The mechanism of action of lithium is not known. It is rapidly absorbed, has a small volume of distribution, and is excreted in the urine unchanged (there is no metabolism of lithium).
Toxic levels > 2 mEq/L
Satyendra Dhar MD,
Lithium Toxicity
The mechanism of action of lithium is not known. It is rapidly absorbed, has a small volume of distribution, and is excreted in the urine unchanged (there is no metabolism of lithium).
Statins & Recommendations
Statins & Recommendations:
Word Cholesterol came from Cholesterine, named by French chemist Michel E. Chevreul (‘solid bile’ in Greek: ‘chole’ for bile and ‘stereos’ for solid). The exact formula of cholesterol was established in 1888 by Friedrich Reinitzer. Merck Labs found the first statin, in 1978, in a fermentation broth of Aspergillus terreus, named mevinolin & later lovastatin.
Statins inhibit the critical step of cholesterol synthesis in which 3-hydroxy-3-methylglutaryl coenzyme A (HMGC) is transformed to mevalonate by the enzyme HMGC reductase. By doing so, they have a potent lipid-lowering effect that reduces cardiovascular risk and decreases mortality. Since the mevalonate pathway also influences endothelial function, the inflammatory response, and coagulation, the effects of statins reach well beyond their cholesterol-lowering properties. As with all drugs, statins may have adverse effects; these include musculoskeletal symptoms, increased risk of diabetes, and higher rates of hemorrhagic stroke. However, the frequency of adverse effects is extremely low and, in selected patient populations, the benefits of statins considerably outweigh the potential risks.
Satyendra Dhar MD,
SKIN RASHES
SKIN RASHES
Skin rashes can occur from a variety of factors, including infections, heat, allergens, immune system disorders, and medications.
A rapid and accurate diagnosis is critically important to make treatment decisions, especially when mortality or significant morbidity can occur without prompt intervention.
Rashes can be divided into petechial/purpuric, erythematous, maculopapular, and vesiculobullous. After this differentiation, the presence of fever and systemic signs of illness should be assessed. Through the breakdown of rashes into these classes, emergency providers can ensure deadly conditions are considered.
Satyendra Dhar MD,
Nail Findings & Associated Conditions
Nail Findings & Associated Conditions
Change in color, texture, or shape can be harmless, but may
suggest an underlying systemic disease.
• Muehrcke's Lines
• Melanoma
• Terry's Lines
• Onychogryphosis
• Clubbed Fingernails
• Mees' lines
• Koilonychia
• Pterygium Unguis
• Green Nail Syndrome
• Leukonychia
• Beau's Lines
• Yellow Nail
Syndrome
• Onycholysis
• Transverse Ridging
• Nail Plate
Crumbling
• Nail Pitting
• Central Nail Canal
• Periungual
Telangiectasia
LUDWIG’S ANGINA
LUDWIG’S ANGINA
This condition was named after a German physician, Wilhelm Friedrich von Ludwig, who first described it in 1836.
Although traditionally associated with pain of cardiac origin, the term “angina” is derived from the Latin word for choke (angere) and the Greek word for strangle (ankhone). In the case of Ludwig’s angina, it refers to the feeling of strangling and choking secondary to lingual airway obstruction, which is the most serious potential complication of this condition.
Ludwig angina is a bilateral infection of the submandibular space that consists of two compartments in the floor of the mouth, the sublingual space, and the submylohyoid (also known as submaxillary) space.
Ludwig's angina usually originates from dental infections in the mandibular molars, particularly the second and third molars, accounting for over 90% of cases.
Satyendra Dhar MD,
Tongue Pathologies (Differential Diagnosis)
Tongue Pathology
Geographic tongue, fissured tongue, and hairy tongue are the most common tongue problems and do not require treatment. Median rhomboid glossitis is usually associated with a candidal infection and responds to topical antifungals. Atrophic glossitis is often linked to an underlying nutritional deficiency of iron, folic acid, vitamin B12, riboflavin, or niacin and resolves with correction of the underlying condition. Oral hairy leukoplakia, which can be a marker for underlying immunodeficiency, is caused by the Epstein-Barr virus and is treated with oral antivirals. Tongue growths usually require a biopsy to differentiate benign lesions (e.g., granular cell tumors, fibromas, lymphoepithelial cysts) from premalignant leukoplakia or squamous cell carcinoma. Burning mouth syndrome often involves the tongue and has responded to treatment with alpha-lipoic acid, clonazepam, and cognitive behavior therapy in controlled trials. Tongue lesions of unclear etiology may require biopsy or referral to an oral and maxillofacial surgeon, head and neck surgeon, or a dentist experienced in oral pathology.
Recognition and diagnosis of tongue abnormalities require examination of tongue morphology and a thorough history, including onset and duration, antecedent symptoms, and tobacco and alcohol use. A complete head and neck examination, with careful assessment for lymphadenopathy, is essential.
Satyendra Dhar MD,
Nuclear myocardial perfusion imaging (MPI)
Nuclear myocardial perfusion imaging (MPI) may be performed by either single-photon emission CT (SPECT) or positron emission tomography (PET). As with stress echocardiography, MPI stress testing may be exercise or pharmacologically induced. MPI involves IV administration of radioactive tracers. A gamma camera detects radio emissions from the tracer that perfuses the myocardium. Tracer uptake depends on flow dynamics as well as myocyte membrane integrity. Color-coded images of myocardial perfusion pre- and post-stress are generated in different axes to allow assessment for each coronary distribution.
Pharmacologic stress testing is an alternative modality in patients who are unable to exercise and with the following conditions:
Patients presenting with unstable angina.
History of heart failure which is not well controlled, and
there is a concern for deterioration.
Poorly controlled blood pressure with systolic blood
pressure significantly higher (>200 mmHg at rest).
Patients with a history of aortic stenosis which is
significantly worse on echocardiogram (aortic valve area <1.0 cm2 and mean
gradient >40 mmHg) and have ongoing symptoms.
Myocardial infarction in the last week.
Acute pulmonary embolism
Acute inflammation of the pericardium or myocardium
Severe pulmonary hypertension
The exercise stress test is not useful when baseline EKG is abnormal such as with left ventricular hypertrophy (LVH), left bundle branch block (LBBB), paced rhythm, Wolff Parkinson White (WPW) syndrome, or greater than 1 mm ST-segment depression. These patients are suitable candidates for testing involving pharmacologic agents.
Regadenoson is a pharmacological stress agent that has been widely used since its approval by the Food and Drug Administration (FDA) in 2008. For many years, dipyridamole and adenosine, which are non-selective adenosine receptor agonists, were more popular. However, these agents are less preferred now due to their undesirable adverse effects as compared to regadenoson.
Satyendra Dhar MD,
Diuretics - Pharmacology
Diuretics - Pharmacology
Thiazides diuretics:
• Inhibit Na+ Cl-
cotransporter in distal tubule
• Chlorothiazide,
Chlorthalidone, Indapamide, Hydrochlorothiazide, Methyclothiazide, Metolazone
Loop diuretics:
• Inhibit Na+K+Cl2-
cotransporter in thick ascending limb
• Bumetanide,
Furosemide, Ethacrynate, Torsemide, Piretanide
Potassium sparing diuretics:
• Inhibit Na+
reabsorption in the collecting duct
• Amiloride,
Spironolactone (Aldactone), Triamterene
Carbonic anhydrase inhibitors:
• Inhibit Na+ and
HC03- in the proximal tubule
• Acetazolamide,
Methazolamide
Osmotic diuretics:
• Promote Na+ and
water loss through the nephron by excretion of non-reabsorbable filtrate
• Glycerin (Glycerol), Isosorbide, Mannitol, Urea
Vasopressin receptor antagonists (also called Vaptans):
• Aquaretics (not a
diuretic as no effect on sodium reabsorption)-promote water excretion by
inhibiting antidiuretic hormone (ADH)-mediated water reabsorption in the
collecting duct
Satyendra Dhar, MD
Adrenal Crisis
Adrenal Crisis
Do not confuse acute adrenal crisis with Addison’s disease. In 1855, Thomas Addison described a syndrome of long-term adrenal insufficiency that develops over months to years, with weakness, fatigue, anorexia, weight loss, and hyperpigmentation as the primary symptoms. In contrast, an acute adrenal crisis can manifest with vomiting, abdominal pain, and hypovolemic shock. When not promptly recognized, adrenal hemorrhage can be a cause of the adrenal crisis. Administration of glucocorticoids in supraphysiologic or stress doses is the only definitive therapy for adrenal crisis.
In 1856, Trousseau termed adrenal insufficiency as "bronze Addison disease," which became known widely as Addison disease. With the discovery of cortisone by Hench, Kendall, and Reichstein in the late 1940s, the life expectancy of patients with adrenal insufficiency dramatically improved, and initial data suggested that life expectancy was normalized. Tuberculosis was the most common cause (70%) during the 1930s. Currently, autoimmune adrenalitis is the most common cause of primary adrenal insufficiency in developed countries, and tuberculosis is still the leading cause of adrenal insufficiency in developing countries.
Satyendra Dhar MD,
Anterior cerebral artery (ACA) strokes
ACA infarcts are rare because of the collateral circulation
provided by the anterior communicating artery. ACA infarct can present as
contralateral hemiparesis with loss of sensibility in the foot and lower
extremity, sometimes with urinary incontinence. This is due to the involvement
of the medial paracentral gyrus. If the lesion is very proximal, it is possible
that there may be cognitive impairment due to lesions in the prefrontal cortex.
Anterior cerebral artery strokes occur in the territory of the anterior cerebral artery which involves the superior and medial part of the parietal lobe along with the midline of the frontal lobe. These are uncommon causes of ischemic infarctions, making up about 0.3%-4.4% of stroke cases in series reports. The clinical presentation of this stoke is variable as it depends on whether the anterior cerebral artery or one of its branches is involved.
Mean arterial pressure (MAP)
Mean arterial pressure (MAP)
* MAP = DP + 1/3(SP – DP) or
* MAP = DP + 1/3(PP)
Where DP is the diastolic blood pressure, SP is the systolic blood pressure, and PP is the pulse pressure.
To perfuse vital organs requires the maintenance of a minimum MAP of 60 mmHg. If MAP drops below this point for an extended period, end-organ manifestations such as ischemia and infarction can occur. If the MAP drops significantly, blood will not be able to perfuse cerebral tissues, there will be a loss of consciousness, and neuronal death will quickly ensue.
Satyendra Dhar MD,
Posterior cerebral artery (PCA) strokes
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Posterior cerebral artery (PCA) strokes can be challenging
to diagnose, due to the variability in symptoms, which may be nonspecific and
inconsistent upon initial presentation.
The incidence of PCA strokes can be estimated between 5% to 10%.
Patients may present in a comatose state via ambulance or may walk to an emergency department without assistance. Patients with a PCA stroke may present with only a headache and mild visual changes such as vision loss, diplopia, inability to see half of the view, or difficulty reading perceiving colors, or recognizing familiar faces.
Satyendra Dhar MD,
