Middle Cerebral Artery (MCA) territory CVA

The middle cerebral artery territory is the most commonly affected territory in a cerebral infarction, due to the size of the territory and the direct flow from the internal carotid artery into the middle cerebral artery, providing the easiest path for thromboembolism.

The neurological deficit will depend on the extent of the infarct and hemispheric dominance, and include:

• contralateral hemiparesis
• contralateral hemisensory loss
• hemianopia
• aphasia: if the dominant hemisphere is involved; may be expressive in anterior MCA territory infarction, receptive in posterior MCA stroke, or global with extensive infarction
• neglect: non-dominant hemisphere.

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ProBNP (pro B-type natriuretic peptide)

 ProBNP (pro B-type natriuretic peptide) is secreted by cardiomyocytes in response to stretch and is quickly cleaved into 2 circulating fragments—the biologically active 32-amino acid C-terminal BNP (B-type natriuretic peptide) and the inert 76-amino acid NT-proBNP (N-terminal pro-BNP). Both fragments are routinely used to aid diagnosis of heart failure, predict outcomes, and to monitor the effects of therapy.

Differences between BNP and NT-proBNP on a biological level really relate to the fact that one is biologically active as a hormone, BNP, whereas NT-proBNP is cleared passively from the body and is not biologically active.

BNP has a much shorter half-life, and NT-proBNP has a longer half-life. NT-proBNP, as a consequence, circulates in higher concentrations in the bloodstream, therefore, more likely to be more sensitive for detecting earlier forms of heart failure because it circulates at somewhat higher levels.

BNP and NT-proBNP are extracted by the kidneys to a comparable extent of only about 15–20%. The calculated biological half-lives of BNP range from 13 to 20 minutes and of NT-proBNP from 25 to 70 minutes.

BNP and NT-proBNP are cleared differentially: BNP is actively removed from the bloodstream (binding to clearance receptors and a much lesser extent by enzymatic degradation by neutral endopeptidase) and also has passive clearance mechanisms, including renal clearance; NT-proBNP is cleared more passively by organs with high rates of blood flow (e.g. muscle, liver, kidneys).

Satyendra Dhar MD,

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Pancreatic pseudocysts

 Pancreatic pseudocysts are fluid collections in the pancreatic tissue or the adjacent pancreatic space. It is surrounded by a well-defined wall and contains essentially no solid material. Most pancreatic pseudocysts occur as a consequence of acute pancreatitis. However, they can also occur in the setting of chronic pancreatitis, postoperatively, or after pancreatic trauma. Pseudocysts may be asymptomatic or may present with a variety of symptoms such as pain, satiety, upper gastrointestinal bleeding, nausea, and vomiting. The maturation period of pancreatic pseudocysts is reported to be approximately 2 to 6 weeks, and during this time, 33% of cysts are expected to spontaneously resolve. However, a substantial number of persistent cysts require treatment, owing to potential complications such as infection, hemorrhage, and cyst rupture.

Satyendra Dhar MD, 

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Circle of Willis and brain circulation

 Circle of Willis and brain circulation

Herophilus of Chalcedon (335-280 BC), “Father of Anatomy,” described the vascular structure at the base of the brain which he named the rete mirabile (Latin for “wonderful net”).  Although works of Herophilus were tragically destroyed on Julius Caesar’s invasion of Alexandria, some of his teaching can be found in the writings of Galen, who was said to have possessed all his work. Thomas Willis (1621–1675), a physician and Professor of Natural Philosophy at Oxford in the mid-17th century, demonstrated with great precision both the structure and the function of one major anastomotic arterial system. For this reason, the name of this structure is interchangeable, either as Willis’ circle or as Willis’ polygon, being one of the most famous eponymous structures in human anatomy. Hippocrates, “father of medicine” first recognized CVA > 2400 years ago & called it apoplexy, Greek term - "struck down by violence". Name described sudden changes occurring in stroke but didn’t necessarily convey what’s actually happening in the brain.

Satyendra Dhar MD, 

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C-REACTIVE PROTEIN

 C-REACTIVE PROTEIN

Discovered by Tillett & Francis in 1930. First identified as a substance in the serum with acute inflammation that reacted with the "c" carbohydrate Ab of the capsule of pneumococcus.

CRP is a pentameric protein synthesized by the liver, whose level rises in response to inflammation. CRP is an acute-phase reactant protein that is primarily induced by the IL-6 action on the gene responsible for the transcription of CRP during the acute phase of an inflammatory/infectious process.

Lab values vary, and there is no standard at present.  However, in general, the result is reported in either mg/dL or mg/L. Hs-CRP is usually reported in mg/L.

Interpretation of CRP levels:

• Less than 0.3 mg/L: Normal (level seen in most healthy adults).
• 0.3 to 1.0 mg/L: Normal or minor elevation (can be seen in obesity, pregnancy, depression, diabetes, common cold, gingivitis, periodontitis, sedentary lifestyle, cigarette smoking, and genetic polymorphisms).
• 1.0 to 10.0 mg/L: Moderate elevation (Systemic inflammation such as RA, SLE, or other autoimmune diseases, malignancies, myocardial infarction, pancreatitis, bronchitis).
• More than 10.0 mg/L: Marked elevation (Acute bacterial infections, viral infections, systemic vasculitis, major trauma).
• More than 50.0 mg/L: Severe elevation (Acute bacterial infections).

Certain medications, such as NSAIDs will falsely decrease CRP levels. Statins, as well, have been known to reduce CRP levels falsely. Recent injury or illness can falsely elevate levels, particularly when using this test for cardiac risk stratification. Magnesium supplementation also can decrease CRP levels.

As mentioned above, mild elevations in CRP can be seen without any systemic or inflammatory disease. Females and elderly patients have higher levels of CRP. Obesity, insomnia, depression, smoking, and diabetes can all contribute to mild elevations in CRP, and the results shall be interpreted with caution in individuals with these comorbidities.

Satyendra Dhar MD, 

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OTTAWA ANKLE RULE

OTTAWA ANKLE RULE

The Ottawa ankle rules are a clinical decision-making strategy for determining which patients require radiographic imaging for ankle and midfoot injuries. Proper application has high (97.5%) sensitivity and reduces the need for radiographs by ~35%

 

The Ottawa Ankle Rules are guidelines indicating that x-ray studies should be obtained if there is a pain in the malleolar zone and 

A) bony tenderness at the distal 6 cm of the fibula –or– 

B) bony tenderness at the distal 6 cm of the tibia –or– inability to take 4 steps immediately after injury. 

The Ottawa Foot Rules indicate that x-rays should be obtained if there is a pain in the midfoot zone and: 

C) bony tenderness at the base of the fifth metatarsal –or– 

D) bony tenderness at the navicular bone tibia –or– inability to take 4 steps immediately after injury

 

Satyendra Dhar MD, @DharSaty

 

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Thrombocytopenia

 Thrombocytopenia 

Work up, differential diagnosis, and management.

 

Satyendra Dhar MD, 

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Goodsall's Rule

 Goodsall's Rule states that 

Fistulas can be described as anterior or posterior relating to a line drawn in the coronal plane across the anus, the so-called transverse anal line. Anterior fistulas will have a direct track into the anal canal. Posterior fistulas will have a curved track with their internal opening lying in the posterior midline of the anal canal. An exception to the rule is anterior fistulas lying more than 3 cm. from the anus, which may open in the anterior midline of the anal canal.

Successful treatment of an anal fistula requires correct identification of the internal opening and accurate delineation of the course of the fistula in relation to the anal sphincters. 

Goodsall’s rule is of limited use in predicting the site of the internal opening of a fistula. The closer the external opening is to the anal verge, the more likely a fistula conforms to the rule. The further a fistula is away from the anal verge, the more likely it follows a horseshoe course and less likely to conform to Goodsall’s rule.

The predictive accuracy of Goodsall’s rule was found to be 84.6% in the case of a fistula with an anterior external opening. While in the case of a fistula with a posterior external opening this found to be 69.1%. Overall predictive accuracy of Goodsall’s rule is 77%. 

 

Satyendra Dhar MD,

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Electrolyte imbalances

 Electrolyte imbalances are common findings in many diseases. The kidney is a principally responsible organ for the retention and excretion of electrolytes and fluids. But other mechanisms like hormonal interactions of antidiuretic hormone, aldosterone, and parathyroid hormone, and factors such as physiological stress play important roles in regulating fluid and electrolyte balance.

Electrolyte imbalances have a very broad range of signs and symptoms, from being completely asymptomatic to having fatal arrhythmias. The coexistence of one or more electrolyte imbalances in individuals with mixed medical conditions can create a complex clinical presentation. However, typically, each electrolyte imbalance presents with signs and symptoms that are more indicative of the specific imbalance.

 

 

Satyendra Dhar MD, 

 

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THYROID EMERGENCIES

 THYROID EMERGENCIES 

Emergencies related to thyroid gland diseases are infrequently observed in clinical practice. They are caused by either overt dysfunction or marked enlargement of the gland that jeopardizes the life of patients and require admission to intensive care units (ICU) in most cases.

 

The first description of thyroid diseases as they are known today was that of Graves’ disease by Caleb Parry in 1786, but the pathogenesis of thyroid disease was not discovered until 1882-86. Thyroidectomy for hyperthyroidism was first performed in 1880, and antithyroid drugs and radioiodine therapy were developed in the early 1940s. Thomas Curling first described hypothyroidism (myxedema) in 1850 and the cause and suitable treatment were established after 1883. 

 

Thyroid-related emergencies are caused by overt dysfunction of the gland which is so severe that requires admission to intensive care units (ICU) frequently. 

 

Severe excess or defect of thyroid hormone is a rare condition, which jeopardizes the life of patients in most cases. Both hypothyroid coma (HC) and thyrotoxic storm (TS) are triggered by precipitating factors, which occur in patients with severe hypothyroidism or thyrotoxicosis, respectively. The pillars of HC therapy are high-dose L-thyroxine and/or tri-iodothyroinine; IV glucocorticoids; treatment of hydro-electrolyte imbalance (mainly, hyponatremia); treatment of hypothermia; often, endotracheal intubation and assisted mechanic ventilation are needed. Therapy of TS is based on beta-blockers, thyrostatics, and IV glucocorticoids; eventually, a high dose of iodide compounds or lithium carbonate may be of benefit. Surgery represents the gold standard treatment in patients with euthyroid massive nodular goiter, although new techniques – e.g., percutaneous laser ablation – are helpful in subjects at high surgical risk or refusing operation.

 

Satyendra Dhar MD, 

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INCIDENTALOMAS

 INCIDENTALOMAS

Once incidentalomas  are detected, appropriate management is dependent on an informed patient's wishes and the clinical situation.

•      Patients presenting with pituitary incidentalomas should undergo pituitary-specific magnetic resonance imaging if the lesion is 1 cm or larger, or if it abuts the optic chiasm.

•       Thyroid incidentalomas are ubiquitous, but nodules larger than 1 to 2 cm are of greater concern.

•       Worrisome pulmonary incidentalomas are those larger than 8 mm or those with irregular borders, eccentric calcifications, or low density. However, current guidelines recommend that even pulmonary incidentalomas as small as 4 mm be followed.

•       Solid hepatic incidentalomas 5 mm or larger should be monitored closely, and multiphasic scanning is helpful.

•       Pancreatic cystic neoplasms have malignant potential, and surgery is recommended for pancreatic cysts larger than 3 cm with suspicious features.

•       Adrenal lesions larger than 4 cm are usually biopsied.

•       The Bosniak classification is a well-accepted means of triaging renal incidentalomas. Lesions at category IIF or greater require serial monitoring or surgery.

•       Benign or probably benign ovarian cysts 3 cm or smaller in premenopausal women or 1 cm or smaller in postmenopausal women do not require follow-up. Ovarian cysts with thickened walls or septa, or solid components with blood flow, should be managed closely.

 

 

Satyendra Dhar MD,

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Albuminuria

 Albuminuria is a major risk factor for progressive renal function decline and is believed to be the initial step in an inevitable progression to proteinuria and renal failure in humans. Thus, reduction of albuminuria is a major target for Reno protective therapy in CKD.

 

Moderately increased albuminuria (previously microalbuminuria) is arbitrarily defined as excretion of 30 to 300 mg albumin/24 h in at least two of three consecutive urine samples. At a concentration of 30 to 300 mg/24 h, albumin is normally not detected by nonspecific tests for protein (e.g., Biuret reaction). Albumin can be detected, however, by use of specific techniques such as dipstick, enzyme-linked immunosorbent assay, nephelometry, and radioimmunoassay. Instead of difficult-to-obtain 24-hour urine collections, the albumin concentration can be determined in spot urine or, better, first-void morning urine samples. The normal range is less than 20 µg/ml.

 

Satyendra Dhar MD,

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