria, hematuria, azotemia) GI (N/V/diarrhea) Heart: classically not, but may create subclinical damage Prognosis: involvement of brain and kidney (50%) / mortality is 90% (10% with treatment but long-term problems arise from heavy use of blood products) Labs: coagulation tests usually normal (unlike DIC), proteinuria, elevated BUN, elevated LDH (out of proportion), Coomb’s negative, fibrin split products (but not DIC levels), bone marrow Bx megakaryocyte hyperplasia, schistocytes (should be plentiful) Diagnosis: sometimes difficult, use labs, skin/gingival biopsy of petechiae, renal biopsy Pathology: extra large forms of vWF circulate due to decreased activity of vWF degrading enzyme ADAMTS 13 (probably due to IgG inhibitors) / platelets stick too much microangiopathic thrombi and hemolytic anemia (schistocytes from RBC’s being sheared in thrombi) Treatment: plasmapheresis – follow platelet count and LDH high dose steroids (possibly other immunosuppressives antiplatelet drugs: ASA 325-1500 / dyprimamidole avoid giving platelets (only aggravates the problem) 2nd line: splenectomy (controversial), chemotherapy, IVIG Prognosis: up to 85% remission with proper treatment TTP-like syndrome (TMA) in HIV patients (~10% < 50CD4, ~3% < 100) (same treatment) Association (50%) with CMV viremia Evans’ syndrome autoimmune hemolytic anemia and thrombocytopenia / positive Coombs’ test and by microspherocytes rather than schistocytes on peripheral smear / more common in children / idiopathic or related to hematologic malignancy Hemolytic Uremic Syndrome (HUS) similar findings as TTP but without neurological involvement / more severe renal disease Mechanism: probably different than TTP
Note: in blacks, E. Coli toxin is an uncommon cause of HUS (unlike Shigella) Treatment: life threatening condition that requires IVIG and/or plasmapheresis, steroids?, transfusions as a sequelae of childhood pneumonia? Henoch-Schönlein-Purpura (HSP) Children 5-15 yrs (occasionally adults) / like IgA nephropathy plus GI problems Presentation: palpable purpura (usu. lower extremities, buttocks) [pic], arthritis, arthralgia, abdominal (GI pain, bleed), renal (glomerulonephritis), CNS, hepatic are rare Note: regular erythema blanches whereas true purpura does not Complications: abdominal intussusception (large > small); barium enema may be curative renal: more in adults, nephritis (30%), may require hemodialysis (20%), chronic renal failure (2%) Associations: lymphoma Diagnosis: urinalysis, abdominal ultrasound, Pathology: skin biopsy - IM shows around blood vessels and dermal zones / neutrophilic predominance around blood vessels / IgG deposition and some C3 Treatment: steroids may help GI manifestations but not renal / severe cases may require other immunosuppressives, plasma exchange, IVIG / dapsone can help skin, joints, GI manifestations / antihistamines for pruritis / follow up with urinalysis Pyelonephritis Acute pyelonephritis (see UTI) 50% have ureteric valve regurge / damage often localized to upper, lower poles (blunt calices), papillary necrosis, pyonephrosis, perinephric abscesses coarse granular casts become fine granular casts
VUR / adherent capsule / U-shaped scar (late) / hyaline casts or thyroidization of tubules glomerular fibrosis, atrophy (focal segmental) / account for 15% of renal transplants
Labs: eosinophils in urine (early in morning) Chronic interstitial nephritis Drugs: NSAIDs (nephrotic, decreased GFR, papillary necrosis, edema), analgesics, lithium (many mechanisms, also causes interstitial fibrosis and nephrogenic diabetes insipidus), gold Toxins: cadmium, lead (Pb), copper (Cu), mercury (Hg) Crystalline: uric acid, oxalate (primary, ethylene glycol, methoxyflurane) Amyloid (nephrotic 75%) Sarcoid (hypercalcemia from 1,25-OH +/- hyperglobulinemia causing distal RTA) Analgesic abuse nephropathy prolonged analgesic use including NSAIDs, acetaminophen, ASA (especially in combination) 2% of ESRD in US / > 2 to 3 kg cumulative dose Pathology: chronic interstitial nephritis bilateral papillary necrosis (25 to 40%) seen on IVP patchy necrosis of the loop of Henle and medullary interstitium Diagnosis: biopsy tubular atrophy and interstitial fibrosis with occasional histiocytes U/S small-sized kidneys (50% to 65%) / middle-aged women Balkan nephritis causes fever, skin rash, renal failure Xanthogranulomatous pyelonephritis rare / foam cells / Proteus sp. / resembles renal cell carcinoma Renal papillary necrosis sort of like ATN on macroscopic scale / papillae can slough off causing obstruction Causes: DM, obstruction, pyelonephritis, analgesic abuse, sickle cell (and sickle cell trait), hypoxia and volume depletion in infants, graft rejection Renal Tubular Disease ATN, RTA, DI, Fanconi’s, etc. Acute Tubular Necrosis (ATN) most common pre-renal / decreased GFR / high recovery rate with proper management / 50% may not have oliguria Causes: NSAIDS, aminoglycosides, IV contrast, rhabdomyolysis, thrombus Diagnosis: FeNa (results are altered by diuretic use), muddy brown casts Treatment: dialysis, fluid, diuretics, DOPA (increases output, but not GFR, will not lower creatinine level) / future: anti-endothelins, GF? toxic nephrosis continuous damage in proximal tubule ischemic tubular necrosis patchy damage focal tubular necrosis hydropic change fatty change hypokalemic nephropathy chronic tubular disease myeloma kidney (see mm) Bence-Jones light chain fragments combine with Tamm-Horsfall proteins, create tubular casts causing obstruction/inflammation Acid-Base Metabolism Anion gap Anion Gap = [Na] – [Cl +HCO3] normal: 8-12 MUDPILES (methanol, uremia, DKA, Paraldehyde, isopropyl, lactate, ethano/ethelyne glycol, salicylates/starvation) Increased acid production (noncarbonic acid) Increased β-hydroxybutyric acid and acetoacetic acid production Insulin deficiency (diabetic ketoacidosis). Starvation or fasting. Ethanol intoxication. Increased lactic acid production tissue hypoxia, sepsis, exercise, ethanol ingestion Systemic diseases (e.g., leukemia, diabetes mellitus, cirrhosis, pancreatitis) Inborn errors of metabolism (IEMs) (carbohydrates, urea cycle, amino acids, organic acids). Increased short-chain fatty acids (acetate, propionate, butyrate, d-lactate) from colonic fermentation viral gastroenteritis Other causes of carbohydrate malabsorption
Increased sulfuric acid Decreased acid excretion: acute and chronic renal failure Anion Gap Ethanol – no Methanol – yes Isopropyl – yes Respiratory compensation for primary metabolic acidosis For every 1 mEq decrease in HCO3 the PCO2 should decrease by 1-1.5 mmHg Osmolality Plasma osmolality (mOsm/kg) = 2([Na+] + [K+]) + [BUN]/2.8 + [glucose]/18 + ethanol/4.6 [pic] Normal Osmolar Gap < 10 mOsm/kg HCO3 metabolism kidney increases serum bicarbonate via reabsorption and addition of new bicarbonate into serum via excretion of titratable acids and the formation of ammonia formation HCO3 Deficit HCO3 to replace (mEq) = Wt (kg) x (0.4)(15-measured HCO3) or = (base deficit )(wt in kg)(0.4) / 2 Note: elevated AG may result from alkalosis freeing up negative charges on proteins (albumin), however, this cannot increase AG > 22 Lactic acidosis (see sepsis) Severe metabolic and respiratory acidosis pancreatitis, vomiting, hypokalemia, tissue necrosis, hypovolemia Treatment: THAM (unproven)
All RTA’s associated with increased renal stones (calcium oxalate) from increased pH Urine anion gap [Na + K] – Cl – ?HCO3 If renal function intact, Ur AG will be negative due to excretion of ammonium chloride salts (high Cl) / Note: must consider unmeasured anions and cations (like Ca) Urine – MM, hypoalbuminemia TTKG (UrK / PlaK) / (UrOsm / PlaOsm) > 8 kidney is wasting K suggests RTA < 3 kidney is not wasting K suggest other cause for hypokalemia Classic Distal RTA (Type I RTA) (hypokalemia) Mechanism: H+ back leak, negative Urine AG Drugs: cyclosporine, amphotericin B, vitamin D intoxication, lithium, analgesics, toluene, cyclamate Proximal RTA (Type II RTA) (normal or hypokalemia) Mechanism: profound HCO3 wasting from kidney / normal to low K (volume contraction causes increased aldosterone) Drugs: carbonic anhydrase inhibitors (acetazolamide, sulfanilamide), mafenamide acetate, and 6-mercaptopurine, sulfanilamide, heavy metals Note: difficult to correct with HCO3, because you simply can’t give it fast enough Type 4 RTA (hyperkalemia) Mechanism: hypoaldosteronism, anti-aldosterone, or anti-adrenergic, or blocking Na+ channels (voltage effect) Decreased aldosterone effect hyperkalemia and acidosis1 more acidosis from hyperkalemia2
ACE inhibitors, K-sparing diuretics (amiloride, triamterene) Heparin (blocks production of aldosterone) B-blockers, cyclosporine, pentamidine Trimethoprim (bactrim) (block Na+ transporter, decreased tubular electronegativity less K+ efflux)
Eliminate cause if possible Bicarbonate (rather than NaCl) – as the extra bicarbonate will help keep the tubule electronegative and help eliminate potassium Lasix may be used (↑ K washout and/or delivery of more Na to ↑ K excretion) Drug-Induced Electrolyte and Acid/Base Abnormalities hypokalemia/hypomagnesemia (increased urinary excretion) gentamicin, cisplatin, diuretics, carboplatin Findings: increased urinary excretion of K+ and Mg++ despite low serum levels
aminoglycoside and cisplatin hypomagnesemia, hypokalemia, metabolic alkalosis (increased K+ and H+ secretion) thiazide and loop diuretics hypokalemia and metabolic alkalosis hypovolemia hyperaldosteronism (increased K excretion) / volume depletion also causes increased HCO3 reabsorption and prolongs metabolic alkalosis (e.g. NG suction) hyponatremia (see lytes) increased ADH secretion/sensitivity with decreased water excretion NSAIDs potentiate ADH action (reduction of prostaglandins that inhibit ADH) Findings: Uosm is less than maximally dilute in the face of low serum Na+ Thiazide diuretics (see below), chlorpropamide, vincristine, IV cyclophosphamide, Cytoxan, clofibrate, narcotics, haloperidol, thioridazine, amitriptyline, fluphenazine, NSAIDs, acetaminophen Thiazide diuretics – no medullary washout allows ADH-water resorption Loop diuretics – medullary washout less ADH-water resorption Note: any diuretic can cause significant NaCl loss with hyponatremia from combination of volume depletion, salt restriction, continued free water intake Cyclophosphamide and vincristine direct antidiuretic effect in the distal tubule - impaired free water excretion Nephrogenic diabetes insipidus (anti-ADH) (see central DI) Mechanism: impaired response to ADH Causes: lithium, cyclophosphamide, ifosfamide, vincristine, demeclocycline / ?hypokalemia and hypercalcemia >12 causes mild nephrogenic DI / rare congenital XLR form / metastatic breast cancer Treatment: thiazides to prevent kidney from diluting urine too much, increase water intake, decreased salt intake Meliturias, amino acidurias Fanconi’s syndrome inherited or acquired (see ARF drugs) Mechanism: proximal RTA with tubular glucosuria (despite euglycemia), phosphaturia, aminoaciduria, bicarbonaturia, saluresis, kaliuresis, and decreased ammonium excretion
KUB 75-90% of stones are radiopaque (non-opaque: cysteine, struvite, uric acid) CT sensitivity (96%) specificity (100%) [best study; non-contrast CT] IVP sensitivity (87%) specificity (96%) U/S sensitivity (15%) specificity (90%) [better for pregnancy]
hypercalcemia (hyper PTH, malignancy, other) GI diseases (small bowel bypass, inflammatory bowel diseases) often cause increased resorption of oxalate and increased CaOx stones renal tubular acidosis (increased urine pH, alkalinization of urine increases formation of CaPO4 stones) Struvite Stones (Staghorn calculi) – not opaque often from UTI with Proteus, staph causing NH4+Mg2+ PO43- stones / often gigantic (will not pass into ureter) / pH > 8 Urate Stones – not opaque hyperuricemia (gout, leukemia, other malignancy), gout present in 20% of patients with urate stones, Lesch-Nyhan Treatment: alkalization of urine helps prevent crystallization of urate stones (takes about 9 days to dissolve 2 cm urate stones) / urate is underexcreted in acid urine matrix stones (other urease-producing bacteria) indinavir stones (organic stones seen in pts taking indinavir) Cysteine Stones (see other) – lucent or opaque 1/7000 (rare) / hereditary defect in tubular amino acid transport of cysteine, ornithine, lysine, arginine (COLA) homocystinuria hexagonal-shaped stones Treatment: diuresis (3L/day) and alkalization of urine (pH > 7) +/- D-penicillamine or tiopronin / moderate salt/protein restriction? / 50% may still require intervention Course: start early in life and if untreated progress to ESRD Renal malformations Anomalies of urethra and bladder ureteral valves kinks in dilated ureter / obstruction vesicoureteral reflux common / serious / pyelonephritis diverticulum congenital or acquired exstrophy of the bladder very rare / abdominal wall defect posterior urethral valves obstruction - oligohydramnios - pulmonary hypoplasia / males Anomalies of position and formation Renal agenesis unilateral - always check before nephrectomy bilateral (Potter’s) - facial, lower extremity deformations / not compatible w/ life
oligomeganephronia (Doll’s kidney) - small, reduced number of pyramids Ask-Upmark kidney - transverse, linear scar from failed lobule
80% unilateral / common / asymptomatic or obstructive, infection Download 3.95 Mb. Share with your friends:
|