Rosen & Barkin's 5-Minute Emergency Medicine Consult (723 page)

• Diagnose via:
  
  • Isolation of organism:
    
    • Blood
      
    • CSF for encephalitis
      
    • Bronchoalveolar lavage for pneumonitis
      
    • Amniotic fluid
      
    • Aqueous humor
      
  • Detection of tachyzoites in tissues or body fluids
    
  • Demonstrating characteristic lymph node pathology
    
• Thorough ocular exam:
  
  • Retinal exam
    
  • Visual acuity
    

• LDH >600/UL associated with toxoplasmosis
  
• CBC:
  
  • Atypical lymphocytes
    
• ABG/pulse oximetry for pulmonary symptoms
  
• IgG antibodies:
  
  • High number of false-positive and false-negative results
    
  • Common tests:
    
    • Sabin–Feldman dye test
      
    • Indirect fluorescent antibody
      
    • Agglutination
      
    • Enzyme-linked immunosorbent assay test
      
• Immunoglobulin M (IgM) antibodies:
  
  • Absence excludes diagnosis in immunocompetent host
    
  • Reference labs may be helpful, such as Remington (650-853-4828 Toxoplasma Serology Laboratory) (
    www.pamf.org/serology
    )
    
  • Diagnoses acute infection
    
  • Appear in 5 days
    
  • Disappear in weeks to months
    
  • Neonatal testing differentiates from maternal infection
    

• Chest radiograph for pulmonary symptoms:
  
  • Pneumonitis associated with reticulonodular pattern
    
• CT head with contrast:
  
  • Multiple bilateral hypodense ring-enhancing lesions
    
• MRI brain:
  
  • High signal abnormalities on T2-weighted images
    
• Serial fetal ultrasonography can be useful in exploring congenital infection of the CNS or other signs.
  

Brain biopsy for encephalitis—definitive diagnosis

• Cryptococcal meningitis
  
• CNS lymphoma
  
• Pneumocystis carinii
  pneumonia
  
• Cytomegalovirus retinitis
  
• Mycobacterial infection
  

TREATMENT

• Treat seizures in standard fashion with diazepam and phenytoin.
  
• Initiate oxygen if hypoxia due to pneumonitis.
  

Toxoplasmic lymphadenitis:

• No antibiotics unless symptoms severe and persistent
  
• Treat symptomatic patients with pyrimethamine and folinic acid plus sulfadiazine or clindamycin for 3–4 wk
  
• Clindamycin may be a useful alternative to sulfadiazine because of the side effects of the latter and in those who are hypersensitive to sulfa
  
• Pyrimethamine and sulfadiazine (Eon Labs 800-526-0225) is available as a combination drug.
  
• Corticosteroids may be useful for ocular complications and CNS disease.
  
• Reassess to determine if longer therapy needed.
  

• Confirmed acute infection by serology/symptoms:
  
  • Treat with pyrimethamine and folinic acid + sulfadiazine or clindamycin for 4–6 wk after resolution of symptoms.
    
  • Alternative medications:
    
    • Trimethoprim–sulfamethoxazole
      
    • Pyrimethamine and folinic acid + dapsone
      
• CNS symptoms + a lesion on CT or MRI:
  
  • Treat empirically with pyrimethamine and folinic acid + sulfadiazine or clindamycin.
    
  • Brain biopsy or CSF to confirm diagnosis
    
  • Administer anticonvulsants only if confirmed prior seizures:
    
    • Poorer outcome for patients on anticonvulsants
      
• Chronic asymptomatic infection:
  
  • No therapy required
    
  • Prophylaxis options for toxoplasmosis in AIDS and immunosuppressed patients:
    
    • Trimethoprim–sulfamethoxazole; lifelong prophylaxis should be considered in HIV patients after consultation.
      
    • Pyrimethamine (75 mg/wk) and dapsone (200 mg/wk) and leucovorin 10–25 mg with each dose pyrimethamine
      

• Treat with pyrimethamine and sulfadiazine for 1 mo.
  
• May add clindamycin
  
• Administer systemic steroids with macular or optic nerve involvement.
  

• Initially treat with spiramycin pending confirmatory tests and consultation (FDA, Division of Special Pathograns and Transplant Drug Products 301-796-1600 or CDC at 404-718-4745).
  
• After the infection is documented, initiate treatment after consultation:
  
  • Spiramycin in the 1st 17 wk
    
  • Pyrimethamine and sulfadiazine after 17 wk
    
• Spiramycin may reduce congenital transmission but does not treat fetus if infection is in placenta; maternal therapy may decrease severity of congenital disease.
  
• Treat congenital infection with sulfadiazine, pyrimethamine, and folinic acid for 12 mo.
  
• Prevention of exposure in seronegative pregnant women is important when contacting cats or their excrement.
  

• Clindamycin:
  
  • 600 mg (peds: 20–40 mg/kg/24 h) IV q6h
    
  • 300 mg (peds: 8–20 mg/kg/24 h) PO q6h
    
  • Useful if patient hypersensitive to sulfa
    
• Dapsone: 50 mg PO per day or 200 mg PO per week (child >1 mo: 2 mg/kg PO per day)
  
• Folinic acid: 5–25 mg PO daily in conjunction with pyrimethamine therapy
  
• Pyrimethamine: 100 mg BID on 1st day loading dose, then 25–50 mg PO per day
  
• Spiramycin: FDA authorization required
  
• Sulfadiazine: 500 mg–2 g (peds: 100–200 mg/kg/24 h div. BID) PO q6h
  
• Trimethoprim–sulfamethoxazole: 5 mg/kg of trimethoprim component IV or PO q12h
  

FOLLOW-UP

• Acute infection with severe systemic symptoms
  
• Immunocompromised patients with:
  
  • Toxoplasmosis encephalitis
    
  • Pneumonitis
    
  • Sepsis
    

• Immunocompetent patients with:
  
  • Mild symptoms
    
  • Ocular
    
• Maternal/congenital infection with mild symptoms
  

Infectious disease consultant

• American Academy of Pediatrics.
  Red Book 2012 Report of the Committee on Infectious Diseases
  . Elk Grove, IL: AAP; 2012.
  
• Centers for Disease Control and Prevention. Guidelines for prevention and treatment of opportunistic infections in HIV infected adults and adolescents.
  MMWR
  . 2009;58:1–207.
  http://www.cdc.gov/mmwr/pdf/rr/rr58e324.pdf
  .
  
• Jones JL, Dargelas V, Roberts J, et al. Risk factors for
  Toxoplasma gondii
  infection in the United States.
  Clin Infect Dis.
  2009;49:878–884.
  
• Kaplan JE, Benson C, Holmes KK, et al. Guidelines for prevention and treatment of opportunistic infections in HIV-infected adults and adolescents: Recommendations from CDC, the National Institutes of Health, and the HIV Medicine Association of the Infectious Diseases Society of America.
  MMWR Recomm Rep.
  2009;58:1–207.
  
• Sciammarella J. Toxoplasmosis. Available at
  http://www.emedicine.com/emerg/topic601.htm
  . Accessed on July 6, 2002.
  

CODES

• 130.0 Meningoencephalitis due to toxoplasmosis
  
• 130.4 Pneumonitis due to toxoplasmosis
  
• 130.9 Toxoplasmosis, unspecified
  

BASICS

• Of 39 million hospital discharges in US, 5.8% (2.3 million) were associated with blood transfusions (2004).
  
• In 2011 there were 30 deaths in US fully attributable to transfusion complications.
  
• Some type of transfusion reaction occurs in 2% of units transfused within 24 hr of use.
  
• Noninfectious complications:
  
  • Febrile nonhemolytic reaction: RBCs 1 in 500 transfusions, platelets 1 in 900
    
  • Allergic reaction (nonanaphylactic): 1 in 3 to 1 in 300
    
  • Anaphylaxis: 1 in 20,000 to 1 in 50,000
    
  • Acute hemolytic reaction: 1 in 38,000 to 1 in 70,000
    
  • Delayed hemolytic reaction: 1 in 4,000 to 1 in 11,000
    
  • Transfusion-associated circulatory overload (TACO): 1 in 100, but as high as 10% in susceptible populations
    
  • Alloimmunization: 1 in 10 to 1 in 100
    
  • Graft-versus-host disease: 1 in 400,000; rare but has >90% mortality.
    
  • Transfusion-related lung injury (TRALI): 1 in 5,000 to 1 in 190,000; represents 13% of reported transfusion-related deaths
    
  • Iron overload: Unknown incidence, depends on volume of blood, often occurs after >100 RBC units
    
  • Hypocalcemia: Unknown incidence
    
  • Hyperkalemia: Unknown incidence
    
• Infectious complications:
  
  • Bacterial contamination: RBCs 1 in 65,000 to 1 in 500,000; platelets 1 in 1,000 to 1 in 10,000:
    
    • Most common bacterial agents:
      Yersinia enterocolitica
      ,
      Pseudomonas spp
      ,
      Serratia spp
      .
      
    • Leading cause of mortality among infectious complications; 17–22% of all cases
      
  • Hepatitis C: 1 in 1.6 million
    
  • Hepatitis B: 1 in 100,000 to 1 in 400,000
    
  • HTLV I and II: 1 in 500,000 to 1 in 3 million
    
  • HIV: 1 in 1.4 million to 1 in 4.7 million
    
  • HAV: 1 in 1,000,000
    
  • B19 parvovirus: 1 in 40,000; post-transfusion anemia rare with scattered case reports
    
  • Parasites:
    Babesia
    and malaria: <1 in 1 million
    
  • Parasites:
    Trypanosoma cruzi
    : 1 in 42,000
    
  • Case reports of Epstein–Barr virus, Lyme disease, brucellosis, human herpesvirus, Creutzfeldt–Jakob disease