Block 6 Pace Quiz 2 Part 1

The patient's presentation of nodules on hands, elbows, and Achilles tendons, along with a family history of early-onset myocardial infarction (AMI), suggests a diagnosis of familial hypercholesterolemia (FH). FH is an autosomal dominant disorder characterized by elevated levels of LDL cholesterol. The patient's lab results show significantly elevated cholesterol and LDL levels, which further support the diagnosis. Other options such as diabetes mellitus type I, MODY, metabolic syndrome, and neurofibromatosis are not consistent with the patient's clinical findings and lab results.

Based on the information provided, the patient is taking 950µg/d of Vitamin A, which is above the RDA (900µg/d) but below the UL (2800µg/d). The UL represents the maximum daily intake that is unlikely to cause adverse effects. Since the patient's intake is below the UL, it is unlikely that they will suffer from symptoms of poisoning. However, their intake is also above the RDA, which suggests that they are not deficient in Vitamin A. Therefore, the most likely scenario is that they have a sufficient intake of Vitamin A and are not deficient, with a probability of about 2%.

Paraaminohipuric acid clearance is used to estimate renal plasma flow (RPF), which can then be used to estimate renal blood flow (RBF). This is because paraaminohipuric acid is freely filtered by the glomerulus and is neither reabsorbed nor secreted by the renal tubules. Therefore, the clearance of paraaminohipuric acid can be used as an indicator of the rate at which plasma is being delivered to the kidneys, allowing for an estimation of RPF and subsequently RBF.

Patients seen in a refugee camp after a famine would be expected to be in negative nitrogen balance because nitrogen loss exceeds dietary nitrogen intake. This means that the amount of nitrogen being lost from the body through excretion (urine and feces) is greater than the amount of nitrogen being consumed through the diet. This imbalance can occur due to inadequate dietary intake, poor absorption of nutrients, or increased losses from the body. In the context of a famine, where food scarcity and malnutrition are common, it is likely that the patients are not able to consume enough nitrogen-containing foods to meet their body's needs, leading to a negative nitrogen balance.

The elevated levels of GPT, AST, ammonia, and creatinine, along with the strong cabbage-like smell, suggest a metabolic disorder. Tyrosinemia I is a rare genetic disorder characterized by the deficiency of the enzyme fumarylacetoacetate hydrolase, which leads to the accumulation of toxic substances in the body, including tyrosine. This can cause liver dysfunction, failure to thrive, and the characteristic odor. Hyperlysinemia, cystinuria, methylmalonic aciduria, and glycine cleavage enzyme deficiency do not present with the same combination of symptoms and laboratory findings as seen in this case.

Buffer 1 would have the highest buffering capacity in the extracellular fluid (ECF) if the concentrations of all buffers are equal because it has the lowest pK' value among the listed buffers. A lower pK' value indicates a stronger buffer, meaning that Buffer 1 is better able to resist changes in pH by accepting or donating hydrogen ions.

The most likely explanation for the baby's renal agenesis is that the ureteric bud failed to appear bilaterally. The ureteric bud is responsible for the formation of the ureters, renal pelvis, calyces, and collecting ducts. If it fails to appear, the kidneys will not develop properly, leading to renal agenesis.

The presence of actively motile amoebic trophozoites in the cerebrospinal fluid suggests an infection caused by Naegleria fowlerii. Naegleria fowlerii is a free-living amoeba that is commonly found in warm freshwater environments, such as lakes and hot springs. It can enter the body through the nasal passages and then travel to the brain, causing a severe and often fatal infection known as primary amebic meningoencephalitis (PAM). Symptoms of PAM include headache, stiff neck, fever, and neurological deficits. Given the patient's history of diving in freshwater environments and the presence of amoebic trophozoites in the cerebrospinal fluid, Naegleria fowlerii is the most likely causative organism.

The area labeled with an asterisk in the electron micrograph represents the urinary space. This is the space within the renal corpuscle where the filtrate from the glomerular capillaries collects before entering the proximal convoluted tubule. The other options, such as the lumen of a proximal convoluted tubule, renal pelvis, glomerular capillary, and minor calyx, do not accurately describe the area labeled with an asterisk in the electron micrograph.

The correct answer is Hemochromatosis. This is supported by the clinical findings of a firm and moderately enlarged liver, along with laboratory results showing elevated serum iron and ferritin levels. The presence of fatty vacuolisation of hepatocytes and hemosiderin deposits on liver biopsy further supports the diagnosis of hemochromatosis, a condition characterized by excessive iron absorption and deposition in various organs. This condition can lead to symptoms such as weakness, weight loss, and skin darkening, which are consistent with the patient's presentation.

The scrotal swelling in a newborn boy, along with constant crying, suggests a hernia. In this case, the most likely type of hernia is an indirect inguinal hernia. Indirect inguinal hernias occur when a part of the intestine protrudes through the inguinal canal, which connects the abdomen to the scrotum. This type of hernia is more common in newborns and can cause scrotal swelling. Other types of hernias, such as diaphragmatic hernia, direct inguinal hernia, femoral hernia, or hernia through Hesselbach's triangle, are less likely to cause scrotal swelling in a newborn.

The clearance of a substance is the volume of plasma from which the substance is completely removed per unit time. In this scenario, the concentration of substance X in the urine is 10 mg/mL, and the volume of urine is 60 mL. Therefore, the amount of substance X excreted in the urine is 10 mg/mL * 60 mL = 600 mg. The steady-state level of substance X in the plasma is 0.1 mg/mL. To achieve this level, 600 mg of substance X must be removed from the plasma. The clearance of substance X can be calculated by dividing the amount of substance X excreted in the urine (600 mg) by the time taken (1 hour = 60 minutes). Therefore, the clearance of substance X is 600 mg/60 min = 100 mL/min. Since clearance measures the rate at which a substance is removed from the plasma, it reflects the glomerular filtration rate (GFR). Therefore, the clearance of substance X measures the GFR.

The correct answer is the Proximal convoluted tubule. This is because the image shows a tubular structure with a brush border on the luminal side, which is a characteristic feature of the proximal convoluted tubule. The other options, such as the distal convoluted tubule and the thin limb of the loop of Henle, have different structural features that are not present in the given image.

In patients with systemic lupus erythematosus, autoantibodies are produced against various self-antigens. Cardiolipin is a phospholipid that is commonly targeted by autoantibodies in patients with lupus. These autoantibodies can lead to the formation of blood clots and cause blood clotting disorders. Therefore, the most likely membrane lipid targeted by autoantibodies in this patient is cardiolipin.

Line 3 best depicts the TF/P ratio for Na+. This is because the TF/P ratio for Na+ should be greater than 1 in the proximal tubule, indicating that Na+ is being reabsorbed from the tubular fluid into the plasma. Line 3 shows a gradual increase in the TF/P ratio for Na+ along the length of the proximal tubule, which is consistent with the reabsorption of Na+.

The increase in hydrostatic pressure in Bowman's space is likely causing the change in creatinine clearance. This increased pressure can lead to a decrease in the filtration rate and clearance of creatinine. It can be caused by factors such as obstruction in the urinary tract or increased pressure in the glomerular capillaries. This can result in a decrease in the glomerular filtration rate and subsequently a decrease in creatinine clearance.

The afferent limb of the cremasteric reflex is the Femoral branch of genitofemoral nerve. This nerve carries sensory information from the skin of the upper anterior thigh and supplies the cremaster muscle, which is responsible for the reflexive elevation of the testicle. The other options listed are not directly involved in the cremasteric reflex.

The correct answer is absorptive movement of chloride ions. In the late part of the proximal tubule, chloride ions are actively transported from the lumen into the epithelial cells. This movement of chloride ions creates a negative charge inside the cells, which in turn generates a positive transepithelial potential difference.

When there is a fall in arterial pressure, the kidneys are able to autoregulate the glomerular filtration rate (GFR) by decreasing the resistance of the afferent arteriole. The afferent arteriole is responsible for supplying blood to the glomerulus, where filtration occurs. By decreasing its resistance, more blood is able to flow into the glomerulus, increasing the GFR. This mechanism helps to maintain a stable GFR despite changes in systemic blood pressure, ensuring that the kidneys continue to function properly.

During the ligation of the Inferior Mesenteric Artery (IMA) at its origin, the lumbar splanchnic nerve is likely to be damaged. This nerve is responsible for maintaining the tonus of the internal sphincter muscles. Damage to the lumbar splanchnic nerve can lead to a loss of control over the internal sphincter muscles, potentially resulting in issues with bowel control and continence.

In portal hypertension, there is increased resistance in the portal-hepatic vascular bed due to obstruction to flow, often related to cirrhosis. When there is obstruction in the portal vein, blood flow can be diverted through collateral veins to bypass the obstruction. The left gastric vein and esophageal veins are important collateral veins that contribute to bypassing the obstruction in portal hypertension. These collateral veins provide an alternative pathway for blood to flow from the portal system to the systemic circulation, helping to alleviate the increased pressure in the portal system.

The most likely cause of the patient's condition is a dropped kidney. This is supported by the finding of a pelvi-ureteric junction kink on upright intravenous urography. A dropped kidney, also known as nephroptosis, occurs when the kidney descends from its normal position due to the lack of supporting structures. This can lead to symptoms such as loin pain and hematuria. The other options, such as cystic kidney, horse shoe kidney, duplex kidney, and infarcted kidney, do not align with the given information and are less likely to be the cause of the patient's condition.

The correct answer is "Ileum has smaller circular folds compared to jejunum." This is because the circular folds, also known as plicae circulares, are prominent features of the small intestine that increase its surface area for absorption. The jejunum has larger and more numerous circular folds compared to the ileum. Therefore, the presence of smaller circular folds is a distinguishing anatomical feature of the ileum.

The man's symptoms of pruritic and erythematous rash on his feet, abdominal pain, diarrhea, fever, and slight anemia, along with the presence of parasite ova in his stool, suggest a parasitic infection. Necator americanus, also known as hookworm, is a common cause of such symptoms. Hookworm infections are acquired by walking barefoot on contaminated soil, which allows the larvae to penetrate the skin. Once inside the body, the hookworms migrate to the intestines, causing abdominal symptoms and can lead to anemia due to blood loss. Therefore, Necator americanus is the most probable organism responsible for the disease.