Although depression is a disorder of unknown cause, many hypotheses have tried to explain the pathophysiology of depression.  Among the most prominent of these hypotheses are those mentioned in the following map of (Phathophysiologic Hypotheses of Depression):

Depression Pathophysiology Concept Map

The first one is “Catecholamines Hypothesis” which proposes that depression is linked to decreased brain levels of the neurotransmitters norepinephrine (NE), serotonin (5-HT), and/or dopamine (DA).  But it has been observed that the administration of antidepressants causes immediate increase in the synaptic levels of monoamines (NE and 5-HT)producing antidepressants adverse effects, while the antidepressive effects are not observed until after few weeks of dosing.  That observation is explained by the second hypothesis which is (Receptor Sensitivity Hypothesis).

•  how antidepressants work (i.e. mechanisms of action) and
• what adverse effects they produce

I hope you gain value from this map, and I look forward to hearing your feedback.

• In viral rhinosinusitis; symptoms last 7 – 10 days and not worsening.  (True)
• In acute bacterial RS; symptoms ≥ 7 days; include: maxillary facial/tooth pain (especially unilateral) with deterioration 10 days after initial improvement.  (True)
• Yellow or green colored nasal discharge means bacterial but not viral rhinosinusitis.  (False)

Explanation:

Bacterial versus Viral Rhinosinusitis

References as numbered in the image:
(1) "Adult Appropriate Antibiotic Use Summary: Physician Information Sheet 
(Adults)." Centers for Disease Control and Prevention. N.p., 01 Sep 2010. 
Web. 17 Nov 2011.
(5) Fauci, Anthony S., First , Eugene Braunwald, et al. "Otitis Media."  
Harrison's Practice Answers on Demand. McGraw-Hill Companies, 2007.
(8) Fauci, Anthony S., First , Eugene Braunwald, et al. "Sinusitis."  
Harrison's Practice Answers on Demand. McGraw-Hill Companies, 2007.
(12) "Clinical Practice Guideline for Sinusitis Treatment (Rhinosinusitis)."  
Medical Associates. Medical Associates, Feb 2011. Web. 24 Nov 2011. 
<http://www.mahealthcare.com>.
(13) EXECUTIVE SUMMARY - Clinical practice guideline on adult sinusitis - 
Richard M. Rosenfeld, MD, MPH, Brooklyn, NY.

This image is part of (Upper Respiratory Tract Infections Concept Map).

Stroke Diagnostic Tests Mind Map

This mind map is part of the upcoming map of (Stroke).  (Stroke Diagnostic Tests Mind Map) includes mechanisms of action, indications, advantages and disadvantages of tests used to diagnose stroke and may be other cardivascular disorders and to differentiate between ischemic and hemorrhagic types of stroke.

Tests which are included in this mind map are categorized as:

A] Tests that View the Brain, Skull or Spinal Cord;

• Computed Tomography (CT) / Computed Axial Tomography (CAT)
• Magnetic Resonance Imaging (MRI)
• Positron Emission Tomography (PET)

B] Tests that View the Heart or Check its Function;

• Electrocardiogram (ECG)
• Echocardiogram

C] Tests that View the Blood Vessels that Supply the Brain;

• Cerebral Angiography
• Carotid Doppler Study
• Transcranial Doppler (TCD)

I hope you find this post valuable and I’m looking forward to know you opinion.

The answers will be posted in a few days.

Subscribe to this blog (on the right) or Register by your email to Zoom out – Pharmacotherapy website to get the answers.  Then, take few seconds to tell your friends about pharmacotherapy questions and answers .. and share this post.

Upper Respiratory Tract Infections Concept Map

Map Explanation:

This map represents the 3 main upper respiratory tract infections which are: otitis media, rhinosinusitis, and pharyngitis.  For each disease,  the map links between pathophysiology, causative microorganisms, how to differentiate between viral and bacterial infections, and how to manage bacterial infections using antibiotics.  The aim of this map is to direct clinicians towards better antibiotic use in order to avoid microbial resistance to antibiotics.

Otitis media concept map

Full map and explanation is presented here

Rhinosinusitis (sinusitis) concept map

This map starts by risk factors and associated conditions of rhinosinusitis that lead to inflammation of the nasal and sinus mucosa and finally to acute rhinosinusitis.  This is followed by possible factors for developing chronic rhinosinusitis.  Some signs and symptoms are stated to help differentiating between viral from bacterial rhinosinusitis.  Nonpharmacological treatment of rhinosinusitis facilitates sinus drainage and relieves symptoms.  Regarding  acute bacterial rhinosinusitis, nonsevere cases could be observed for 7 days with administration of nonpharmacological treatment.  On the other hand, moderately severe to severe cases should be treated using antibiotics.

Pharyngitis concept map

This part concentrates on acute pharyngitis, the main etiology is infectious, including mainly viral infection and to a smaller extent infection by Group A beta hemolytic streptococcus (GABHS).  Although, it is difficult to differentiate clinically, there are some signs that might be helpful to differentiate viral from GAS pharyngitis.  Diagnosis of pharyngitis depends on the 4 Centor criteria, Rapid Antigen Detection Test (RADT), and Throat Culture.  Management of viral pharyngitis doesn’t require antibiotics.   Antibiotics (penicillin, or erythromycin for a penicillin-allergic patient) are necessary in managing GAS pharyngitis in order prevent acute rheumatic fever.

The full map (without copyright watermarks) is available as a printable version that enables you to print the map on nine A4 papers and make a poster of them, so you’ll be able to study it as one unit without computer screen limits.  Get Upper Respiratory Tract Infections Concept Map – PRINTABLE VERSION.

If you live in Egypt, to get this map, please contact me on mahatef@zoomout-ph.com for more suitable payment methods.

The comparison between the symptoms of cold, allergy, and sinusitis would help referral bodies – as pharmacists – be more informative to their patients.  Open Is-it-cold-allergy-or-sinusitis-fact-sheet?  fact sheet and don’t forget to subscribe to this blog to get my next concept map (Upper Respiratory Tract Infection).

Otitis Media Concept Map

Map Explanation

Otitis media (OM) is the second most common disease of childhood, after upper respiratory infection (URI). OM is also the most common cause for childhood visits to a physician’s office.

(Definition)

It is and inflammatory condition of the middle ear that results from dysfunction of the eustachian tube in association with local infection.   This definition is followed by otitis media risk factors that help in predisposing the disease.

(Pathophysiology)

When a local infection like upper respiratory infections or chronic rhinosinusitis occurs, tissues of eustachian tube swell, so fluid is trapped in it.  The fluid may be infected by pathogens causing acute otitis media (AOM) in which ear infection pushes eardrum causing the signs and symptoms of acute otitis media (e.g. red, sore, thickened, bulging, immobile eardrum and pain).  But if the fluid was not infected, this would result in otitis media with effusion (OME), in which fluid is in the middle ear without signs or symptoms of infection.

Acute otitis media is caused mainly by viruses.  Among the most common bacteria that cause AOM there are: Streptococcus pneumoniae,  Haemophilus influenzae, and Moraxella catarrhalis.

Management of acute otitis media includes:

• Symptomatic treatment using analgesics and antipyretics.
• Observation versus antibiotic use.  This is should be determined according to “Criteria for Initial Antibacterial Treatment” table on the right of the map.
• Follow-up after at least 3 months.
• Management of recurrent AOM.

If antibiotic therapy is chosen for managing AOM, then the antibiotic of choice is amoxicillin, because it has the best pharmacodynamic profile (time above the minimum inhibitory concentration [MIC₉₀] in the middle ear fluid for more than 40% of the dosing interval), it is of narrow spectrum for avoiding microbial resistance, and because it is of low cost and high safety.

If the symptoms persist or worsen 48-72 hours after the administration of amoxicillin or observation, or exposure to antibiotics within 30 days, then there is a need to use an agent that acts against β-lactamase-producing H. influenzae, M. catarrhalis and/or drug resistant S. pneumoniae.  So, another course of high-dose amoxicillin and clavulanate potassium or azithromycin would be required.

Consider patients who are allergic to penicillin (suitable options are stated in the map).

Ceftriaxone injection (50 mg/kg/d), 1-day course could be used in certain cases (stated in the map).

According to University of Michigan Health System guidelines,

Otitis media with effusion (OME) should be managed by:

• Clinical reevaluation at 3 month intervals.
• Referral to otolaryngology for persistent abnormal findings or complications like: hearing loss or language delay.  Children with an asymptomatic middle ear effusion (no developmental or behavioral problems) can be followed without referral.
• Parental education regarding approaches to maximizing language.

(Diagnosis)

It is important to distinguish between AOM and OME cases for making therapeutic decisions and to avoid unnecessary prescription of antibiotics in OME cases.  Thus, diagnostic certainty for AOM is based on all 3 of the following criteria (as stated by American Academy of Pediatrics and American Academy of Family Physicians): acute onset, middle ear effusion (MEE), and middle ear inflammation.  On the other hand, OME is fluid in the middle ear without signs or symptoms of infection.

I hope that you find this map helpful in your study and practice.  And I’m looking forward to hearing your opinion. Get the printable version of this map.

Otitis media concept map is a part of the larger map of Upper Respiratory Tract Infections.

Hypertension - Pathophysiology and Treatment Concept Map

Map Explanation:

This map shows you the links between the mechanisms of hypertension and how antihypertensive agents work.   Blood pressure is a product of of cardiac output and total peripheral vascular resistance, so the increase in one or both of these factors leads to hypertension.   Blood pressure is controlled by neural and humoral systems which include:

• Renin-Angiotensin Aldosterone System,
•  Increased sympathetic discharge,
•  Increased sodium  and chloride concentrations in extracellular fluid volume, and
•  Vasodilators deficiency

Hypertension pathophysiology

This part of the map explains each of hypertension contributing factors including the inter-related links between them.

Antihypertensive agents are stated around the pathophysiology part to illustrate the effect or the site of action of each agent on the pathophysiology using dotted lines.

Hypertension pathophysiology part of the map starts with Renin Angiotensin System (RAS) that ends by the production of angiotensin II which is a vasoconstrictor that stimulates the autonomic centers in the brain resulting in increased sympathetic discharge.  It also stimulates aldosterone and antidiuretic hormone.  Antidiuretic hormone is also stimulated by increased sodium and chloride concentration in the extracellular fluid, causing sodium and water retention and increase in peripheral vascular resistance.

The increase in the sympathetic discharge increases heart rate and contractility, so increasing cardiac output.  Norepinephrine causes vasoconstriction and induces kidney sodium retention resulting in an increase in peripheral vascular resistance.

Another factor for the development of hypertension is the deficiency in the synthesis of vasodilators as nitric oxide and prostacyclin and the degradation of bradykinin which is also a vasodilator, in the face of normal release of endothelin and the increased release of Angiotensin I and Angiotensin II which are vasoconstrictors.

Pharmacological treatment of hypertension

It includes the following agents:

ACE inhibitors mechanism of action includes inhibiting Angiotensin Converting Enzyme (ACE), blocking the degradation of bradykinin and stimulating the synthesis of some vasodilators, so decreasing tissue peripheral resistance.

Angiotensin II Receptor Blockers (ARB) block angiotensin 2 receptors.

The mechanism of action of diuretics includes decreasing plasma and stroke volume and so decreasing blood volume which in turn decreases cardiac output.  Thiazide diuretics also decrease peripheral vascular resistance by mobilizing Na & water from arteriolar walls and by acting as direct vasodilators on blood vessels.

Aldosterone antagonists are potassium sparing diuretics that competitively bind to aldosterone receptors and so decreasing both cardiac output and peripheral vascular resistance.

Direct vasodilators work directly on blood vessels.

Dihydropyridine calcium channel blockers block voltage-gated calcium channels (VGCC) in blood vessels causing vasodilatation.  While, nondihydropyridine calcium channel blockers block voltage-gated calcium channels (VGCC) in cardiac muscles, so they act as negative chronotropic, negative dromotropic and negative inotropic agents and cause decrease in cardiac output.

Sympathetic depressants act on different sites to decrease the sympathetic discharge.  Among the commonly used sympathetic depressants are beta blockers.  Beta blockers also inhibit renin release so decrease tissue peripheral resistance in addition to their negative inotropic and negative chronotropic affects that decrease cardiac output.

Due to the large size of the map, you might find it difficult for printing or studying from the computer screen. This is why the printable version of (Hypertension – Pathophysiology and Treatment Concept Map) is released. Now, you will be able to print the map on seven A4 papers and study it as one unit. Get Hypertension – Pathophysiology and Treatment Concept Map – PRINTABLE VERSION.
If you live in Egypt, to get this map, please contact me on mahatef@zoomout-ph.com for more suitable payment methods.

This was an explanation for hypertension pathophysiology linked by mechanisms of action of antihypertensive agents and effects on cardiac output and/or peripheral vascular resistance and consequently blood pressure.  I hope you gain value from this map, and I look forward to hearing your feedback.

Explanation:

Asthma Epidemiology:

Age

• All ages affected, but more prevalent in early life
  • Peak age: 3 years
• ~50% of cases develop before 10 years of age.
• Another one-third of cases occur before 40 years of age.

Reference:

Fauci, Anthony S, et al. Harrison's Practice Answers on Demand. 
McGraw-Hill Companies, 2007. Web.

The answer will be posted in a few days.

Subscribe to this blog or Register by your email to Zoom out – Pharmacotherapy website to get the answer.  Then, take few seconds to tell your friends about pharmacotherapy questions and answers .. and share this below.