Potential risk factors for hernia formation
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Transcript Potential risk factors for hernia formation
IN THE NAME OF
GOD
F.SAMADIAN
NEPHROLOGIST
Peritonitis and Exit Site Infection
the introduction of Y-set and double-bag
disconnect systems has reduced this to
approximately one episode per patient
every 24 months
Potential routes of infection:
Intraluminal
Periluminal
Transmural
Hematogenous
Transvaginal
Intraluminal:
This allows bacteria to gain access to the
peritoneal cavity via the catheter lumen
Periluminal:
Bacteria present on the skin surface can
enter the peritoneal cavity via the
peritoneal catheter tract
Transmural:
Bacteria of intestinal origin can enter the
peritoneal cavity by migrating through the
bowel wall
This is the usual mechanism of peritonitis
associated with diarrheal states and/or
instrumentation of the colon and may
be seen also with strangulated hernia
Hematogenous:
Less commonly, peritonitis is due to
bacteria that have seeded the peritoneum
from a distant site by way of the
bloodstream
Transvaginal:
it may explain some instances of Candida
peritonitis
The responsible pathogen is almost
always a bacterium, usually of the Grampositive variety
The occurrence of fungal peritonitis (e.g.,
Candida) is uncommon
Infections with Mycobacterium
tuberculosis or other type of mycobacteria
have been reported but are unusual
Diagnostic criteria for peritonitis:
At least two of the following three conditions
should be present:
symptoms and signs of peritoneal inflammation
cloudy peritoneal fluid with an elevated
peritoneal fluid cell count (more than 100/mcL)
due predominantly (more than 50%) to
neutrophils
demonstration of bacteria in the peritoneal
effluent by Gram stain or culture
Symptoms and signs:
The most common symptom of peritonitis is
abdominal pain
However, peritonitis should be suspected
whenever a patient suffers from generalized
malaise, particularly if nausea, vomiting, or
diarrhea is also present
Not all abdominal pain in a patient
receiving PD is peritonitis
Strangulated hernia is a common mimic
for peritonitis
Cloudiness of the fluid:
The peritoneal fluid generally becomes
cloudy when the cell count exceeds 50100/mcL
In most patients, sudden onset of cloudy
fluid with appropriate abdominal symptoms
is sufficient evidence of peritonitis to
warrant initiation of antimicrobial therapy
However, peritoneal fluid cloudiness may
be due to other factors (e.g., fibrin, blood,
or, rarely, malignancy or chyle)
On the other hand, a relatively translucent
peritoneal fluid does not completely
exclude the possibility that peritonitis is
present (early in the course of peritonitis)
The absolute peritoneal fluid cell count in
CAPD patients is usually <50 cells/mcL
and is often <10 cells/mcL
Normally, the peritoneal fluid contains
predominantly mononuclear cells
(macrophages, monocytes, and, to a
lesser extent, lymphocytes)
The percentage of neutrophils does not
normally exceed 15% of the total
nonerythrocyte cell count and a value
>50% strongly suggests peritonitis,
whereas one >35% should raise suspicion
Vancomycin or a first-generation
cephalosporin such as cefazolin or
cephalothin is used in combination with an
antibiotic to cover Gram-negative
organisms such as ceftazidime
It is now recommended that
aminoglycosides be avoided if possible in
patients with residual renal function
because of their nephrotoxicity
CAPD
Loading dose: Infuse 2 L of 1.5% dextrose
dialysis solution containing:
1 g ceftazidime
1 g cefazolin
1,000 units/L heparin
Allow to dwell for 3-4 hours.
Continue regular CAPD schedule. Add 125 mg
per L ceftazidime, 125 mg/L cefazolin, and 1,000
units/L heparin to each dialysis solution bag
If a patient appears toxic recommend a
single loading dose IV
Duration of therapy:
If patient improvement is prompt,
antimicrobial therapy should be continued
for a total of 14 days
If a cephalosporin is being used, then
some physicians will switch to PO therapy
after the first 5 days
Severe S. aureus infections require
antimicrobials for 3 weeks, and treatment
with one IP antistaphylococcal drug plus
PO rifampin is recommended
Patients in whom S. aureus peritonitis
develops not uncommonly are found to
carry this organism in the nose
This can be accomplished with intranasal
mupirocin (b.i.d. for 5 days every 4 weeks)
or oral rifampin (300 mg b.i.d. for 5 days
every 3 months
Exit site infection
Approximately one fifth of peritonitis
episodes are temporally associated with
exit site and tunnel infections
Etiology and pathogenesis:
Exit site infections are predominantly due to S.
aureus or Gram-negative organisms, particularly
Pseudomona
In contrast to peritonitis, S. epidermidis is the
causative organism in <20% of patients
eradication of the carrier state is very helpful to
effective management
Treatment is dependent on whether there
is erythema alone or erythema in
conjunction with purulent drainage
In the former case, topical treatment with
hypertonic saline compresses, hydrogen
peroxide, or mupirocin 2% ointment is
usually sufficient
Treatment is more problematic and more
prone to failure when there is purulent
drainage
some exit site infections extend into the
subcutaneous tunnel
The major risk factor for exit site infection
is staphylococcal nasal carriage
Persistently positive nasal cultures are
associated with a 3-4 fold increase in risk
of staphylococcal exit site infection
Protocols used include
-rifampin (600 mg PO for 5 days),
-mupirocin (2% ointment twice daily for 5
days every 4 weeks)
-trimethoprim-sulfamethoxazole (singlestrength tablet three times weekly)
Mechanical Complications of Peritoneal
Dialysis
The instillation of dialysis fluid into the
peritoneal cavity is accompanied by an
increase in intra-abdominal pressure (IAP)
The two principal determinants of the
magnitude of the increased IAP are
dialysate volume and the position of the
patient during the dwell
The supine position is associated with the
lowest IAP for a given dialysate volume;
sitting entails the highest
Hernia formation
as many as 10%-20% of patients may
develop a hernia at some time on
peritoneal dialysis
Potential risk factors for hernia formation
-Large dialysis solution volume
-Sitting position
-Isometric exercise
-Valsalva maneuver (e.g., coughing)
-Recent abdominal surgery
-Pericatheter leak or hematoma
-Obesity
-Multiparity
-Congenital anatomical defects
Many different types of hernias have been
described in the peritoneal dialysis patient
Types of hernias reported in peritoneal
dialysis patientsVentral
Epigastric
Pericatheter
Umbilical
Inguinal (direct and indirect)
Femoral
Spigelian
Richter
Foramen of Morgagni
Cystocele
Enterocele
Pericatheter hernias need to be
differentiated from masses caused by a
hematoma, seroma, or abscess
Ultrasonography
CTscan
MRI
Small hernias pose the greatest risk of
incarceration or strangulation of bowel
Abdominal wall and pericatheter leak
Abdominal wall leak may be difficult to
diagnose clinically
It may be mistaken for ultrafiltration failure
when dialysate returns are less than the
instilled volume
The diagnosis should be considered with:
-decreased effluent volumes
-weight gain
-protuberant abdomen
-absence of generalized edema
The patient should stand during the
examination as this may reveal asymmetry
of the abdomen
Diagnosis can be proven using contrast
CT scanning
Pericatheter leak usually occurs as a
postoperative complication of catheter
implantation
In most cases, the leak seals
spontaneously
If it persists, the catheter should be
removed and reinserted at another site
In contrast to pericatheter leaks,
abdominal wall leaks can occur early or
late
Sometimes surgical repair is feasible
Vaginal leaks can also occur
Some may result from tracking of dialysate
through the fallopian tubes and may
resolve with tubal ligation
Genital edema:
Dialysate can reach the genitalia by two
routes
One is by traveling through a patent
processus vaginalis to the tunica vaginalis,
resulting in hydrocele
The second route is through a defect in
the abdominal wall, often associated with
the catheter
This complication is often painful and
distressing to the patient who is quick to
bring it to medical attention
CT peritoneography should be performed
to distinguish which route has led to the
genital swelling (i.e., anterior abdominal
wall or processus vaginalis)
Peritoneal dialysis should be temporarily
stopped
Bed rest and scrotal elevation are helpful
A leak via a patent processus vaginalis
can be repaired surgically
If the leak is through the anterior
abdominal wall, replacement of the
catheter can be helpful
Respiratory complications:
Hydrothorax
Under the influence of raised IAP,
dialysate can travel from the peritoneal to
the pleural cavity, leading to a pleural
effusion composed of dialysis effluent
These defects may be congenital, in
which case hydrothorax can occur with the
first dialysis exchange, or acquired,
whereby hydrothorax can be a late
complication
They occur almost exclusively on the right
side, probably because the left
hemidiaphragm is mostly covered by heart
and pericardium
Symptoms of hydrothorax range from
asymptomatic pleural effusion to severe
shortness of breath
Such symptoms may worsen with
administration of hypertonic dialysate,
which raises IAP
Thoracentesis can be done for diagnosis
or to relieve symptoms
The most diagnostic feature of the pleural
fluid is the very high glucose level,
although this is not always a consistent
finding
transudative
It is typically transudate, with variable
numbers of leukocytes
Radionuclide scanning with technetium is
also helpful
Back pain:
The presence of dialysate in the peritoneal
cavity both raises IAP and swings the
center of gravity forward, producing
lordotic stress on the lumbar vertebrae
and paraspinal muscles
Some patients benefit from the
performance of more frequent
exchanges with smaller dialysate
volumes
Metabolic Complications of Peritoneal
Dialysis
Glucose absorption
Glucose has the advantage of being
cheap, stable, and relatively nontoxic to
the peritoneum
up to 100g per day of glucose may be
absorbed, which represents 500-800 kcal
per day
This constitutes a significant portion of the
recommended total energy intake of about
2,500 kcal per day (35 kcal/kg per day) in
a 70-kg patient
In some patients, this provides a welcome
source of calories since achieving the
nutritional recommendation for PD is often
difficult
In patients who start PD obese, the
glucose loading from PD may contribute to
further weight gain
glucose absorption results in increased
insulin secretion, which together with
insulin resistance (a common feature of
chronic renal failure) results in plasma
insulin levels that are persistently high
Hyperinsulinemia may be an independent
risk factor for the development of
atherosclerosis
Patients who were previously well
controlled on oral hypoglycemics often
require increased doses of these
medications, and they may even require a
change to insulin therapy after the
initiation of PD
To minimize glucose absorption, patients
should be advised on appropriate salt
and water management, which will
diminish the need for hypertonic solutions
to maintain fluid balance
Lipid abnormalities
patients on PD have a variety of lipid
abnormalities
Typically, they have high total and LDL
cholesterol, high triglycerides, low HDL
cholesterol, high apoB, low apoA-I, and
high lipoprotein(a) levels
Compared with hemodialysis patients, the
most striking differences are the high apoB
protein and LDL cholesterol levels, which
are usually normal in hemodialysis
patients
Protein loss:
PD is associated with significant loss of
protein across the peritoneum
This loss is about 0.5 g/L of dialysate
drainage, but may be higher and account
for as much as 10-20 g per day
The major component of the protein losses
is albumin
Acute peritoneal inflammation is
associated with substantially greater
protein losses, and a rapid reduction in
serum albumin is common during
episodes of peritonitis
The protein loss itself may become an
indication to terminate peritoneal dialysis
temporarily or, on occasion, permanently
Hypokalemia/hyperkalemiakm:
PD solution contains no potassium
Usually only patients who are
noncompliant in performing their dialysis
exchanges or who have excessive
potassium intake have ongoing problems
with hyperkalemia
However, hypokalemia has been reported
in 10%-30% of CAPD patients
These cases are usually associated with
poor nutritional intake, and most can be
managed by liberalizing the diet
Dialysis solution calcium level
PD solutions are available with 2.5 mEq/L
or 3.5 mEq/L calcium concentrations
The 3.5 mEq/L dialysis solution keeps the
patient in positive calcium balance
The standard solution is now considered
to be the 1.25 mM (2.5 mEq/L) calcium
solution
Hypocalcemia is not common in patients
on PD because of the widespread use of
calcium-based phosphate binders and
vitamin D