Posts tagged flu

Effects of influenza on the respiratory system

Left: Acute hemorrhagic and ulcerative laryngotracheitis
Right: Right lung - showing consolidation, grey hepatization (lower lobe), and congestive edema (upper lobe). There is a large hemorrhage in the center of the hepatized lobe.

Happy Flu Season!

I’ve said it before, and I’ll say it again - even if the flu is just a few days of misery for you, it’s often far more serious than you might think for many others out there. It’s worth making sure you get the vaccine every year so you don’t spread infection, and, if you do get infected, stay the hell at home.

Hepatization is the conversion of a tissue or organ to a “liver-like” substance. In the lungs, this occurs when they become engorged with effused matter, such as red blood cells, neutrophils, and fibrin, which clog up the alveoli to the point that the lungs are impervious to air, where this has occurred. Grey hepatization is the second stage in lung hepatization - at this point, the red blood cells have broken down, leaving only the fibrinogen exudate and dead tissue behind.

Laryngotracheitis is an inflammatory response in the larynx and trachea. The trachea is lined with the same epithelial cells as much of the bronchial tree, and all influenza strains are able to infect those cells. This is why, whether you have a “light” case of the flu or a deathly-serious case, coughing and throat pain still occur. When the infection is bad enough, the coughing can lead to ulceration of the tissue below the epithelium, which can lead to bleeding into the lungs, or coughing up blood.

In cases involving “consolidation”, there is generally an opportunistic pneumonia taking hold. The bacterial exotoxins and sometimes the patient’s own immune system, break down epithelial cells that separate and define the alveolar sacs. The surface area given by these epithelial layers is what allows a high volume of oxygen to be absorbed with each breath we take. When those cell layers are destroyed, the oxygenation of blood is severely decreased.

Pathology of Influenza. Charles Winternitz, Isabel Wason, and Frank McNamara, 1920.

Autopsy No. 98 - Mucosal Inflammation and Hemorrhage in Influenza Drawing of a section through a trachea showing necrotizing hemorrhagic inflammatory process of the mucosa. Patient otherwise healthy young male. Contracted influenza December 1919. One of the more interesting points of the 1918 flu pandemic (otherwise known as the Spanish Flu) is the cytokine storm process that killed so many of the healthy young adults who contracted it. Their immune system was strong and reactive, and would respond to invading pathogens by launching a massive attack. Normally, this would have been good, but the H1N1 flu strain was (and is) known to induce a much larger reaction than was necessary. The immune system, instead of just killing invaders, would end up overwhelming the patient, and symptoms resulting from that over-reaction (such as hemorrhage and edema in the lungs) were the top killers of healthy adults who contracted the disease. One of the primary symptoms of the 1918 H1N1 virus was that the cytokine storms combined with the infecting pathogen ended up as a uniquely hemorrhagic influenza. There were even large numbers of reports of people hemorrhaging from petechiae on the skin, in addition to the intestinal, tracheal, and mucous membrane hemorrhages that were widespread. Hemorrhaging from the pleurae of the lungs was particularly fatal. Pathology of Influenza. Charles Winternitz, Isabel Watson, and Frank McNamara, 1920.

Autopsy No. 98 - Mucosal Inflammation and Hemorrhage in Influenza

Drawing of a section through a trachea showing necrotizing hemorrhagic inflammatory process of the mucosa. Patient otherwise healthy young male. Contracted influenza December 1919.

One of the more interesting points of the 1918 flu pandemic (otherwise known as the Spanish Flu) is the cytokine storm process that killed so many of the healthy young adults who contracted it. Their immune system was strong and reactive, and would respond to invading pathogens by launching a massive attack. Normally, this would have been good, but the H1N1 flu strain was (and is) known to induce a much larger reaction than was necessary. The immune system, instead of just killing invaders, would end up overwhelming the patient, and symptoms resulting from that over-reaction (such as hemorrhage and edema in the lungs) were the top killers of healthy adults who contracted the disease.

One of the primary symptoms of the 1918 H1N1 virus was that the cytokine storms combined with the infecting pathogen ended up as a uniquely hemorrhagic influenza. There were even large numbers of reports of people hemorrhaging from petechiae on the skin, in addition to the intestinal, tracheal, and mucous membrane hemorrhages that were widespread. Hemorrhaging from the pleurae of the lungs was particularly fatal.

Pathology of Influenza. Charles Winternitz, Isabel Watson, and Frank McNamara, 1920.

Right lung with surface hemorrhages Lung moderately enlarged due to influenza. Note the consolidation of infectious activity in the blue area. The Pathology of Influenza. M. C. Winternitz, Isabel M. Wason, and Frank P. McNamara, 1920.

Right lung with surface hemorrhages

Lung moderately enlarged due to influenza. Note the consolidation of infectious activity in the blue area.

The Pathology of Influenza. M. C. Winternitz, Isabel M. Wason, and Frank P. McNamara, 1920.

Section of trachea showing necrotizing hemorrhagic inflammatory process of the mucosa Happy flu season! The Pathology of Influenza. M. C. Winternitz, Isabel M. Wason, and Frank P. McNamara, 1920.

Section of trachea showing necrotizing hemorrhagic inflammatory process of the mucosa

Happy flu season!

The Pathology of Influenza. M. C. Winternitz, Isabel M. Wason, and Frank P. McNamara, 1920.

Everyone’s heard of how devastating the 1918 flu epidemic was. Sometimes it’s hard to truly understand the scope of things when all you see is massive numbers and statistics. This photograph was taken in a family’s home on the East coast (unsure where, but was urban) when a neighbor (who was a reporter) hadn’t heard from the family for several days. The father, mother, and infant child had all died, and the other five young children were all critically ill, and four of them would have likely died within the day. The five children were taken to a hospital and all five recovered, though two of them took over five weeks to be stable enough to leave. I don’t know what happened to the kids after that. It was noted that they were from a Catholic family (not sure why it was relevant). Perhaps it was large enough that their parents siblings were willing to take them in. Many children who lost parents ended up in orphanages and were easily exploited. Some took to the streets. It was a bleak outlook.

Everyone’s heard of how devastating the 1918 flu epidemic was. Sometimes it’s hard to truly understand the scope of things when all you see is massive numbers and statistics.

This photograph was taken in a family’s home on the East coast (unsure where, but was urban) when a neighbor (who was a reporter) hadn’t heard from the family for several days. The father, mother, and infant child had all died, and the other five young children were all critically ill, and four of them would have likely died within the day. The five children were taken to a hospital and all five recovered, though two of them took over five weeks to be stable enough to leave.

I don’t know what happened to the kids after that. It was noted that they were from a Catholic family (not sure why it was relevant). Perhaps it was large enough that their parents siblings were willing to take them in. Many children who lost parents ended up in orphanages and were easily exploited. Some took to the streets. It was a bleak outlook.