POST INFECTIOUS HYDROCEPHALUS:
The Most Common Cause of Hydrocephalus in Uganda
Benjamin C. Warf, M.D.
Lynda MacGowen, R.N.
The CURE Children's Hospital of Uganda opened in January, 2001. In the last 9
months, 353 neurosurgical operations have been performed. Of these, 221 were
initial operations to treat hydrocephalus (either VP shunt placement or endoscopic
third ventriculostomy), 49 were spina bifida repairs, and 10 were encephalocele
repairs. Therefore, 63% of all neurosurgical operations have been for the initial
treatment of hydrocephalus.
Hydrocephalus results when the cerebrospinal fluid (CSF) outflow from the brain and
its subsequent absorption does not keep pace with its production within the brain.
This can result from several causes, including congenital abnormality, infection (e.g.
meningitis), intracranial hemorrhage, and brain tumor.
CURE Children's Hospital of Uganda treats patients from across Uganda, and this
provides an opportunity to evaluate the demographics of hydrocephalus nationwide.
In addition, ours is the only institution providing treatment for this condition aside
from the university hospital (Mulago) in Kampala. This presentation reviews the
patients with hydrocephalus presenting to us for the 8 months from the time of
opening through September 7, 2001.
Among all patients with previously untreated hydrocephalus, the average age at
presentation was 10 months (median 5 months), and the average length of time the
hydrocephalus had gone untreated since the time it was first noted was 4 months
(median 6 months). We anticipate that increased public awareness will improve the
timeliness of treatment in the future.
Of the 168 new patients with hydrocephalus in this review, 61% had a history
consistent with hydrocephalus caused by infection (meningitis/ventriculitis). This
suggests that post infectious hydrocephalus (PIHC) is the chief cause of
hydrocephalus in this population.
A febrile illness with seizures preceding the onset of hydrocephalus was the most
common history, followed by febrile illness only, seizures only, “infection”, and
“septicemia”.
The average time from the illness to the noted onset of the
hydrocephalus (increasing head circumference and bulging anterior fontanelle) was
2.7 weeks (median 2 weeks, range 16 weeks). This latter fact closely relating the
illness to the onset of hydrocephalus in time supports the assumption that the illness
was causally related to the hydrocephalus in these previously normal children.
The average age at time of illness was 1.3 months. In 68% of patients the onset of
the illness was at 1 month of age or less, with about 50% being 1 week or less, and
about 60% being 2 weeks of age or less. This is a very important observation
because it suggests that in the majority of patients with post infectious
hydrocephalus (PIHC), the condition was the result of neonatal meningitis.
Therefore, it appears that neonatal meningitis may be the single major
cause of hydrocephalus in Uganda.
Although studies in Uganda have been insufficient, numerous previous studies
elsewhere over several decades have demonstrated the most common organisms in
neonatal meningitis to be E. coli and group B Streptococcus (60-90%). Neonatal
meningitis is contributed to by the immature immune system of the newborn,
maternal complications, and unclean environment. The mortality has been reported
at anywhere from 15% to 75% (with higher mortalities reported in the older
literature), and the incidence of subsequent hydrocephalus among survivors has been
reported to be as high as 30%.
The consideration of meningitis in other age groups is different. In this study, the
onset of illness was between 1 and 3 months of age in 18%. The most common
organisms in this age group include group B Streptococcus and Streptococcus
pneumoniae. In the remainder of our patients (14%), the onset of illness was
between 3 and 9 months. The most common pathogen of meningitis in this age
group is Haemophilus influenza type B, which has been virtually eliminated in Europe
and North America by the HiB vaccine. This immunization is not currently available
in Uganda.
Post infectious hydrocephalus (PIHC) may be caused by blockage of CSF flow at the
aqueduct of Sylvius or the outlets of the IVth ventricle, blockage of flow within the
subarachnoid spaces, or an impediment to CSF absorption. Neonatal meningitis has
been previously reported to cause inflammation and destruction of the ependymal
lining of the ventricles and inflammatory exudates and scarring which may obstruct
the aqueduct, the outlets of the IVth ventricle, or the basal subarachnoid spaces
around the IVth ventricle.
Our findings in these patients (with PIHC) have included a small IVth ventricle in
44% on preoperative ultrasound imaging (which has correlated 100% with an
obstructed aqueduct in patients undergoing ventriculoscopy).
Intraventricular
septations were also a common finding on ultrasound, indicative of prior ventriculitis.
At endoscopy, the following findings were common among patients with PIHC:
aqueduct obstructed by a web of tissue; yellow deposits on ependyma and choroid
plexus; hemosiderin staining on ependyma, floor of 3rd ventricle, and around
aqueduct; intraventricular webbing and anatomic distortion; scarring and atrophy of
choroid plexus. All of this provides evidence of previous inflammation as the
cause of the hydrocephalus in these patients, and that the hydrocephalus is
often noncommunicating.
Placement of a ventriculoperitoneal shunt (VPS) has been the standard treatment for
PIHC. Endoscopic third ventriculostomy (ETV) is another alternative, but some
modern authors have suggested PIHC as a contraindication to ETV. Our experience,
however, suggests otherwise at this point.
Among these 168 patients with hydrocephalus of all types, 163 shunts have been
placed, and 64 endoscopic operations for attempted ETV have been performed during
the period of review. Two types of shunts have been used: an American made
Codman shunt and an Indian made Chhabra shunt. The cost of each shunt is about
$650 USD and $35 USD, respectively. We were very interested in the relative
performance of these shunts in general, and in PIHC in particular, because the
economic ramifications are potentially important.
We have thus far found no
significant difference in performance between the two shunts, with the possible trend
toward a slightly higher incidence of valve malfunction in the Chhabra shunt. CSF
protein was significantly elevated in only a minority of PIHC patients at the time of
shunt placement (13%), and valve malfunction and shunt obstruction incidence has
not been higher among PIHC patients than among shunted patients with
hydrocephalus of other etiologies thus far. Therefore, there is thus far no
apparent advantage of the more expensive Codman shunt over the much
less expensive Chhabra shunt, and shunting in children with PIHC has been
as successful as for children with hydrocephalus from other causes.
Post infectious hydrocephalus (with a prior history of meningitis) has been considered
a contraindication to ETV by some authors. This is because of the concern that the
principle etiology of the hydrocephalus is impairment of CSF absorption (i.e.
communicating hydrocephalus). We began performing ETV at CURE Children's
Hospital of Uganda 3 months ago. In our experience thus far, at 1 to 3 month’s
follow up, ETV has been a successful treatment in 79% of the 32 patients
with PIHC who have undergone ETV. The reasons contributing to this success
may include the fact that the majority of PIHC in our patients arose from neonatal
meningitis (which may have led to non-communicating hydrocephalus) and the fact
that there was evidence of aqueduct obstruction in 70% of PIHC patients undergoing
ETV.
In conclusion: 1) Neonatal meningitis appears to be the single most common
cause of hydrocephalus in Uganda. 2) This is a public heath/preventative
medicine issue, which needs to be addressed. 3) ETV is a very effective
treatment for post infectious hydrocephalus. 4) When a shunt must be
used, inexpensive Chabra shunts perform well, and may be more cost
effective.