By I. Myxir. Cumberland University.
Certain general anesthetics can sensitize the myocardium to stimulation by dobutamine discount minocycline online amex, thereby increasing the risk for dysrhythmias minocycline 50mg fast delivery. Phenylephrine • Receptor specificity: alpha1 • Chemical classification: noncatecholamine Phenylephrine [Neo-Synephrine discount minocycline 50mg on line, others] is a selective alpha agonist. The1 drug can be administered locally to reduce nasal congestion and parenterally to elevate blood pressure. Also, phenylephrine can be coadministered with local anesthetics to delay anesthetic absorption. Albuterol • Receptor specificity: beta2 • Chemical classification: noncatecholamine Therapeutic Uses Asthma Albuterol [Proventil, Ventolin, VoSpire, others] can reduce airway resistance in asthma by causing beta -mediated bronchodilation. Because albuterol is2 relatively selective for beta receptors, it produces much less activation of2 cardiac beta receptors than does isoproterenol. As a result, albuterol and other1 beta -selective agents have replaced isoproterenol for therapy of asthma. Accordingly, patients should be warned not to exceed2 recommended doses because doing so may cause undesired cardiac stimulation. If dosage is excessive, albuterol can cause tachycardia by activating beta receptors1 in the heart. Ephedrine • Receptor specificity: alpha, alpha, beta, beta1 2 1 2 • Chemical classification: noncatecholamine Ephedrine is referred to as a mixed-acting drug because it activates adrenergic receptors by direct and indirect mechanisms. Owing to the development of more selective adrenergic agonists, uses for ephedrine are limited. By promoting beta2-mediated bronchodilation, ephedrine can benefit patients with asthma. By activating a combination of alpha and beta receptors, ephedrine can improve hemodynamic status in patients with shock. Because ephedrine activates the same receptors as epinephrine, both drugs share the same adverse effects: hypertension, dysrhythmias, angina, and hyperglycemia. All of the drugs presented here are also discussed in chapters that address specific applications (Table 13. Other uses include control of superficial bleeding, delay of local anesthetic absorption, and management of cardiac arrest. Identifying High-Risk Patients Epinephrine must be used with great caution in patients with hyperthyroidism, cardiac dysrhythmias, organic heart disease, or hypertension. Administration Considerations The concentration of epinephrine solutions varies according to the route of administration (see Table 13. To avoid serious injury, check solution strength to ensure that the concentration is appropriate for the intended route. By stimulating the heart, epinephrine can cause anginal pain, tachycardia, and dysrhythmias. By activating alpha receptors on blood vessels, epinephrine can cause intense1 vasoconstriction, which can result in severe hypertension. If extravasation occurs, infiltrate the region with phentolamine to minimize injury. When combined with certain general anesthetics, epinephrine can induce cardiac dysrhythmias. Baseline Data Full assessment of cardiac, hemodynamic, and renal status is needed. Identifying High-Risk Patients Dopamine is contraindicated for patients with tachydysrhythmias or ventricular fibrillation. Caution is also needed in patients with angina pectoris and in those receiving tricyclic antidepressants or general anesthetics. Administration Considerations Administer by continuous infusion, employing an infusion pump to control flow rate. If extravasation occurs, stop the infusion immediately and infiltrate the region with an alpha-adrenergic antagonist (e. Ongoing Monitoring and Interventions Evaluating Therapeutic Effects Monitor cardiovascular status continuously. By stimulating the heart, dopamine may cause anginal pain, tachycardia, or dysrhythmias. Baseline Data Full assessment of cardiac, renal, and hemodynamic status is needed. Caution is also needed in patients with angina pectoris and in those receiving tricyclic antidepressants or general anesthetics. Minimizing Adverse Effects Major adverse effects are tachycardia and dysrhythmias. When combined with certain general anesthetics, dobutamine can cause cardiac dysrhythmias. With one exception, all of the adrenergic antagonists produce reversible (competitive) blockade. Unlike many adrenergic agonists, which act at alpha- and beta-adrenergic receptors, most adrenergic antagonists are more selective. As a result, the adrenergic antagonists can be neatly divided into two major groups (Table 14. We begin by discussing the therapeutic and adverse effects that can result from alpha- and beta-adrenergic blockade, after which we discuss the individual drugs that produce receptor blockade. It is much easier to understand responses to the adrenergic drugs if you first understand the responses to activation of adrenergic receptors. Alpha-Adrenergic Antagonists Therapeutic and Adverse Responses to Alpha Blockade In this section we discuss the beneficial and adverse responses that can result from blockade of alpha-adrenergic receptors. Therapeutic Applications of Alpha Blockade Most clinically useful responses to alpha-adrenergic antagonists result from blockade of alpha receptors on blood vessels. Blockade of alpha receptors in the eyes and blockade of alpha receptors have1 2 no recognized therapeutic applications. Essential Hypertension Hypertension (high blood pressure) can be treated with a variety of drugs, including the alpha-adrenergic antagonists. Alpha antagonists lower blood pressure by causing vasodilation by blocking alpha receptors on arterioles and1 veins. Dilation of veins lowers arterial pressure by an indirect process: in response to venous dilation, return of blood to the heart decreases, thereby decreasing cardiac output, which in turn reduces arterial pressure. The role of alpha-adrenergic blockers in essential hypertension is discussed further in Chapter 39. Reversal of Toxicity From Alpha Agonists1 Overdose with an alpha-adrenergic agonist (e. When this occurs, blood pressure can be lowered by reversing the vasoconstriction with an alpha-blocking agent. By infiltrating the region with phentolamine (an alpha-adrenergic antagonist), we can block the vasoconstriction and thereby prevent injury. Symptoms include dysuria, increased frequency of daytime urination, nocturia, urinary hesitancy, urinary urgency, a sensation of incomplete voiding, and a reduction in the size and force of the urinary stream. Benefits derive from reduced contraction of1 smooth muscle in the prostatic capsule and the bladder neck (trigone and sphincter). Pheochromocytoma A pheochromocytoma is a catecholamine-secreting tumor derived from cells of the sympathetic nervous system.
Unilateral damage to the recurrent laryngeal nerve will result in inability to tightly adduct the two vocal folds discount minocycline line, resulting in hoarseness buy generic minocycline 50 mg on line. In addition cost of minocycline, the protective function of the rima glottidis may be lost, and food or liquid that does not go down the esophagus may flow into the trachea and cause a choking response. In the supraglottic region (above the vocal fold), the mucosa is innervated by the internal branch of the superior laryngeal nerve. In the infraglottic region (below the fold), the mucosa is innervated by the recurrent laryngeal nerve. Thus, damage to the superior and recurrent laryngeal nerves may also have deficits in reflex behaviors that depend on sensory input from the larynx. Which of the following nerves is responsible for carrying the sensa- tion for this pain? The posterior cricoarytenoid muscles are the only muscles that abduct the vocal folds and are necessary to widen the rima glottidis for breathing. Injury to the recurrent laryngeal nerve is common during thyroid surgery and may lead to the inability to tightly adduct the two vocal folds, resulting in hoarseness. In addition, the protective function of the rima glottidis may be lost, and food or liquid that does not go down the esophagus may flow into the trachea and cause a choking response. The laryngeal mucosa above the vocal cords is innervated by the superior laryngeal nerve, whereas mucosa below the vocal cords is innervated by the recurrent laryngeal nerve. On examination, he has a blood pressure of 150/90 mmHg and a normal body temperature. If the deficits were to resolve before 24 h, it would be called a transient ischemic attack. If the deficits were to continue beyond 24 h, it would be called a cerebrovas- cular accident, or stroke. Differentiating between the two is important because fibrinolytic therapy (medication that dissolves blood clots) would be contraindicated with hemorrhagic strokes. In this patient, the bruits identified on the carotid arteries are likely due to increased rate and tur- bulence of blood flow through the stenotic vessels. Immediate management of this patient would include administration of an antiplatelet medication such as aspirin and/or clopidogrel. After stabilization of the patient, carotid endarterectomy surgery may be indicated. Be able to review the somatotopic organization of sensory and motor regions in the brain 2. Be able to list the branches of the common carotid artery and the vascular sup- ply to the brain and identify the sites most susceptible to formation of athero- sclerotic plaques 3. The cerebrum is involved in the major functions of sensory perception, motor control, and the associational processing that integrates the two. The surface or cortex of the cerebrum is folded into a number of ridges (gyri) separated by valleys (sulci) of different depths. The brain is divided into lobes named for the overlying cranial bones: frontal, temporal, parietal, and occipital. The precentral gyrus controls voluntary motion, whereas the postcentral gyrus is the site of somatosensory perception. The sensory and motor areas are arranged according to a somatotopic organi- zation. The lower extremity is represented medially along the gyrus; the upper extremity, more laterally; and the head and neck, most laterally. The tracts going to and from the sensory and motor areas cross in the lower brain and spinal cord to control the opposite side of the body. Another important region is the motor speech area (Broca area), which is a small gyrus in the anterior parietal cortex of the left brain, called the operculum, just superior to the temporal lobe. These basic organizational features are important because they help physicians identify the region of the brain damaged by a stroke or hemorrhage. Thus, numbness or paralysis of the right upper extremity indicates damage on the left side of the brain, which will frequently involve the motor speech area. The blood supply to the brain is from the common carotid and the vertebral arteries (Figure 37-1). The vertebral artery ascends through the transverse foramina of the cervical vertebrae without giving off any major branches. The common carotid bifurcates at about the level of the hyoid bone (vertebrae C3 and C4). The external carotid ascends to provide branches to structures outside the cra- nium. The internal carotid ascends without major branches to enter the cranium through the carotid canal. After a relatively tortuous course through the sphenoid bone and the cavernous sinus, the internal carotid emerges into the middle cranial fossa. In the region of the sella turcica and surrounding the pituitary stalk, the vertebral and carotid circulations anastomose through a complex structure called the circle of Willis, which is formed posteriorly by the bifurcation of the basilar into left and right posterior cerebral arteries. Branches of the external carotid artery: 1 = superior thyroid, 2 = lingual, 3 = facial, 4 = ascending pharyngeal, 5 = occipital, 6 = posterior auricular, 7 = maxillary, 8 = superficial temporal, 9 = internal carotid. The left and right anterior cerebrals anastomose through the anterior communicating branch. The middle cerebral and posterior cerebral arteries anastomose through the poste- rior communicating branch. The most common sites of occlusion are bifurcation of the internal and external carotids and bifurcation of the anterior and middle cerebral arteries. Occasionally, small pieces of an atherosclerotic plaque will break off (embolize) and obstruct a smaller artery. The middle cerebral artery and its branches are most commonly affected by this process. This artery ascends through the Sylvian fissure along the superior border of the temporal lobe. As a consequence, many strokes produce deficits in movement and sensation of the face and upper extremities and in language. The anterior triangle is further divided by the omohyoid and digastric muscles into four additional triangles: submental, submandibular, muscular, and carotid. The common carotid artery ascends in the neck deep to the contents of the muscular triangle. These muscles are the sternothyroid, ster- nohyoid, and superior belly of omohyoid. It then goes through the carotid triangle, which is bordered by the superior belly of omohyoid, posterior belly of digastric, and sternocleidomastoid muscles. The common carotid bifurcates at the level of the hyoid bone (C3), and the internal carotid continues posteriorly. This fascial membrane originates from the other three layers of deep fascia that are in the neck: superficial layer of deep fascia, prevertebral fascia, and pretracheal/buccopharyngeal fascia. The sinus branch of the glossopha- ryngeal nerve courses within the sheath to innervate the carotid body and sinus.
The claim that use of a loading dose will shorten the time to plateau may appear to contradict an earlier statement order minocycline 50mg with visa, which said that the time to plateau is not affected by dosage size buy generic minocycline 50 mg on-line. For any specified dosage 50 mg minocycline amex, it will always take about four half-lives to reach plateau. When a loading dose is administered followed by maintenance doses, the plateau is not reached for the loading dose. Rather, we have simply used the loading dose to rapidly produce a drug level equivalent to the plateau level for a smaller dose. To achieve plateau level for the loading dose, it would be necessary to either administer repeated doses equivalent to the loading dose for a period of four half-lives or administer a dose even larger than the original loading dose. Decline From Plateau When drug administration is discontinued, most (94%) of the drug in the body will be eliminated over an interval equal to about four half-lives. The time required for drugs to leave the body is important when toxicity develops. If a drug has a short half-life, body stores will decline rapidly, thereby making management of overdose less difficult. When an overdose of a drug with a long half-life occurs, however, toxic levels of the drug will remain in the body for a long time. Pharmacodynamics Pharmacodynamics is the study of the biochemical and physiologic effects of drugs on the body and the molecular mechanisms by which those effects are produced. To participate rationally in achieving the therapeutic objective, an understanding of pharmacodynamics is essential. Dose-response relationships determine the minimal amount of drug needed to elicit a response, the maximal response a drug can elicit, and how much to increase the dosage to produce the desired increase in response. Basic Features of the Dose-Response Relationship The basic characteristics of dose-response relationships are illustrated in Fig. The most obvious and important characteristic revealed by these curves is that the dose-response relationship is graded. Because drug responses are graded, therapeutic effects can be adjusted to fit the needs of each patient by raising or lowering the dosage until a response of the desired intensity is achieved. B, The same dose-response relationship shown in A but with the dose plotted on a logarithmic scale. Note the three phases of the dose-response curve: Phase 1, The curve is relatively flat; doses are too low to elicit a significant response. Phase 2, The curve climbs upward as bigger doses elicit correspondingly bigger responses. Phase 3, The curve levels off; bigger doses are unable to elicit a further increase in response. The curve is flat during this phase because doses are too low to elicit a measurable response. During phase 2, an increase in dose elicits a corresponding increase in the response. As the dose goes higher, eventually a point is reached where an increase in dose is unable to elicit a further increase in response. Maximal Efficacy and Relative Potency Dose-response curves reveal two characteristic properties of drugs: maximal efficacy and relative potency. A, Efficacy, or maximal efficacy, is an index of the maximal response a drug can produce. B, Potency is an index of how much drug must be administered to elicit a desired response. In this example, achieving pain relief with meperidine requires higher doses than with morphine. Note that, if administered in sufficiently high doses, meperidine can produce just as much pain relief as morphine. Maximal Efficacy Maximal efficacy is defined as the largest effect that a drug can produce. The concept of maximal efficacy is illustrated by the dose-response curves for meperidine [Demerol] and pentazocine [Talwin], two morphine-like pain relievers (see Fig. As you can see, the curve for pentazocine levels off at a maximal height below that of the curve for meperidine. This tells us that the maximal degree of pain relief we can achieve with pentazocine is smaller than the maximal degree of pain relief we can achieve with meperidine. Put another way, no matter how much pentazocine we administer, we can never produce the degree of pain relief that we can with meperidine. Accordingly, we would say that meperidine has greater maximal efficacy than pentazocine. Despite what intuition might tell us, a drug with very high maximal efficacy is not always more desirable than a drug with lower efficacy. This may be difficult to do with a drug that produces extremely intense responses. If we only want to mobilize a modest volume of water, a diuretic with lower maximal efficacy (e. Similarly, in a patient with a mild headache, we would not select a powerful analgesic (e. Rather, we would select an analgesic with lower maximal efficacy, such as aspirin. Relative Potency The term potency refers to the amount of drug we must give to elicit an effect. Potency is indicated by the relative position of the dose-response curve along the x (dose) axis. These curves plot doses for two analgesics—morphine and meperidine—versus the degree of pain relief achieved. As you can see, for any particular degree of pain relief, the required dose of meperidine is larger than the required dose of morphine. Because morphine produces pain relief at lower doses than meperidine, we would say that morphine is more potent than meperidine. The only consequence of having greater potency is that a drug with greater potency can be given in smaller doses. It is important to note that the potency of a drug implies nothing about its maximal efficacy! In everyday parlance, people tend to use the word potent to express the pharmacologic concept of effectiveness. That is, when most people say, “This drug is very potent,” what they mean is, “This drug produces powerful effects. Drug-Receptor Interactions Introduction to Drug Receptors Drugs produce their effects by interacting with other chemicals. Receptors are the special chemical sites in the body that most drugs interact with to produce effects. We can define a receptor as any functional macromolecule in a cell to which a drug binds to produce its effects.
Speculum examination reveals a tear in the posterior vaginal fornix which is not actively bleeding and the cervix is healthy order genuine minocycline. J Offer immediate admission to hospital 30 A 26-year-old immigrant woman attends antenatal clinic at 34 weeks with her sister-in-law who translates for her buy 50mg minocycline with visa, as she speaks no English at all purchase 50mg minocycline free shipping. This is her ﬁrst pregnancy and she is having growth scans on account of recur- rent ante-partum haemorrhage. The growth of the baby is ﬁne, but when you are auscultating the fetal heart you notice some circular lesions on the maternal abdomen that look like cigarette burns. B Arrange an independent translator and ask about domestic abuse Domestic violence is a common problem that crosses social boundaries and some- times results in extreme outcomes, that is, the death of the woman. In some areas of the country up to a quarter of women booking for antenatal care will have expe- rienced some sort of domestic abuse that can take many forms: violence, sexual abuse, psychological abuse, control of her fnances, and so forth. Clinicians should be aware of the existence of agencies and facilities able to help protect the woman and be able to discuss the subject with a patient at short notice. Women should be asked about the possibility of domestic abuse at some stage in their antenatal care without any other family members or acquaintances being present, in case they are part of the problem. If a woman discloses that she is being subjected to violence, you may need to arrange admission to a place of safety such as hospital. There could be child pro- tection issues if he is harming the children as well so if there are children in the equation, don’t forget their needs. A Advise against fying B Advise against travel after 32 weeks of gestation C Advise against travel after 36 weeks of gestation D Aspirin 75 mg for duration of fight and several days afterwards E Avoid fying in frst trimester F Graduated compression stockings G Hydration and mobilization during fight H Low molecular weight heparin for duration of fight I Low molecular weight heparin for fight and several days afterwards 268 09:38:04. She fractured her tibia and ﬁbula 2 days ago and is wearing a plaster on her leg but the airline has assured her that a wheelchair will be available for her use at the airport. She is concerned about the risks of air travel in pregnancy and seeks your advice. A Advise against ﬂying The recent fracture with plaster is hazardous because signifcant swelling can occur in fight, which might compromise the circulation to the limb. She seeks your advice because she is concerned about the risk of thromboembolism and is wondering about catching a train instead. J Reassurance/no special measures needed For short-haul fights no specifc measures are likely to be required. B Advise against travel after 32 weeks of gestation The main worry is the risk of going into labour in fight and delivering without appropriate medical aid, which is clearly more of a risk with twins rather than a singleton pregnancy. If the pregnancy were singleton, you would advise against travelling after 37 weeks although some airlines insist on 36 weeks as a cutoff. A Advise against ﬂying Although airline cabins are pressurized, the barometric pressure is signifcantly lower than at sea level. Severe anaemia with a haemoglobin <75 gm/L is a con- traindication to air travel because of the potential reduction in blood oxygen satu- ration of 10 per cent due to reduced pO2 at altitude. Select the most appropriate method for delivering the required learning objective. You are asked to ensure that they have been taught to do speculum examination by the end of their ﬁrst week. H Practical simulation session using a dummy The best way to learn any practical technique is to see it demonstrated then to have a go at it yourself preferably with feedback. The only way to deliver that to a medical student having a go for the frst time is to run a practical session using a dummy, before you let them loose on a patient. E Mini clinical evaluation exercise Mini clinical evaluation exercise is ideal for watching a trainee interact with a patient and giving feedback to improve their performance. From the preceding list choose the most likely diagnosis given the examination fndings. On examination she has pink linear wrinkles, and she has clearly been scratching them. H Striae gravidarum She could have any itching skin condition but the description of linear wrinkles means that these are likely to be striae. E Polymorphic eruption of pregnancy Sparing of the umbilicus suggests this diagnosis A Amlodipine B Bendrofumethazide C Hydralazine D Labetalol E Magnesium Sulphate F Methyldopa G Nifedipine H Ramipril These clinical scenarios relate to pregnant women presenting with hypertensive problems. On admission her blood pressure is repeated twice and found to be 165/100 mgHg and 158/110 mmHg. D Labetalol Although this woman clearly has pre-eclampsia and may need magnesium sul- phate and delivery, you must stabilise her blood pressure frst as she is at risk of intracerebral bleeding with a blood pressure this high. She attends surgery after a posi- tive pregnancy test and thinks that she is probably 7 weeks pregnant. Having talked to her husband, she is not too upset and is intending to keep the pregnancy. Send her for a routine booking scan mentioning the coil on the scan request form E. Not only that, miscarriage is more likely to be complicated by infection if the coil is still present, so the advice is to remove it. There is a risk of ectopic pregnancy when a woman conceives with a coil in situ so an earlier scan than 12 weeks is indicated. Which of these options is the most appropriate course of action for the midwife in charge of the ward to take? Write to the woman and ask her to return the list This is a serious breach of confdentiality and the person responsible for informa- tion governance will have to be informed. Her ankles and feet are so swol- len that she has had to wear sandals instead of shoes and can no longer wear her rings. On examination she does have bilateral varicose veins and both ankles are mildly oedematous but there is no redness or tenderness in either leg. Her oedema is likely to be physiological related to pregnancy and is not a problem (apart from the discomfort) unless she does develop pre-eclampsia. As she has varicose veins too, some of her discomfort may be alleviated by compression stockings. She has no gastrointestinal symptoms, is using the pill for contraception, and is halfway through a packet. On examination there is suprapubic tenderness and bimanual pelvic exami- nation elicits cervical motion tenderness. Take triple swabs and prescribe appropriate antibiotics according to sensitivities B. If the culture reveals gonorrhoea you might need to change the ofoxacin because of increasing resistance to quinolones in the United Kingdom. Reduce the risk of litigation in relation to labour Maternity dashboards were introduced a few years ago to give the obstetricians and midwives working in a hospital some idea of how their services were perform- ing in relation to neighbouring hospitals. Obviously the demographics of the local population will have some effect on the outcomes, but sometimes problems are fagged up that can be solved by changing protocols and guidelines, for example, reducing the induction rate will produce a fall in the caesarean section rate. Which one of the following statements is true with regard to psychiatric problems in pregnant women? A previous history of puerperal psychosis carries a recurrence risk of 5 per cent B.
This patient has many “red flag” symptoms in her presentation: her age buy line minocycline, new-onset pain buy 50 mg minocycline free shipping, and history of weight loss generic minocycline 50mg otc. The elevated calcium level and mild renal failure are suggestive of multiple myeloma. Plain radiographs of the axial and appendicular skeleton may illustrate the lytic bone lesions often seen in t his disease. This in d ivid u al h as cau d a eq u in a syn d r o m e an d r eq u ir es im m ed iat e su r gi- cal d ecompr ession t o avoid lon g-t er m n er ve d en er vat ion an d in cont in en ce/ lower ext remit y weakness. D ia gn o st ic evalu at io n o f lo w b ack p a in wit h em p h a sis o n im a gin g. Graded activity for low back pain in occupational health care: a randomized, controlled trial. He prefers to keep his knee bent, since straightening the kn e e cause s t he p ain to worse n. A ye ar ag o, h e d id h ave som e p ain an d swe llin g at the b ase of his gre at toe on the left foot, which was not as severe as this episode, and resolved in 2 or 3 days after taking ibuprofen. His only medical history is hypertension, which is controlled with hydrochlorothiazide. His head and neck examinations are unremarkable, his chest is clear, and his heart is tachycardic but regular, with no gallops or murmurs. His rig h t kn e e is s wo lle n, w it h a m o d e ra t e e ffu sio n, a n d a p p e a rs e r yt h e m a t o u s, warm, and very tender to palpation. O ne year ago, he had pain and swelling at the base of his great toe for several days that resolved with ibuprofen. H is right knee is swollen, with a moderate effu- sion, and appears eryt hemat ous, warm, and very t ender t o palpat ion. Most likely diagnosis: Acute monoarticular arthritis, likely cryst alline or infec- tious, most likely gout because of history. Next step: Asp ir at ion of the kn ee join t t o sen d flu id for cell cou n t, cu lt u r e, an d cr yst al an alysis. Best initial treatment: If the joint fluid analysis is consistent with infection, he needs drainage of the infected fluid by aspiration and administration of anti- biotics. Be familiar with the use of synovial fluid analysis to determine the etiology of arthritis. Co n s i d e r a t i o n s A middle-aged man presents with an acute attack of monoarticular arthritis, as evidenced by knee effusion, limit ed range of mot ion, and signs of inflammat ion (low-grade fever, erythema, warmth, tenderness). The two most likely causes are infect ion (eg, St a phylococcu s a ur eu s) and crystalline arthritis (eg, gout or pseudo- gou t ). If the patient is at r isk, gon ococcal ar t h r it is is also a p ossibilit y. T h e rapid on set of sever e sympt oms during t he current att ack is consist ent wit h acut e gout y art hrit is. In this patient, the attack could have been precipitated by the use of alcohol, which increases uric acid product ion, and h is use of t hiazide diuret ics, which decrease renal excretion of uric acid. Unt reated sept ic arthrit is could lead to rapid dest ruct ion of the joint, so joint aspiration and empiric antibiot ic therapy are appropriate until his cultures and crystal analysis are available. For that r eason, acute monoarthritis should be considered a medical emergency and invest igat ed and t reat ed aggressively. Accurate diagnosis st arts with a good history and physical examination supple- mented by additional diagnostic testing, such as synovial fluid analysis, radiography, and occasionally synovial biopsy. Pat ient s wit h cr yst al-in du ced ar t h r it is may give a hist ory of recurrent, self-limit ed episodes. Precipit at ion of an att ack by surgery or some other stress can occur with both crystalline disorders, but gout is far more common than is pseudogout. T h e clin ical cour se can provide some clues t o the et i- ology: septic arthritis usually worsens unless treated; osteoarthritis worsens with physical activity. In gonococcal arthritis, there are often migratory arthralgias and tenosynovitis, oft en involving the wr ist an d h an ds, associ- ated with pustular skin lesions, before progressing t o a pur u lent mon oar t h r it is or oligoarthritis. N ongonococcal causes of septic arthritis often involve large weight- bearing joints, such as the knee and hip. The basic approach in physical examination is to differentiate arthritis from inflammat ory condit ions adjacent to t he joint, such as cellulit is or bursit is. True arthritis is ch ar act er iz ed by swelling and redness around the joint, and painful limita- tion of motion in all planes, dur in g active and passive motion. Jo i n t m o v e m e n t t h a t i s not limited by passive motion suggests a soft tissue disorder such as bursitis rather than arthritis. Synovial fluid analysis helps to differentiate between inflammatory and noninflammatory causes of arthritis. Fluid analysis typically includes gross examination, cell count and differential, Gram st ain and culture, and cryst al analysis. Table 33– 1 gives t he t ypical result s t hat can help one distinguish between noninflammatory conditions such as osteoarthritis, inflammatory art hrit is such as cryst alline disease, and sept ic arthrit is, which is most often a bacterial infection. N on- inflammatory effusions should have a white blood cell count less t han 1000 to 3 2000/ mm wit h less t h an 2 5% t o 50 % p olym or p h on u clear ( P M N ) cells. If the fluid is inflammatory, the joint should be considered infected until proven otherwise, esp e- cially if the pat ient is febr ile. Even if cryst als are s een, infect io n must be excluded when the synovial fluid is inflammatory! C r yst als an d in fect ion m ay coexist in the sam e joint, an d ch ron ic ar t h rit is or previous joint damage, such as occurs in gout, may predispose that joint to hematogenous infection. In septic arthritis, Gram stain and culture of the synovial fluid is positive in 60% to 80% of cases. False-negative results may be related to prior antibiotic use or fast idious microorgan isms. Somet imes, the diagn osis r est s on demon st rat ion of gon ococcal in fec- tion in another site, such as urethritis, with the typical arthritis-dermatitis syn- drome. Synovial biopsy may be required when the cause of monoarthritis remains unclear, and is usually necessary to diagnose arthritis caused by tuberculosis or hemochromatosis. Plain radiographs usually are unremarkable in cases of inflammatory arthritis; the typical finding is soft tissue swelling. Chondrocalcinosis or lin ear calcium depo- sit ion in joint cart ilage suggest s pseudogout. Generally, patients require initiation of treatment before all test results are available. W h en sept ic art h rit is is suspect ed, the clinician sh ould cult ure the joint fluid and st art ant ibiot ic t herapy; t he ant ibiot ic choice should be init ially based on the Gram stain and, when available, the culture results. If the Gram st ain is negat ive, t he clinical picture should dict at e ant imicrobial select ion. For example, if the pat ient has t he t ypical present at ion of gonococcal arthritis, intra- venous ceftriaxone is the usual initial therapy, usually with rapid improvement in sympt oms. N ongonococcal sept ic art h rit is usually is caused by gram-posit ive organisms, most often S aureus, so t r eat ment would involve an antistaphylococcal antibiotic such as vancomycin, daptomycin, or linezolid. If cultures demonstrate organisms that are sensitive to beta-lactams, antibiotic therapy can be guided by the culture and susceptibility results.
In addition order minocycline 50mg on line, the plan encourages intake of whole-grain products discount 50 mg minocycline with amex, fish generic minocycline 50mg otc, poultry, and nuts and recommends minimal intake of red meat and sweets. Accordingly, patients should limit alcohol intake: most men should consume no more than 1 ounce/day; women and lighter weight men should consume no more than 0. In addition, exercise reduces the risk for cardiovascular disease and reduces all-cause mortality. Accordingly, patients should be encouraged to develop an exercise program if they have not already done so. An activity as simple as brisk walking 30 to 45 minutes most days of the week is beneficial. In patients with hypertension, smoking can reduce the effects of antihypertensive drugs. Consequently, a program of weight management and exercise is recommended for patients who are overweight. For optimal cardiovascular effects, all adults older than 14 years should take in 4700 mg of potassium a day. If hypokalemia develops secondary to diuretic therapy, dietary intake may be insufficient to correct the problem. In this case the patient may need to use a potassium supplement, a potassium-sparing diuretic, or a potassium-containing salt substitute. In epidemiologic studies, high calcium intake is associated with a reduced incidence of hypertension. Among patients with hypertension, a few may be helped by increasing calcium intake. To maintain good health, calcium intake should be 1300 mg/day for adults older than 14 years. The decision to use drugs should be the result of collaboration between prescriber and patient. Consequently, for most patients, it should be possible to establish a program that is effective and yet devoid of objectionable side effects. As indicated, arterial pressure is the product of cardiac output and peripheral resistance. Cardiac output is influenced by four factors: (1) heart rate, (2) myocardial contractility (force of contraction), (3) blood volume, and (4) venous return of blood to the heart. Opposition occurs because the “set point” of the baroreceptors is high in people with hypertension. These signals produce reflex tachycardia and vasoconstriction—responses that can counteract the hypotensive effects of drugs. Clearly, if treatment is to succeed, the regimen must compensate for the resistance offered by this reflex. Taking a beta blocker, which will block reflex tachycardia, can be an effective method of compensation. Consequently, as therapy proceeds, sympathetic reflexes offer progressively less resistance to the hypotensive effects of medication. After its release, 1 renin catalyzes the conversion of angiotensinogen into angiotensin I, a weak vasoconstrictor. The resultant increase in blood volume increases venous return to the heart, causing an increase in cardiac output, which in turn increases arterial pressure. In this section we survey the principal mechanisms by which drugs produce these effects. The numbering system used in the following text corresponds with the system used in Fig. Note that some antihypertensive agents act at more than one site: beta (β) blockers act at sites 4 and 8a, and thiazides act at sites 6 and 7. The hemodynamic consequences of drug actions at the sites depicted are shown in Table 39. Sympathetic Mecamylamine† Ganglionic blockade reduces sympathetic stimulation of the heart and blood ganglia vessels. Adrenergic nerve Reserpine Reduced norepinephrine release decreases sympathetic stimulation of the terminals heart and blood vessels. Cardiac beta1 Metoprolol Beta blockade decreases heart rate and myocardial contractility. Aldosterone Eplerenone Blockade of aldosterone receptors in the kidney promotes excretion of receptors sodium and water and thereby reduces blood volume. Because use is so limited, the last one available—mecamylamine—was voluntarily withdrawn from the U. In the United States reserpine is the only drug in this class still on the market. One of these agents—sodium nitroprusside—is used only for hypertensive emergencies. The result is peripheral vasodilation, renal vasodilation, and suppression of aldosterone-mediated volume expansion. The result is peripheral vasodilation, renal vasodilation, and suppression of aldosterone-mediated volume expansion. Hence blockade results in peripheral vasodilation, renal vasodilation, and suppression of aldosterone-mediated volume expansion. Blockade of aldosterone receptors in the kidney promotes excretion of sodium and water and thereby reduces blood volume. Classes of Antihypertensive Drugs In this section we consider the principal drugs employed to treat chronic hypertension. Drugs for hypertensive emergencies and hypertensive disorders of pregnancy are considered separately. Reduced vascular resistance develops over time and is responsible for long-term antihypertensive effects. The mechanism by which thiazides reduce vascular resistance has not been determined. In fact, hydrochlorothiazide is used more widely than any other antihypertensive drug. This can be minimized by consuming potassium-rich foods and using potassium supplements or a potassium-sparing diuretic. For most individuals with chronic hypertension, the amount of fluid loss that loop diuretics can produce is greater than needed or desirable. Most adverse effects are like those of the thiazides: hypokalemia, dehydration, hyperglycemia, and hyperuricemia. However, because of their ability to conserve potassium, these drugs can play an important role in an antihypertensive regimen.