Why does the lupus malar rash spare the nasolabial folds?

Malar rash (also known as the “butterfly rash,”) is an acute manifestation of lupus (SLE) seen in over 50% of patients. It is a bilateral, erythematous maculopapular rash which spares the nasolabial folds. The rash will last anywhere from days to weeks, and it can be painful/ itchy. It is a photosensitivity phenomenon.

Suspected Mechanism: the nasolabial folds are a relatively UV protected surface and therefore less affected.

REFERENCES:

  1. Amre Nouh, Jodi Speiser, José Biller. Chapter 3 – Acquired neurocutaneous disorders. Handbook of Clinical Neurology. Volume 132, 2015, Pages 29-73
  2. Fitzpatrick’s Color Atlas and Synopsis of Clinical Dermatology, 8e. Klaus Wolff, Richard Allen Johnson, Arturo P. Saavedra, Ellen K. Roh. THE SKIN IN IMMUNE, AUTOIMMUNE, AUTOINFLAMMATORY, AND RHEUMATIC DISORDERS.

Oligoarticular vs. Polyarticular Arthritis

As its name suggests, Monoarticular involves one joint.

Oligoarticular is defined as involving greater than one joint but less than 5 joints.

Polyarticular is defined as greater than or equal to 5 joints.

This pattern/ number of joint involvement is typically defined within the first 6 months of disease onset.

REFERENCES

  1. Macaubas C, Nguyen K, Milojevic D, Park JL, Mellins ED. Oligoarticular and polarticular JIA: epidemiology and pathogenesis. Nature reviews Rheumatology. 2009;5(11):616-626. doi:10.1038/nrrheum.2009.209.
  2. Lin YT, Wang CT, Gershwin ME, Chiang BL. The pathogenesis of oligoarticular/polyarticular vs systemic juvenile idiopathic arthritis. Autoimmun Rev. 2011 Jun;10(8):482-9. doi: 10.1016/j.autrev.2011.02.001. Epub 2011 Feb 12.

Paget’s Disease and High-output Cardiac Heart Failure

Paget’s disease of the bone (accelerated bone turnover and remodeling, resulting in impaired bone integrity and overgrowth) is one of the rare causes of high-output cardiac heart failure.

WHY? It causes extensive hyper vascularization of the bone marrow.  This can cause arteriovenous shunting and lower peripheral vascular resistance. Significant bone involvement (>15%) may lead to heart failure.

REFERENCES

  1. Heistad DD, Abboud FM, Schmid PG, Mark AL, Wilson WR. Regulation of blood flow in Paget’s disease of bone. J Clin Invest 1975;55:69-74.
  2. Arnalich F, Plaza I, Sobrino JA, Oliver J, Barbado J, Pena JM, et al. Cardiac size and function in Paget’s disease of bone. Int J Cardiol 1984;5:491-505.
  3. Schneider D, Hofmann MT, Peterson JA. Diagnosis and treatment of Paget’s disease of bone. Am Fam Physician. 2002 May 15;65(10):2069-72.

How does Allopurinol work?

Allopurinol => enzyme xanthine oxidase inhibitorallopurinol-mechanism

Therefore blocks the conversion of the purine metabolites (hypoxanthine and xanthine) into uric acid.

NOTE: Allopurinol is used to prevent gout attacks, not to treat them once they occur.

Indications for use:

  1. Recurrent gouty attacks (>3 within 1 year)
  2. Presentation of Gouty tophi
  3. Renal insufficiency or recurrent nephrolithiasis with hyperuricemia
  4. Tumour lysis syndrome

References

1. Pacher et. al. Therapeutic Effects of Xanthine Oxidase Inhibitors: Renaissance Half a Century after the Discovery of Allopurinol. Pharmacol Rev. 2006 Mar; 58(1): 87–114.doi:  10.1124/pr.58.1.6