In this post, we are going to examine POLYURIA AND POLYDIPSIA Case Study No. 12


A 45-year-old woman with a history of hypothyroidism presented to her doctor with frequent urination, including urination up to 3 times per night for more than 3 months. Due to his work as a teacher, he saw a constant need to drink water, especially cold water and was affected by frequent trips to the toilet. I have no health problems other than hypothyroidism and I don’t take my medication regularly.


Peripherally, the patient is warm and well perfused, with no evidence of dehydration. Examination of her heart, lungs, and abdomen is unremarkable. Neurologic examination is normal. Urine dipstick is negative.



What is the differential diagnosis for this presentation, and what further tests are required?
2. What are the principles of a water deprivation test, and how should the results shown in Figure 1.1 be interpreted?
3. Discuss the pathophysiology of the likely diagnosis, and suggest how the patient

may be treated.



This woman presents with polyuria, nocturia and polydipsia. There are four main types of diagnosis for these symptoms. (1) diabetes mellitus, (2) diabetes insipidus, which may be of root or renal origin, (3) hypercalcemia, which may occur as above in severe cases, (4) primary polydipsia (PP). Therefore, the investigation should describe one of the above diagnoses. For diabetes mellitus, a diabetic finger prick may be performed, but legitimate fasting or randomized hypoglycemia should be considered. A simple urine test can detect glucose, which is an indication of this diagnosis. Blood sugar levels tested should be checked for hypercalcemia.

Diabetes insipidus is a rare condition in which there is excessive urination due to insufficient or inactivity of antidiuretic drugs (ADH), the hormones behind the pituitary gland, also known as arginine vasopressin (AVP ). . DHA is released from the posterior pituitary into the circulatory system as blood osmolality increases and increases water reabsorption by inserting aquaporin-2 (AQP2) along the apical membrane at the tip. nephron. . ADH insufficiency leads to basal diabetes insipidus (CDI), in renal failure, nephrotic diabetes insipidus (NDI). Screening for diabetes insipidus includes lab tests and hydration tests. Hypernatremia can be diagnosed after dehydration and there may be a lack of fluid in the urine.

Urine osmolality

The conclusion of the experiment was that for CDI the change in ADH deficiency resulted in higher production, while in NDI the inability of the kidney to respond to ADH meant that the change was additionally caused. by ADH is ineffective. CDI is usually idiopathic, but in most cases autoantibodies to ADH-secreting cells in the hypothalamus are visible. Additionally, these patients tend to come in contact with other autoimmune diseases, so our patients are more likely to fall into this category because they have a history of hypothyroidism. Other causes of CDI include malignant neoplasms of the brain (such as germcytoma and craniopharyngioma), neurosurgery, headaches, and invasive diseases (such as Langerhans cell histiocytosis).
There is also a genetic predisposition to the disease, most of which is acquired by autosomal dominant factors with mutations in the ADH gene. The treatment for diabetes insipidus depends on whether it is caused by the brain or the kidneys. CDI responds well to ADH substitution, primarily from its synthetic drug, desmopressin (DDAVP). High doses of DDAVP can be used for mild cases of NDI, but the treatment of NDI requires the administration of a number of principles (eg, treatment of metabolic abnormalities, drug discontinuation). However, treatment is only necessary if the patient is severely dehydrated with a urine output greater than 4 liters per day.



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