📚 NEET MDS Lecture Notes
Candidiasis
General PathologySystemic Candidiasis (Candidosis; Moniliasis)
Invasive infections caused by Candida sp, most often C. albicans, manifested by fungemia, endocarditis, meningitis, and/or focal lesions in liver, spleen, kidneys, bone, skin, and subcutaneous or other tissues.
Infections due to Candida sp account for about 80% of all major systemic fungal infections.
Symptoms and Signs
Esophagitis is most often manifested by dysphagia. Symptoms of respiratory tract infections are nonspecific, such as cough. Vaginal infections cause itching, burning, and discharge. Candidemia usually causes fever, but other symptoms are typically nonspecific. Sometimes, a syndrome develops resembling bacterial sepsis, with a fulminating course that may include shock, oliguria, renal shutdown, and disseminated intravascular coagulation.
Hematogenous endophthalmitis starts as white retinal plaques that can cause blindness as destructive inflammation progresses, extending to opacify the vitreous and causing potentially irreversible scarring. Most often, there are no symptoms in early stages of Candida endophthalmitis. If treatment is not begun before symptoms appear, significant or even total loss of vision is likely to occur in the affected eye. In neutropenic patients, eye involvement is more often manifested by retinal hemorrhages; papulonodular, erythematous, and vasculitic skin lesions may also develop.
Antihypertensives drugs Classification
PharmacologyAntihypertensives Drugs
CATEGORIES
I. Diuretics to reduce blood volume
Chlorothiazide (Diuril)
II. Drugs that interfere with the Renin-Angiotensin System
A. Converting enzyme inhibitors Captopril , enalapril, Lisinopril
B. Angiotensin receptor antagonists Saralasin Losartan
III. Decrease peripheral vascular resistance and/or cardiac output
A. Directly acting vasodilators
1. calcium channel blockers Nifedipine , Diltiazem, amlodipine
2. potassium channel activators Minoxidil
3. elevation of cGMP Nitroprusside
4. others Hydralazin e
B. Sympathetic nervous system depressants
1. α-blockers Prazosin, phentolamine, phenoxybenzamine
2. β-blockers Propranolol ,Metoprolol, atenolol
3. norepinephrine synthesis inhibitors Metyrosine
4. norepinephrine storage inhibitors Reserpine
5. transmitter release inhibitors Guanethidine
6. centrally acting: decrease
sympathetic outflow Clonidine , methyldopa
Sympatholytics And Alpha Adrenergic Blockers
PharmacologySympatholytics And Alpha Adrenergic Blockers
Types
1. Alpha 1-receptor blockers: prazocin,doxazocin.
2. Centrally acting alpha 2- agonists: methyldopa, clonidine.
3. Peripherally acting adrenergic antagonists: reserpine.
4. Imidazoline receptor agonists: rilmenidine, moxonidine.
Advantages
- Alpha1- receptor blockers and imidazoline receptor agonists improve lipid profile and insulin sensitivity.
- Methyldopa: increases renal blood flow. Drug of choice during pregnancy.
- Reserpine: neutral metabolic effects and cheap.
Indications:
- Diabetes mellitus: alpha1- receptor blockers, imidazoline receptor agonists.
- Dyslipidemia: alpha 1- receptor blockers, imidazoline receptor agonists.
- Prostatic hypertrophy: alpha 1- receptor blockers.
- When there is a need for rapid reduction in blood pressure: clonidine.
Side Effects
- Prazocin: postural hypotension, diarrhea, occasional tachycardia, and tolerance (due to fluid retention).
- Methyldopa: sedation, hepatotoxicity, hemolytic anemia, and tolerance.
- Reserpine: depression, lethargy, weight loss, peptic ulcer, diarrhea, and impotence
- Clonidine: dry mouth, sedation, bradycardia, impotence, and rebound hypertension if stopped suddenly.
Considerations
- Prazocin, methyldopa, and reserpine should be combined with a diuretic because of fluid retention.
Direct Arterial Vasodilators
Types: hydralazine, diazoxide, nitroprusside, and minoxidil
Serotonin or 5-hydroxytryptamine
PharmacologySerotonin or 5-hydroxytryptamine (5-HT)
It is a neurotransmitter, widely distributed in the CNS, beginning in the midbrain and projecting into thalamus, hypothalamus, cerebral cortex, and spinal cord. CNS serotonin is usually an inhibitory neurotransmitter and is associated with mood, the sleep-wake cycle.
Serotonin is thought to produce sleep by inhibiting CNS activity.
In the blood, 5-HT is present in high concentration in platelets (regulator of platelets function) and also high concentration in intestine
Pharmacological effects:
Smooth muscles. 5-HT stimulates the G.I smooth muscle; it increases the peristaltic movement of intestine.
Serotonin contracts the smooth muscle of bronchi;
Blood vessels. If serotonin is injected i.v, the blood pressure usually first rises, because of the contraction of large vessels and then falls because of arteriolar dilatation. Serotonin causes aggregation of platelets.
Specific agonists
- Sumatriptan a selective 5-HT1D used in treatment of acute migraine.
- Buspirone a selective 5-HT1A used in anxiety.
- Ergotamine is a partial agonist used in migraine. It acts on 5-HT1A receptor.
Nonspecific 5-HT receptor agonist
o Dexfenfluramine used as appetite suppressant.
Specific antagonists
o Spiperone (acts on 1A receptor) and
o Methiothepin (acts on 1A, 1B, 1D receptors)