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Saturday, April 15, 2017

Death From Simple Infections: Disorders of Neutrophils

White blood cells (WBC) are made in our bone marrow and are absolutely imperative to fight infection. Without WBCs, we would succumb to even the most benign viruses and bacteria (i.e. germs) in our environment and die at a very early age. Once WBCs are made, they are released into the blood to mix with the RBCs (cells that carry oxygen) and circulate around our body. Stem cells in the bone marrow give rise to multiple WBC types, namely lymphocytes (T cells and B cells), neutrophils, basophils, eosinophils, and monocytes. Each type of WBC has a specific function. Eosinophils, for example, are important when fighting parasitic infectious. Many people are familiar with the Human Immunodeficiency virus (HIV), a disorder of T cells which impairs the body's ability to fight life-threatening bacterial and fungal infections. Neutrophils play a major function in our first line of defense against bacteria and fungi, and problems with them can carry grave consequences.



Neutrophils are typically first to the scene of an infection or traumatic injury. They are very quick, and their lifespan is only a few days. They follow chemical trails left behind by inflammation and, when they arrive, they suck bacteria into the center of their cell where some sanitizing then takes place- trapped bacteria are basically bathed in hydrogen peroxide. Two things can go wrong in this fight against the bacteria: either the neutrophils fail to work correctly, or the numbers of neutrophils are far too low to overpower invaders. Mildly low levels lead to oral/vaginal/rectal ulcers, ear infections, and skin abscesses. Severely low levels lead to overwhelming infection and death.



Disorders of the FUNCTION of neutrophils:
Congenital Leukocyte Adhesion Deficiency 1. Neutrophil movement is affected, so they are slow and fail to arrive to the scene of the infection. Newborn infants have delayed separation of their umbilical cord or infection where the cord meets the belly (omphalitis)

Chronic Granulomatous Disease. The release of the hydrogen peroxide inside the cell ("respiratory burst") doesn't work properly. Children need lifetime antibiotics (bactrim)

Hyperimmunoglobulin E Syndrome. The neutrophils don't follow the chemical trail to the site of infection like they are supposed to. Levels of an immune globulin called IgE are very high, and children have recurrent "cold" (non-red, non-tender) staph abscesses.

Chediak-Higashi Syndrome. There is a problem bringing the bacteria into the cell to sanitize them. Children also have albinism and their condition is worsened by infection with Epstein-Barr virus (EBV)


Disorders of the NUMBER of neutrophils:
External factors. Neutropenia caused by viruses (some viruses "shock" the stem cells and cause them to stop functioning for a period of time) or cancer chemotherapy

Autoimmune disorders. Neonatal Isoimmune Neutropenia occurs briefly in infants, whereby their mothers release antibodies that cross the placenta and attack their neutrophils. The disorder will resolve in less than 3 months. After 3 months, the baby can make their own antibodies against neutrophils leading to autoimmune neutropenia of infancy or chronic benign neutropenia.

Genetic syndromes. Shwachman-Diamond and Kostman Syndrome are characterized by low levels of neutrophils. Another interesting disorder is termed cyclic neutropenia, characterized by 3 day periods of neutropenia occurring every 21 days.

Thursday, November 17, 2016

New Antibody Discovered Highly Effective Against HIV

A recent article in the Journal of Immunology highlighted a groundbreaking discovery in the fight against the human immunodeficiency virus (HIV). Funded by the National Institute of Health (NIH) and the National Institute of Allergy and Infectious Diseases (NIAID), Dr. Mark Connors and his team discovered an antibody named N6 that appeared to neutralize over 98 percent of the HIV isolates tested. What is particularly promising was the ability to eradicate even the known resistant strains.

To date, the discovery of a vaccine has been difficult due to the rapidly changing structure of the proteins on the surface of the virus. The N6 antibody, however, is particularly adept at binding a more consistent portion of the virus called the CD4 binding site, which allows it to attach to human cells.
The N6 antibody joins the ranks of the VRC01 antibody, which was discovered in 2010 and is in clinical trials, but it's effectiveness is far greater. This may translate to a vaccine that will finally prevent HIV from evading our immune system, saving countless lives and cutting healthcare costs. 


Monday, October 31, 2016

What happens in the NICU?

The Neonatal Intensive Care Unit (NICU), in contrast to the newborn nursery, is a highly specialized unit with skilled staff prepared to handle the most dangerous postnatal complications of sick or premature infants. Babies can be found in incubators known as isolettes, which control their temperatures. The  average gestational age (GA) at birth is between 38 and 42 weeks, and an infant delivered before 37 weeks is considered to be "premature". The last trimester (12 weeks) in the womb is an important time for the baby's growth, and underdeveloped organs are vulnerable. The NICU staff, led by a neonatologist, monitors around the clock to identify and manage any problems. Here are a few of the most common:

Apnea: when a baby, typically less than 35 weeks GA, stops breathing momentarily for OVER 20 seconds. This can be central (the brain needs help reminding the baby to breathe, which is treated with caffeine) or obstructive (managed with suctioning and repositioning).



Bronchopulmonary Dysplasia (BPD): when the baby's lungs do not have a change to fully develop, they will need help to breathe until their lungs mature. This may include supplemental oxygen using either a nasal cannula, CPAP, or mechanical ventilation. Typically, OB/GYN doctors help prevent this by giving steroids (betamethasone) to mothers within 24 hours of their delivery if between 24-34 weeks GA. After delivery of a preterm infant, the neonatologist may provide further protection by coating the newborn's lungs in a material called surfactant. BPD is diagnosed if any newborn requires 28 or more days of oxygen support, and is further classified as mild, moderate, or severe depending on how much oxygen he or she is on at 36 weeks GA.


Polycythemia or Anemia: when the baby's hematocrit (ratio of red cells in the blood) is greater than 65% or below 30%, respectively. Anemia of prematurity occurs in the second month of life.

Patent Ductus Arteriosis: persistence of a connection between the right sided chamber of the heart and the aorta, which normally closes at birth. Characterized by tachypnea (fast breathing), cardiac murmur, and a low mean arterial pressure (MAP). Diagnosed with an echocardiogram.

Retinopathy of Prematurity: poor formation of the blood vessels of the eyes, occurs in most infants less than 28 weeks GA, screened for by an ophthalmologist if the baby is <30 weeks GA.

Necrotizing Enterocolitis: when the baby's bowel becomes overwhelmed with bacteria, leading to air in the walls of the intestines and can lead to perforation. Usually occurs in very preterm infants and is characterized by poor feeding, abdominal distension, and bloody stools.

Intraventricular Hemorrhage: when there is bleeding into spaces within the baby's brain known as the ventricles. Usually occurring within the first 3 days of birth and in very premature infants (<1500 grams) who have not fully developed their brains yet.


Problems in full term newborns (>37 weeks) that may require a NICU stay include hypoglycemia, poor feeding, poor tone, meconium aspiration syndrome, transient tachypnea of the newborn, infection, hyperbilirubinemia, and anatomical/chromosomal abnormalities.

Saturday, February 6, 2016

A Swollen Pediatric Joint

A 6 year old girl with a swollen right knee in the absence of trauma, fever, rash or lymphadenopathy. Symptoms are worse in the early morning, and improve throughout the day. She also complains of eye pain. What is the diagnosis?




Juvenile Idiopathic Arthritis (oligoarticular type)


Arthritis in children is not uncommon. When encountered by pediatricians, it is characterized into one of three subtypes: systemic, oligoarticular, and polyarticular.


  • The oligoarticular type is the most common. Usually occuring around 5 years old, it is seen in the large joints (but not the hips) and is known for it's casual but unique association with uveitis (irritation of the eye) and a positive ANA (an antibody in the blood). If left untreated, this uveitis can lead to glaucoma when they are older.
  • The polyarticular type is the second most common, and usually affects the large and small joints on both sides symmetrically. Older children with bloodwork that is rheumatoid factor positive are likely to progress to arthritis as adults.
  • The systemic type is often easiest to recognize, as an adolescent will often present with fever, a salmon-colored rash, and lymphadenopathy. Many different joints can be affected, and treatment requires disease-modifying drugs (DMARDs). Untreated systemic JIA can progress to a dangerous condition known as macrophage activating syndrome. 


The disease is manageable when caught early, and is typically managed by a specialist known as a rheumatologist. An early step is be sure the swelling isn't the result of an athletic injury or fall. The pediatrician will be sure to rule out more serious causes such as a septic (infected) joint.

Thursday, September 17, 2015

Heat Illness in Children

Pediatricians often caution their patients to "drink more water" on hot days or while exercising, but what is the reasoning behind this? 


Children and adolescents have two disadvantages when it comes to heat illness, which makes them more susceptible. Both their decreased sweat response (we cool off by sweating) and their poor thirst response (the feeling of being thirsty) when compared to adults. It is for this reason that heat illness is the 3rd leading cause of death in athletes in the U.S. The illness is categorized by the degree of temperature elevation:

Heat Cramps
Mild dehydration leads to cramps in the hamstrings or calves, and responds well to electrolyte fluid replacement. 

Heat Exhaustion
Characterized by a 100-103 degree body temperature, along with headache, weakness, nausea and vomiting. The treatment is to remove the clothes, apply ice packs to the body and to place the patient under cooling fans. Fluids are given for rehydration, whether by mouth or via an IV. 

Heat Stroke
A medical emergency characterized by a body temperature of >104 degrees paired with intense sweating caused by overexertion. The patient is immediately cooled to prevent organ damage, and IV fluids are administered. Unfortunately, the result is death in 50% of cases,


Athletes are encouraged to drink water every 20 minutes, and if exercise exceeds 1 hour then an electrolyte-rich sports drink is indicated.