Tikz flow chart and beamer

I am creating a beamer presentation. I have following tikz flow chart. The problem is the chart appears to be cluttered and is not accomodated on a single slide.

Here is the code

\documentclass[12pt,a4paper]{beamer}
\usepackage[latin1]{inputenc}
\usepackage[english]{babel}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{makeidx}
\usepackage{graphicx}
\usepackage{lmodern}
\usetheme{CambridgeUS}
\usefonttheme{professionalfonts}
\usepackage{tikz}
%\usetheme{AnnArbor}
\author{Dr Vaibhav Banait}
\title{Dysphagia - a serious symptom}
\begin{document}
\begin{frame}
\maketitle
\end{frame}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{frame}{Dysphagia}
\begin{center}

% Define block styles
\tikzstyle{block} = [rectangle, draw, fill=blue!20,
text width=5em, text centered, rounded corners, minimum height=4em]

\begin{tikzpicture}[scale=0.15, node distance=2cm, auto]
% Place nodes
\node [] (Dysphagia) {Food sticks in chest after swallowing};
\node [ below of=Dysphagia] (Esophageal){Esophageal dysphagia};
\node [ below left  of=Esophageal] (Mechanical) {Solids only };
\node [ below of = Mechanical](Mechanical1){Mechanical};
\node [ below left of =Mechanical1](Intermittent){Intermittent};
\node [ below right of =Mechanical1](Progressive){Progressive};
\node [ below left of =Progressive](heartburn){Chronic heart burn};
\node [below of=heartburn](peptic){Peptic stricture};
\node[below right of =Progressive](age){Age more than50};
\node[below of =age](ca){Ca Esophagus };
\node [below of =Intermittent](Web){Esophageal web };
\node [below right of=Esophageal](Solidliquids){Solid and liquids=motor };

\node[below right of =Solidliquids](Intermittent1){Intermittent };
\node[below left of =Solidliquids](Progressive1){Progressive};
\node [below of =Intermittent1](chestpain){Chest Pain};
\node [below of =chestpain ](DES){Diffuse esophageal spasm};
\node [below left of = Progressive1](heartburn1){Chronic heart burn};
\node [below of =heartburn1](scleroderma){Scleroderma};
\node [below right of = Progressive1](resp){Respiratory symptoms};
\node[below of =resp](achalasia){achalasia};
% Draw edges
\path [draw] (Dysphagia)--(Esophageal);
\path [draw] (Esophageal)--(Mechanical);
\path[draw](Esophageal)--(Solidliquids);
\path[draw](Mechanical)--(Mechanical1);
\path[draw](Mechanical1)--(Progressive);
\path[draw](Mechanical1)--(Intermittent);
\path[draw](Progressive)--(heartburn);
\path[draw](Progressive)--(age);
\path[draw](heartburn)--(peptic);
\path[draw](age)--(ca);
\path[draw](Intermittent)--(Web);
\path[draw](Solidliquids)--(Intermittent1);
\path[draw](Solidliquids)--(Progressive1);
\path[draw](Intermittent1)--(chestpain);
\path[draw](Intermittent1)--(DES);
\path[draw](Progressive1)--(resp);
\path[draw](resp)--(achalasia);
\path[draw](Progressive1)--(heartburn1);
\path[draw](heartburn1)--(scleroderma);
% \path [line] (Vaibhav) -- (Vibhor);

\end{tikzpicture}

\end{center}

\end{frame}

\end{document}

-
Welcome to the site, user34083. Have a look at Chapter 11.6: Special Syntax for Specifying Trees in the TikZ/PGF manual. – John Wickerson Jul 24 '13 at 5:52
You can scale the flow chart to adapt it to the slide's size; a general answer with some references is Scaling tikz mindmaps within a beamer frame while a specific answer for flow charts is Messy flowchart using tikz. – Claudio Fiandrino Jul 24 '13 at 6:26

As John wickerson commented, your flow graph is a tree. forest is a package designed to easily type and draw this kind of trees. But, because this tree is to large to fit inside a frame you can use \resizebox command to adjust it to your slide.

\documentclass[12pt,a4paper]{beamer}
\usepackage[latin1]{inputenc}
\usepackage[english]{babel}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{makeidx}
\usepackage{graphicx}
\usepackage{lmodern}
\usetheme{CambridgeUS}
\usefonttheme{professionalfonts}
\usepackage{tikz}
%\usetheme{AnnArbor}
\author{Dr Vaibhav Banait}
\title{Dysphagia - a serious symptom}
\usepackage{forest}
\begin{document}
\begin{frame}
\maketitle
\end{frame}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{frame}{Dysphagia}

\centering

\resizebox{\textwidth}{.8\textheight}{
\begin{forest}
[Food sticks in chest after swallowing
[Esophageal dysphagia
[Solids only
[Mechanical
[Intermittent
[Esophageal web]]
[Progressive
[Chronic heart burn
[Peptic stricture]]
[Age more than50
[Ca Esophagus]]]]]
[Solid and liquids=motor
[Intermittent
[Chest Pain]
[Diffuse esophageal spasm]]
[Progressive
[Respiratory symptoms
[achalasia]]
[Chronic heart burn
[Scleroderma]]]]]]
\end{forest}
}
\end{frame}
\end{document}


-
was there no way the tikz package rendered the tree correctly – Vaibhav Jul 24 '13 at 11:41
@user34083: I'm not sure about your comment. If it means that you want to use some TikZ command on your tree, forest is based on TikZ so you can use tikzstyles , nodes, path, ... Please, take a look a forest manual (just type texdoc forest on your command line) or search for forest in TeX.SX. – Ignasi Jul 24 '13 at 11:53
forest sty does not appear to be standard latex package. How can I install on ubuntu? It does not appear to be a part of writelatex sharelatex monkeylatex-online services either. – Vaibhav Jul 24 '13 at 13:41
@user34083 I use MikTeX on windows, so I cannot help you to much but you can start with how-do-i-install-an-individual-package-on-a-linux-system‌​. – Ignasi Jul 25 '13 at 8:26