Myocarditis, Pericarditis, Bacteremia, Septicemia and Fungemia Flashcards
Myocarditis:
Definition and Classification
Inflammation of the myocardium and may be caused
by infectious or non infectious causes
Classified:
Fulminant
Acute,
Chronic
Myocarditis:
Causes
Most commonly caused by viruses:
-Coxsackie B viruses most common cause of viral
myocarditis-Inability to mount an effective
immune responses on myocardial infections
Viral Causes:
- Coxsackie B
- other entero viruses
- Influenza
- Mumps
- Coxsackie A viruses
- Echoviruses
- Cytomegalovirus
- Epstein-Barr
Occasionally caused by bacteria:
-As a result of bacteremia
- Direct extension from a contiguous focus
- Bacterial toxin:
The toxin produced by Corynebacterium diphtheriae severely damages the myocardium and conduction system
The cardiac damage seen in patients with Clostridium perfringens infection may be the result of toxin, metastatic abscess formation, or both
Myocarditis:
Clinical Picture
Fever
Chest pain
Dyspnea
Chest X-rays may show an enlarged heart
Pericardial effusion is often present
ECG changes are a frequent feature
Myocarditis:
Lab Diagnosis
Virus isolation - pharyngeal washings and stool specimens
Myocardial biopsy show - histological examination and/or virus isolation
Myocarditis:
Treatment
Antiviral therapy for certain viruses e.g. ganciclovir for
cytomegalovirus
Symptomatic and supportive:
- Bed rest
- Analgesia (aspirin), NSAIDs (non-steroid anti-inflammatory drugs)
- Corticosteroids
Pericarditis
Definition and Classification
Inflammation of the pericardium caused by infectious and noninfectious processes
Generally classified as acute, recurrent, or chronic
Pericarditis:
Causes
Most common causes are enteroviruses
Bacteria rarely may cause purulent pericarditis, usually as a complication of pneumonia
Mycobacterium tuberculosis can cause pericarditis, usually as a complication of pulmonary tuberculosis
Bacterial pericarditis results from the following infection routes:
-Spread from a contiguous focus of infection within the chest, either after surgery or trauma
-Spread from a focus of infection within the heart most
commonly from endocarditis
-Hematogenous infection
-Direct inoculation as a result of penetrating injury or
cardiothoracic surgery
Routes of infection for Tuberculous pericarditis:
-Hematogenous focus present from the time of primary
infection
-As a result of lymphatic spread from peritracheal,
peribronchial, or mediastinal lymph nodes
-Or by contiguous spread from a focus of infection in lung or pleura
Occasionally other viruses
Pericarditis:
Causes: Viral/Bacterial and Fungal
Viral Causes:
-Enteroviruses (coxsackie A and B, echoviruses)-most common causes
- Cytomegalovirus
- Epstein-barr virus
Bacterial Causes:
- Staphylococcus aureus
- Streptococcus pneumoniae
- ß-hemolytic streptococci
- Neisseria meningitidis Enterobacteriaceae
- Mycobacterium tuberculosis
Fungal Causes:
-Histoplasma
-Aspergillusspecies
-Candida species
-Invasive fungal infection especially in immune
compromised patients
Pericarditis:
Clinical Features-Types
The presentation varies depending on the cause and can be categorised as either:
Viral Pericarditis
Bacterial Pericarditis and
Tuberculosis Pericarditis
Pericarditis:
Clinical Features-Viral Pericarditis
Chest pain is an important feature
- Often retrosternal, radiating to the shoulder and neck
- Typically aggravated by breathing and lying supine
Fever occur in more than half of the patients
A concurrent or prodromal flulike illness with malaise, arthralgia, myalgia and occasionally cough with sputum is also present
Pericarditis:
Clinical Features-Bacterial Pericarditis
Purulent pericarditis is the most serious manifestation of bacterial pericarditis
It is characterized by gross pus in the pericardium or microscopically purulent effusion
It is an acute, fulminant illness with fever
Chest pain is uncommon
Fatal if untreated-Death is mostly due to cardiac tamponade, systemic toxicity, cardiac
decompensation, and constriction
Pericarditis:
Clinical Features-Tuberculosis Pericarditis
May present as acute pericarditis, cardiac tamponade, silent (often large) relapsing pericardial effusion, effusive-constrictive pericarditis, toxic symptoms with persistent fever, and acute, subacute, or chronic constriction
The mortality in untreated patients is also high
Pericarditis:
Laboratory Diagnosis
Viruses:
- Isolation of virus from pharyngeal washings, faeces or pericardial fluid
- Serology
- PCR
Bacteria:
-Culture of pericardial fluid or pericardial tissue (esp. in patients with thickened pericardium) and blood cultures
Pericarditis:
Treatment
Viruses:
- Specific anti-viral therapy, if available e.g. ganciclovir for CMV
- Pericardial fluid drainage
- Symptomatic and supportive
Bacteria:
- Pericardial drainage
- Occasionally pericardiectomy
- Appropriate antibiotic therapy
Fungi:
-Amphotericin B
-Pericardial drainage may be
necessary
Mycobacterium tuberculosis:
- Drainage
- Pericardiectomy
- Anti-tuberculosis drugs
- Corticosteroids to reduce inflammatory response
Systemic Inflammatory Response Syndrome(SIRS)
Refer to host inflammatory response to infection or non infectious injury
Defined as the clinical cluster of two or more of: • Temperature >38⁰C or <36⁰C
Heart rate >90 beats/minute
Respiratory rate >20 breaths/minute or paCO2 <4.3 kPa (32mmHg)
White cell count >12 000 cells/mm3, <4 000 cells/mm3 or >10% blasts
