Neonatal Autopsy

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NEONATAL AUTOPSY TECHNIQUE

SPECIAL DISSECTION PROCEDURES

MAIN DEFINITIONS

AND TERMS IN NEONATOLOGY

THE DEATH OF NEWBORN:

– it is a lethal outcome before the 28th day of life

• PERINATAL DEATH:

– death before delivery, during delivery or during first 7 days of life

• FULL-TERM NEWBORN:

– newborn delivered between 38-42 hbd

– PREMATURE NEWBORN

– newborn delivered 26-37 hbd

• POSTMATURE NEWBORN:

– newborn delivered after the 42 hbd

• VIABLE FETUS:

– fetus delivered with weight over 1000g and length over 36-38 cm

• AN INFANT WITH POSTMATURITY SYNDROME

IS CALLED ALSO DYSMATURE OR POSTTERM

• Postmature infant with characteristic skin changes; the skin is dry, cracking, and desquamating.

Apgar Score Rates

• Respiration, crying

• Reflexes, irritability

• Pulse, Heart rate

• Skin color of body and extremities

• Muscle tone

• A system of evaluating a newborn’s physical condition by assigning a value (0,1,2) to each of five criteria

MAIN CAUSES OF DEATH IN INFANCY

Cause of Death

• Natural:

– immaturity

– malformation

– disease of heart

– lungs or brain

– meconium aspiration

– Rh incompatibility

Cause of Death

• Accidental:

– cord prolapse

– prolonged labor

– cord round the neck

– placenta previa; death of mother

– aspiration of blood

• Criminal:

– strangulation with cord

– drowning in milk or water

– omission to feed

POSTMORTEM EXAMINATION OF

FETUS AND NEWBORN

• The cause of death should be established on basis of:

– obstetrical medical history

– clinical examination of child with laboratory tests

– postmortem examination:

• gross examination,

• histological examination

• examination of afterbirth

EXTERNAL EXAMINATION OF

NEWBORN AND FETUS

Differences

• Signs of death:

– rigor mortis

– livor (hypostatic blotch) putrefaction

• Measurements of head, chest, abdominal circumferences, length and weight; facial measurements

• Skin-color; elasticity of subcutaneous tissue

• Examination of head

– pupillary membrane, development of ear and nose cartilage

• Umbilical cord

– localization, changes of proximal and distal end of umbilical cord

External examination of the Newborn and Fetus

Rigor mortis (stiffness of death; caused by chemical change in the muscle after death)

– Occurs as ATP is depleted, preventing relaxation of muscle fibers begins to develop several hours after death; rigor initially develops in the jaw,

• Followed by upper and lower extremities

– in newborn occurs very early (even 20 min after death)

• Infection, terminal seizure, electrocution, strenuous exercise or high body temperature may cause rigor to develop more rapidly

• In hot weather, rigor dissipates more rapidly; in cold weather, rigor may persist longer

• Livor

(hypostatic blotch, settling of the blood in the lower portion of the body; intensity of color depends upon the amount of reduced hemoglobin)

• Initially, livor is due to blood settling within vessels, and thus can shift with movement of the body and will blanch with pressure later, blood will hemolysis and diffuse out of the vascular space; at this point, livor is fixed; it will not shift with movement of the body and is nonblanchable

• Weaker than in adults without possibility of dislocation even after 5 hours after death

• Lack of livor in full termed newborn- suspicion of anemia, hemorrhage more intensive livor- in full termed newborn occurs in case of cyanosis in carbon monoxide poisoning, livor is cherry red in color

Livor Mortis

• Discoloration does not occur in the areas of the body that is in contact with the ground or another object

• As the vessel wall become permeable due to decomposition, blood leaks trough them and stains the tissue

– fixation of hypostasis

External examination of newborn and fetus

• Postmortem drying of the tongue and mucosal membranes darkens the tissues, imparting a

Pseudohemorrhagic appearance

• drying up- lips, ends of fingers, auricles

External examination of newborn and fetus

Putrefaction (decomposition of proteins) it results in breakdown of cohesion between tissues

– Green discoloration of the lower abdomen, due to overgrowth of colonic bacteria

– Green-black discoloration and swelling of the face and neck

– Red-brown purge fluid may extrude from the nose and mouth; this should not be confused with blood

• Gas formation causes diffuse swelling of the body, most noticeable in the abdomen

• Skin slippage and blistering; hair slippage from the scalp

• Marbling occurs due to breakdown of hemoglobin within blood vessels

• In infants occur very early; firstly near subcutaneous blood vessels and livors

Measurement of head, chest, abdominal circumference, length and weight; facial measurement

• Head circumference,

• Mento-occipitaldiameter,

• Fronto-occipital diameter,

• Biperietal diameter

• LENGTH : crown-heel

(from the vertex to heel with feet situated perpendicular)

Facial measurement

• Persistent pupillary membrane (PPM) is a condition of the eye involving remnants of a fetal membrane that persist as strands of tissue crossing the pupil;

– It exists in the fetus as a source of blood supply for the lens

– It normally atrophies from the time of birth to the age of four to eight weeks;

• PPM occurs when this atrophy is incomplete

Umbilical cord-localization, proximal and distal end of cord

• The degree of fetal maturity

• Wet or dried, smooth, with knots or without

• Features of inflammation in proximal end of cord - distal end of cord- regular and uniformly cut

• Irregular end of cord-delivery without medical help

Internal examination of newborn and fetuses: main differences

• Autopsy of head: special techniques opening of scull, caput succedaneum

• „collar incision” (y-shaped, with sharp scalpel) with bypass of umbilicus

• Opening of trachea in situ

• Pulmonary water loading test, gastro-intestinal test

• Estimation of abdominal cavity (30-40 ml of blood leads to death)

• Estimation of patency of Botall’s duct and foramen ovale

Autopsy of Head

• CAPUT SUCCEDANEUM (pressure of the presenting part of the scalp against the dilating cervix during delivery; management...)

• Description of fontanells

• Bones defects of scull (due to injury or congenital abnormalities)

• Special techniques opening the scull

• Examination of dura mater, cerebral falx, tentorium of the cerebellum, subdural hematoma

Caput Succedaneum

• An abnormal collection of fluid under the scalp on top of the skull that may or may not cross the suture lines, depending on the size

• Pressure on the presenting part of the fetal head against the cervix during labor may cause edema of the scalp

• This diffuse swelling is temporary and will be absorbed within 2 or 3 days

Different methods opening the scull

• „basket” incision

• „butterfly” opening of scull

• with creating two large bone flaps

Butterfly

• this method is superb for demonstration of posterior fossa abnormalities

WITH CREATING TWO LARGE BONE

FLAPS

• To preserve the superior sagital sinus

– the incision 1 cm lateral on both sides of the midline, preserving sagital sinus between

¨Collar Incision¨ with by pass of umbilicus:

• The incision is roughly y-shaped

• It begins at the shoulders, anterior to the acromial process

• The upper limbs of incision penetrate to the ribs and meet at the level of the xiphoid process

• The descending limbs of the incision extends along the midline from the xyphoid process

• Above the umbilicus the incision divides towards the inguens

Examination of oral cavity and the opening of trachea in situ

• The examination and description of oral cavity, pharynx and upper part of larynx (foreign bodies, injures, anatomical abnormalities)

• Opening of trachea in situ (we stick knife in the middle of trachea; contents of larynx, trachea)

• HYDROSTATIC PULMONARY WATER-LOADING

TEST

• HYDROSTATIC GASTRO-INTESTINAL TEST

Still Birth

• When child (born after 28 weeks) did not breath or show any sign of life at any time after being expelled from the mother

• Common causes are prematurity, anoxia, birth trauma especially intracranial hemorrhage due to excess molding, placental abnormality

Dead Birth

• When child has died in the utero and shows one of the following signs after complete birth

• Rigor mortis at delivery

• Maceration (aseptic autolysis after 3-4 days in uterus filled with amniotic fluid and no air); the earliest sign of maceration is skin slippage, which can be seen in 12 hours after death in utero; the body of the macerated fetus is soft, flaccid, and flattens out when placed on a level surface; it has a sweetish disagreeable odor.;

• Mummification: is the condition in which the fetus dries up, shriveled in the uterus.; it occurs when fetus dies from deficient supply of blood, when the liquor amni is scanty

MACERATION OF FETUSES

Interuterine Maceration – Softening due to decomposition

• iIntrauterine aseptic autolysis of body

– fetal tissues get soaked with amniotic fluid, blood serum,

• Tissue enzymes and acid properties of calcium soaps in meconium

– lack of specific smell of putrefaction

– the lesions are located uniformly

– advanced lesions- head as fluctuating cyst with palpable separated bones of scull

Macerated stillborn fetus

• Death was due to a true knot with obstruction of venous return from the placenta 10 cm from the abdomen. Total length was 65 cm.

Note the marked congestion of the cord distal to the knot

Signs of Live birth

• Shape of chest

– the position of diaphragm- found at the level of 4th or 5th rib; if no

• Respiration, 6th or 7th rib after breathing

• Lungs- after respiration, volume is increased, margins become rounded, consistency becomes soft, spongy, elastic and crepitant; the hydrostatic test by placing the lung tied at bronchi into water- if floats suggests respiration but an unexpanded lung may float from putrifaction and the expanded lung may sink from disease like acute edema, pneumonia

• Stomach- air is swallowed into the stomach during respiration

• other signs of live birth- caput succedaneum, air in GI tract, clothed body

Pulmonary Water Loading Test

• In cases suspected for infanticide; was the child alive after birth ?

• After the opening of abdominal cavity we describe the diaphragm,

• The appearance of lungs, pleura

• We open pericardial sac

• Ligation of stomach beneath the diaphragm

• Evisceration of thorax with description of surface of the lungs, color of the lungs; gas bubbles, marble-like pattern of the surface

– pulmonary water-loading test

• Put all organs into the water- they sink or float on the surface of the water

• Cut the trachea and bronchi (contents)

• Cut off the thymus

• Estimation of patency of Botall’s duct

• Cut off lungs and put them into water

• Classical examination of lungs

• Cut off each lobe and put into water

• Cut the lungs into slices, pieces and put into water

False Positive

• Putrefaction gas

• State after resuscitation

False Negative

• Infanticide when placental circulation is still present

• In pre termed newborns- insufficiency of respiratory centers or respiratory muscles

• Disruption of placental circulation during delivery with aspiration of amniotic fluid

• Congenital abnormalities and obstacle in respiratory tract

Gastrointestinal Test

• In cases suspected for infanticide

• To check if the child was born alive or death

• After ligation of stomach, small and large intestine we put into the water

• Check which part of gastrointestinal part floats on the water surface

• Positive result of the test:

– Newborn breath after delivery

– After resuscitation of newborn

– Putrefaction lesions

• Negative result of test:

• Stomach and intestine sink in water – child died before the first breath or delivered dead

– POSITIVE RESULT OF GASTROINTESTINAL AND

PULMONARY WATER-LOADING TEST child breath after delivery

– POSITIVE RESULT OF GASTROINTESTINAL AND

NEGATIVE PULMONARY WATER-LOADING TEST – child breath after delivery

AUTOPSY IN FAT EMBOLISM

The Presence of Fat Emboli Suggest

That injury of body was intravital

• Fat from the bone marrow and subcutaneous tissue

• Fat from organs

• Not emulsificated fat from blood serum

– during autopsy we take some tissue samples from brain, lungs, myocardium and fix them in formalin

– we can’t put them into the alcohol- it dissolves the fat

• Fat emboli- requires specialized techniques

(frozen sections, SUDAN III staining)

Autopsy in Pneumothorax

Causes of pneumothorax:

• Primary

– SPONTANOUS PNEUMOTHORAX

– TRAUMATICPNEUMOTHORAX

- blunt trauma or penetrating injury to

– the chest wall

- rib fracture

- rupture of esophagus

– young slim man congenital sub pleural bull

• Secondary:

– congenital cystic adenomatoid malformation

– chronic obstructive pulmonary disease

– neoplasm of pleura

– tuberculosis

– sarcoidosis

– in children, additional causes include measles, inhalation of a foreign body

• CT scan of the chest showing a pneumothorax on the person's left side

• The air-filled pleural cavity (black) and ribs

(white) can be seen

• Complications of pneumothorax:

– CT scan of the chest showing a pneumothorax on the person's left side

– the air-filled pleural cavity (black) and ribs (white) can be seen

• Recurrence- many people who have had one pneumothorax have another, usually within three years of the first

• Persistent air leak- air may sometimes continue to leak if the opening in the lung won't close; surgery may eventually be needed to close the air leak

• Low blood oxygen levels (hypoxemia)

• Cardiac arrest

• Respiratory failure

• Shock

When Pneumothorax is suscpected we do the test

• After surgical procedures in the chest in tuberculosis

• During preparation of cervical integument and chest we can not cause the injury intercostal space

• We preparate integument from the second intercostal space to xiphoid process to form a kind of pocket and we pour water into it

• We tap the intercostal spaces with knife and we observe if any gas bubbles get out onto the surface of water

• After cutting off the sternum we pour water into pleural cavity in which the pneumothorax was diagnosed

• Through the trachea we flow some air and observe where the place of injury is

Sudden Infant Death Syndrome SIDS

• „sudden death of an infant under 1 year of age which remains unexplained after a thorough case investigation, including performance of a complete autopsy, examination of death scene, and review the clinical history”

• Is the leading cause of death between age 1 month and 1 year in developed

• Countries

„cot death” -cause ???

• Recognission after the excluding alternative causes of death

SIDS – Postmortem abnormalities detect is cases of sudden unexpected infant death

• Multiple petechie on the thymus, viceral and parietal pleura, and epicardium

• Pulmonary congestion

• Astrogliosis of the brain stem and cerebellum

• Hypoplasia of the arcuate nucleus

• Extramedullaryhematopoiesis

• No symptoms

• Babies who die of SIDS do not appear to suffer or struggle

Autopsy - not able to confirm a cause of death

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