Medullary sponge kidney is a congenital disorder of the kidneys characterized by cystic dilatation of the collecting tubules in one or both kidneys. Individuals with medullary sponge kidney are at increased risk for kidney stones and urinary tract infection (UTI). Patients with MSK typically pass twice as many stones per year as do other stone formers without MSK. While having a low morbidity rate, as many as 10% of patients with MSK have an increased risk of morbidity associated with frequent stones and UTIs. While many patients report increased chronic kidney pain, the source of the pain, when a UTI or blockage is not present, is unclear at this time. Renal colic (flank and back pain) is present in 55% of patients. Women with MSK experience more stones, UTIs, and complications than men. MSK was previously believed not to be hereditary but there is more evidence coming forth that may indicate otherwise. Signs and symptoms
Most cases are asymptomatic or are discovered during an investigation of blood in the urine. Symptomatic patients typically present as middle-aged adults with renal colic, kidney stones, nephrocalcinosis and/or recurrent urinary tract infections; however, MSK also may affect children very rarely. In addition to the typical clinical phenotype of recurrent stone disease, other clinical profiles have now been recognized, that is, an indolent, almost asymptomatic MSK, and a rare form characterized by intractable pain.
In cases of acute high doses, for example in people receiving daily doses of 2 grams of vitamin B6 per kilogram of body weight, symptoms may be irreversible and may additionally cause pseudoathetosis.In the immediate 2–6 weeks following discontinuation of vitamin B6, patients may experience a symptom progression before gradual improvement begins. This is known as coasting and is encountered in other toxic neuropathies. A vitamin B6 substance dependency may exist in daily dosages of 200 mg or more, making a drug withdrawal effect possible when discontinued. See also
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Further reading
A chapter with a story about a woman experiencing a severe case of Megavitamin-B6 syndrome titled "The Disembodied Lady" appears in Chapter 3 of The Man Who Mistook His Wife for a Hat: Oliver Sacks; Oliver W. Sacks (1998). "Chapter 3: The Disembodied Lady". The Man Who Mistook His Wife For A Hat: And Other Clinical Tales. Simon and Schuster. pp. 43–52. ISBN 978-0-684-85394-9. An ethnographic study of an online support group for megavitamin B6 syndrome appears in: Laura D. Russell (16 December 2019). "Chapter 9: Making Collective Sense of Uncertainty: How Online Social Support Communities Negotiate Meaning for Contested Illnesses". In Nichole Egbert; Kevin B Wright (eds.). Social Support and Health in the Digital Age. Rowman & Littlefield. pp. 171–191. ISBN 978-1-4985-9535-3. External links
StatPearls - Vitamin B6 Toxicity