# PUO GUIDE — Pyrexia of unknown origin

> Pyrexia of unknown origin (iPhone/iPad app by ATIF ELNIL.)

- Source: https://appshunter.io/ios/app/puo-guide/id6763405026 (this page in markdown: same URL + `.md`)
- Developer: [ATIF ELNIL](https://appshunter.io/developer/1886307011)
- Category: Medical, Education
- Price: Free with in-app purchases
- Age rating: 17+
- Requires: iOS 26.4 · 1 MB
- Languages: American English
- Released: 2026-05-21
- Data updated: 2026-06-04
- User reviews in markdown: https://appshunter.io/ios/app/puo-guide/id6763405026/reviews.md

## What is PUO GUIDE?

PUO Guide is an evidence-based clinical reference application for healthcare professionals covering the full diagnostic and management workup of Pyrexia of Unknown Origin (PUO).

Developed by Dr Atif Elnil MBBS MRCP, Neurology Department, St George's Hospital, London, this app translates current NICE, IDSA, BSI, WHO, and ACR/EULAR guidelines into a structured, mobile-optimised reference tool for use at the bedside, in clinic, and during examination preparation.

*** WHAT'S INSIDE ***

- Definition & Classification: Petersdorf/Beeson original criteria and Durack/Street modern revised definition. Four PUO categories clearly explained: Classic, Nosocomial, Neutropenic, and HIV-associated.

- Diagnostic Algorithm: Stepwise 7-stage evidence-based pathway from history through to Tier 3 investigations, including fever pattern recognition, relative bradycardia (Faget sign), and key laboratory and clinical diagnostic clues.

- Tiered Investigations: Comprehensive three-tier investigation table: Tier 1 universal screen, Tier 2 directed tests, and Tier 3 advanced/invasive investigations including FDG-PET-CT guidance with sensitivity and specificity data.

- Causes by Category: Expandable sections covering all four major aetiology groups: Infectious (bacterial, viral, parasitic - including full malaria species guide), Non-Infectious Inflammatory (NIID: connective tissue disease, vasculitis, granulomatous, autoinflammatory), Neoplastic, and Miscellaneous.

- Management: Condition-specific treatment summaries including antimicrobial regimens, AQUAMAT trial data for severe malaria, GCA emergency protocol, HLH-2004 treatment pathway, and disease-modifying therapies for inflammatory conditions.

- Special Populations: Dedicated sections for Immunocompromised patients (HIV CD4-guided approach, transplant timeline, neutropenic fever MASCC scoring), Elderly patients, Paediatric PUO (PFAPA, Kawasaki disease, systemic JIA), and Pregnancy.

- Red Flags: Urgent clinical scenarios requiring immediate action, clearly highlighted with management steps.

- Common Pitfalls: Eight evidence-based diagnostic traps frequently encountered in PUO workup.

- 29 Clickable References: Every section is fully cited with direct links to PubMed, NICE, WHO, RCOG, and ESC guideline sources.

*** DESIGNED FOR ***

Physicians, registrars, specialist trainees, foundation doctors, nurse practitioners, and medical students. Particularly useful for MRCP, USMLE, PLAB, and specialist certificate examination (SCE) preparation.

*** IMPORTANT ***

This application is for educational and professional reference purposes only. It does not constitute medical advice and must not replace the clinical judgement of a qualified healthcare professional. Always verify drug doses against the current BNF, SPC, or local formulary, and follow local institutional guidelines.
One-time purchase · No subscription · Works fully offline.

Content reviewed 2026. Evidence based on NICE, IDSA, WHO, BSI, ESC, ACR/EULAR, and RCOG guidelines.

## Pricing and in-app purchases

Base price: Free.

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| Full Access — PUO Guide | $4.99 | one-time |



## Version history (last 1 release)

### 1.0 — 2026-05-21

No release notes.

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All apps by ATIF ELNIL: https://appshunter.io/developer/1886307011

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-04.*