Approach to the sick Infant

Arun Abbi MD

Neonatal Physiology/Anatomy

Infants have different Physiology and anatomy than adults

They are dependant on their primary caregiver for hydration and nutrition

They are also unable to communicate to adults and therefore often present later in the course of an illness

They have less cardiorespiratory reserve than adults

Airway

1. Primarily a Nasal Breather This is relevant when an infant presents with URI Sx and has trouble breathing due to nasal

congestion2. Larger tongue

Makes intubation harder prone to upper airway obstruction when

bagging and when infant becomes obtunded

Breathing

Normal Respiratory rate for Newborns - 30 - 60 /min Infants (1-6 months) - 30 - 50 /min

Tachypnea, Accessory muscle use and Grunting are signs of Respiratory distress

FEEDING is the most physically demanding thing that infants do. When they present with diseases causing respiratory

compromise, they stop feeding - this is a sign of a SICK INFANT

BRADYCARDIA - late sign of hypoxia

Circulation

Normal HR -

Neonate- 90 - 150 Infant - 100 -130

BP - (70 + 2 X age) Neonate - 60 - 80 - syst Infant - 80 - 100

Infants can not increase their stroke volume. They increase their cardiac output by becoming tachycardic (compensatory mechanism of shock)

Circulation

The Ductus closes in the first 2 weeks of life

Infants with right to left shunts will present with cyanosis.

Infants with left to right shunts will present with CHF (coarctation of the Aorta, VSD, ASD)

Circulation

Signs of Shock 1. LETHARGY 2. POOR FEEDING 3. DELAYED CAP REFILL 4. HYPOTHERMIA 5. TACHYCARDIA 6. HYPOTENSION (Late Sign)

Metabolic

The infant has diminished glycogen stores and a high metabolic rate. Hypoglycemia is a common symptom for a sick infant

when they are not feeding CHECK A CHEMSTRIP in an infant who has not been

feeding for > 12 hrs and is lethargic Hypoglycemia - glucose 4 cc/kg of D10W

Infants have a high surface area to body weight ratio This predisposes them to hypothermia due to much

greater heat loss

Approach to the sick infant

Perform an initial brief assessment and determine LOC and stability

Get a chemstrip quickly while getting the history Hx from time of discharge till ED presentation

Discharge weight/gestational age Length of labour Rupture of Membranes Group B step? FEEDING HX (how much and how often)

Assessment

Overall appearance Alert versus lethargic Vital signs Fontanalle Cardiac exam/peripheral pulses Abdomen

Tender Palbable liver?

Genitals Any ambiguous genitalia?

Differential Diagnosis

There are a multitude of different causes for a SICK APPEARING INFANT

1. Infection

2. Cardiac diseases

3. Metabolic disorders

4. Gastrointestinal disorders

5. Child abuse

PNEUMONIC FOR SICK INFANT

THE MISFITS T rauma H eart disease and Hypovolemia E ndocrine M etabolic (electrolyte disturbance) I nborn Errors of Metabolism S epsis F ormula Mishaps (under/overdilution) I ntestinal Catastrophes (volvulus,intussusception,NEC) T oxins and poisons S eizures

Case 1

6 day old male presents with increased lethargy and decreased feeding for 24 hours

Mother brings in child to ER

Patient born at term NSVD (no complications

Exam

Child appears mildly jaundiced

Child is slightly lethargic but not irritable

VitalsRR - 46 P - 144 BP 73/35 T - 36.2 Sat

95% (RA)

Labs

BGL - 4.4WBC - 13.2

Neuts 9.5Lymphs - 3.6

CH6 - normalBili - 404 (normal < 340)

What do you want to do?

1. Phototherapy

2. Send home and encourage more breast feeding with formula supplementation

3. More tests

Tests

Cath Urine Moderate bacteria10 - 20 wbc

CXR - nil acute

LP

WBC - 150

RBC - 1

Gram Stain - gram neg rods

Treatment

Ampiciliin - 50mg/kg/dose Q6h

Cefotaxime - 50mg/kg/dose Q6h

Consider acyclovir 10mg/kg if conerned about neonatal herpes

No Dexamethasone for neonates

Infection

Bacterial UTI, pneumonia, Meningitis. Group B strept, Listeria, E Coli, Staph

Viral RSV, enterovirus, neonatal herpes

Infections

Infants will present with lethargy, poor feeding, tachycardia and tachypnea

They may have a fever (>38.0 C) or be hypothermic

Infants do not have the ability to localize infections till about 3 months of age.

Meningitis can’t be ruled out clinically < 3 months of age

Infections UTI is the most common infection

Get a catheter specimen if an infant is sick

Respiratory infections present with tachypnea, grunting/wheezing (RSV)

Meningitis will have nonspecific signs and will be diagnosed on LP

Bugs - Group B Strept, E coli, Listeria

Infections

Treat infants if they appear sickDrugs -

Amp/Gent Cefotaxime/ampicillin

Case 2

10 day old male who presents to the ER with decreased feeding for 24 hours

Mother states the child has only taken 4 oz in the last 24 hours

Child had one bloody mucousy BM

Born at term and no complications

Case 2 Exam

Child appears lethargic

Pt is tachypneic with some accessory muscle use

Case 2 Cont’d

Any Concerns???

What do you want to check?

What else do you want to know?

BGL - 1.1

Treatment of hypoglycemia

Give 4 cc/kg of D10W (10% glucose) and reassess BGL Q 30 minutes

CXR

Mild increased perhilar markings

DDX

Query pneumonia versus cardiac

Patient has a palpable liver and has diminished pulses peripherally

Case 2

Cardiac Diseases

The Patent Ductus Arteriosis closes and 7 - 14 days.

Infants with Right - Left shunts present with cyanosis - not relieved with oxygen

Infants with Left - Right shunts/ Coarct present with signs of CHF

Cardiac Diseases

Other presentations can include SVT - causing CHF. The rate is usually around 240 and there is minimal variation (239 - 241)

Viral myocarditis can present at any age with cardiogenic shock

Cardiac Diseases - CHF Infants presenting with CHF will have signs of

1. Respiratory distress Tachypnea, indrawing, accessory muscle use, crackles

2. Hepatomegaly 3. JVD 4. Peripheral edema

CXR will show signs of CHF- usually increased perihilar markings with an enlarged heart

A Cap gas is useful to determine if the infant is in shock

Cardiac Diseases- Treatment CHF

1. Oxygen

2. If BP is low - initiate inotropes - dopamine or epinephrine

3. Lasix 1mg/kg iv

4. PGE 1 - 0.05 - 0.1 units/kg

5. Intubate if infant is in persistent shock

6. Arrange for echocardiogram

Cardiac Diseases - Right to Left Shunt These infants present with cyanosis that is

unresponsive to oxygen. Oxygen saturations will be low

Treatment is PGE 1 - 0.05 - 0.1 units/kg/min to keep the ductus open

Transfer to a centre where a permanent shunt can be inserted in the heart

Case 3

2 week old child presents with lethargy and fatigue

Patient has been vomiting for 16 hours and mother is concerned about dehydration

Nurse places child on the monitor

Exam

Child is dehydrated

Child is lethargic and had decreased cap refill

Chest is clear

Abdomen is soft and nontender

Concerns?

DDXGet a stat Cap gas to look at the K+Will see low Na+ with a high K+ and a

normal anion gap

Metabolic Disorders 1. Dehydration -

hypernatremia, hyponatremia

2. Congenital adrenal hyperplasia

3. Urea cycle defects

4. Hypothyroidism

5. Toxins - ASA, ETOH

Metabolic Disorders1. Dehydration -

Will see delayed cap refill. Decreased skin turgor, lethargy, tachycardia, dry mucous membranes

Tx - fluids - 20 cc/kg of NS - then reassess

Metabolic Disorders

2. Congenital Adrenal Hyperplasia Will see ambiguous genitalia

in females but males may have a hyperpigmented scrotum 1 - fluids 20 cc/kg- fluids 2. - Insulin/glucose for K+ (often resolves with fluids) 3. Dexamethasone 0.2 mg/kg iv

3. Urea Cycle Defects Check the glucose - need to draw an “ammonia” level, serum ketones,

Urine for reducing substances, ketones and pH, serum lactate

Case 4

2 day old presents with vomiting after feeding

Patient was sent home day of birth and presents 36 hours later as he is vomiting with feeding for the last 12hours

Case 4

Child is alert and looking around

Chest is clear

Abdomen is mildly distended and moderately tender

DDX?

Gastrointestinal disorders

1. Gastroenteritis 2. Pyloric Stenosis 3. Intussusception 4. Appendicitis 5. Necrotizing Enterocolitis 6. Midgut volvulus 7. Duodenal atresia

Initial Management

Check BGL Start IV D10W NS at 4 cc/kg/hr Check Urine If abdomen is quite tender - surgical consult If not sure - then get Upper GI/US of abdomen Start antibiotics (cefotaxime)

Gastrointestinal

1. Gastroenteritis - presents with vomiting and diarrhea Rotavirus is a common cause

Tx - oral rehydration if possible - otherwise IV

2. Pyloric stenosis - presents with projectile vomiting. Often bilious. 3- 6

weeks of age Diagnosis is made by US

Gastrointestinal

3. Intussusception

Usually 6 months - 18 months of age. Sx

Vomiting, poor feeding, bloody stoolsAbdominal pain that is intermittentMay see a paucity of gas in the RLQ

Diagnosis - air contrast enema - also a good therapeutic maneuver

Gastrointestinal

4. Neonatal Appendicitis High mortality Presents with poor feeding and abdominal pain/tenderness. Abdominal distension

5. Necrotizing Entercolitis Seen in premature infants who have anoxic insults at birth Bloody stools Distended abdomen Pneumatosis intestinalis on X-ray

Gastrointestinal

6. Midgut volvulusPresents similar to neonatal appendicitis -

pain, distension, lethargy and poor feedingHigh mortality as it leads to necrosis of

most of the small bowel

Case 5

Patient is a 4 week old female who was born at 34 weeks (38 weeks corrected)

Child was DC home after 10 days due to some feeding difficulties

Exam

Child is lethargic and has poor tone

Chest is clear with no accessory muscle use

Abdomen is soft and nontender

CVS - normal heart sounds/pulses and no murmers

Labs

Cath urine - cleanCXR - nil acuteCBC

WBC - 12.7HgB - 114 (slightly low)Platelets - 240

Concerns?

Further Tests?

LP

WBC - 30

RBC - 12 000

Glucose 5.5

Protein -normal

Child Abuse

Can present at any age In infants - will appear as a septic infant without a

fever Lethargy is usually due to intra-cerebral

hemorrhages Retinal hemorrhages are diagnostic of Shaken baby

syndrome Other signs of abuse are often rare Diagnosis often made with LP - bloody

KEY POINTS

1. Infants have diminished reserve 2. Feeding is their most physically demanding

activity. Any cardiorespiratory illness will lead to

diminished feeding

3. If lethargic - check a CHEMSTRIP 4. If child is ill and no focus is found, think of

child abuse