NOSOCOMIAL INFECTIONS

NOSOCOMIAL INFECTIONS:  On our way to clinical setting, we always have chief complaints.  So we are seeking advice from a trained medical personnel from either a Public or Private Health Centre or Clinic, Hospital or in a health outreach service.  Whether our general problem is diagnosed or not, it's severity will predetermine our admission or immediate discharge after the medical interventions are done.  Usually while in the hospital setting, patients usually suffer from diseases they did not come with, or they were not present and diagnosed at the time of admission and we call these nosocomial or hospital acquired infections.  We may actually look at it in one way but if you are very observant, nosocomial infections can affect patients, health workers and non medical stuff attendants in the hospital settings.

   

Some of the most common infections acquired include but not limited to respiratory tract infections such as pneumonia, flu and cough, skin infection, conditions that affect the gastrointestinal tract and tropical disease. In this discussion, we are going to look at the causes of such infections, their transmission and preventive measures employed in hospital setting to overcome them.

THE ORIGIN OF NOSOCOMIAL INFECTIONS:  Emergency of hospital acquired infections can depend on three major factors as described below depending on the possible origin of infections;

a)  Health worker related issues:  Some of the causes of hospital acquired infections will be related to health workers and the health setting it's self.  First, when patients come to the health facility, they should be oriented about the goings and makeup of that specific clinical setting.  This is to ensure that any medical procedure is done correctly and any medical waste is disposed off the right way.  Sometimes this does not happen and you find the patients are doing things according to their own understanding and confusion, on the expense of health workers and administrators failure to orient them.  A good example of this is the improper disposal of medical waste that maybe very infectious in bins and areas where they are hazardous to the hospital population.  This can lead transmission of infections not only to patients but also to hospital waste handlers.

The other way health workers are responsible for hospital acquired infections is via negligence and poor medical practices.  This is uncommon but we can not forget to talk about it.  It should be noted that before performing any invasive procedure on the patient, safety precautions must be put in place.  These include protective gears to the patient and or the medical work especially disinfecting and use of sterile equipment.  Once this is not done, the origin of blood indwelling microbes will not be preventable and one of the most common nosocomial infection in that respect will be sepsis.

Although the fear and anxiety related to illness can barely be eliminated, the patient should have some feeling of comfort for the period they are supposed to stay with in the facility and utilize the available resources with no fear.

b)  Patient related issues:  Although the health worker contributes a lot towards emergency of hospital acquired infections, the biggest percentage of root causes come from the patients themselves.  Some of the patient related issue that you don't want to under look include misuse of hospital facilities and contamination of hospital linen, fomites and aiding instruments.  This superimposed by ignorance about disinfection, sterilization and proper handling of medical material in the hospital settings is the leading cause of transmission of the most common infectious agents responsible for hospital acquired infections.

c)  Environmental issues:  The nearby environment also plays a role in development of hospital acquired infections.  First, the health facility is the collection of many patients with different illnesses and therefore anyone admitted there is exposed.  With inevitable human interactions, diseases will easily be able to get access into the nearby population.

The other environmental issue that may play a role in development of hospital acquired infections is presence of disease-carrying vectors.

PREVENTION OF NOSOCOMIAL INFECTIONS:  Some of the ways we can prevent nosocomial infections are universal and they rotate on good hygiene and proper practicing methods for health workers.  Now with the reinforcement of Standard Operating Procedures (SOPs) following the COVID 19 pandemic, hospital acquired infections can even be prevented more and more. 

CONCLUSION:  Hospital acquire infections can as well be contacted from our homes and communities but the difference here is that, exposure in the hospital settings is as good as in prisons, armed forces barracks, and any other long term stationed gathering.

RELATED;

1.  THE HUMAN MICROBIOME

2.  NORMAL FLORA OF THE HUMAN BODY

3.  DYNAMICS OF THE HUMAN BODY-SYSTEMS MAKE-UP

4.  HOSPITAL ACQUIRED PNEUMONIA

5.  DYNAMICS OF INFECTIOUS DISEASES

6.  CAUSATIVE AGENTS OF HOSPITAL ACQUIRED INFECTIONS

PATHOPHYSIOLOGY OF PEPTIC ULCER DISEASE

OBJECTIVES OF THE DISCUSSION:  By the end of the discussion, the reader/medical student will be able to;

1.  Outline the most common causes of peptic ulcer disease

2.  Describe the process involved in development of peptic ulcer disease

PATHOPHYSIOLOGY PEPTIC ULCER DISEASE:  Peptic ulcer disease is caused by 3 main factor namely; 1)  Microbes specifically Helicobacter pyroli which contributes to more than 95% of the cases.

2)  Hypersecretion of gastric juice in the stomach which may lead to autodigestion of the protein portions of the stomach walls.

3.  Use of aggressive factors including but not limited to alcohol, smoking or use of Nicotine and tar.

The pathophysiology of peptic ulcer disease is erosion of the mucus layer protecting the stomach from corrosive Hydrochloric acid co-produced with pepsin, and subsequent autodigestion of stomach walls leading to inflammation, followed by wounds and if not treated in time, perforation.  If you would like to read more about peptic ulcers management and treatment options, follow the links in the related section below.

RELATED;

1.  Helicobacter pyroli

2.  Nicotine

3.  Peptic ulcer disease

4.  Proton pump inhibitors

THE HUMAN KIDNEYS

INTRODUCTION: The two kidneys are located in the upper abdominal cavity on either side of the vertebral column, behind the peritoneum. The upper portions of the kidneys rest on the lower surface of the diaphragm and are enclosed and protected by the lower rib cage. The kidneys are embedded in adipose tissue that acts as a cushion and is in turn covered by a fibrous connective tissue membrane called the renal fascia, which helps hold the kidneys in place.

BASIC ANATOMY OF THE KIDNEY: Each kidney has an indentation called the hilus on its medial side. At the hilus, the renal artery enters the kidney, and the renal vein and ureter emerge. The renal artery is a branch of the abdominal aorta, and the renal vein returns blood to the inferior vena cava. The ureter carries urine from the kidney to the urinary bladder.

INTERNAL STRUCTURE OF THE KIDNEY: In a coronal or frontal section of the kidney, three areas can be distinguished. The lateral and middle areas are tissue layers, and the medial area at the hilus is a cavity. The outer tissue layer is called the renal cortex; it is made of renal corpuscles and convoluted tubules. These are parts of the nephron and are described in details in our next discussion. The inner tissue layer is the renal medulla, which is made of loops of Henle and collecting tubules which are also, parts of the nephron. The renal medulla consists of wedge-shaped pieces called renal pyramids. The tip of each pyramid is its apex or papilla. The third area is the renal pelvis, and this is not a layer of tissues, but rather a cavity formed by the expansion of the ureter within the kidney at the hilus. Funnel shaped extensions of the renal pelvis, called calyces or in singular: calyx, enclose the papillae of the renal pyramids. Urine flows from the renal pyramids into the calyces, then to the renal pelvis and out into the ureter.

THE NEPHRON: The nephron is the structural and functional unit of the kidney. Each kidney contains approximately 1 million nephrons. It is in the nephrons, with their associated blood vessels, that urine is formed. Each nephron has two major portions: a renal corpuscle and a renal tubule. Each of these major parts has further subdivisions, and we shall discuss more about them later.

RELATED;

1.  RENAL FAILURE

2.  WATER INTAKE AND OUTPUT

3.  ALDOSTERONE

4.  ADRENAL GLANDS

4.  ACIDITY AND ALKALINITY OF BODY SYSTEMS

REFERENCES

THE HUMAN SPLEEN

 

INTRODUCTION: The spleen is located in the upper left quadrant of the abdominal cavity, just below the diaphragm, behind the stomach. The lower rib cage protects the spleen from physical trauma and it is one of the organs in the human body that plays various roles in immunity as discussed in our previous articles. In the fetus, the spleen produces red blood cells, a function assumed by the red bone marrow after birth. After birth the spleen is very much like a large lymph node, except that its functions affect the blood that flows through it rather than lymph.

FUNCTIONS OF THE SPLEEN: The functions of the spleen after birth are:

1. Contains plasma cells that produce antibodies to foreign antigens.

2. Contains fixed macrophages (RE cells) that phagocytize pathogens or other foreign material in the blood. The macrophages of the spleen also phagocytize old red blood cells and form bilirubin and by way of portal circulation, the bilirubin is sent to the liver for excretion in bile.

3. Stores platelets and destroys them when they are no longer useful.

SIGNIFICANCE OF THE SPLEEN: The spleen is not considered a vital organ, because other organs compensate for its functions if the spleen must be removed, in a surgical procedure known as spleenectomy. The liver and red bone marrow will remove old red blood cells and platelets from circulation. The many lymph nodes and nodules plus the liver, will phagocytize pathogens and have lymphocytes to be activated and plasma cells to produce antibodies. It should however be noted that, a person without a spleen is somewhat more susceptible to certain bacterial infections such as pneumonia and meningitis.

RELATED;

1.  THE ENDOCRINE PANCREAS

2.  THE PITUITARY GLAND

3.  THE LIVER

4.  METABOLIC PROFILE OF ORGANS

5.  IMMUNITY

REFERENCES

VACCINES

INTRODUCTION: Vaccines have always been developed and used for ages so far. The purpose of vaccines is to prevent disease for known infectious agents and following thorough scientific demonstration and investigations in animal species such as mice, rats, rabbits among others, safer and effective vaccines are developed for prevention of various intended diseases. The safer and effectively developed vaccine against disease X is then used in the human populations to eradicate the disease.

COMPOSITION OF VACCINES: A vaccine contains an antigen that the immune system will respond to, just as it would to the actual pathogen. To look at the antigen more closely, it will have some resemblance to the intended pathogen in order to be able to stimulate the immune system.

TYPES OF VACCINES: The types of vaccine antigens are;

1. A killed or weakened also known as attenuated pathogen,

2. Part of a pathogen such as a bacterial capsule, or an inactivated bacterial toxin called a toxoid.

PATHOPHYSIOLOGY: Because the vaccine itself does not cause disease with very rare exceptions, the fact that antibody production to it is slow is not detrimental to the person. The vaccine takes the place of the first exposure to the pathogen and stimulates production of antibodies and memory cells. On exposure to the pathogen itself, the memory cells initiate rapid production of large amounts of antibody, enough to prevent disease.

EXAMPLES OF VACCINES: We now have vaccines for many diseases. The tetanus and diphtheria vaccines contain toxoids, the inactivated toxins of these bacteria. Vaccines for pneumococcal pneumonia and meningitis contain bacterial capsules. These vaccines cannot cause disease because the capsules are non-toxic and nonliving; there is nothing that can reproduce. Influenza and rabies vaccines contain killed viruses. Measles and the oral polio vaccines contain attenuated (weakened) viruses. Although attenuated pathogens are usually strongly antigenic and stimulate a protective immune response, there is a very small chance that the pathogen may regain its virulence and cause the disease with proper clinical practice.

RELATED;

1.  ACTIVE IMMUNISATION

2.  BCG VACCINATION

3.  PASSIVE IMMUNISATION

4.  ORGANS OF THE IMMUNE SYSTEM

5.  INNATE IMMUNITY

REFERENCES

DISSEMINATED INTRAVASCULAR COAGULATION (DIC)

INTRODUCTION: Disseminated intravascular coagulation (DIC) is a potentially life-threatening sign and not a disease itself, of a serious underlying disease mechanism. In this condition there is a problem that predominates and over activate the immune system which in turn over responds.

TRIGGERS OF DIC: Disseminated Intravascular Coagulation may be triggered by sepsis, trauma, cancer, shock, abruptio placentae, toxins, or allergic reactions. The severity of DIC is variable, but it is potentially life threatening.

PATHOPHYSIOLOGY OF DIC: In DIC, the normal hemostatic mechanisms are altered so that tiny clots form within the microcirculation of the body. These clots consume platelets and clotting factors, eventually causing coagulation to fail and bleeding to result. This bleeding disorder is characterized by low platelet and fibrinogen levels; prolonged prothrombin time (PT), partial thromboplastin time (PTT), and thrombin time; and elevated fibrin degradation products (D-dimers).

CLINICAL MANIFESTATIONS: Clinical manifestations of DIC are primarily reflected in compromised organ function or failure, clot formation followed by ischemia to all or part of the organ and or, less often, bleeding.

1. Patient may bleed from mucous membranes, venipuncture sites, and gastrointestinal and urinary tracts.

2. Bleeding can range from minimal occult internal bleeding to profuse hemorrhage from all orifices.

3. Patients typically develop multiple organ dysfunction syndrome (MODS), and they may exhibit renal failure as well as pulmonary and multifocal central nervous system infarctions as a result of microthromboses, macrothromboses, or hemorrhages.

4. Initially, the only manifestation is a progressive decrease in the platelet count; then, progressively, the patient exhibits signs and symptoms of thrombosis in the organs involved.

ASSESSMENT AND DIAGNOSTIC FINDINGS: Clinically, the diagnosis of DIC is often established by a drop in platelet count, an increase in PT and activated partial thromboplastin time (aPTT), an elevation in fibrin degradation products, and measurement of one or more clotting factors and inhibitors.

MEDICAL MANAGEMENT: The most important management issue is treating the underlying cause of DIC. A second goal is to correct the secondary effects of tissue ischemia by improving oxygenation, replacing fluids, correcting electrolyte imbalances, and administering vasopressor medications. If serious hemorrhage occurs, the depleted coagulation factors and platelets may be replaced. A heparin infusion, which is a controversial management method, may be used to interrupt the thrombosis process. Other therapies include recombinant activated protein C and AT infusions.

RELATED;

1.  BLOOD CLOTTING AND IT'S PREVENTION

2.  BLOOD AND IT'S COMPONENTS

3.  THE ABO BLOOD GROUPING

4.  BLOOD PLASMA

5.  THROMBOCYTOPENIA

6.  NOSE BLEEDING

REFERENCES

STEM CELLS

INTRODUCTION: Stem cells are characterized by their ability of possessing self-renewal capability and capacity to generate differentiated cell lineages. These cells in short terms are broad in perspective that later in their life span, can give rise to different cell types.

PROPERTIES OF STEM CELLS: There are different cellular properties that would otherwise be absent in other cell types and let us briefly look at them.

1. Self-renewal capacity and capacity to generate differentiated cell lineages. Here, a stem cell will be able to regain it’s ability to carry out cellular activities following damage or destruction, and then be able to divide and even produce other cell types.

2. Asymmetric replication: This is characterized by division of stem cell into two cells: One daughter cell which gives rise to mature cells, and then the other cell remains as undifferentiated stem cell which retains the self-renewal capacity.

TYPES OF STEM CELLS: Stem cells are of different types and located in different parts of the body.

1. Embryonic stem cells: During development of embryo, the blastocysts contain undifferentiated pluripotent stem cells, which are called as embryonic stem cells or ES cells. These cells can form cells of all three germ cell layers. Their normal function is to give rise to all cells of the human body.

2. Adult or sometimes known as somatic stem cells: Adult stem cells are less undifferentiated than ES cells found in adults. They are found among differentiated cells within a tissue. They have more limited capacity to generate different cell types than ES cells. They usually differentiate into particular tissue. Their normal function is tissue homeostasis.

3. Induced pluripotent stem cells (iPS cells): This is achieved by transferring the nucleus of adult cells to an enucleated oocyte. These are used for therapeutic cloning in the treatment of human diseases.

SITES OF STEM CELLS

1. Bone marrow: This contains two types of stem cells; The Hematopoietic stem cells (HSCs), and these can generate all of the blood cell lineages, and are used for the treatment of hematologic diseases. They can also be collected directly from the bone marrow, from umbilical cord blood, and from the peripheral blood. The other type are the Marrow stromal cells (MSCs): They can generate chondrocytes, osteoblasts, adipocytes, myoblasts, and endothelial cell precursors depending on the tissue to which they migrate.

2. Intestinal epithelium: Stem cells may be located immediately above Paneth cells in the small intestine or at the base of the crypt in the colon.

3. Liver: The liver contains stem cell in the canals of Hering, which are capable of differentiating into hepatocytes and biliary cells.

4. Cornea: Located in the limbus region between the conjunctiva and the cornea.

5. Skin: Located in the bulge area of the hair follicle, in the sebaceous glands, and in the lower layer of the epidermis.

RELATED;

1.  FORMED ELEMENTS FROM STEM CELLS

2.  THE ORIGIN OF CANCER

3.  HEMOGLOBIN AND RED BLOOD CELLS

4.  FETAL CIRCULATION

REFERENCES

ADRENAL GLANDS

INTRODUCTION: The two adrenal glands are located one on top of each kidney, which gives them their other name of suprarenal glands. Each adrenal gland consists of two parts: an inner adrenal medulla and an outer adrenal cortex. The hormones produced by each part have very different functions.

ADRENAL MEDULLA: The cells of the adrenal medulla secrete epinephrine and norepinephrine, which collectively are called catecholamines and are sympathomimetic. The section of both hormones is stimulated by sympathetic impulses from the hypothalamus, and their functions duplicate and prolong those of the sympathetic division of the autonomic nervous system.

EPINEPHRINE AND NOREPINEPHRINE: Epinephrine also known as Adrenalin and norepinephrine also known as noradrenalin, are both secreted in stress situations and help prepare the body for the so called fight or flight response. Norepinephrine is secreted in small amounts, and its most significant function is to cause vasoconstriction in the skin, viscera, and skeletal muscles throughout the body, which raises blood pressure.

The other counterpart epinephrine, secreted in larger amounts, increases the heart rate and force of contraction and stimulates vasoconstriction in skin and viscera and vasodilation in skeletal muscles. It also dilates the bronchioles, decreases peristalsis, stimulates the liver to change glycogen to glucose, increases the use of fats for energy, and increases the rate of cell respiration. Epinephrine in this sense, is more effective than sympathetic stimulation, however, because the hormone increases energy production and cardiac output to a greater extent.

ADRENAL CORTEX: The adrenal cortex secretes three types of steroid hormones;

1. Mineralocorticoids,

2. Glucocorticoids, and

3. Sex hormones.

The sex hormones which for females are the estrogens and for the males are the androgens baring some similarity to testosterone, are produced in very small amounts contribute to rapid body growth during early puberty. They may also be important in supplying estrogen to women after menopause and to men throughout life and are discussed in our previous discussions as in the links below.

RELATED;

1.  EPINEPHRINE

2.  THE NEUROTRANSMITTER SYSTEMS

3.  DOPAMINE

4.  THE ENDOCRINE PANCREAS

5.  ADRENERGIC BLOCKING DRUGS

REFERENCES