ABSTRACT- Nocardial brain abscesses are a rare central nervous system infection with high morbidity and mortality.
Infection is acquired through inhalation or direct inoculation which then spreads hematogenously to other organs. They
are usually associated with immunocompromised patients but may appear in otherwise healthy individuals. They should
be considered in the differential diagnosis of brain abscesses. Serological tests are not useful. Culture reports are
important in establishing a diagnosis. Early diagnosis, evacuation and long term treatment might help in reducing
significant morbidity and mortality. Here we present a case of nocardial cerebellar abscess in an immunocompetent male.
Key-words- Cerebellar abscess, Nocardiosis, Immunocompetent male
The genus Nocardia is a ubiquitous group of environmental
bacteria that usually manifest as an opportunistic
infection in immunocompromised host and critical
infection in immunocompetent patients is extremely rare .
Immunocompetent patients usually develop localized
cutaneous lesions such as cellulitis, abscesses,
sporotrichoid forms of infections 
patients present as pulmonary, cutaneous or disseminated
nocardiosis . Disseminated disease is defined by the
presence of two or more organs infected by Nocardia and is
characterized by hematogenous spread of microbes into
brain, eye, bone, joint, heart, kidney, skin or other organs
and tissues. Nocardia cerebral abscess (NCA) is rare,
constituting approximately 1-2% of all cerebral abscesses.
Nocardia asteroides is responsible for up to 86% of all
nocardial infections . Cerebral abscess of Nocardia
carries considerably higher mortality rates of 55% and 20%
in immunocompromised and immunocompetent patients,
respectively . If left untreated, disseminated nocardiosis
has a mortality rate of greater than 85% .
Nocardiosis has the ability to disseminate any organ, most
commonly the central nervous system (CNS) and has a
tendency to relapse or progress despite being given the
appropriate therapy. Here we present a case of brain
(cerebellar) abscess by Nocardia species in an
A fifty year old male, farmer by occupation, was admitted
to our hospital with complaints of headache and difficulty
in speaking for twenty days. Patient was asymptomatic 2
months prior to presentation and then developed fever and
headache. He was diagnosed with tuberculosis by a local
doctor and was started on anti tubercular treatment
(ATT).He developed multiple episodes of emesis. He went
to a Medical College where he was diagnosed as a with left
upper lobe pneumonia with glioma. His condition did not
improve and hence was referred to our hospital. On
admission he had fever, headache, slurred speech, vomiting
and blurred vision.
On examinations; pupils were sluggish in reaction and
normal in size. The patient’s consciousness level was
12(E4V2M6)on the Glasgow coma scale (GCS) 
heart rate was 65bpm, blood pressure 124/85, SpO2 96%,
respiratory rate 16/min, hemoglobin 15.1gm/dl, total count
9.37X109/L, (N60%, L30%, E04%, M06%), platelet
244.00X109/L. Direct ,indirect, total bilirubin was within
normal limit. Serologically patient was non reactive to HIV,
HBsAg, HCV. Liver transaminases (SGOT, SGPT) raised
slightly, urea 55mg/dl, routine CSF examination revealed a
cell count of 20 with predominance of lymphocytes
The patient did not have a history of hypertension, diabetes,
coronary artery disease and seizures. MRI Brain with
contrast performed a day after admission revealed a right
(Rt) cerebellar space occupying lesion (Fig.1). Rt
paramedian suboccipital craniectomy with removal of
abscess and decompression was performed.
Fig1. MRI brain showing large irregular shaped intra
in Rt cerebellar hemisphere surrounded by
contrast study showing peripheral
Abscess was sent for AFB smear, fungal elements,
culture/sensitivity and histopathology. Acid fast staining
showed partially acid fast thin filamentous branching
structure morphologically resembling (Fig 2).
A modified acid fast staining (MAFS) with 1% acid alcohol
was done which showed acid fast structures. Gram stain
showed Gram positive thin beaded branching filamentous
structure. Pus was then inoculated onto blood agar,
sabourauds dextrose agar, brain heart infusion agar (BHIA)
and BHIA with blood at370C and 250C. It grew dry white
colonies on day three at both temperatures. Growth was
reconfirmed using MAFS. Tubes were further incubated for
pigment production and were checked every two days.
Orange pigment production was noted on eighth day.
Fig. 2 Showing thin branched filamentous acid fast
Histopathological examination report revealed cerebellar
abscess with filamentous structures morphologically
consistent with Nocardia.
After identification ATT was stopped and he was started
imipenem, cilastin and amikacin intravenously. His
condition started improving. He was followed without any
Nocardia an opportunistic gram positive, branched,
filamentous aerobic bacterium first described by Edmond
Nocard in 1888 . The organism enters the body by
airborne route causing infections of lung or by skin
inoculation causing localized skin infections. From lung the
infection can be disseminated to CNS by hematogenous
spread .CNS infections occur in 44% of patients with
systemic nocardiosis . The etiological factors responsible
for systemic nocardiosis include chronic lung disease,
malignancies, diabetes mellitus, alcoholism,
immunosuppressive state, organ transplant, renal disease,
tuberculosis, collagen vascular diseases, preceding
operations, chronic lung disease, trauma.
The incidence of disseminated nocardiosis is increasing
with the advent of acquired immunodeficiency syndrome,
due to advancements in the diagnostic techniques and in the
treatment strategies leading to long term survival of the
immunocompromised patients. However, due to its rarity it
is seldom kept as a primary diagnosis and is often mistaken
for malignancy. In Forty percent cases of NCA lung
infections present with non specific sign and symptoms and
usually go unnoticed with no involvement of other organs.
In these cases involvement of lung can only be confirmed
on imaging 
. Most of the cases (57%) are supratentorial
but cerebellar abscesses are also reported in few studies
The morbidity and mortality related to NCA is 30% as
compared to 10% for other abscesses. [8-11]
undergoing craniotomy with excision have better survival
than patients treated with aspiration alone (76% vs 50%).
and 70% among patients undergoing non-operative
therapy. The incidence of single Nocardial brain abscesses
is 54 % 
. The mortality rate is reported to be 33% in
patients with single abscesses and 66% in those with
multiple abscesses [4, 12].
Although many cases of NCA have been reported so far,
but still cerebral nocardiosis is misdiagnosed as brain
malignancy or other pathological lesions. Diagnosis of
Nocardia solely depends on microbiology techniques.
Adequate and appropriate sample should be obtained and
sent to the laboratory as soon as abscess is suspected. It is
important to obtain cultures from tissue biopsies when
disseminated infection is considered. Gram stain showing
filamentous branched gram positive bacilli is the most
sensitive method for diagnosis. Further it can be seen as
acid fast structures in MAFS .
Early diagnosis and treatment is required and the possibility
of nocardiosis should be considered in all brain abscesses.
Serological tests are not helpful and only cultures can
establish a diagnosis of nocardial abscess. Once confirmed
empirical sulfonamides should be started. Various other
antibiotics like imipenem, minocycline, linezolid,
amoxicillin/clavulanate, third generation cephalosporins
have been tried for treatment of nocardiosis with good
outcome. Due to recurrence of disease, prolonged
therapy is advocated even after cure .
The antibacterial agents most active are the sulfonamides
such as trimethoprim-sulfamethoxazole, others being
amikacin, minocycline and imipenem. If individuals are
allergic to sulpha drugs or present themselves with
disseminated nocardiosis a combination of amikacin and
ceftriaxone should be considered. It is recommended that
immunocompetent patients should be treated for at least six
months. In case of brain abscess high dose intravenous
antibiotics for 3-6 weeks followed by oral antibiotics for 12
months is recommended. No randomized trials have been
performed to determine the most effective antibiotic
regimen for nocardiosis. However,
trimethoprim-sulfamethoxazole is considered the mainstay
of therapy since most studies have shown a favorable
susceptibility to this antibiotic .
CNS nocardiosis usually results after pulmonary
nocardiosis but pulmonary infection or other focus of
infection could not be substantiated in this patient at the
time of admission. Since the patient was a farmer and was
diagnosed as a case of pneumonia, inoculation or inhalation
can be suspected. In this patient, an early diagnosis with
help of smear examination and culture confirmation made
institution of appropriate antibiotics possible. The patient
was followed without any complains.
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