Jeffrey A Brinker, M.D.
- Professor of Medicine
- Joint Appointment in Radiology and Radiological Science
Although the spread of or (less likely) rifampicin may cause an autoimmune multi-resistant organisms can be minimized by judicious use haemolytic anaemia due to the production of antibodies to of antibiotics and the instigation of tight infection-control the antibiotic which binds to the red blood cells purchase escitalopram 20 mg otc anxiety 2015. This could be measures purchase escitalopram with amex anxiety symptoms 6 year molars, there is a continuing need for the development of further confirmed by performing a direct Coombs’ test in which the patient’s serum in the presence of red cells and the well-tolerated cheap escitalopram 20 mg otc anxiety disorder nos, easily administered, broad-spectrum anti- drug would cause red cell lysis. It should be noted in the patient’s record that At present, their use is restricted and should be administered certain antibiotics led him to have a haemolytic anaemia. He complains of worsening shortness of breath, present when he woke up that morning. Physical sputum is viscous and green, his respiratory rate is 20 breaths examination was normal and he was sent home with parac- per minute at rest but, in addition to wheezes, bronchial etamol and vitamins. Examination revealed a scribes amoxicillin which has been effective in previous exac- temperature of 39°C, blood pressure of 110/60mmHg, neck erbations of chronic obstructive pulmonary disease in this stiffness and a purpuric rash on his arms and legs which did patient. Twenty-four hours later, the patient is brought to not blanch when pressure was applied. Answer Question this young man has meningococcal meningitis and requires In addition to controlled oxygen and bronchodilators, which benzylpenicillin i. The previously abnormal chest, the concurrent flu epidemic and the rapid deterioration suggest Staphylococcus, but Streptococcus pneumoniae and Legionella are also possi- ble pathogens. Other death in Victorian England, but its prevalence fell markedly atypical (non-tuberculous) mycobacterial infections are less with the dramatic improvement in living standards during the common, but are occurring with increasing frequency in twentieth century. However, the initial use of four drugs is advisable in combination with at least three (and often four) drugs. The initial four-drug combination drug-resistant individual which will multiply free of competi- therapy should also be used in all patients with non-tuberculous tion from its drug-sensitive companions. The multi-drug strat- mycobacterial infection, which often involves organisms that egy is therefore more likely to achieve a cure, with a low relapse are resistant to both isoniazid and pyrazinamide. The British Thoracic with open active tuberculosis are initially isolated to reduce the Society now recommends standard therapy for pulmonary risk of spread, but may be considered non-infectious after 14 tuberculosis for six months. Continue isoniazid Treat with antimycobacterial and rifampicin drugs according to sensitivities for 4 further months for 4 further months Sputum No negative? Yes Continue treatment Check compliance Stop treatment Recheck sputum regularly Figure 44. In cases where compliance with a daily production of this metabolite in the liver and are regimen is a problem, the initial two months of triple or quadru- associated with increased toxicity; ple chemotherapy can be given on an intermittent supervised • bone marrow suppression, anaemia and agranulocytosis; basis two or three times a week. If they are fully sensitive, treatment will Pharmacokinetics continue with daily rifampicin plus isoniazid for a further four Isoniazid is readily absorbed from the gut and is widely dis- months. Between 40 and 45% of peo- sensitivities reveal isoniazid resistance, treatment with ethamb- ple in European populations are rapid acetylators (Chapter 14). The t1/2 of isoniazid is less than 80 minutes in fast acetylators the duration of chemotherapy will also need to be extended if and more than 140 minutes in slow acetylators. Approximately either isoniazid, rifampicin or pyrazinamide has to be discon- 50–70% of a dose is excreted in the urine within 24 hours as a tinued because of side effects. Abnormally high and potentially toxic the treatment of tuberculosis which is resistant to multiple concentrations of isoniazid may occur in patients who are both drugs is more difficult, and regimens have to be individual- slow acetylators and have renal impairment. Because of its high lipophilicity, it diffuses easily wise healthy people who are Mantoux test positive are assumed through cell membranes to kill intracellular organisms, such as to be infected with very small numbers of organisms and are Mycobacterium tuberculosis. It is also used to treat nasopharyn- treated for one year with isoniazid as a single agent. Isoniazid only Large doses of rifampicin produce toxic effects in about one- acts on growing bacteria. It is • sensory peripheral neuropathy, observed more commonly important to monitor hepatic transaminases, particularly in slow acetylators, and prevented by supplemental in patients at high risk of liver dysfunction (e. It is metabolized by deacetylation Ethambutol is well absorbed (75–80%) from the intestine. The and both the metabolite and parent compound are excreted in plasma t1/2 is five to six hours. Toxicity is excreted unchanged in the urine, it is contraindicated in renal increased by biliary obstruction or impaired liver function. Less than 10% appears unchanged in the urine and thus stan- dard dosing is unaffected by renal failure. Pyrazinamide tant interactions associated with reduced concentration and is most active against slowly or intermittently metabolizing therapeutic failure are common, and include: organisms, but is inactive against atypical mycobacteria. Pyrazinamide should be avoided if there is a • sex steroids (rendering oral contraception unreliable); history of alcohol abuse, because of the occurrence of hepatitis • immunosuppressants (including ciclosporin, tacrolimus, (see below). If the effect of such a drug is not closely these include: monitored in the weeks following cessation of rifampicin treatment and the dose reduced accordingly, serious compli- • flushing, rash and photosensitivity; cations (e. It inhibits patients); some strains of Mycobacterium tuberculosis, but other organ- • sideroblastic anaemia (rare); isms are completely resistant. Pharmacokinetics Pyrazinamide is converted by an amidase in the liver to Mechanism of action pyrazinoic acid. This then undergoes further metabolism by the mechanism of action of ethambutol is unclear. Pyrazinamide and its metabolites are excreted via the kidney, and renal fail- Adverse effects ure necessitates dose reduction. Use Testing of colour vision and visual fields should precede Streptomycin is an aminoglycoside antibiotic.
- Cognitive tests (psychometric tests)
- Cystoscopy and retrograde urethrogram (x-ray) to look for narrowing of the urethra
- Recent weight loss or gain
- Injection drug users who share needles
- Stiff or rigid abdomen
- Scarring after radiation or chemotherapy
- You have redness or puckering of the skin, or flattening or indentation of the nipple
- A strong family history of familial hypercholesterolemia or early heart attacks
In patients more than 50 years old order 5mg escitalopram free shipping anxiety symptoms for teens, the likelihood of a recurrence is lower (30%–40%); however buy cheap escitalopram 10mg on line anxiety medications, shoulder stiffness is a concern and order generic escitalopram pills anxiety leg pain, therefore, shoulder motion should be instituted early. In the case of recurrent dislocations in a young person, surgical recon- struction is best performed on an elective basis. Rotator cuff tears may occur as part of the dislocation or fracture/dis- location of the shoulder. Such separations are frequently sports injuries sustained in a fall on the “point of the shoulder” and can be divided into six classes. Type I is a sprain of the acromioclavicular ligaments, with tenderness in that joint on palpation. The X-ray, taken with the patient standing and the arm hanging down, with or without weight on it, shows the clavicle to be riding higher, but still in some contact with the acromion. The muscles that insert on the clavicle tend to pull it up superiorly, result- ing in an obvious deformity. This injury may be quite painful, but relatively speaking, is nowhere near as painful, dangerous, or requiring of any emer- gent treatment as a dislocated shoulder. Skeletal Trauma 59 difﬁcult to reduce because they may protrude through the fascia of the trapezius. Fractures of the Shaft of the Humerus Humeral shaft fractures are common, and their patterns vary. Displace- ment is generally caused by eccentric muscular pull with action of the supraspinatus, pectoralis major, and the deltoid determining the displace- ment of the proximal fragment (Fig. The long muscles determine the displacement if the fracture is below the deltoid insertion. Treatment of the humeral shaft fracture has traditionally been conservative; options include coaptation plaster splints, which serve as a functional brace, as popularized by Sarmiento. Deltoid Deltoid Deltoid Supraspinatus Pectoralis Major Coracobrachialis Radial Biceps Triceps Figure 2-10. The deformity of the humeral shaft fracture is dependent on the muscles that insert above and below the fracture. Sauer In fractures at the junction of the middle and distal third of the humerus, the radial nerve is vulnerable to injury. Fortunately, most of these nerve injuries are neuropraxias; hence, excellent recovery can be expected. In more-comminuted fractures of the humeral shaft, open reduction and internal ﬁxation are currently popular. Elbow and Forearm Supracondylar Fractures in Children this notorious fracture, the supracondylar fracture in children, presents a “mineﬁeld” for the orthopedic surgeon. In early stages, one must be vigi- lant in evaluating the child for vascular compromise, speciﬁcally compart- ment syndrome. In an effort to minimize these disastrous complications, aggressive early closed reduction and percutaneous pinning currently form the treat- ment of choice. Alternatives such as open reduction or overhead traction are, nevertheless, available. Closed reduction is best accomplished in the operating room with ade- quate anesthesia. Considering the risk of vascular compromise, these frac- tures should be treated emergently. With the C-arm (ﬂuoroscopy) in place, a closed reduction is performed and two Kirschner wires are driven across the fracture site percutaneously. A plaster splint is then used to hold the elbow initially, with cast application in several days. In 3 weeks, the pins are generally removed, and in 3 more weeks the cast is discontinued. It is normal for there to be a good deal of stiffness after such an event occurs in a child. The key to postoperative management is to emphatically tell the parents not to make the child move the elbow. In other words, if the child is left alone, in a reasonably short time a good deal of motion is automati- cally regained. Because of the cartilaginous growth centers (physes, epiphyses, and apophyses) around the child’s elbow, diagnosis may be difﬁcult. The inex- perienced practitioner may beneﬁt from review of comparison views of the normal elbow. Distal Humeral Fractures in Adults these intraarticular fractures of the distal humerus are difﬁcult to treat and are often followed by stiffness and arthritis. Therefore, an early open reduction and anatomic restoration of the articular surfaces with rigid ﬁxa- tion of the fragments to the shaft of the humerus give the best result. The ulnar nerve, because of its location, is at risk and generally has to be moved from the cubital tunnel and transported anteriorly. Skeletal Trauma 61 is to restore function by an anatomic restoration of the fragments and ini- tiation of early motion. It is generally agreed that if a traumatized elbow is immobilized for 3 weeks or more, a poor result will follow. Functional elbow motion is approximately 30 to 100 degrees; this will allow the hand to reach the mouth (Fig. Dislocation of the Elbow Most elbow dislocations occur in a fall on the extremity, and the ulna is pushed posterior to the humerus. Reduction of a posterior elbow disloca- tion is easily accomplished for the most part by closed means using manual traction and manipulation. Intravenous sedation and augmentation with local anesthetic injected into the joint is usually adequate for manipulation.
The choice depends on the particulars of the patient escitalopram 20mg low cost anxiety symptoms vision, the (d) Proteus: Urinary tract infection order escitalopram with paypal anxiety buzzfeed, enteritis; infecting organism and the drug safe escitalopram 10 mg anxiety meme. Sulfonamides self-limiting or untreatable (viral) infec- displace bilirubin from protein binding sites— tions. Tetracyclines deposit in the developing Some of the B complex group of vitamins and teeth and bone—discolour and weaken them— vit K synthesized by the intestinal flora is utilized are contraindicated below the age of 6 years. Renal and hepatic function Cautious use alter this flora may result in vitamin deficiencies. Local factors the conditions prevailing at the site of infection greatly affect the action 6. However, trimetho- Cephalosporins Ethambutol prim and fluoroquinolones attain high concen- Vancomycin Flucytosine tration in prostate due to ion trapping. Nalidixic acid Talampicillin β-lactams, sulfonamides, fluoroquinolones and Nitrofurantoin Tetracyclines (except doxycycline) nitrofurantoin frequently cause allergy. Impaired host defence Integrity of host Antimicrobials in liver disease defence plays a crucial role in overcoming an infection. Pyogenic infections occur readily in Drugs to be avoided Erythromycin estolate Tetracyclines neutropenic patients, while if cell-mediated Pyrazinamide Nalidixic acid immunity is impaired (e. Even then suppresses anaerobes by exposure to oxygen, and complete eradication of the organism may not improves diffusion of the antibiotic into the occur. Bacteria adhering to foreign surfaces erythromycin are safe, while safety data on most create a biofilm around them and grow very others is not available. Therefore, manufacturers slowly, rendering them difficult to reach and less label ‘contraindicated during pregnancy’. They (c) Haematomas foster bacterial growth; tetra- carry risk of acute yellow atrophy of liver, cyclines, penicillins and cephalosporins get pancreatitis and kidney damage in the mother, bound to the degraded haemoglobin in the as well as cause teeth and bone deformities in haematoma. Aminoglycosides can cause foetal (d) Lowering of pH at the site of infection ear damage. Animal studies indicate increased reduces activity of macrolide and amino- risk to the foetus, especially with fluoro- glycoside antibiotics. Though abscess impairs bacterial transport processes metronidazole has not been found teratogenic, which concentrate aminoglycosides in the its mutagenic potential warrants caution in its bacterial cell, rendering them less susceptible. Genetic factors Primaquine, nitrofurantoin, tetracycline or a combination such as gentamicin sulfonamides, chloramphenicol and fluoroquino- + a cephalosporin may be used (with metronida- lones carry the risk of producing haemolysis in zole or clindamycin if anaerobes are suspected). Successful chemotherapy treatment cannot be delayed: as in serious must be rational and demands a diagnosis. A clinical (c) Bacteriological services are available and diagnosis should first be made, at least tenta- treatment can be delayed for a few days: as tively, and the likely pathogen guessed. As such, they provide only qualitative results; may serve as indicators, and cannot be blindly pneumonia, leprosy, amoebiasis, herpes simplex, extrapolated to the clinical situation in every patient and for etc. Broth cultures with break-point concentration (concentration that demarcates between sensitive and resistant 2. A good guess can be made from the bacteria) of antibiotics probably yield more reliable results. A Gram plates using serial dilutions of the antibiotic is more stained smear examination of infected material informative. The curved line separating pneumonia, empyema, meningitis, osteomyelitis, the clear zone from the zone with bacterial growth divides urinary tract infection, wound infection, etc. If the organism is killed, no growth will occur; but this may not be always possible. Relative toxicity: Obviously, a less toxic to guide selection of antibiotics in clinical practice. Pharmacokinetic profile: For optimum resumption is known as ‘postantibiotic effect’ and is the time action the antibiotic has to be present at the site required for reattainment of logarithmic growth. It is generally calculated from the time required to attain 10 fold increase of infection in sufficient concentration for an in bacterial count in the culture for antibiotic exposed and adequate length of time. The same daily dose a narrow-spectrum drug which selectively affects of gentamicin produces better action when given the concerned organism is preferred, because as a single dose than if it is divided into it is generally more effective than a broad- 2–3 portions. A drug which penetrates better and site of infection, while the static drug only attains higher concentration at the site of prevents increase in their number. For less severe Every combination is unique; the same drugs infections, an oral antibiotic is preferable; but may be synergistic for one organism but anta- for serious infections,. However, general guidelines cellulitis, septicaemias, a parenteral antibiotic are: would be more reliable. This should be done only with a specific purpose and not blindly in the hope that (b) Two bactericidal drugs are frequently addi- if one is good, two should be better and three tive and sometime synergistic if the organism should cure almost any infection. Penicillins by acting on Depending on the drug pair as well as the orga- the cell wall may enhance the penetration of nism involved, either synergism (supra-additive the aminoglycoside into the bacterium. Thus, (c) Combination of a bactericidal with a bacterio- a synergistic drug sensitizes the organisms to static drug may be synergistic or antagonistic the action of the other member of the pair. In general: may also manifest as a more rapid lethal action of the combination than either of the individual (i) If the organism is highly sensitive to the cidal members resulting in faster cure of the infec- drug—response to the combination is equal to tion. Synergistic prolongation of postantibiotic the static drug given alone (apparent antagonism), effect has also been demonstrated for combina- because cidal drugs act primarily on rapidly tions of β-lactams with an aminoglycoside, and multiplying bacteria, while the static drug retards by addition of rifampin to a variety of antibiotics. It is of erythromycin for group A Streptococci and little value in most acute and short-lived nalidixic acid + nitrofurantoin for E. To broaden the spectrum of anti- • Penicillin + sulfonamide for actinomycosis microbial action this is needed in: • Streptomycin + tetracycline for brucellosis • Streptomycin + chloramphenicol for K.
The thoracic spine should have approximately 10 to 40° of kyphosis and the lumbar spine should have approximately 40 to 60° of lordosis 10mg escitalopram with amex anxiety monster. The lumbar spine should arithmetically have 30° more lordosis than thoracic kyphosis buy cheap escitalopram 20mg anxiety 2 days after drinking. It is clear from this brief discussion that understanding normal and abnormal spinal anatomy and our ability to clearly describe it is important purchase 5 mg escitalopram with amex anxiety 9 things. This knowledge is at the heart of our ability to develop and implement treatment options for spinal deformity. It is also necessary so that we can evaluate the effect of our interventions and compare alternative treatments for similar deformities. If there are an atypical number of vertebrae, the sagittal measures will be performed as shown in Table 1 below. The thoracolumbar region (T10-L2) will remain constant regardless of the number of vertebral bodies in that region. For example, it is possible to have one extra vertebra if there are thirteen thoracic segments or one less vertebra if there are eleven thoracic segments. Table 1 Normal 12 Thoracic/5 Lumbar T5-T12 T10-L2 T12-S1 Atypical 11 Thoracic/6 Lumbar T5-"T12"* T10-L2 "T12"-S1* 11 Thoracic/5 Lumbar T5-T11 T10-L2 T11-S1 11 Thoracic/4 Lumbar T5-T11 T10-L2 T11-S1 13 Thoracic/4 Lumbar T5-T12 T10-L2 T12-S1 13 thoracic/5 Lumbar T5-T12 T10-L2 T12-S1 * See step 3 of labeling and measuring under atypical vertebra and Figure 2a and 2b on page 7. Pedicle morphology in thoracic adolescent idiopathic scoliosis: Is pedicle fxation an anatomically viable technique? Zindrick M, Wiltse L, Doornik A: Analysis of the morphometric characteristics of the thoracic and lumbar pedicles. Segmental analysis of the sagittal plane alignment of the normal thoracic and lumbar spines and thoracolumbar junction. Lumbosacral Transitional Vertebra and their relationship with lumbar extradural defects. Pelvic Incidence: A Fundamental Pelvic Parameter for Three Dimensional Regulation of Spinal Sagittal Curves. Lumbopelvic Lordosis and Pelvic Balance on Repeated Standing Lateral Radiographs of Adult Volunteers and Untreated Patients with Constant Low Back Pain. An analysis of sagittal spinal alignment in 100 asymptomatic middle and older aged volunteers. Radiographic analysis of sagittal plane alignment and balance in standing volunteers and patients with low back pain matched for age, sex, and size: A prospective controlled clinical study. Compensatory spinopelvic balance over the “hip axis” and better reliability in measuring lordosis to the pelvic radius on standing lateral radiographs of adult volunteers and patients. Comparison of standing sagittal spinal alignment in asymptomatic adolescents and adults. Lumbosacral Transitional Vertebra and their relationship with lumbar extradural defects. A distance of 72" produces an acceptable amount of magnifcation and distortion and is therefore preferred. The use of a compensating flter between the patient and the x-ray beam assures that proper density is maintained between the easily penetrated thoracic cavity and the denser lumbosacral region. Proper placement of a gonad shield may be utilized to protect the patient but should not cover important osseous anatomy. Variations in grid ratios, flm/screen combinations, x-ray machine generators, and patient size and shape make establishing exact recommendations for appropriate exposure of scoliosis flms impossible. Since fnal exposures are dependent on many variables, radiographic quality may vary between institutions and from department to department. Therefore, for the spinal deformity surgeon, it is essential to identify radiology technicians that can reliably manipulate all the variables in order to produce consistent images that clearly delineate the osseous anatomy to be evaluated and measured. As a reminder, all radiographs, including those for spondylolisthesis, are taken in an upright position to show the true position of the spine. If the leg length discrepancy is > 2cm, the x-ray should be taken with a block to level the pelvis. This will place the patient’s arms at approximately a 45° angle to the vertical axis of the body (Figures 1 – 4). If there is greater than a 2 cm leg length discrepancy, the x-ray should be taken with a block to level the pelvis. Figure 7 Figure 8 Supine 14 Clinical Photographs and Radiographic Methodology to Evaluate Spinal Deformity Mandatory Radiographs: 1a. Figure 10 15 Clinical Photographs and Radiographic Methodology to Evaluate Spinal Deformity Mandatory Radiographs: 1a. Supine Sidebenders – Mandatory that all three curves are visualized Bending flms of the proximal thoracic and lumbar curves are seen on the left sidebender for right Main thoracic (typically thoracic curves. If minor curves are small (< 25°) on the upright image and the sagittal plane is within normal limits, one can assume that those curves are nonstructural. No proximal thoracic bender Figure 18 Figure 19 17 Clinical Photographs and Radiographic Methodology to Evaluate Spinal Deformity Mandatory Radiographs: 1c. Standing Lateral – Acceptable Image Radiograph should be obtained with patient’s left side against the cassette (patient facing the observer’s right). It is not uncommon to have a good quality radiograph where T2 is not clear but all other landmarks (C7, T5, T10, T12, L2, and the sacrum) are visible. Push Prone Apply pressure to push on the structural curve(s) while stabilizing point(s) on the opposite side of the body.
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All-trans retinoic acid (Tretinoin) is used with polyunsaturated fats increases vit E requirement buy 5 mg escitalopram free shipping anxiety 6 letters, while antioxidants like cystein effective escitalopram 5mg anxiety symptoms grinding teeth, topically order escitalopram 5 mg with mastercard anxiety frequent urination, while 13-cis retinoic acid (Isotretinoin) methionine, selenium, chromenols prevent some is given orally for acne (see Ch. However, retinol, it is not stored but rapidly metabolized vit E might be having some more specific action and excreted in bile and urine. No act through nuclear retinoid receptors which clear-cut vit E deficiency syndrome has been function in a manner analogous to the steroid described in humans, but vit E deficiency has receptors: activation results in modulation of been implicated in certain neuromuscular diseases protein synthesis. In the target cells (epithelial, in children, neurological defects in hepatobiliary gonadal, fibroblast) synthesis of certain proteins disease and some cases of haemolytic anaemia. The risk of retrolental fibroplasia in premature infants exposed to high oxygen concentrations can be reduced disease as well as many types of cancers (lung, by 100 mg/kg/day oral vitamin E. Alongwith vit A to enhance its absorption and storage, As a result, vit E and others are being aggressively and in hypervitaminosis A to reduce its toxicity. Large doses (400–600 mg/day) have been reported to afford symptomatic improvement in intermittent them for prophylaxis of these conditions. Learning claudication, fibrocystic breast disease and nocturnal from mass media, people on their own also are muscle cramps. However, the For its antioxidant property, vit E has been evidence of a beneficial effect is highly promoted for recurrent abortion, sterility, contradictory. Therefore, it would be well been reported; abdominal cramps, loose motions advised to adopt a healthy lifestyle, viz. It is present in the outer layers of cereals some epidemiological observations, cohort studies (rice polishing), pulses, nuts, green vegetables, and prospective trials β carotene, vit C and yeasts, egg and meat. Absorption and fate Physiological amounts are absorbed ketoacids and hexose monophosphate shunt. When large doses are given orally, some Requirement is dependent upon carbohydrate passive diffusion also occurs. Physiological role After conversion in the body Pyrithiamine and oxythiamine are synthetic to Thiamine pyrophosphate, it acts as a coenzyme thiamine antagonists. Tea also contains a thiamine in carbohydrate metabolism: decarboxylation of antagonist. Body does not significantly store riboflavin; larger doses are excreted unchanged in urine. Thiamine and Dry beriberi: Neurological symptoms are promi- riboflavin are both synthesized by colonic bacteria but this nent—polyneuritis with numbness, tingling, does not become available to the host. Thiamine Wet beriberi: Cardiovascular system is primarily and riboflavin are devoid of pharmacological affected—palpitation, breathlessness, high output actions. Characteristic lesions are angular stomatitis; sore and raw tongue, lips, throat, ulcers Therapeutic uses in mouth; vascularization of cornea. Glucose infusion unmasks Therapeutic uses To prevent and treat aribo- marginal thiamine deficiency. Acute alcoholic intoxication: thiamine 100 mg Niacin (vit B ) 3 is added to each vac of glucose solution infused. Chemistry and source Niacin refers to Most neurological symptoms in chronic alcoholics Nicotinic acid as well as Nicotinamide—pyridine are due to thiamine deficiency—peripheral compounds, initially termed pellagra preventing neuritis, Wernick’s encephalopathy, Korsakoff’s factor. Sources are liver, fish, meat, cereal husk, psychosis: give 100 mg/day parenterally. In neurological and cardiovascular disorders, the amino acid tryptophan (mainly from hyperemesis gravidarum, chronic anorexia and animal protein) can be regarded as a provitamin, obstinate constipation—thiamine has been used as it is partially converted in the body to nicotinic even without definite proof of its deficiency— acid (60 mg tryptophan = 1 mg nicotinic acid). Thus, daily tivity reactions sometimes occur on parenteral requirement of niacin is affected by the amount injection. Absorption and fate Niacin is completely absorbed from Riboflavin (vit B ) gastrointestinal tract. Physiological amounts are metabolized 2 in the body, while large doses are excreted unchanged in Chemistry and source A yellow flavone com- urine. These pyridine nucleotides act as hydrogen Adverse effects Nicotinic acid, in pharmacolo- acceptors in the electron transport chain in tissue gical doses, has many side effects and toxicities respiration, glycolysis and fat synthesis. Pyridoxine (vit B6) Nicotinic acid (but not nicotinamide) in large doses is a vasodilator, particularly of cutaneous Chemistry and source Pyridoxine, Pyriodoxal vessels. Deficiency symptoms Niacin deficiency Dietary sources are—liver, meat, egg, soybean, produces ‘Pellagra’, cardinal manifestations of vegetables and whole grain. They are oxidized in the legs and face which later turn black, crack and body and excreted as pyridoxic acid. Physiological role and actions Pyridoxine and Diarrhoea—with enteritis, stomatitis, glossitis, pyridoxamine are readily oxidized to pyridoxal, salivation, nausea and vomiting. Pyridoxal depen- Dementia—with hallucinations preceded by dent enzymes include transaminases and decar- headache, insomnia, poor memory, motor and boxylases involved in synthesis of nonessential sensory disturbances. High to dietary deficiency, niacin absorption is impaired protein diet increases pyridoxine requirement. Other B vitamin deficiencies are often Pyridoxine has been shown to interact with associated. Prolonged intake of large Therapeutic uses doses of pyridoxine can give rise to dependence, and mega doses (0. However, suppression of lactation has been in divided doses orally or parenterally. Striking noted in nonsuckling postpartal women given high improvement occurs in 1–2 days, but skin doses of pyridoxine: may be due to increased lesions take weeks to months.