NEONATAL AUTOPSY TECHNIQUE SPECIAL DISSECTION PROCEDURES

NEONATAL AUTOPSY TECHNIQUE SPECIAL DISSECTION PROCEDURES

MAIN DEFINITIONSAND 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 pressurelater, 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