Emergency · LIVE

Palchak pediatric head trauma

Apply the Palchak 2003 derivation and return high or low risk of brain injury from five caller-assigned findings after blunt head trauma in a child 0-17 years. Scalp hematoma scores only when age is 0, 1, or 2.

LIVE $0.005 USDC GET /api/calc/palchak

Markdown: /docs/palchak.md · Canonical: https://magentlab.com/docs/palchak

Not a medical device. Not a diagnosis, dose, or listing recommendation.

What it computes

Apply the Palchak 2003 derivation and return high or low risk of brain injury from five caller-assigned findings after blunt head trauma in a child 0-17 years. Scalp hematoma scores only when age is 0, 1, or 2.

When to use

When an agent has caller-assigned findings after blunt head trauma in a child 0-17 years and needs the Palchak 2003 low-risk rule, not PECARN, CATCH, CHALICE, Canadian CT Head, or NEXUS.

When not to use

• Not a medical device. Not a diagnosis. magent does not examine the child or order CT.
• This tool is the Palchak 2003 derivation only. It is not PECARN, not CATCH, not CHALICE, not the Canadian CT Head Rule, and not NEXUS.
• Age is integer years 0-17. Scalp hematoma counts toward high risk only when age is 0, 1, or 2; the flag is parsed but does not score at age 3-17.
• Headache is a published Palchak 2003 predictor and is scored at all ages 0-17 as assigned by the caller.
• The caller assigns all five findings. magent does not examine the child.

Formula

high if any applicable predictor (abnormal_mental_status, clinical_signs_skull_fracture, history_of_vomiting, scalp_hematoma only if age <= 2, headache); else low; ct_not_low_risk iff high

Citation

Title

A decision rule for identifying children at low risk for brain injuries after blunt head trauma

Authors

Palchak MJ, Holmes JF, Vance CW, et al.

Source

Ann Emerg Med. 2003;42(4):492-506

DOI

10.1067/S0196-0644(03)00425-6

Worked example

Also searched as

• Palchak rule
• Palchak 2003
• Palchak head trauma
• Palchak pediatric head CT
• Palchak decision rule
• Palchak blunt head trauma
• children low risk brain injury Palchak
• Palchak 2003 Ann Emerg Med

Try

Opens the live endpoint. Unpaid browser requests show the paywall; agents should send Accept: application/json.

/api/calc/palchak?age=10&abnormal_mental_status=false&clinical_signs_skull_fracture=false&history_of_vomiting=false&scalp_hematoma=false&headache=false

Full URL: https://api.magentlab.com/api/calc/palchak?age=10&abnormal_mental_status=false&clinical_signs_skull_fracture=false&history_of_vomiting=false&scalp_hematoma=false&headache=false

Call

Expect HTTP 402 until you retry with PAYMENT-SIGNATURE. Incomplete query params return HTTP 400 before any quote or charge.

curl -i -H "Accept: application/json" "https://api.magentlab.com/api/calc/palchak?age=10&abnormal_mental_status=false&clinical_signs_skull_fracture=false&history_of_vomiting=false&scalp_hematoma=false&headache=false"

Parameters

Bulk (POST)

POST the same path with a JSON items array. The first item is the GET unit; each additional item is $0.002. Invalid items return HTTP 400 before settlement.

POST /api/calc/palchak Max 25 unit_amount + extra_item_amount * (n - 1) extra $0.002 PREVIEW

• 1 to 25 items. Each item uses the same keys as the GET query parameters.
• POST of 1 item costs the same as GET. Lists longer than 25: chunk into multiple POSTs. Extra items still execute; do not pad dummy rows.
• The first invalid item fails the whole request (index in the 400 JSON). You are not charged.
• HTTP 200 is {count, path, items}. Each items[i] is the GET 200 body for that row.
• Catalog misses (empty matches, found=false) stay paid 200s inside that slot.
• x402 resource URL is this path plus n and body_sha256. Browsers that prefer text/html get the same paywall as GET; Pay retries POST with the same items.

Example request (fixture)

{
  "items": [
    {
      "abnormal_mental_status": "false",
      "age": "10",
      "clinical_signs_skull_fracture": "false",
      "headache": "false",
      "history_of_vomiting": "false",
      "scalp_hematoma": "false"
    },
    {
      "abnormal_mental_status": "false",
      "age": "10",
      "clinical_signs_skull_fracture": "false",
      "headache": "false",
      "history_of_vomiting": "false",
      "scalp_hematoma": "false"
    }
  ]
}

Open bulk paywall →

Opens a two-item fixture on the API host. Unpaid browsers get the same MetaMask paywall as GET; Pay retries POST with those items.

Example 200 (fixture)

{
  "count": 2,
  "path": "/api/calc/palchak",
  "items": [
    {
      "disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.",
      "citation": {
        "authors": "Palchak MJ, Holmes JF, Vance CW, et al.",
        "doi": "10.1067/S0196-0644(03)00425-6",
        "id": "palchak-2003",
        "pmid": "14520320",
        "source": "Ann Emerg Med. 2003;42(4):492-506",
        "title": "A decision rule for identifying children at low risk for brain injuries after blunt head trauma"
      },
      "formula": "palchak",
      "formula_expression": "high if any applicable predictor (abnormal_mental_status, clinical_signs_skull_fracture, history_of_vomiting, scalp_hematoma only if age <= 2, headache); else low; ct_not_low_risk iff high",
      "age_years": 10,
      "low_risk": true,
      "criteria": [
        {
          "factor": "abnormal_mental_status",
          "met": false
        },
        {
          "factor": "clinical_signs_skull_fracture",
          "met": false
        },
        {
          "factor": "history_of_vomiting",
          "met": false
        },
        {
          "factor": "scalp_hematoma",
          "met": false
        },
        {
          "factor": "headache",
          "met": false
        }
      ],
      "high_risk": false,
      "ct_not_low_risk": false
    },
    {
      "disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.",
      "citation": {
        "authors": "Palchak MJ, Holmes JF, Vance CW, et al.",
        "doi": "10.1067/S0196-0644(03)00425-6",
        "id": "palchak-2003",
        "pmid": "14520320",
        "source": "Ann Emerg Med. 2003;42(4):492-506",
        "title": "A decision rule for identifying children at low risk for brain injuries after blunt head trauma"
      },
      "formula": "palchak",
      "formula_expression": "high if any applicable predictor (abnormal_mental_status, clinical_signs_skull_fracture, history_of_vomiting, scalp_hematoma only if age <= 2, headache); else low; ct_not_low_risk iff high",
      "age_years": 10,
      "low_risk": true,
      "criteria": [
        {
          "factor": "abnormal_mental_status",
          "met": false
        },
        {
          "factor": "clinical_signs_skull_fracture",
          "met": false
        },
        {
          "factor": "history_of_vomiting",
          "met": false
        },
        {
          "factor": "scalp_hematoma",
          "met": false
        },
        {
          "factor": "headache",
          "met": false
        }
      ],
      "high_risk": false,
      "ct_not_low_risk": false
    }
  ]
}

Response

Example JSON

Machine form of the same example. Frozen fixture. Not a live lookup.

{
  "disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.",
  "citation": {
    "authors": "Palchak MJ, Holmes JF, Vance CW, et al.",
    "doi": "10.1067/S0196-0644(03)00425-6",
    "id": "palchak-2003",
    "pmid": "14520320",
    "source": "Ann Emerg Med. 2003;42(4):492-506",
    "title": "A decision rule for identifying children at low risk for brain injuries after blunt head trauma"
  },
  "formula": "palchak",
  "formula_expression": "high if any applicable predictor (abnormal_mental_status, clinical_signs_skull_fracture, history_of_vomiting, scalp_hematoma only if age <= 2, headache); else low; ct_not_low_risk iff high",
  "age_years": 10,
  "low_risk": true,
  "criteria": [
    {
      "factor": "abnormal_mental_status",
      "met": false
    },
    {
      "factor": "clinical_signs_skull_fracture",
      "met": false
    },
    {
      "factor": "history_of_vomiting",
      "met": false
    },
    {
      "factor": "scalp_hematoma",
      "met": false
    },
    {
      "factor": "headache",
      "met": false
    }
  ],
  "high_risk": false,
  "ct_not_low_risk": false
}

Client errors (HTTP 400)

Invalid params return 400 without charge. Shared HTTP 402 and 503 meanings: Payments.

Related tools

• PECARN pediatric head CT — Apply the Kuppermann 2009 PECARN prediction trees and return high, intermediate, or low risk of clinically important brain injury from caller-assigned findings after pediatric head trauma.
• CATCH — Apply the Osmond 2010 CATCH derivation and return high, medium, or low risk plus whether CT of the head is indicated from seven caller-assigned findings after pediatric minor head injury.
• CHALICE — Apply the Dunning 2006 CHALICE rule and return whether CT is required from caller-assigned history, examination, and mechanism findings after head injury in a child younger than 16.
• Canadian CT Head Rule — Apply the Stiell 2001 Canadian CT Head Rule and return whether CT is indicated from caller-assigned high-risk and medium-risk findings after minor blunt head injury.

Payment

Unpaid requests return HTTP 402 even if query parameters or POST items are missing or invalid, so CDP and agents can index the path. After a PAYMENT-SIGNATURE, invalid params return HTTP 400 JSON before settlement. magent does not charge. Fix the params, then request a new 402 quote for that complete URL. Catalog misses (empty matches, found=false) are valid paid 200s. Unpaid valid requests return HTTP 402 with a base64 PAYMENT-REQUIRED header. HTTP 503 is not a new quote: retry the same PAYMENT-SIGNATURE. Full handshake and shared payment errors: Payments. Stdio MCP: /docs/mcp.

Guarantees

• HTTP 402 is unpaid, including a missing query. After PAYMENT-SIGNATURE, invalid parameters return HTTP 400 before settlement. You are not charged. HTTP 402 never includes the tool JSON.
• exact: settlement finishes before the tool (paymentFlow upfront). batch-settlement: verify/deposit before the tool; chargedCumulativeAmount commits after HTTP 2xx. Uncertain or failed settlement fails closed (HTTP 503). Retry the same PAYMENT-SIGNATURE.
• HTTP 402 is unpaid only. Do not sign a second authorization because of a 503.
• Execution is timeout-bounded and concurrency-capped.
• Calculator inputs are stored encrypted for allowlisted operators (Magent Console). They are not in public logs, SSH lookups, catalog, or rollups. Request logs store path without query.