NETWORK (SNOWBALL) SAMPLING

 

INTRODUCTION:  Network sampling, sometimes referred to as snowball or chain sampling, holds promise for locating samples difficult or impossible to obtain in other ways or that had not been previously identified for study. Network sampling takes advantage of social networks and the fact that friends tend to have characteristics in common. When you have found a few participants with the necessary criteria, you can ask for their assistance in getting in touch with others with similar characteristics. 

INITIATION OF THE PROCESS:  The first few participants are often obtained through convenience or purposive sampling methods, and the sample size is expanded using network or snowball sampling.  This sampling method is rarely used in quantitative studies, but it is commonly used in qualitative studies. In qualitative research, network sampling is an effective strategy for identifying participants who know other potential participants who can provide the greatest insight and essential information about an experience or event that is identified for study.

SUITABILITY OF THE METHOD:  This strategy is also particularly useful for finding participants in socially devalued populations, such as alcoholics, child abusers, sex offenders, drug addicts, and criminals. These individuals are seldom willing to identify themselves as fitting these categories. Other groups, such as widows, grieving siblings, or individuals successful at lifestyle changes, can be located using this strategy. These individuals are outside the existing healthcare system and are difficult to find. 

LIMITATIONS OF THE METHOD:  Biases are built into the sampling process because the participants are not independent of one another. However, the participants selected have the expertise to provide the essential information needed to address the study purpose.

RELATED;

1.  PROBABILITY SAMPLING  

2.  SYSTEMATIC SAMPLING  

3.  ACCIDENTAL SAMPLING

4.  RESEARCH METHODOLOGY

REFERENCES

KAPOSI'S SARCOMA

INTRODUCTION:  Kaposi’s sarcoma (KS) is the most common HIV-related malignancy and involves the endothelial layer of blood and lymphatic vessels. In people with AIDS, epidemic KS is most often seen among male homosexuals and bisexuals. AIDS related KS exhibits a variable and aggressive course, ranging from localized cutaneous lesions to disseminated disease involving multiple organ systems. 

CLINICAL MANIFESTATIONS:  Cutaneous lesions can occur anywhere on the body and are usually brownish pink to deep purple. They characteristically present as lower-extremity skin lesions.  Lesions may be flat or raised and surrounded by ecchymosis and edema; they develop rapidly and cause extensive disfigurement.  The location and size of the lesions can lead to venous stasis, lymphedema, and pain. 

COMMON SITES INVOLVED:  Common sites of visceral involvement include the lymph nodes, gastrointestinal tract, and lungs. Involvement of internal organs may eventually lead to organ failure, hemorrhage, infection, and death. 

ASSESSMENT AND DIAGNOSIS: Diagnosis is confirmed by biopsy of suspected lesions. Prognosis depends on extent of tumor, presence of other symptoms of HIV infection, and the CD4 count.  Pathologic findings indicate that death occurs from tumor progression, but more often from other complications of HIV infection. 

MEDICAL MANAGEMENT: Treatment goals are to reduce symptoms by decreasing the size of the skin lesions, to reduce discomfort associated with edema and ulcerations, and to control symptoms associated with  mucosal or visceral involvement. No one treatment has been shown to improve survival rates. Radiation therapy is effective as a palliative measure to relieve localized pain due to tumor mass (especially in the legs) and for KS lesions that are in sites such as the oral mucosa, conjunctiva, face, and soles of the feet. 

PHARMACOLOGICAL THERAPY:  Patients with cutaneous KS treated with alpha-interferon have experienced tumor regression and improved immune system function. Alpha-interferon is administered by the intravenous (IV), intramuscular, or subcutaneous route. Patients may self-administer interferon at home or receive interferon in an outpatient setting.  Nonsteroidal anti-inflammatory drugs (NSAIDs) and opioids are used as well. 

RELATED;

1.  INVASION OF HUMAN CD4 CELL BY HIV 

2.  HIV/AIDS  

3.  ANTIRETROVIRAL DRUGS (ARVs)

4.  MEDICAL CONDITIONS

REFERENCES

DEPRESSION

 

INTRODUCTION:  Depression is a disorder characterized by a sad or despondent mood. Many symptoms are associated with depression, including lack of energy, sleep disturbances, abnormal eating patterns, and feelings of despair, guilt, or hopelessness. Depression is the most common mental health disorder of elderly adults, encompassing a variety of physical, emotional, cognitive, and social considerations.

CRITERIA FOR DIAGNOSIS OF DEPRESSION:  The American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV), describes the following criteria for diagnosis of a major depressive disorder:

A depressed affect plus at least five of the following symptoms lasting for a minimum of 2 weeks: 

1)  Difficulty sleeping or sleeping too much.  

2)  Extremely tired; without energy.

3)  Abnormal eating patterns (eating too much or not enough).

4)  Vague physical symptoms (gastrointestinal [GI] pain, joint/muscle pain, or headaches).

5)  Inability to concentrate or make decisions.

6)  Feelings of despair, guilt, and misery; lack of self-worth.

7)  Obsessed with death (expressing a wish to die or to commit suicide).

8)  Avoiding psychosocial and interpersonal interactions.

9)  Lack of interest in personal appearance or sex.

10)  Delusions or hallucinations. 

AGGREVIATING FACTORS TO DEPRESSION:  The majority of depressed patients are not found in psychiatric hospitals but in mainstream society. For proper diagnosis and treatment to occur, recognition of depression is often a collaborative effort among health care providers.  For example, it might be the pharmacist who recognizes that a customer is depressed when the customer buys natural or over-the-counter (OTC) remedies to control anxiety symptoms or to induce sleep.

Situational depression occurs when the depression is the result of a circumstance in a person’s life, for example, loss of a job or unfavorable event at home such as death, children leaving home, or divorce.  Dysthymic disorder is characterized by less severe depressive symptoms that may prevent a person from feeling well or functioning normally. Because depressed patients may be found in multiple settings, health workers should be proficient in the assessment of patients afflicted with these conditions. Some women experience intense mood shifts associated with hormonal changes during the menstrual cycle, pregnancy, childbirth, and menopause. 

WOMEN AND DEVELOPMENT DEPRESSIVE DISORDER:  Up to 80% of women who give birth experience postpartum depression during the first several weeks after birth of their baby. About 10% of new mothers experience a major depressive episode within 6 months related to the dramatic hormonal shifts that occur during postdelivery. Along with the hormonal changes, additional situational stresses, such as responsibilities at home or work, single parenthood, and caring for children or for aging parents, may contribute to the onset of symptoms. If mood is severely depressed and persists long enough, many women will likely benefit from medical treatment, including women with premenstrual dysphoric disorder, depression during pregnancy, postpartum mood disorders, or menopausal distress. Because of the possible consequences of perinatal mood disorders, some state agencies mandate that all new  mothers receive information about mood shifts prior to their discharge after giving birth.  Health care providers in obstetrician’s offices, pediatric outpatient settings, and family medicine centers are encouraged to conduct routine screening for symptoms of perinatal mood disorders.

RELATED;

1.  SEDATIVE-HYPNOTICS  

2.  ZOLPIDEM

3.  PHARMACOLOGY AND THERAPEUTICS

REFERENCES

PHYSICAL VERSUS PSYCHOLOGICAL DEPENDENCE

 

INTRODUCTION:  Whether a substance is addictive is related to how easily an individual can stop taking the agent on a repetitive basis. When a person has an overwhelming desire to take a drug and cannot stop, this condition is referred to as substance dependence. Substance dependence is classified into two categories, physical dependence and psychological dependence. 

PHYSICAL DEPENDENCE:  This refers to an altered physical condition caused by the adaptation of the nervous system to repeated substance use. Over time, the body’s cells become accustomed to the presence of the unnatural substance.  With physical dependence, uncomfortable symptoms known as withdrawal result when the agent is discontinued. Alcohol, sedatives, nicotine, and CNS stimulants are examples of substances that with extended use may easily cause physical dependence. Repeated doses of opioids, such as morphine and heroin, may produce physical dependence rather quickly, particularly when the drugs are taken intravenously.

PSYCHOLOGICAL DEPENDENCE:  In contrast, psychological dependence refers to a condition in which no obvious physical signs of discomfort are observed after the agent is discontinued. The user, however, will have an overwhelming desire to continue drug-seeking behavior despite obvious negative economic, physical, or social consequences. Associated intense craving may be connected with the patient’s home or social environment. Strong psychological craving may continue for months or even years and can be responsible for relapses during therapy. For psychological dependence to occur, relatively high doses of drugs are usually taken for a prolonged period. Examples are marijuana and antianxiety drugs. On the other hand, psychological dependence may develop quickly after only one use, as with crack cocaine, a potent, rather inexpensive, form of the drug. 

WITHDRAWAL SYNDROME:  Once a person becomes physically dependent and the substance is discontinued, withdrawal syndrome may occur. Prescription drugs are often used to reduce the severity of withdrawal symptoms. For example, alcohol withdrawal might be treated with the short-acting benzodiazepine oxazepam; opioid withdrawal might be treated with methadone. Symptoms of nicotine withdrawal might be relieved with replacement therapy in the form of nicotine patches or chewing gum. 

For withdrawal from CNS stimulants, hallucinogens, marijuana, or inhalants, specific pharmacologic intervention is generally not indicated. Symptoms of withdrawal may be particularly severe for those who are dependent on alcohol or sedatives. Because of the severity of the symptoms, the process of withdrawal from these agents is probably best accomplished in a substance abuse treatment facility.  With chronic substance abuse, people will often associate use of the substance with their conditions and surroundings, including social contacts with other users who are also taking the drug. Users tend to revert to drug-seeking behavior when they return to the company of other substance abusers. Counselors often encourage users to refrain from associating with past social contacts or having relationships with other substance abusers to lessen the possibility for relapse.

RELATED;

1.  PHARMACOKINETICS  

2.  DRUG METABOLISM

3.  CENTRALLY ACTING MEDICATIONS

4.  SEDATIVE-HYPNOTICS

REFERENCES 

DRUG METABOLISM

Introduction:  Metabolism, also called biotransformation, is the process of chemically converting a drug to a form that is usually more easily removed from the body. Metabolism involves complex biochemical pathways and reactions that alter drugs, nutrients, vitamins, and minerals. The liver is the primary site of drug metabolism, although the kidneys and cells of the intestinal tract also have high metabolic rates. Medications undergo many types of biochemical reactions as they pass through the liver, including hydrolysis, oxidation, and reduction.

Microsomal enzyme systems:  During metabolism, the addition of side chains, known as conjugates, makes drugs more water soluble and more easily excreted by the kidneys. Most metabolism in the liver is accomplished by the hepatic microsomal enzyme system. This enzyme complex is sometimes called the P-450 system, named after cytochrome P-450 (CYP-450), which is a key component of the system. The cytochrome P450 enzyme system

Enzyme induction and the role of prodrugs:  As they relate to pharmacotherapy, the primary actions of the hepatic microsomal enzymes are to inactivate drugs and accelerate their excretion. In some cases, however, metabolism can produce a chemical alteration that makes the resulting molecule more active than the original. For example, the narcotic analgesic codeine undergoes biotransformation to morphine, which has significantly greater ability to relieve pain. In fact, some agents, known as prodrugs, have no pharmacologic activity unless they are first metabolized to their active form by the body. Examples of prodrugs include benazepril and, proinsulin and losartan. Changes in the function of the hepatic microsomal enzymes can significantly affect drug metabolism. A few drugs have the ability to increase metabolic activity in the liver, a process called enzyme induction. For example, phenobarbital causes the liver to synthesize more microsomal enzymes. By doing so, phenobarbital increases the rate of its own metabolism as well as that of other drugs metabolized in the liver. In these patients, higher doses of medication may be required to achieve the optimum therapeutic effect. 

Considerations for liver functioning states:  Certain patients have decreased hepatic metabolic activity, which may alter drug action. Hepatic enzyme activity is generally reduced in infants and elderly patients; therefore, pediatric and geriatric patients are more sensitive to drug therapy than middle-age patients. Patients with severe liver damage, such as that caused by cirrhosis, will require reductions in drug dosage because of the decreased metabolic activity. Certain genetic disorders have been recognized in which patients lack specific metabolic enzymes; drug dosages in these patients must be adjusted accordingly. Metabolism has a number of additional therapeutic consequences.  

The roles of fast-pass effect:  For example, drugs absorbed after oral administration cross directly into the hepatic portal circulation, which carries blood to the liver before it is distributed to other body tissues. Thus, as blood passes through the liver circulation, some drugs can be completely metabolized to an inactive form before they ever reach the general circulation. This first-pass effect is an important mechanism, since a large number of oral drugs are rendered inactive by hepatic metabolic reactions. Alternative routes of delivery that bypass the first-pass effect (e.g., sublingual, rectal, or parenteral routes) may need consideration for these drugs. 

RELATED;

1.  ABSORPTION  

2.  PHARMACOKINETICS

REFERENCES

DRUG ABSORPTION

 

Introduction: Absorption is a process involving the movement of a substance from its site of administration, across body membranes, to circulating fluids. Drugs may be absorbed across the skin and associated mucous membranes, or they may move across membranes that line the gastrointestinal (GI) or respiratory tract. Most drugs, with the exception of a few topical medications, intestinal anti-infectives, and some radiologic contrast agents, must be absorbed to produce an effect. Absorption is the primary pharmacokinetic factor determining the length of time it takes a drug to produce its effect. Pharmacokinetics

In order for a drug to be absorbed it must dissolve. The rate of dissolution determines how quickly the drug disintegrates and disperses into simpler forms; therefore, drug formulation is an important factor of bioavailability. Bioavailability

In general, the more rapid the dissolution, the faster the drug absorption and the faster the onset of drug action. For example, famotidine administered as an orally disintegrating tablet dissolves within seconds and after being swallowed is delivered to the stomach where it blocks acid secretion from the stomach, thereby treating conditions of excessive acid secretion. Pepticulcer disease: Histamine H2 receptor blockers

At the other extreme some drugs have shown good clinical response as slowly dissolving drugs such as liothyronine sodium (T3) and thyroxine (T4) administered for resolution of hypothyroid symptoms. In some instances it is advantageous for a drug to disperse rapidly. In other cases, it is better for the drug to be released slowly where the effects are more prolonged for positive therapeutic benefit. Absorption is conditional on many factors. Drugs in elixir or syrup formulations are absorbed faster than tablets or capsules. Drugs administered in high doses are generally absorbed more quickly and have a more rapid onset of action than those given in low concentrations. The speed of digestive motility, surface area, pH, lipid solubility, exposure to enzymes in the digestive tract, and blood flow to the site of drug administration also affect absorption. Because drugs administered IV directly enter the bloodstream, absorption to the tissues after the infusion is very rapid. IM medications take longer to absorb. Drug distribution

Other factors that influence the absorption of medications include the following: Drug formulation and dose, Size of the drug molecule, Surface area of the absorptive site, Digestive motility or blood flow, Lipid solubility, Degree of ionization, Acidity or alkalinity (pH), Interactions with food and other medications. The degree of ionization of a drug also affects its absorption. A drug’s ability to become ionized depends on the surrounding pH. Aspirin provides an excellent example of the effects of ionization on absorption. In the acid environment of the stomach, aspirin is in its non-ionized form and thus readily absorbed and distributed by the bloodstream. As aspirin enters the alkaline environment of the small intestine, however, it becomes ionized. In its ionized form, aspirin is not as likely to be absorbed and distributed to target cells.

Unlike acidic drugs, medications that are weakly basic are in their nonionized form in an alkaline environment; therefore, basic drugs are absorbed and distributed better in alkaline environments such as in the small intestine. The pH of the local environment directly influences drug absorption through its ability to ionize the drug.

Drug–drug or food–drug interactions may influence absorption. Many examples of these interactions have been discovered. For example, administering tetracyclines with food or drugs containing calcium, iron, or magnesium can significantly delay absorption of the antibiotic.  High-fat meals can slow stomach motility significantly and delay the absorption of oral medications taken with the meal. Dietary supplements may also affect absorption.

RELATED;

1.  DRUG DISTRIBUTION  

2.  PHARMACOKINETICS

3.  PHARMACOLOGY AND THERAPEUTICS

REFERENCES

ANTIBACTERIAL PROPERTIES OF GOLDENSEAL

 

INTRODUCTION:  Goldenseal (Hydrastis canadensis) was once a common plant found in woods in the eastern and midwestern United States. Native Americans used the root for a variety of medicinal applications, including skin diseases, ulcers, and gonorrhea. Recent uses include the treatment of colds and other respiratory tract infections, infectious diarrhea, eye infections, vaginitis, wounds, canker sores, and cancer.

Goldenseal was once reported to mask the appearance of drugs in the urine of patients wanting to hide drug abuse but this claim has since been proved false. The roots and leaves of goldenseal are dried and are available as capsules, tablets, salves, and tinctures. Two of the active ingredients in goldenseal are berberine and hydrastine, which are reported to have antibacterial properties.

When used topically or locally, goldenseal is claimed to be of value in treating bacterial and fungal skin infections and oral conditions such as gingivitis and thrush. As an eyewash, it can soothe inflamed eyes. Considered safe for most people, it is contraindicated in pregnancy and hypertension. Hypertension: Pregnancy and drug use

RELATED;

1.  GINSENG FOR CARDIOVASCULAR DISEASE  

2.  GARLIC FOR CARDIOVASCUAR DISEASE

REFERENCES

PHARMACOKINETICS

 

INTRODUCTION: The term pharmacokinetics is derived from the root words pharmaco, which means “medicine,” and kinetics, which means “movement or motion.” Pharmacokinetics is thus the study of drug movement throughout the body. In practical terms, it describes how the body deals with medications. Pharmacokinetics is a core subject in pharmacology, and a firm grasp of this topic allows the medical professionals to better understand and predict the actions and side effects of medications in patients. Drugs face numerous obstacles in reaching their target cells.  When we are addressing pharmacokinetic aspects of a drug, we shall be looking at its absorption from the site of injection or administration, distribution in the body tissues, metabolism and then it excretion from the body.

ABSORPTION OF DRUGS:  For most medications, the greatest barrier is crossing the many membranes that separate the drug from its target cells. A drug taken by mouth, for example, must cross the plasma membranes of the mucosal cells of the gastrointestinal tract and the capillary endothelial cells to enter the bloodstream. The plasma membrane

To leave the bloodstream, the drug must again cross capillary cells, travel through the interstitial fluid, and depending on the mechanism of action, the drug may also need to enter target cells and cellular organelles such as the nucleus, which are surrounded by additional membranes.  These are examples of just some of the barriers that a drug must successfully penetrate before it can produce a response. 

METABOLISM OF DRUGS:  While moving toward target cells and passing through the various membranes, drugs are subjected to numerous physiological processes. For medications given by the enteral route, stomach acid and digestive enzymes often act to break down the drug molecules. Enzymes in the liver and other organs may chemically change the drug molecule to make it less active.  If the drug is seen as foreign by the body, phagocytes may attempt to remove it, or an immune response may be triggered. 

DRUG EXCRETION:  The kidneys, large intestine, and other organs attempt to excrete the medication from the body. These examples illustrate pharmacokinetic processes: how the body handles medications. The many processes of pharmacokinetics are grouped into four categories: absorption, distribution, metabolism, and excretion as we have briefly seen here, and we shall be seeing in our next discussions in details.

RELATED;

1.  ROUTES OF DRUG ADMINISTRATION  

2.  BIOAVAILABILITY

3.  DYNAMICS OF DRUGS AND THE HUMAN BODY

4.  DRUG METABOLISM

5.  THE PLASMA MEMBRANE

6.  PHARMACOLOGY AND THERAPEUTICS

REFERENCES

MACROPHAGES AND NEUTROPHILS

 

INTRODUCTION: Many of the cells of the immune system have a phagocytic ability, at least at some point during their life cycles. Phagocytosis is an important and effective mechanism of destroying pathogens during innate immune responses. Innateimmunity

The phagocyte takes the organism inside itself as a phagosome, which subsequently fuses with a lysosome and its digestive enzymes, effectively killing many pathogens. On the other hand, some bacteria including Mycobacteria tuberculosis, the cause of tuberculosis, may be resistant to these enzymes and are therefore much more difficult to clear from the body. Mycobacteriatuberculosis

Macrophages, neutrophils, and dendritic cells are the major phagocytes of the immune system.

MACROPHAGES: A macrophage is an irregularly shaped phagocyte that is amoeboid in nature and is the most versatile of the phagocytes in the body. Macrophages move through tissues and squeeze through capillary walls using pseudopodia. They not only participate in innate immune responses but have also evolved to cooperate with lymphocytes as part of the adaptive immune response. Adaptiveimmunity

Macrophages exist in many tissues of the body, either freely roaming through connective tissues or fixed to reticular fibers within specific tissues such as lymph nodes. When pathogens breach the body’s barrier defenses, macrophages are the first line of defense. They are called different names, depending on the tissue: Kupffer cells in the liver, histiocytes in connective tissue, and alveolar macrophages in the lungs.

NEUTROPHILS: A neutrophil is a phagocytic cell that is attracted via chemotaxis from the bloodstream to infected tissues. These spherical cells are granulocytes. A granulocyte contains cytoplasmic granules, which in turn contain a variety of vasoactive mediators such as histamine. In contrast, macrophages are agranulocytes. An agranulocyte has few or no cytoplasmic granules. Whereas macrophages act like sentries, always on guard against infection, neutrophils can be thought of as military reinforcements that are called into a battle to hasten the destruction of the enemy. Although, usually thought of as the primary pathogen-killing cell of the inflammatory process of the innate immune response, new research has suggested that neutrophils play a role in the adaptive immune response as well, just as macrophages do.

MONOCYTES: A monocyte is a circulating precursor cell that differentiates into either a macrophage or dendritic cell, which can be rapidly attracted to areas of infection by signal molecules of inflammation.

RELATED;

1.  RED BLOOD CELLS  

2.  LEUKOCYTES

3. ANATOMY AND PHYSIOLOGY

REFERENCES

MEGALOBLASTIC ANEMIA

 

INTRODUCTION: In the anemias caused by deficiencies of vitamin B12 or folic acid, identical bone marrow and peripheral blood changes occur because both vitamins are essential for normal DNA synthesis. DNA,the genetic material

PATHOPHYSIOLOGY:

Folic Acid Deficiency: Folic acid is stored as compounds referred to as folates. The folate stores in the body are much smaller than those of vitamin B12, and they are quickly depleted when the dietary intake of folate is deficient (within 4 months). Folate deficiency occurs in people who rarely eat uncooked vegetables. Alcohol increases folic acid requirements; folic acid requirements are also increased in patients with chronic hemolytic anemias and in women who are pregnant. Some patients with malabsorptive diseases of the small bowel may not absorb folic acid normally.

Vitamin B12 Deficiency: A deficiency of vitamin B12 can occur in several ways. Inadequate dietary intake is rare but can develop in strict vegetarians who consume no meat or dairy products. Faulty absorption from the GI tract is more common, as with conditions such as Crohn’s disease or after ileal resection or gastrectomy. Another cause is the absence of intrinsic factor. A deficiency may also occur if disease involving the ileum or pancreas impairs absorption. The body normally has large stores of vitamin B12, so years may pass before the deficiency results in anemia.

Clinical Manifestations: Symptoms of folic acid and vitamin B12 deficiencies are similar, and the two anemias may coexist. Symptoms are progressive, although the course of illness may be marked by spontaneous partial remissions and exacerbations. Gradual development of signs of anemia (weakness, listlessness, and fatigue). Possible development of a smooth, sore, red tongue and mild diarrhea (pernicious anemia). Mild jaundice, vitiligo, and premature graying. Confusion may occur; more often, paresthesias in the extremities and difficulty keeping balance; loss of position sense. Lack of neurologic manifestations with folic acid deficiency alone. Without treatment, patients die, usually as a result of heart failure secondary to anemia.

ASSESSMENT AND DIAGNOSTIC FINDINGS: Schilling test (primary diagnostic tool): Complete blood cell count (Hgb value as low as 4 to 5 g/dL, WBC count 2,000 to 3,000 mm3 , platelet count fewer than 50,000 mm3 ; very high MCV, usually exceeding 110 m3 ). Serum levels of folate and vitamin B12 (folic acid deficiency and deficient vitamin B12)

MEDICAL MANAGEMENT: Folic Acid Deficiency: Increase intake of folic acid in patient’s diet and administer 1 mg folic acid daily. Administer IM folic acid for malabsorption syndromes. Prescribe additional supplements as necessary, because the amount in multivitamins may be inadequate to fully replace deficient body stores. Prescribe folic acid for patients with alcoholism as long as they continue to consume alcohol.

MEDICAL MANAGEMENT: Vitamin B12 Deficiency: Provide vitamin B12 replacement: Vegetarians can prevent or treat deficiency with oral supplements with vitamins or fortified soy milk; when the deficiency is due to the more common defect in absorption or the absence of intrinsic factor, replacement is by monthly IM injections of vitamin B12. A small amount of an oral dose of vitamin B12 can be absorbed by passive diffusion, even in the absence of intrinsic factor, but large doses (2 mg/day) are required if vitamin B12 is to be replaced orally. To prevent recurrence of pernicious anemia, vitamin B12 therapy must be continued for life.

RELATED;

1.  CONDITIONS OF ANEMIA  

2.  COMPOSITION OF BLOOD

3.  MEDICAL CONDITIONS

REFERENCES

MYOCARDIAL INFARCTION

 

INTRODUCTION: Myocardial infarction (MI) is the formal term for what is commonly referred to as a heart attack. It normally results from a lack of blood flow (ischemia) and oxygen (hypoxia) to a region of the heart, resulting in death of the cardiac muscle cells. An MI often occurs when a coronary artery is blocked by the buildup of atherosclerotic plaque consisting of lipids, cholesterol and fatty acids, and white blood cells, primarily macrophages. It can also occur when a portion of an unstable atherosclerotic plaque travels through the coronary arterial system and lodges in one of the smaller vessels. The resulting blockage restricts the flow of blood and oxygen to the myocardium and causes death of the tissue.  MIs may be triggered by excessive exercise, in which the partially occluded artery is no longer able to pump sufficient quantities of blood, or severe stress, which may induce spasm of the smooth muscle in the walls of the vessel.

SIGNS AND SYMPTOMS: In the case of acute MI, there is often sudden pain beneath the sternum (retrosternal pain) called angina pectoris, often radiating down the left arm in males but not in female patients. Until this anomaly between the sexes was discovered, many female patients suffering MIs were misdiagnosed and sent home. In addition, patients typically present with difficulty breathing and shortness of breath (dyspnea), irregular heartbeat (palpations), nausea and vomiting, sweating (diaphoresis), anxiety, and fainting (syncope), although not all of these symptoms may be present. Many of the symptoms are shared with other medical conditions, including anxiety attacks and simple indigestion, so differential diagnosis is critical. It is estimated that between 22 and 64 percent of MIs present without any symptoms.

ASSESSMENT AND DIAGNOSIS: An MI can be confirmed by examining the patient’s ECG, which frequently reveals alterations in the ST and Q components. Some classification schemes of MI are referred to as ST-elevated MI (STEMI) and non-elevated MI (non-STEMI). In addition, echocardiography or cardiac magnetic resonance imaging may be employed.

Blood tests: Common blood tests indicating an MI include elevated levels of creatine kinase MB (an enzyme that catalyzes the conversion of creatine to phosphocreatine, consuming ATP) and cardiac troponin (the regulatory protein for muscle contraction), both of which are released by damaged cardiac muscle cells. 

MEDICAL MANAGEMENT: Immediate treatments for MI are essential and include administering supplemental oxygen, aspirin that helps to break up clots, and nitroglycerine administered sublingually (under the tongue) to facilitate its absorption. Despite its unquestioned success in treatments and use since the 1880s, the mechanism of nitroglycerine is still incompletely understood but is believed to involve the release of nitric oxide, a known vasodilator, and endothelium-derived releasing factor, which also relaxes the smooth muscle in the tunica media of coronary vessels.

Longer-term treatments include injections of thrombolytic agents such as streptokinase that dissolve the clot, the anticoagulant heparin, balloon angioplasty and stents to open blocked vessels, and bypass surgery to allow blood to pass around the site of blockage. If the damage is extensive, coronary replacement with a donor heart or coronary assist device, a sophisticated mechanical device that supplements the pumping activity of the heart, may be employed.

RISK FACTORS: Important risk factors for MI include cardiovascular disease, age, smoking, high blood levels of the low-density lipoprotein (LDL, often referred to as “bad” cholesterol), low levels of high-density lipoprotein (HDL, or “good” cholesterol), hypertension, diabetes mellitus, obesity, lack of physical exercise, chronic kidney disease, excessive alcohol consumption, and use of illegal drugs.

RELATED;

1. HYPERTENSION  2. DIABETES MELLITUS  3. OBESITY

REFERENCES

PROCHLORPERAZINE

Therapeutic Class: Antiemetic

Pharmacologic Class: Phenothiazine antipsychotic

ACTIONS AND USES: Prochlorperazine is a phenothiazine, a class of drugs usually prescribed for psychoses. The phenothiazines are the largest group of drugs prescribed for severe nausea and vomiting, and prochlorperazine is the most frequently prescribed antiemetic in its class. Prochlorperazine acts by blocking dopamine receptors in the brain, which inhibits signals to the vomiting center in the medulla. Dopamine

As an antiemetic, it is frequently given by the rectal route, where absorption is rapid. It is also available in tablet, extended-release capsule, and IM formulations.

ADMINISTRATION ALERTS: Administer 2 hours before or after antacids and antidiarrheals. Pregnancy category C.

ADVERSE EFFECTS: Prochlorperazine produces dose-related anticholinergic side effects such as dry mouth, sedation, constipation, orthostatic hypotension, and tachycardia. When used for prolonged periods at higher doses, extrapyramidal symptoms resembling those of Parkinson's disease are a serious concern, especially in older patients.

Contraindications: This drug should not be used in patients with hypersensitivity to phenothiazines, in comatose patients, or in the presence of profound CNS depression. It is also contraindicated in children younger than age 2. Patients with narrow-angle glaucoma, bone marrow suppression, or severe hepatic or cardiac impairment should not take this drug.

INTERACTIONS: Drug-Drug: Prochlorperazine interacts with alcohol and other CNS depressants to cause additive sedation. Antacids and antidiarrheals inhibit the absorption of prochlorperazine. When taken with phenobarbital, metabolism of prochlorperazine is increased. Use with tricyclic antidepressants may produce increased anticholinergic and hypotensive effects.

RELATED;

1. NAUSEA AND VOMITING  

2. ENTERIC NERVOUS SYSTEM

3.  PHARMACOLOGY AND THERAPEUTICS

REFERENCES

LITERATURE REVIEW

 

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

1.  Understand the importance of literature in medical research methods

2.  Identify the different sources of literature when it comes to medical research

INTRODUCTION: Researchers almost never conduct a study in an intellectual vacuum; their studies are usually undertaken within the context of an existing knowledge base. Researchers undertake a literature review to familiarize themselves with that knowledge base although, some qualitative researchers deliberately bypass an in-depth literature search before entering the field to avoid having their inquiries constrained or biased by prior work on the topic. Qualitative research: Bias  

In our discussion here, we are looking at the functions that a literature review can play in a research project and the kinds of material covered in a literature review. Suggestions are provided on finding references, reading research reports, recording information, and organizing and drafting a written review.

PURPOSES OF A LITERATURE REVIEW: Literature reviews can serve a number of important functions in the research process as well as important functions for health workers seeking to develop an evidence-based practice. For researchers, acquaintance with relevant research literature and the state of current knowledge can help with the following:

1. Identification of a research problem and development or refinement of research questions or hypotheses.  In most cases if the medical research student have failed to generate a research problem, a very immediate solution will be reading some literature concerning some of the most commonly encountered problems.  For example, I have recently written about the most prevailing researchable problems in Uganda 2023 and you can read about them from here.

2. Orientation to what is known and not known about an area of inquiry, to ascertain what research can best make a contribution to the existing base of evidence.

3. Determination of any gaps or inconsistencies in a body of research.

4. Determination of a need to replicate a prior study in a different setting or with a different study population.

5. Identification or development of new or refined clinical interventions to test through empirical research.

6. Identification of relevant theoretical or conceptual frameworks for a research problem.

7. Identification of suitable designs and data collection methods for a study.

8. For those developing research proposals for funding, identification of experts in the field who could be used as consultants.

9. Assistance in interpreting study findings and in developing implications and recommendations.

A literature review helps to lay the foundation for a study, and can also inspire new research ideas. A literature review also plays a role at the end of the study, when researchers are trying to make sense of their findings. Most research reports include summaries of relevant literature in the introduction. A literature review early in the report provides readers with a background for understanding current knowledge on a topic and illuminates the significance of the new study. Written research reviews are also included in research proposals that describe what a researcher is planning to study and how the study will be conducted.

RELATED;

1. WRITING A RESEARCH PROPOSAL

2. MOST PREVAILING RESEARCH PROBLEMS 2023

REFERENCES

PARKINSON’S DISEASE

 

INTRODUCTION: Parkinson’s disease is a slowly progressive degenerative neurologic disorder affecting the brain centers that are responsible for control and regulation of movement. The degenerative or idiopathic form of Parkinson’s disease is the most common; there is also a secondary form with a known or suspected cause. The cause of the disease is mostly unknown but research suggests several causative factors (eg, genetics, atherosclerosis, viral infections, head trauma). The disease usually first appears in the fifth decade of life and is the fourth most common neurodegenerative disease.

PATHOPHYSIOLOGY: Parkinson’s disease is associated with decreased levels of dopamine resulting from destruction of pigmented neuronal cells in the substantia nigra in the basal ganglia region of the brain. Dopamine  The loss of dopamine stores in this area of the brain results in more excitatory neurotransmitters than inhibitory neurotransmitters, leading to an imbalance that affects voluntary movement. Cellular degeneration causes impairment of the extrapyramidal tracts that control semiautomatic functions and coordinated movements; motor cells of the motor cortex and the pyramidal tracts are not affected.

CLINICAL MANIFESTATIONS: The cardinal signs of Parkinson’s disease are tremor, rigidity, bradykinesia (abnormally slow movements), and postural instability. Resting tremors: a slow, unilateral turning of the forearm and hand and a pill-rolling motion of the thumb against the fingers; tremor at rest and increasing with concentration and anxiety. Resistance to passive limb movement characterizes muscle rigidity; passive movement may cause the limb to move in jerky increments (lead-pipe or cog-wheel movements); stiffness of the arms, legs, face, and posture are common; involuntary stiffness of passive extremity increases when another extremity is engaged in voluntary active movement. Impaired movement: Bradykinesia includes difficulty in initiating, maintaining, and performing motor activities. Loss of postural reflexes, shuffling gait, loss of balance (difficulty pivoting); postural and gait problems place the patient at increased risk for falls.

OTHER CHARACTERISTICS: Autonomic symptoms that include excessive and uncontrolled sweating, paroxysmal flushing, orthostatic hypotension, gastric and urinary retention, constipation, and sexual dysfunction. Psychiatric changes may include depression, dementia, delirium, and hallucinations; psychiatric manifestations may include personality changes, psychosis, and acute confusion. Auditory and visual hallucinations may occur. Hypokinesia (abnormally diminished movement) is common. As dexterity declines, micrographia (small handwriting) develops. Masklike facial expression. Dysphonia (soft, slurred, low-pitched, and less audible speech).

ASSESSMENT AND DIAGNOSTIC METHODS: Patient’s history and presence of two of the four cardinal manifestations: tremor, rigidity, bradykinesia, and postural changes. Positron emission tomography (PET) and single photon emission computed tomography (SPECT) scanning have been helpful in understanding the disease and advancing treatment. Medical history, presenting symptoms, neurologic examination, and response to pharmacologic management are carefully evaluated when making the diagnosis.

MEDICAL MANAGEMENT: Goal of treatment is to control symptoms and maintain functional independence; no approach prevents disease progression.

PHARMACOLOGIC THERAPY: Levodopa is the most effective agent and the mainstay of treatment. Anticholinergic agents to control tremor and rigidity. Amantadine hydrochloride (Symmetrel), an antiviral agent, to reduce rigidity, tremor, and bradykinesia. Dopamine agonists (eg, pergolide, bromocriptine mesylate), ropinirole, and pramipexole are used to postpone the initiation of carbidopa and levodopa therapy. Monoamine oxidase inhibitors (MAOIs) to inhibit dopamine breakdown. Catechol-O-methyltransferase (COMT) inhibitors to reduce motor fluctuation. Antidepressant drugs. Antihistamine drugs to allay tremors.

RELATED;

1.  STROKE

2.  MEDICAL CONDITIONS

REFERENCES