Pearl of the Day: Complications of Vascular Access for Hemodialysis

Complications of Vascular Access for Hemodialysis- more frequent with autologous vein, polytetrafluorethylene, or bovine carotid artery graft (as opposed to native artery or vein) - account for more inpatient hospital days than any other complication of hemodialysis

Thrombosis and Stenosis - most common causes of inadequate dialysis flow (<300 mL/min) - grafts have higher rate of stenosis than fistulas - signs: loss of bruit or thrill over access - treatment: angiographic clot removal or angioplasty within 24 hours; direct injection of alteplase can be considered for thrombosis

Vascular Access Infections - 2 - 5% of AV fistulas, 10% of grafts - etiology: Staphylococcus aureus (most common), Gram-negative bacteria - signs/symptoms: hypotension, fever, leukocytosis - may not have pain, erythema, swelling, or discharge from access site - after 6 months, approximately 1/2 of patients with dialysis catheter develop bacteremia - diagnosis: peripheral and catheter blood cultures drawn simultaneously -> catheter is confirmed source if colony count is 4 times higher in catheter culture than peripheral culture - treatment: vancomycin IV (drug of choice) +/- gentamicin (if Gram-negative organisms suspected); consider access removal if fever for > 2 - 3 days

Hemorrhage - rare - causes: aneurysms, anastosmosis rupture, overanticoagulation

Management of Hemorrhage 1. manual pressure to puncture sites for 5 - 10 min and observe for 1 - 2 hours if ceased 2. apply pressure for 10 min using absorbable gelatin sponges soaked in reconstituted thrombin or chemical thrombotic (e.g., transexamic acid) 3. protamine 0.01 mg per unit of heparin dispensed during dialysis - if dose is unknown, protamine 10 - 20 mg is sufficient to reverse typical dose of heparin (usually 1000 to 2000 U) 4. desmopressin acetate 0.3 mcg/kg IV can be used as adjunct in consultation with nephrologist or vascular surgeon 5. consider placing figure-8 suture 6. tourniquet proximal to vascular access while awaiting urgent vascular surgery consultation

Vascular Access Aneurysms - caused by repeated punctures - usually asymptomatic, possibly occasional pain or impingement neuropathy - rarely rupture

Vascular Access Pseudoaneurysms - from subcutaneous extravasation of blood from puncture sites - signs: bleeding, infection at access site - diagnosis: arterial Dopper ultrasound studies - treatment: surgery

Vascular Insufficiency - usually occurs in extremity distal to vascular access - due to shunting of arterial blood to venous side of access - "steal syndrome" - signs/symptoms: exercise pain, nonhealing ulcers, cool/pulseless digits - diagnosis: Doppler ultrasound or angiography - treatment: surgery

High-output Heart Failure - occurs when >20% of cardiac output is diverted through access - signs/symptoms: Branham sign (drop in heart rate after temporary access occlusion) - diagnosis: Doppler ultrasound to measure flow rate - treatment: surgical banding of access

Resources Tintinalli's Emergency Medicine, 8th Edition

Pearl of the Day: Empyema

Empyema Background - pleural space infection with pus, positive Gram stain/culture, or parapneumonic effusion - predisposing factors: aspiration pneumonia, respiratory disease impairing ciliary function, alcoholism, malignancy, immuncompromise

Causes and Common Organisms - pneumonia -> Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus influenza - lung abscess, esophageal rupture -> mixed oropharyngeal anaerobes - thoracotomy -> Gram-negative bacilli - immunocompromised pneumonia -> tuberculosis, fungal infections - chest trauma -> S. aureus, Gram-negative bacilli - contiguous abdominal infection -> Gram-negative bacilli, anaerobes

Signs/Symptoms - unresolving fever, cough, dyspnea, pleuritic chest pain, malaise - weight loss, night sweats, anemia - decreased tactile fremitus, friction rub, dullness to percussion

Diagnosis - diagnostic criteria: aspiration of grossly purulent material on thoracentesis and at least one of the following: thoracentesis fluid with positive Gram stain or culture, pleural fluid glucose < 40 mg/dL, pH < 7.1, or LDH > 1000 IU/L

Stages of Disease 1. Exudative: <48 hours, free-flowing pleural effusion amenable to chest tube drainage 2. Fibrinopurulent: fibrin strands form in pleural fluid -> loculations; chest tube drainage is unlikely 3. Organizational: several weeks later; extensive fibrosis with "pleural peel" that restricts lung expansion

Treatment - treat underlying cause - definitive treatment: drainage + antibiotics - respiratory or cardiac distress -> thoracentesis - recommended antibiotics: piperacillin/tazobactam 3.375 - 4.5 g IV q6h or imipenem 0.5 - 1 g IV q6h - may add vancomycin for increased risk of MRSA (e.g., patients recently hospitalized, invasive medical device, from long-term healthcare facility, in contact sports, live in unsanitary conditions) - exudative empyema -> chest tube thoracostomy with antibiotics +/- intrapleural fibrinolytic agents if in fibrinopurulent stage - loculated empyema -> video-assisted thoracoscopic surgery - organizational stage -> surgical removal of fibrous peel

Resources Tintinalli's Emergency Medicine, 8th Edition

Pearl of the Day: Periorbital Infections

Periorbital Infections Periorbital Cellulitis - infection of eyelids and periocular tissues anterior to orbital septum - average age: 2 years; most patients < 10 years - spreads from local infection (e.g., conjunctivitis, dacryoadenitis, dacryocystitis, hordeolum), paranasal sinusitis, hematogenous spread from nasopharyngeal pathogens, upper respiratory tract infections - most common pathogens: S. pneumoniae, Streptococcus pyogenes, H. influenzae, Moraxella catarrhalis

Signs/Symptoms - erythematous, tender, swollen, warm eyelid and periorbital area - excessive tearing - no limitation in extraocular muscles, proptosis, pain with eye movement, normal visual acuity - may have difficulty opening eyelid

Management - may require CT scan of orbits to rule out orbital cellulitis - well-appearing, afebrile -> oral antibiotic therapy (e.g., amoxicillin-clavulanate, cephalexin) - severe periorbital cellulitis -> IV antibiotic therapy (e.g., ceftriaxone + vancomycin)

Blepharitis - inflammation of lid margins - anterior blepharitis: inflammation of eyelid where eyelashes attach, usually infectious in nature - posterior belpharitis: inflammation of inner portion of eyelid margin in contact with eye, usually due to dysfunction of meibomian gland - average age: 40 - 50 years - most common etiology: reaction to deltalike toxin from overgrowth of S. epidermidis - symptoms: conjunctival injection, crusting, pruritic eyelids, photophobia, occasionally eye pain - treatment: daily cleansing of edges of eyelids and eyelashes, warm compresses; severe cases require erythromycin or bacitracin-polymyxin ointment

Dacryocele - small bluish-hued palpable mass at nasolacrimal duct without conjunctival erythema or discharge - due to obstruction at valve of Hasner and common canaliculus - treatment: urgent referral to ENT or ophthalmology for possible marsupialization

Dacryoadenitis - inflammation of lacrimal gland - chronic dacryoadenitis is caused by noninfectious inflammatory disorders (e.g., Sjogren's, sarcoidosis, thyroid disesase) - acute dacryoadenitis is usually infectious (from EBV, mumps virus, coxsackievirus, CMV, VZV, S. aureus, streptococci, Neisseria gonorrhea, Chlamydia trachomatis, Brucella melitensis) - viral dacryoadenitis causes less intense discomfort and erythema - treatment: mild infections can be treated with oral first-generation cephalosporin (e.g., cephalexin) or trimethoprim/sulfamethoxazole if MRSA is suspected; severe infections require IV antibiotics (e.g., nafcillin, vancomycin)

Dacryocystitis - inflammation of lacrimal duct or sac usually caused from obstruction - common pathogens:  Streptococcus pneumoniae, staphylococci, Haemophilus influenzae - initial chronic mucopurulent discharge that progresses to erythema and swelling to inframedial eye - usually secondary bacterial infection following viral upper respiratory infection - diagnosis: applying gentle pressure with finger or cotton swab applied to nasolacrimal sac causes reflux of mucopurulent material (should be cultured) - if improperly treated, can lead to periorbital and orbital cellulitis - treatment: usually requires hospital admission with IV antibiotics (e.g., cefuroxime, cefazolin, clindamycin, +/- vancomycin)

Resources Tintinalli's Emergency Medicine, 8th Edition Periorbital Infections, Medscape, https://emedicine.medscape.com/article/798397-overview