Acute and sustained changes in sodium balance during nifedipine treatment in essential hypertension

Article Abstract:

The cause of essential hypertension is not known. Various types of medications are effective in treating this type of high blood pressure, some of which affect the body's sodium and water balance in different ways, while others affect blood vessel constriction. Nifedipine is a calcium channel blocker, a drug that prevents the movement of calcium into cells such as the muscles that line arterial walls, preventing contraction of the muscles and leading to dilation of blood vessels. An additional effect of nifedipine therapy is to acutely increase excretion of sodium and water, and this increase appears to be greater in subjects with high blood pressure. It is unclear whether the increased water and sodium excretion occurs only temporarily or is maintained throughout treatment, resulting in a long-term reduction in sodium balance. Changes in sodium balance and in hormones that regulate sodium balance were evaluated in eight patients with mild to moderate essential hypertension, before and after a month of nifedipine treatment. Upon switching from placebo (inert) treatment to nifedipine, urinary sodium excretion increased and blood pressure decreased, as expected. A significant weight loss also occurred, and patients were in negative sodium balance (i.e. they excreted more than they ingested). Plasma levels of atrial natriuretic peptide (ANP) decreased, while plasma renin activity (PRA) and aldosterone levels increased during nifedipine therapy. ANP causes excretion of sodium and water, renin leads to increased blood pressure, and aldosterone causes sodium retention. Thus, the changes in these hormones are in reaction to effects of nifedipine, in an attempt to restore previous blood pressure and sodium status. When nifedipine was discontinued, blood pressure increased, urinary sodium excretion decreased, and patients retained an amount of sodium similar to that which was lost at the start of therapy. Hormonal changes reversed, with ANP rising and PRA and aldosterone decreasing. The study indicates that changes in sodium balance are sustained during nifedipine treatment. These changes are similar to those seen with diuretic therapy, may contribute to the decreases in blood pressure associated with nifedipine therapy, and may also be useful in conditions such as congestive heart failure. (Consumer Summary produced by Reliance Medical Information, Inc.)

Drug therapy, Nifedipine, Sodium metabolism

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Acute lumbosacral epidural abscess after percutaneous transluminal angioplasty

Article Abstract:

Epidural abscess (the outer layer of tissue covering the spinal cord and brain and the localization of pus due to tissue destruction) should be considered in a patient with symptoms of fever, elevated white blood cell count, back pain and spinal tenderness. The progression of symptoms of epidural abscess usually follows a specific sequence over the course of four to nine days: back pain and fever; radicular pain (pain along the routes of spinal nerves) and paresthesia (pins and needles sensation); progressive radicular weakness; and paralysis with loss of bowel and bladder control. Staphylococcus aureus is the most common bacterial cause of epidural abscess, and in most cases, is related to trauma, infections in the skin and urinary tract, or intravenous contamination. Cardiac catheterization and percutaneous angioplasty are procedures which are performed under sterile technique and involve the insertion of a narrow flexible tube through the skin into major vessels. Back pain and fever following either of these procedures is unusual. This case study reports an episode of epidural abscess which occurred in a 52-year-old male who had percutaneous translumenal angioplasty two weeks after suffering a heart attack. The patient began to experience chills, nausea and back pain two days later and was subsequently started on antibiotics. An extensive work-up, including MRI (magnetic resonance imaging) and myelogram (x-ray of the spinal cord after injection of radiopaque dye), was initiated to identify the cause of his progressive symptoms. By the time the patient was found to have a blockage at the fourth lumbar space of his spinal cord, he had lost bowel and bladder control and was unable to walk. Immediate surgery revealed a large amount of purulent material. The surgery, which consisted of laminectomies from LS-S5, effected a gradual return to strength on the part of the patient and compete recovery of bowel and bladder control.

Complications and side effects, Demographic aspects, Staphylococcus aureus, Transluminal angioplasty, Balloon angioplasty, Abscess

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Spontaneous rupture of a renal artery aneurysm in polyarteritis nodosa: critical review of the literature and report of a case

Article Abstract:

Polyarteritis nodosa (PAN, a systemic inflammatory disorder affecting small and medium-sized blood vessels) was first described in association with spontaneous renal (kidney) hemorrhage over 80 years ago; less than 50 cases have been reported. This case study presents a 25-year-old male with a history of a 25-pound weight loss within four months, intermittent left upper abdominal pain after eating, and bizarre complaints, indicative of mental instability, such as coughing up bugs. The patient was found to be hypertensive; blood pressure readings were recorded up to 180/110. His white blood cell count was elevated and CT (computed tomography) scan indicated previous tissue damage in his right kidney. The patient subsequently developed intense right upper abdominal pain radiating to his back and he collapsed. Another CT revealed a hematoma (mass of blood) around his right kidney. The patient required transfusions. Arteriogram (x-ray of arteries after intravenously infusing radiopaque dye) indicated multiple aneurysms (abnormal dilations in a weakened wall of a blood vessel) in both kidneys. An artery which supplied the right kidney and the bleeding aneurysm was blocked by Gelfoam (absorbable gelatin sponge which stops bleeding). The patient was continued on medications to reduce inflammation and high blood pressure. His condition gradually improved; his mental status returned to normal and he gained weight. In reviewing previous literature of PAN, it appears that rupture of arterial aneurysm is the most common cause of renal hemorrhage. Young men with a history of high blood pressure and flank or abdominal pain and anemia are most often affected. Prompt arteriography can aid diagnosis and promote swift repair of the ruptured aneurysm either by surgery or Gelfoam.

Care and treatment, Arteritis, Aneurysms, Aneurysm, Gelfoam (Medical instrument)

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