A newborn develops a painful subcutaneous hard nodule on the arm with erythematous skin. Which is a complication of subcutaneous fat necrosis?

Appeared in: UP NHM CHO 7 Sept 2022 (Shift-2)

Explanation

Subcutaneous fat necrosis (SCFN) is an inflammatory condition of the fat tissue in newborns, often following perinatal stress like asphyxia or hypothermia.
Hypercalcemia (high blood calcium) is the most significant and potentially life-threatening systemic complication of SCFN.
The mechanism involves the extra-renal production of active vitamin D (1,25-dihydroxyvitamin D) by macrophages within the granulomatous inflammation of the necrotic fat, leading to increased calcium absorption.
This complication can develop weeks to months after the skin lesions appear, necessitating long-term monitoring.

Option A: Hyperkalemia (elevated potassium) is not associated with the pathophysiology of subcutaneous fat necrosis. The primary metabolic disturbance seen in this condition is related to calcium regulation.
Option C: Hyponatremia (low sodium) is not a recognized complication of SCFN. The condition does not involve a mechanism that would lead to sodium depletion or dilution.
Option D: SCFN is a panniculitis, meaning it is an inflammation and necrosis of the subcutaneous fat (adipose) tissue. It does not directly cause necrosis of nerve tissue.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Complications of Subcutaneous Fat Necrosis (SCFN) in newborns as background academic context rather than a clinical decision trigger.
A key nursing responsibility is monitoring infants with SCFN for signs of hypercalcemia, which include irritability, poor feeding, vomiting, and changes in urination patterns.
Serum calcium levels must be checked periodically for up to 6 months after the diagnosis of SCFN, even if the skin lesions have resolved, due to the risk of delayed-onset hypercalcemia.
Parental education is crucial. Nurses should teach parents to recognize the symptoms of hypercalcemia and understand the importance of follow-up appointments for blood monitoring.

How to Approach the Question

First, analyze the clinical presentation described in the stem: a newborn with a 'painful subcutaneous hard nodule' and 'erythematous skin'. This points to an inflammatory process in the subcutaneous tissue.
Recognize these features as classic signs of Subcutaneous Fat Necrosis (SCFN) of the newborn.
The question asks for a 'complication'. This requires you to access your knowledge about the systemic effects of this specific skin condition, not just its local appearance.
Evaluate the options. Consider the pathophysiology of SCFN, which involves granulomatous inflammation.
Recall that granulomatous diseases can cause dysregulation of vitamin D metabolism, leading to electrolyte imbalances.
Specifically, connect granulomatous inflammation with increased production of active vitamin D and the subsequent risk of hypercalcemia. This makes 'Hypercalcemia' the most plausible complication among the choices.

Concept Tested & Keywords

Concept Tested: Complications of Subcutaneous Fat Necrosis (SCFN) in newborns.
Stem keywords: newborn, painful subcutaneous hard nodule, erythematous skin, subcutaneous fat necrosis
Lead-in keywords: complication
Clinical cues: The combination of a newborn with firm, red skin nodules points towards a panniculitis (inflammation of fat) like SCFN.
Negative lead-in flag: false

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E6 Nelson Textbook of Pediatrics(2024) — Volume 2 p. 1941-1943

Practise the full UP NHM CHO 7 Sept 2022 (Shift-2)

Attempt every question from this paper in a timed mock, then review the full solution for each one.