Pseudohypoaldosteronism (PHA) is a condition that mimics hypoaldosteronism. However, the condition is due to a failure of response to aldosterone, and levels of aldosterone are actually elevated, due to a lack of feedback inhibition. Types
Presentation
PHA2 is clinically characterised by hypertension, hyperkalaemia, metabolic acidosis and normal renal function. Mechanism
PHA2 is also known as familial hyperkalaemic hypertension, or Gordon syndrome. The underlying genetic defect leads to increased sodium chloride reabsorption in the distal tubule in the kidney, leading to volume expansion, hypertension and lowered renin levels. The hyperkalemia found in PHA2 is proposed to be a function of diminished sodium delivery to the cortical collecting tubule (potassium excretion is mediated by the renal outer medullary potassium channel ROMK in which sodium reabsorption plays a role). Alternatively, WNK4 mutations that result in a gain of function of the Na-Cl co-transporter may inhibit ROMK activity resulting in hyperkalemia. Unlike in PHA1 in which aldosterone resistance is present, in PHA2 the volume expansion leads to relatively low aldosterone levels. Treatment
Treatment of severe forms of PHA1 requires relatively large amounts of sodium chloride. These conditions also involve hyperkalemia.In contrast, PHA2 (Gordons syndrome) requires salt restriction and use of thiazide diuretics to block sodium chloride reabsorption and normalise blood pressure and serum potassium. History
This syndrome was first described by Cheek and Perry in 1958.
Throughout the brain, the placement of these neurons is normally quite precise. If this system doesnt work exactly right, neurons can develop outside their appropriate areas. If this happens then the firing or circuitry of the brain is not right, and an abnormal, epileptic circuit can result. Treatment
Identification of the underlying cause plays an important role in treatment. Brain abscesses or tumors can be—at least temporarily or partially, if not fully and permanently—surgically treated and chemotherapy and/or radiotherapy is given to the patient. If seizures do continue, various anticonvulsant medication regimens that can be tolerated by the patient can be tested and if need be, administered, either orally, or in emergency conditions such as status epilepticus after tonic-clonic (grand mal) seizures, intravenously. If stroke or other similar, transient disorders occur (cerebrovascular accident, or transient ischemic attack, TIA), then neurological imaging of the affected lobes or hemispheres of the brain can be performed (CT, MRI, PET, etc.) and, if not absolutely contraindicated, antithrombolytic therapy might be given if it can be tolerated due to the seizures; if a hemorrhagic stroke has occurred and surgery can be performed to cauterize the vessel or otherwise stop the bleeding, it will be attempted if it can be done safely. References


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