Brain Abscess and Empyema

Question 1

What is a focal, suppurative infection within the brain parenchyma, typically surrounded by a vascularized capsule?

Answer 1

Brain abscess

Question 2

Term often employed to describe a nonencapsulated brain abscess.

Answer 2

Cerebritis

Question 3

Predisposing conditions leading to a bacterial brain abscess.

Answer 3

Otitis media

Mastoiditis

Paranasal sinusitis

Pyogenic infections in the chest and other body sites Penetrating head trauma/neurosurgical procedure

Dental Infections

Question 4

Pathogens implicated for immunocompetent individuals brain abscess

Answer 4

SEAS

Streptococcus spp (40%)

Enterobacteriaceae (25%)

Anaerobes (30%)

Staphylococci (10%)

Question 5

Pathogens implicated for Immunocompromised hosts with underlying HIV infection, organ transplantation, cancer or immunosuppressive therapy

Answer 5

i CCANT protect myself

Candida spp.

C. neoformans

Aspergillus

Nocardia spp.

Toxoplasma gondii

Question 6

Most common in Latin America and immigrants from Latin America

Answer 6

Taenia solium (neurocysticercosis)

Question 7

Pathogen in India and East Asia

Answer 7

Mycobacterial infection

Question 8

True or false, in 25% of cases, no obvious primary source of infection is found.

Answer 8

True. This is also called a CRYPTOGENIC BRAIN ABSCESS.

Question 9

Where do otogenic abscesses occur predominantly in the brain?

Answer 9

Temporal lobe (55-75%)

Cerebellum (20%)

Question 10

Abscesses that develop as a result of direct spread of information from the frontal, ethmoidal, or sphenoidal sinuses and those that occur due to dental infections are located in the _________.

Answer 10

Frontal lobes

Question 11

In which age group is paranasal sinusitis associated with?

Answer 11

Young males in their second and third decades of life.

Question 12

True or False. Hematogenous abscesses are usually multiple and occur in the territory supplied by the MCA (middle cerebral artery).

Answer 12

TRUE. Hematogenous abscesses are often multiple, and multiple abscesses often (50%) have a hematogenous origin.

Question 13

Stages in the formation ob brain abscess

Answer 13

Early cerebritis stage ( Day 1-3)

Late cerebritis stage (day 4-9)

Early capsule formation (day 10-13)

Late capsule formation (day 14 and beyond)

Question 14

Characterized by perivascular infiltration of inflammatory cells, which surround a central core of coagulative necrosis. Marked edema surrounds the lesion at this stage.

Answer 14

Early Cerebritis Stage

Question 15

Characterized by pus formation leads to enlargement of the necrotic center, which is surrounded at its border by an inflammatory infiltrate of macrophages and fibroblasts. A thin capsule of fibroblasts and reticular fibers gradually develops, and the surrounding area of cerebral edema becomes more distinct.

Answer 15

Late Cerebritis

Question 16

Characterized by the formation of a capsule that is better developed on the cortical than on the ventricular side of the lesion. This stage correlates with the appearance of a ring-enhancing capsule on neuroimaging studies.

Answer 16

Early Capsule formation.

Question 17

There is a well-formed necrotic center surrounded by a dense collagenous capsule. The surrounding area of cerebral edema has regressed, but marked gliosis with large numbers of reactive astrocytes has developed outside the capsule .

Answer 17

Late capsule formation.

Question 18

True or False. The classic clinical triad of headache, fever, and a focal neurologic deficit is present in >75% of cases.

Answer 18

False. Present in <50% of cases.

Question 19

What is the most common symptom in patients with brain abscess?

Answer 19

Headache (occurs in >75% of patients)

Question 20

_________ is the most localizing sign of a frontal lobe abscess.

Answer 20

Hemiparesis.

Question 21

Abscess located in the ________ may present with a distubance of language (dysphasia)

Answer 21

Temporal lobe

Question 22

_________ & ________ are signs of a cerebellar abscess.

Answer 22

Nystagmus and Ataxia

Question 23

Appearance of brain abscess (cerebritis) on MRI.

Answer 23

Cerebritis appears on MRI as an area of low-signal intensity on T1-weighted images with irregular postgadolinium enhancement and as an area of increased signal intensity on T2-weighted images .

Question 24

Appearance of brain abscess on T1-weighted MRI.

Answer 24

On contrast-enhanced T1-weighted MRI, a mature brain abscess has a capsule that enhances surrounding a hypodense center and surrounded by a hypodense area of edema.

Question 25

Appearance of brain abscess T2-weighted MRI

Answer 25

On T2-weighted MRI, there is a hyperintense central area of pus surrounded by a well-defined hypointense capsule and a hyperintense surrounding area of edema.

Question 26

True or False. CSF Analysis in patients with brain abscess is vital as it can change the therapy for the patient.

Answer 26

False.

CSF analysis contributes nothing to diagnosis or therapy, and LP increases the risk of herniation.

LP should not be performed in patients with known or suspected focal intracranial infections such as abscess or empyema;

Question 27

Differential diagnosis in patients that have fever, headache, focal neurologic signs and seizure activity.

Answer 27

Brain abscess

Subdural empyema

Bacterial Meningitis

Viral meningoencephalitis

Superior sagittal thrombosis

Acute Disseminated encephalomyelitis

Question 28

Emperical therapy of community-acquired brain abscess in an immunocompetent patients

Answer 28

3rd or 4th generation cephalosporin + metronidazole

Question 29

Therapy for patients with penetrating head trauma or recent neurosurgical procdures.

Answer 29

Treatment should include ceftazidime as the third-generation cephalosporin to enhance coverage of Pseudomonas spp. and vancomycin for coverage of staphylococci.

Meropenem plus vancomycin also provides good coverage in this setting.

Question 30

When will you refer to surgery for excision of a bacterial abscess via craniotomy or craniectomy?

Answer 30

Complete excision of a bacterial abscess via craniotomy or craniectomy is generally reserved for multiloculated abscesses or those in which stereotactic aspiration is unsuccessful.

Question 31

Medical therapy alone is not optimal for treatment of brain abcess and is reserved for which group of patients (Give me 4)

Answer 31

1. Neurosurgically inacessible
2. Small < 2-3 cm
3. Nonencapsulated cerebritis
4. for patients whose condition is too tenuous to allow performance of a neurosurgical procedure

Question 32

What is the minimum duration of treatment for bacterial abscess?

Answer 32

6-8 weeks of parenteral antibiotic therapy

Question 33

Is prophylactic anticonvulsive therapy indicated in the management of brain abscess?

Answer 33

patients should receive prophylactic anticonvulsant therapy because of the high risk (~35%) of focal or generalized seizures. Anticonvulsant therapy is continued for at least 3 months after resolution of the abscess, and decisions regarding withdrawal are then based on the EEG.

If the EEG is abnormal, anticonvulsant therapy should be continued.

If the EEG is normal, anticonvulsant therapy can be slowly withdrawn, with close follow-up and repeat EEG after the medication has been discontinued.

Question 34

What is the most common parasitic disease of the CNS worldwide?

Answer 34

Neurocysticercosis

T. solium

Question 35

What is the most common manifestation of neurocysticercosis?

Answer 35

New onset partial seizures with or without secondary generalization.

Question 36

_________ is a parasitic disease caused by T. gondii and acquired from the ingestion of undercooked meat and from handling of cat feces.

Answer 36

TOXOPLASMOSIS

Question 37

True or False. It is when the cysticerci first lodges into the brain that the inflammatory response is greatly manifested and may even present with seizures.

Answer 37

False.

When the cysticerci first lodge in the brain, they frequently cause little in the way of an inflammatory response. As the cysticercal cyst degenerates, it elicits an inflammatory response that may present clinically as a seizure.

Question 38

What is the most common finding and evidence that the parasite is no longer viable in neurocysticercosis?

Answer 38

Parenchymal brain calcification.

Question 39

What are the MRI findings of Toxoplasmosis?

Answer 39

MRI findings of toxoplasmosis consist of multiple lesions in the deep white matter, the thalamus, and basal ganglia and at the gray-white junction in the cerebral hemispheres. With contrast administration, the majority of the lesions enhance in a ringed, nodular, or homogeneous pattern and are surrounded by edema.

Question 40

True or False. Primary Toxoplasma infection is often asymptomatic.

Answer 40

TRUE.

Question 41

What drugs are given in the treatment of neurocysticerosis?

Answer 41

Albendazole and Praziquantel.

The dose of albendazole is 15 mg/kg per day in two doses for 8 days.

The dose of praziquantel is 50 mg/kg per day for 15 days

Question 42

Treatment for Toxoplasmosis.

Answer 42

Sulfadiazine, 1.5–2.0 g orally qid, plus pyrimethamine, 100 mg orally to load, then 75–100 mg orally qd, plus folinic acid, 10–15 mg orally qd.

Question 43

Rationale of giving folinic acid in the treatment for Toxoplasmosis.

Answer 43

Folinic acid is added to the regimen to prevent megaloblastic anemia.

Question 44

What is the duration of treatment for Toxoplasmosis?

Answer 44

Therapy is continued until there is no evidence of active disease on neuroimaging studies, which typically takes at least 6 weeks, and then the dose of sulfadiazine is reduced to 2–4 g/d and pyrimethamine to 50 mg/d.

Question 45

What is the most common predisposing condition leading to subdural empyema?

Answer 45

Sinusitis, typically involved the frontal sinuses, either alone or in combination with the ethmoid and maxillary sinuses.

Question 46

Most common causative organisms of sinusitis-associated SDE.

Answer 46

(Same with brain abscess for immunocompetent individuals)

SEAS

STREPTOCOCCI (aerobic and anaerobic)

ENTEROBACTERIACEAE

ANAEROBIC BACTERIA
STAPHYLOCOCCI

Question 47

What are the organisms implicated in SDE following a neurosurgical procedure or head trauma?

Answer 47

Staphylococci

Gram-negative bacilli

Question 48

Patients with SDE typically present with _______ and ________.

Answer 48

Fever and progressively worsening headache.

Question 49

What is the most common focal neurologic deficit seen in SDE?

Answer 49

Contralateral hemiparesis or hemiplegia

Question 50

What is the definitive step in the management of SDE?

Answer 50

Emergent neurosurgical evacuation of the empyema, either through craniotomy, craniectomy, or burr-hole drainage

Question 51

Empirical Antimicrobial therapy for Community acquired SDE?

Answer 51

Third generation cephalosporin (cefotaxime, ceftriaxone), Vancomycin, Metronidazole

Question 52

Antimicrobial therapy for patients with hospital-acquired SDE (may have infections due to Pseudomonas spp. or MRSA)

Answer 52

Carbapenem + Vancomycin

No need to add Metronidazole if meropenem is being used.

Question 53

Duration of treatment for SDE.

Answer 53

Parenteral antibiotic therapy should be continued for a minimum of 3–4 weeks after SDE drainage. Patients with associated cranial osteomyelitis may require longer therapy.

Question 54

True or False. Cerebral vein and sinuses have no valves and therefore blood can flow in either direction.

Answer 54

True

Question 55

What is a common predisposing condition for septic thrombosis of the superior sagittal sinus?

Answer 55

Bacterial Meningitis

Question 56

What conditions can contibute to cerebral venous sinus thrombosis?

Answer 56

Dehydration from vomiting

Hypercoagulable states

Immunologic abnormalities (like circulation antiphospholipid antibodies)

Question 57

Which presents with headache, fever, nausea and vomiting, confusion, and focal or generalized seizures. There may be a rapid development of stupor and coma. Weakness of the lower extremities with bilateral Babinski’s signs or hemiparesis is often present.

Answer 57

Septic thrombosis of the superior sagittal sinus

Question 58

What structures pass through the cavernous sinus?

Answer 58

oculomotor nerve,

the trochlear nerve,

the abducens nerve,

the ophthalmic and maxillary branches of the trigeminal nerve

Internal carotid artery