Hemolytic Disease of the Newborn and Fetus

Hemolytic Disease of the Newborn and Fetus
By:Renee Newman Wilkins, MS, MT(ASCP), CLS(NCA)
CLS 325/435 Clinical Immunohematology
School of Health Related Professions
University of Mississippi Medical Center

What is HDN?
* Destruction of the RBCs of the fetus and newborn by antibodies produced by the mother
* Only IgG antibodies are involved because it can cross the placenta (not IgA or IgM)
Mother’s antibodies
Pathophysiology
* Although transfer of maternal antibodies is good, transfer of antibodies involved in HDN are directed against antigens on fetal RBCs inherited by the father
* Most often involves antigens of the Rh and ABO blood group system, but can result from any blood group system
* Remember: The fetus is POSITIVE for an antigen and the mother is NEGATIVE for the same antigen

Pathophysiology
* HDN develops in utero
* The mother is sensitized to the foreign antigen present on her child’s RBCs usually through some seepage of fetal RBCs (fetomaternal hemorrhage) or a previous transfusion
* HDN occurs when these antibodies cross the placenta and react with the fetal RBCs

ABO HDN
* ABO incompatibilities are the most common cause of HDN but are less severe
* Usually, the mother is type O and the child has the A or B antigen…Why?
* ABO HDN can occur during the FIRST pregnancy b/c prior sensitization is not necessary
* ABO HDN is less severe than Rh HDN because there is less RBC destruction
o Fetal RBCs are less developed at birth, so there is less destruction by maternal antibodies
Diagnosis of ABO HDN
* Infant presents with jaundice 12-48 hrs after birth
* Testing done after birth on cord blood samples:
Treatment of ABO HDN
* Only about 10% require therapy
* Phototherapy is sufficient
* Rarely is exchange transfusion needed
* Phototherapy is exposure to artificial or sunlight to reduce jaundice
* Exchange transfusion involves removing newborn’s RBCs and replacing them with normal fresh donor cells

Phototherapy
Fluorescent blue light in the 420-475 nm range
Exchange transfusion
* CMV negative
* Irradiated
* Fresh Whole Blood (to avoid Ca++)
* Maternal blood if possible
* Leukoreduced

What type of blood to give fetus:

Rh HDN
* Mother is D negative (d/d) and child is D positive (D/d)
* Most severe form of HDN
* 33% of HDN is caused by Rh incompatibility
* Sensitization usually occurs very late in pregnancy, so the first Rh-positive child is not affected
o Bleeds most often occur at delivery
o Mother is sensitized
o Subsequent offspring that are D-positive will be affected

About 1 in 10 pregnancies involve an Rh-negative mother and an Rh-positive father
FetoMaternal Hemorrhage
* Sensitization occurs as a result of seepage of fetal cells into maternal circulation as a result of a fetomaternal hemorrhage

Risk
* Rh-negative women can be exposed to Rh-Positive cells through transfusion or pregnancy
* Each individual varies in their immune response (depends on amount exposed to)
Pathogenesis
* Maternal IgG attaches to antigens on fetal cells
o Sensitized cells are removed by macrophages in spleen
o Destruction depends on antibody titer and number of antigen sites
o IgG has half-life of 25 days, so the condition can range from days to weeks
* RBC destruction and anemia cause bone marrow to release erythroblasts, hence the name “erythroblastosis fetalis”)

Increased immature RBCs
Pathogenesis
* When erythroblasts are used up in the bone marrow, erythropoiesis in the spleen and liver are increased
Bilirubin
* Hemoglobin is metabolized to bilirubin
Diagnosis & Management
* Serologic Testing (mother & newborn)
* Amniocentesis and Cordocentesis
* Intrauterine Transfusion
* Early Delivery
* Phototherapy & Newborn Transfusions

Serologic testing on mother
* ABO and Rh testing
* Antibody Screen
* Antibody ID
* Paternal phenotype
* Amniocyte testing
* Antibody titration
Marsh score
Example:
Amniocentesis & Cordocentesis
* About 18-20 weeks’ gestation
* Cordocentesis takes a sample of umbilical vessel to obtain blood sample
* Amniocentesis assesses the status of the fetus using amniotic fluid
Analysis of amniotic fluid (example)
Liley graph
What to do?
* Intrauterine transfusion is done if:
* Removes bilirubin
* Removes sensitized RBCs
* Removes antibody

Other treatments
* Early Delivery
* Phototherapy (after birth)
* Newborn transfusion

Postpartum testing
* ABO – forward only
* Rh grouping – including weak D
* DAT
* Elution
Prevention
* RhIg (RhoGAM®) is given to the mother to prevent immunization to the D antigen

Postpartum administration of RhIg
Dose
Rosette Test
* A qualitative measure of fetomaternal hemorrhage

Fetomaternal Hemorrhage:
Kleihauer-Betke acid elution
Calculating KB test
Step 1) stain and count the amount of fetal cells out of 1000 total cells counted
Step 2) calculate the amount of fetal blood in cirulation by multiplying %fetal cells by 50 mL
Step 3) divide mL of fetal blood by 30 (each vial protects against a 30 mL bleed
Step 4) Round the calculated dose up and add one more vial for safety

Considerations
* RhIg is of no benefit once a person has formed anti-D
* It is VERY important to distinguish the presence of anti-D as:
o Residual RhIg from a previous dose OR
o True immunization from exposure to D+ RBCs
* RhIg is not given to the mother if the infant is D negative (and not given to the infant)

* Make sure presence of anti-D is not due to antenatal administration of Rh immune globulin
Hemolytic Disease of the Newborn and Fetus.ppt

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Zoonotic Helminthiasis

ZOONOTIC HELMINTHIASIS
* Helminth: parasitic worm (Greek)
o Platyhelminthes (flukes, tapeworms)
o Nematodes (roundworms)

* Pathogenic helminths are some of most common parasites
* Worlwide distribution
* Toxocariasis (visceral/ocular larval migrans)
o Toxocara canis, T. cati
* Meningoencephalitis
o Balysascaris procyonis
* Trichinosis
o Trichinella spiralis
* Taeniasis
o Taenia soleum, T. saginata
* Hydatid disease
o Echinococcus granulosus, E. multilocularis

TOXOCARIASIS
* Agent:
o Toxocara canis - roundworm of dogs and cats
o Toxocara cati - roundworm of cats (less frequently involved)
* Other names for diseae:
o visceral larval migrans (VLM)
o ocular larval migrans (OLM)

TOXOCARIASIS
Egg
Adult female - head
* Life cycle:
Epidemiology
* Reservoir:
o dogs, cats, small mammals
* Distribution:
o worldwide, most attention in US and UK
o seroprevalence: 3%; 23% in some groups
* Transmission:
o direct or indirect by ingestion of infective eggs from fecal contamination or contaminated soil
o larvae in contaminated undercooked liver from poultry, beef

Clinical features
* Incubation period:
o children - weeks to months
o OLM may be 2-4 years later
* Symptoms:
o asymptomatic to chronic, mild disease (usually)
o predominantly in young children
o increasingly recognized in adults
o symptoms related to migration of larval stage through tissues
* Symptoms:
o VLM - may persist for year or longer
+ fever
+ anorexia
+ weight loss
+ cough
+ eosinophilia
+ rash
+ hepatosplenomegaly
+ death (rarely) due to severe cardiopulmonary and neurologic manifestations
* Symptoms:
o OLM
+ misdiagnosed as retinoblastoma, leading to surgical enucleation
+ endophthalmitis at entry of larva
+ loss of vision
+ eosinophilia rare
+ visceral manifestation rare
+ occurs in children and adults
Diagnosis
* Direct (fecal) examination no use - larva does not develop into adult, no ova passed in feces
* Antibody detection confirmatory only in presence of clinical signs and history
o EIA (enzyme immunoassay)
+ larval antigen extracts from
# embryonated eggs
# cultured TES (Toxocara excretory-secretory antigens) - preferred
+ 1:32

Treatment
* Supportive treatment
* Anthelmentics - effectiveness uncertain
o DEC (diethylcarbamazine)
o Albendazole
o Mebendazole
* Corticosteroids for severe eye problems

Prevention/Control
* Education, especially pet owners
* Routine examination of pets
* Effective deworming program for puppies and kittens
* Removal of feces from environment
* Routine hygiene after handling pets, soil

TAENIASIS
* Agent:
o Tanea soleum - pork tapeworm
o T. saginata - beef tapeworm
* Other names for disease:
o taeniasis - intestinal infection of either tapeworm in animals or humans
o cystiserciasis; cysticercosis - tissue infection with T. soleum larva

Epidemiology
* Reservoir:
o humans definitive host for both T. saginata and T. soleum
* Occurrence:
o worldwide
o highest in Latin America, Africa, SE Asia, Eastern Europe
o T. soleum rare in US, Canada, UK, but increasingly recognized in immigrants

Epidemiology
* Transmission:
Clinical features
* Incubation period:
o taeniasis - eggs appear in 8-14 weeks
o cystercosis - days to years
* Symptoms:
o Taeniasis
+ mild abdominal symptoms
+ occasionally appendicitis or cholangitis from migrating proglottids
+ passage of proglottids (active or passive)
Clinical features
* Cysticercosis:
TANEIASIS
Diagnosis
* Taeniasis
* Cysticercosis
Treatment
* Taeniasis
o praziquantel
* Cystercosis
o praziquentel if active cystercosis, but only under hospitalization due to acute inflammatory reaction; steroids given to control inflammation
o surgical
+ shunt - ventriculoperitoneal shunt to drain CSF
+ cyst removal
+ endoscopic fenestration (hole in cyst wall)

Prevention/Control
* Education
* Identification and immediate treatment of infected individuals
* Freezing meat at -5ºC (23ºF) for > 4 days effectively kills cysticerci
* Irradiation

Agent
Echinococcus granulosus
E. multilocularis
E. vogeli
E. oligarthrus
Disease
Cystic hydatid disease;
unilocular echinococcosis
Alveolar hydatid disease;
multilocular echinococcosis
Polycystic alveolar disease
Rare in humans

UNILOCULAR ECHINOCOCCOSIS
Hydatid “sand”-protoscolices from fluid aspirate of hydatid cyst
Note: normally invaginated; evaginates in saline (right)

Epidemiology
* Transmission:

Clinical features
* Incubation period: months to years
* Symptoms:
o cysts grow slowly, asymptomatic until noticeable mass effect
o compatible with slow-growing tumor
o symptoms depend on location, size, and number of cysts
o anaphylactoid reaction if cyst ruptures/leaks

MULTILOCULAR ECHINOCOCCOSIS
Epidemiology
Clinical features
POLYCYSTIC ECHINOCOCCOSIS
Clinical features
Diagnosis
Serological diagnosis
Treatment
DIPHYLLOBOTHRIASIS
Epidemiology
* Occurrence:
Clinical features
Diagnosis
Treatment
Prevention and Control
ANISAKIASIS
Epidemiology
* Occurrence:
Clinical features
Diagnosis
* Direct examination:
o parasite coughed up
o Fiber optic exam
o laparotomy
* Radioallergosorbent (skin test) developed but not available commercially

Treatment
* surgical excision
Prevention and control
* Avoid ingestion of raw/undercooked fish
* Heating for 10 minutes @ 140ºF (60ºC)
* Freezing:
o “blast freezing” for 15 hours @ -31ºF (-35ºC)
o regular freezing for 7 days @ -10ºF (-23ºC)
* irradiation
* proper cleaning/evisceration as soon as caught

Zoonotic Helminthiasis.ppt

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Parasitic Pathogens Affecting the CNS

Parasitic Pathogens Affecting the CNS
By:Mark F. Wiser
Department of Tropical Medicine
School of Public Health

Protozoa Affecting the CNS
Rare cases
Free-living ameba
Rare invasion of the brain
Entamoeba histolytica
Cerebral Malaria
Plasmodium falciparum
African Sleeping Sickness
African Trypanosomes
Associated with congenital defects and AIDS
Toxoplasma gondii
Disease

Protozoan
Amebas Affecting the CNS
* Entamoeba histolytica
o normally found in large intestine
o can become invasive (primarily liver)
* Free-living Amebas

GAE; skin or lung lesions
Balamuthia mandrillaris
GAE; skin or lung lesions; amebic keratitis
Acanthamoeba species
PAM

Naegleria fowleri
Diseases
Ameba

Toxoplasma gondii
* cosmopolitan distribution
* seropositive prevalence rates vary
o generally 20-75%
* generally causes very benign disease in immunocompetent adults
o congenital transmission
o AIDS associated
* tissue cyst forming coccidia
o predator-prey life cycle
o felines are definitive host
o infects wide range of birds and mammals (intermediate hosts)

Definitive Host
* adult forms
* sexual reproduction

Intermediate Host
* immature forms
* asexual reproduction

chronic stage = bradyzoites
acute stage = tachyzoites
* ingestion of sporulated oocysts (cat feces + incubation)
* ingestion of zoites (undercooked meat)
* congenital infection (only during acute stage)
* organ transplants
o chronic infection in donor
o immunosuppression
* blood transfusions (only during acute stage)

Human Transmission
Acquired Postnatal Toxoplasmosis
* 1-2 week incubation period
* acute parasitemia persists for several weeks until development of tissue cysts
o often asymptomatic (>80%)
o a common symptom is lymphadenopathy without fever
o occasionally mononucleosis-like (fever, headache, fatigue, myalgia)
* likely persists for life of patient
* immunosuppression can lead to reactivation (eg, organ transplants)

Congenital Toxoplasmosis
* 1o infection must occur during or shortly before pregnancy
o can only occur once
o 1/3 will pass infection to fetus
* incidence ~1 per 1000 births
* severity varies with age of fetus
o move severe early in pregnancy
o more frequent later in pregnancy
* infection can result in: spontaneous abortion, still birth, premature birth, or full-term ą overt disease
* typical disease manifestations include: retinochoroiditis, psychomotor disturbances, intracerebral calcification, hydrocephaly, microcephaly

Toxoplasmic Encephalitis
* common complication associated with AIDS during the 1980's
* recrudescence of latent infection
* multifocal disease associated with immunosuppression
* lesions detectable with CT or MRI
* little spread to other organs
* symptoms include: lethargy, apathy, incoordination, dementia
* progressive disease  convulsions
* usually fatal if untreated

Diagnosis
* various serological tests
* active (acute) vs chronic infection
o compare samples at 2 week intervals
o IgM > IgG; Ab titers
* seldom by direct parasite demonstration
o biopsy
o inoculation into mice or cell culture (only acute stage)
* CT scans or MRI for toxoplasmic encephalitis

Prevention
But dog contact is highly correlated with Toxoplasma transmission.
Several studies show no correlation between cat contact and Toxoplasma.

An Enigma
Some Helminths Affecting the CNS
Taenia solium and Cysticercosis
* adult tapeworm infects GI tract of humans
* larval stages infect tissues causing cysticercosis or neurocysticercycosis
* most common parasitic disease of the CNS
* endemic throughout much of the developing world
o especially prevalent in Central and South America, Sub-Saharan Africa, Southeast Asia and Central and Eastern Europe
* prevalence of 3.6% in some regions of Mexico
* greatest cause of acquired epilepsy worldwide

Cysticercosis in the United States
* has become an important parasitic disease, particularly in California
* estimated that 1000 new cases of neurocysticercosis will be diagnosed each year
* increasing prevalence attributed to the migration of large numbers of rural immigrants from developing countries
* also improvements in neuro-imaging leading to better diagnosis

http://www.dpd.cdc.gov/dpdx/
Disease States
* Taeniasis = adult tapeworm in small intestine
o Usually asymptomatic (eggs or proglottids in feces)
o Vague abdominal symptoms occasionally report
* Cysticercosis = T. solium larvae in human tissues (eg, muscle)
o Usually asymptomatic
o Painless subcutaneous nodules in arms and chest
* Neurocysticercosis (NCC) = cysts in the central nervous system
o Most severe manifestation

Pathogenesis of Cysticerci
* larva (cysticercal cysts) survive up to 5 years
* living larva produce little inflammation
* death of larva leads to inflammation and edema resulting in symptoms
* cellular reaction eventually destroys parasite and leaves a calcified nodule

Clinical Manifestations
* presentation is varied—depends on stage, number, size and location of cysts
* seizures/convulsions most common symptoms
* blocked circulation of CSF can lead to intracranial hypertension or hydrocephalus
* occasionally large cysts can mimic tumors
* can also cause a variety of mental and motor changes

Diagnosis
* onset of epileptic seizures
* person from endemic area
* CT scans and MRI are most useful
o 1-2 cm cystic lesions
o with or without edema and inflammation
* some serological tests available
o problems with sensitivity and specificity

Treatment
* symptomatic treatment (eg, antiepileptic drugs)
o spontaneous cures noted especially in children
* praziquantel and albendazole kill the cysts faster
o limited clinical benefit
o administer with corticosteroids (anti-inflammatory)
* surgical excision of cysts was previous treatment

Prevention and Control
* Enhanced personal hygiene
* Thorough cooking/ freezing of pork to kill cysticerci
* Enhanced environmental sanitation
o proper disposal of human feces
* Agricultural inspection of pork
* Vaccination of pigs?

Parasitic Pathogens Affecting the CNS.ppt

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