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Physiology of abortion
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SEPTIC ABORTIO
N
Grp 4D1
The CaseA 34-year old woman,
gravida 2, para 1, at 14 weeks gestation presented with severe,
crampy, lower abdominal pain, nausea, vomiting and anorexia. There was no report of ruptured membrane or illness prior to presentation. On review of systems, she denied any fever, chills, cough, ear pain, dysuria or headaches.
In the emergency room, she was found to have a fever of 39.2°C
and developed vaginal bleeding. Physical examination was
significant for diffuse abdominal tenderness over bilateral lower abdominal quadrants, right greater than left. There was no neck stiffness, sinus tenderness, or crackles on lung examination. Ear examination was normal.
Laboratory results showed• A white blood cell count of 23, 200 per mm3
with a neutrophil predominance• normal liver function test, urinalysis, and electrolytes•A vaginal ultrasound showed intrauterine pregnancy at 12 weeks gestation.
Laboratory Results
The patient was started on
piperacillin-tazobactam for broad antibiotic coverage given
the unclear source of infection. On hospital day 2, her symptoms were much improved, though she continued to have fever of 38.6°C with a white blood cell count of 300,500 per mm3 . The patient subsequently passed tissue later that day with a vaginal ultrasound showing abortion in progress.
She then underwent dilatation
and curettage for incomplete septic abortion. Subsequently, her fever lyzed,
had resolution of her abdominal pain and no further signs of infection. Blood and placenta cultures came back positive for penicillin-sensitive Streptococcus pneumoniae.
The patient’s antibiotic was
changed to penicillin, and she was discharged home to complete a 14-day course of
therapy. On her 2-week hospital follow-up, she remained well, with no complaints of fever or any other signs of infection.
OBJ
ECTI
VES
The risk factors in Septic Abortion
The complications of Septic Abortion
The immune defenses of the body and major components of each system
The factors which participate in the generation of fever
To discuss
Definition
Septic AbortionA septic abortion is an abortion associated with an infection inside a pregnant woman's uterus.
The infection can occur during or just before or after an abortion.
Types
Abortion Spontaneous abortion
which is referred to as a miscarriage.
Elective surgical or medical abortion
meaning the woman chose to terminate her pregnancy
Type of Abortion Description
Spontaneous Abortion This is when the abortion occurs naturally as opposed to being induced.
Induced Abortion The pregnancy is terminated artificially.
Threatened Abortion There is bleeding and sometimes pelvic pain but the cervix is closed and ultrasound indicates an ongoing pregnancy within the uterus.
Inevitable Abortion The pregnancy is not continuing.
Complete Abortion An inevitable abortion and the uterus has completely emptied itself.
Incomplete Abortion An inevitable abortion with products of the pregnancy still present in the uterus.
Missed Abortion There are no reasons to have suspected that the pregnancy is not going to continue but the embryo has died.
Septic Abortion The abortion has been complicated by infection.
Recurrent or habitual Abortion
Most authorities recommend that these terms should be used only for three or more consecutive abortions although there is a tendency towards two.
Early Abortion Abortion in the first few weeks of the pregnancy.
Late Abortion Abortion after the first few weeks.
First trimester Abortion Abortion before thirteen weeks of pregnancy.
Second trimester Abortion
Abortion after thirteen weeks and before twenty four weeks.
Risk Factors
The fetal membranes surrounding the unborn child have ruptured, sometimes without being detected
The woman has a sexually transmitted infection such as chlamydia
An intrauterine device (IUD) was left in place during the pregnancy
Tissue from the unborn child or placenta is left inside the uterus after a miscarriage
Unsafe abortion was made to end the pregnancy
Insertion of tools, chemicals, or soaps into the uterus
How is the condition diagnosed?diagnostic criteria:
a) temperature of 38°C (100.4°F) of at least 24 hours duration not due to other causes
b) history of mechanical termination
c) presence of septic cervical discharge
d) presence of uterine, parametrial or adnexal tenderness
Diagnostics Tests:
CBC, or complete blood count pregnancy ultrasoundcultures of blood or uterine contentsBlood chemistry
Complications
-Vaginal Bleeding*May be accompanied by hypolvolemia
-Septic Shock*Caused by release of toxins by
organisms such as E.Coli, Klebsiella, Proteus etc.*Warm extremities and hypotension
-Abcess*Massive pelvic and abdominal
abscesses -pouch of Douglas*Accompanied by high fever, abdominal
cramps and reduced bowel sounds-Acute Renal Failure
*Urinary output < 30mls per hour despite adequate hydration and blood transfusion adequate hydration -Death
Immune Defenses
What are the immune defenses of
the body? Major components of each
system.MeridaMirabelMonghit
Immune System
• Innate Immunity (Non-specific or Natural)
• Acquired Immunity (Specific or Adaptive)
Immune System
Innate Immunity
• Immunity that occurs naturally as a result of a person's genetic constitution or physiology and does not arise from a previous infection or vaccination.
• Also called genetic immunity, inherent immunity, native immunity, natural immunity, nonspecific immunity.
Immune System
Innate Immunity• no need for prolonged induction• act quickly – immediate direct response 0-4
hrs– rapid induced 4-96 hrs
• failure ==> adaptive immune response
• Pathogen recognized by receptors encoded in the germline: pattern recognition receptors
• Receptors have broad specificity, i.e., recognize many related molecular structures called PAMPs (pathogen-associated molecular patterns)
• No memory of prior exposure
Immune System
Component of Innate Immunity
1st Line of Defense• Mechanical Barriers• Chemical & Biochemical
Inhibitors• Biological Barriers
2nd Line of Defense• Cellular Components• Soluble Factors• Inflammatory Barriers
Immune System
1st Line: Mechanical Barriers
• Intact skin • Mucous coat• Mucous secretion• Blinking reflex and tears• The hair at the nares• Coughing and sneezing
reflex
Immune System
1st Line: Chemical Inhibitors
• Sweat and sebaceous secretion
• Hydrolytic enzymes (saliva)
• HCl (stomach)• Proteolytic enzyme (small
intestine) • Lysozyme (tears)• Acidic pH (adult vagina)
Immune System
2nd Line: Cellular Components
• Phagocytes– Neutrophils–Macrophages– Dendritic Cells– Natural Killer Cells–Mast Cells– Basophils– Eosinophils
2nd Line: Soluble Factors
• Complement • Interferons (αβγ)• Properdins• Beta Lysine• Lactoferrin, Transferrin• Lactoperoxidase• Lysozyme
Immune System
2nd Line: Complement System
2nd Line: Inflammatory Barriers
• Release of chemical mediators– (Histamine, fibrin, kinins,
cytokines)
• Vasodilation of capillaries
Immune System
ImmunityImmunity
Acquired Immunity
Humoral Cell-mediated
Innate Immunity
Humural ImmunityB-cell immunityImmunity
Humural ImmunityB-cell immunityImmunity
B Lymphocyte T lymphocytePreprocessed in Liver and Bone Marrow
Thymus Gland
B lymphocyte + antibodies (reactive agent)
T lymphocyte itself
More diverse – millions of types of antibodies
Immunity
After Preprocessi
ng
Lymphoid Tissue
Immunity
Immunity
Antibodiesalso called immunoglobulins are proteins manufactured by the
body that help fight against foreign substances called antigens
When an antigen enters the body, it stimulates the immune system to produce antibodies.
Immunity
Antibodies
Immunity
Classes Antibodies
IgM Complement activation
IgG Complement activation
IgA Localized protection inexternal secretions
IgDAntigen recognition by Bcells
IgEReagin activity; releaseshistamine from basophilsand mast cells
Immunity
MoA of Antibodies
1.Direct attack2.Activation of the
“Complement System”
Immunity
Direct Action
1. Agglutination2. Precipitation3.Neutralization4.Lysis
Immunity
Complement System
Cell-Mediated Immunity
• Second type of acquired immunity
• formation of large numbers of activated T lymphocytes that are specifically crafted in the lymph nodes to destroy the foreign agent
Immunity
T Lymphocytes
• Preprocessed in the thymus
• Some of the T cells (helper cells) activate specific B lymphocytes
• Upon exposure to antigen, T lymphocytes proliferate and release large numbers of activated, specifically reacting T cells
Immunity
• T lymphocyte memory cells are formed in the same way that B memory cells are formed in the antibody system
• Subsequent exposure to the same antigen produces a more rapid release of activated T cells
Immunity
• T-cell responses are extremely antigen specific
• three major types of antigen-presenting cells:–Macrophages–B lymphocytes–dendritic cells
Immunity
Types of T Cells
• Helper T Cells• Cytotoxic T Cells• Suppressor T Cells
Allergy and Hypersensitivity
• An important undesirable side effect of immunityImmunity
Streptococcus pneumoniae
• not a normal inhabitant of the vaginal flora– does not survive in its acidic pH• pH could be alkalinized from the rupture of the
membranes• allow S. pneumoniae to thrive in the
vagina
– appeared to be the cause of chorioamnionitis and premature rupture of the membranes
• Physiologic changes in the lower genital tract:– decreased in pH– Increased glycogen in the vaginal epithelium
• place the pregnant woman at risk for intra-amniotic infection
• The most common route: ascending infection from one or more of the endogenous flora of the cervix or vagina– The most frequent causative pathogens are
Aerobic Bacteria
• intraamniotic infection– spontaneous rupture of membranes weakening the
membranes
• direct effect of microorganisms on the membranes
• indirectly by activation of the host defense mechanisms
• produce an enterotoxin that transfers into the bloodstream– provoking the overstimulation of the immune system
Recommended Penicillin G, 5 million units IV initial dose, then 2.5 million units IV every 4 hours until delivery
Alternative Ampicillin, 2 g IV initial dose, then 1 g IV every 4 hours or 2 g every 6 hours until delivery
If penicillin allergica Patients not at high risk for anaphylaxis
Cefazolin, 2 g IV initial dose, then 1 g IV every 8 hours until delivery
Patients at high risk for anaphylaxis and with GBS susceptible to clindamycin and erythromycin
Clindamycin, 900 mg IV every 8 hours until deliveryOR Erythromycin, 500 mg IV every 6 hours until delivery
GBS resistant to clindamycin or erythromycin or susceptibility unknown
Vancomycin, 1 g IV every 12 hours until delivery
Fever, which means a body temperature above the usual range of normal, can be
caused by abnormalities in the brain itself or by toxic substances that affect the
temperature-regulating centers.Fever
• Many proteins, breakdown products of proteins, and certain other substances, especially lipopolysaccharide toxins released from bacterial cell membranes, can cause the set-point of the hypothalamic thermostat to rise. Substances that cause this effect are called pyrogens.
Fever
• Pyrogens released from toxic bacteria or those released from degenerating body tissues cause fever during disease conditions. When the set-point of the hypothalamic temperature-regulating center becomes higher than normal, all the mechanisms for raising the body temperature are brought into play, including heat conservation and increased heat production.
Fever
Fever
• When bacteria or breakdown products of bacteria are present in the tissues or in the blood, they are phagocytized by the blood leukocytes, by tissue macrophages, and by large granular killer lymphocytes. All these cells digest the bacterial products and then release the substance interleukin-1—also called leukocyte pyrogen or endogenous pyrogen—into the body fluids.
Fever